National Library of Energy BETA

Sample records for tomography ct scanners

  1. Compact conscious animal positron emission tomography scanner

    DOE Patents [OSTI]

    Schyler, David J. (Bellport, NY); O'Connor, Paul (Bellport, NY); Woody, Craig (Setauket, NY); Junnarkar, Sachin Shrirang (Sound Beach, NY); Radeka, Veljko (Bellport, NY); Vaska, Paul (Sound Beach, NY); Pratte, Jean-Francois (Stony Brook, NY); Volkow, Nora (Chevy Chase, MD)

    2006-10-24

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal for an event, generating an address signal representing a detecting channel, generating a detector channel signal including the time and address signals, and generating a composite signal including the channel signal and similarly generated signals. The composite signal includes events from detectors in a block and is serially output. An apparatus that serially transfers annihilation information from a block includes time signal generators for detectors in a block and an address and channel signal generator. The PET scanner includes a ring tomograph that mounts onto a portion of an animal, which includes opposing block pairs. Each of the blocks in a block pair includes a scintillator layer, detection array, front-end array, and a serial encoder. The serial encoder includes time signal generators and an address signal and channel signal generator.

  2. Technical Note: Measurement of bow tie profiles in CT scanners using radiochromic film

    SciTech Connect (OSTI)

    Whiting, Bruce R.; Dohatcu, Andreea C.; Evans, Joshua D.; Williamson, Jeffrey F.; Politte, David G.

    2015-06-15

    Purpose: To provide a noninvasive technique to measure the intensity profile of the fan beam in a computed tomography (CT) scanner that is cost effective and easily implemented without the need to access proprietary scanner information or service modes. Methods: The fabrication of an inexpensive aperture is described, which is used to expose radiochromic film in a rotating CT gantry. A series of exposures is made, each of which is digitized on a personal computer document scanner, and the resulting data set is analyzed to produce a self-consistent calibration of relative radiation exposure. The bow tie profiles were analyzed to determine the precision of the process and were compared to two other measurement techniques, direct measurements from CT gantry detectors and a dynamic dosimeter. Results: The radiochromic film method presented here can measure radiation exposures with a precision of ?6% root-mean-square relative error. The intensity profiles have a maximum 25% root-mean-square relative error compared with existing techniques. Conclusions: The proposed radiochromic film method for measuring bow tie profiles is an inexpensive (?$100 USD + film costs), noninvasive method to measure the fan beam intensity profile in CT scanners.

  3. -CT CT)Computed Tomography(. ,. , -100 ,

    E-Print Network [OSTI]

    Pinsky, Ross

    sigma . ." , : ·B.sc "BA- · " Lean/six sigma - ·-Green/Black Belt ·. · , , .' , ·" . " * . : ·) B.A ,(-. ·4-6. ·) QFD, CtQ breakdown, DfSS, SPC, AQP, FMEA, Control Plan.( ·Six Sigma GB/EE/Mechanics/Physics/SW/Algorithms/Materials /Application Development) · · - · · Process Improvement Engineer : · . · -six

  4. ModPET: A Novel Small-Animal PET System Positron Emission Tomography (PET) and PET/CT systems have become the gold standard for imaging

    E-Print Network [OSTI]

    Arizona, University of

    for Gamma-Ray Imaging, we are developing a novel small-animal PET scanner that utilizes common modularModPET: A Novel Small-Animal PET System Positron Emission Tomography (PET) and PET/CT systems have these results to their human counterparts. Current small-animal PET scanners are very costly and complicated

  5. Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative reconstruction

    SciTech Connect (OSTI)

    Brady, Samuel L.; Shulkin, Barry L.

    2015-02-15

    Purpose: To develop ultralow dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). Methods: A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultralow doses (1035 mA s). CT quantitation: noise, low-contrast resolution, and CT numbers for 11 tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% volume computed tomography dose index (0.39/3.64; mGy) from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUV{sub bw}) of various diameter targets (range 837 mm), background uniformity, and spatial resolution. Radiation dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative dose reduction and noise control. Results: CT numbers were constant to within 10% from the nondose reduced CTAC image for 90% dose reduction. No change in SUV{sub bw}, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols was found down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62% and 86% (3.2/8.30.9/6.2). Noise magnitude in dose-reduced patient images increased but was not statistically different from predose-reduced patient images. Conclusions: Using ASiR allowed for aggressive reduction in CT dose with no change in PET reconstructed images while maintaining sufficient image quality for colocalization of hybrid CT anatomy and PET radioisotope uptake.

  6. Toward a Flexible and Portable CT Scanner Jeff Orchard1

    E-Print Network [OSTI]

    Orchard, Jeffery J.

    School of Computer Science, University of Waterloo, Canada jorchard@uwaterloo.ca 2 Systems Design scanner that could be deployed at the scene of a car accident to acquire tomographic images before mov. At the conclusion, we outline several hurdles that must be overcome in order to build a working prototype

  7. FPGA-Based Data Acquisition System for a Positron Emission Tomography (PET) Scanner

    E-Print Network [OSTI]

    Hauck, Scott

    FPGA-Based Data Acquisition System for a Positron Emission Tomography (PET) Scanner Michael of performing complex discrete signal processing algorithms with clock rates of above 100MHz. This combined with FPGAs low expense, ease of use, and selected dedicated hardware make them an ideal technology for a data

  8. A prototype fan-beam optical CT scanner for 3D dosimetry

    SciTech Connect (OSTI)

    Campbell, Warren G.; Rudko, D. A.; Braam, Nicolas A.; Jirasek, Andrew [University of Victoria, Victoria, British Columbia V8P 5C2 (Canada); Wells, Derek M. [British Columbia Cancer Agency, Vancouver Island Centre, Victoria, British Columbia V8R 6V5 (Canada)

    2013-06-15

    Purpose: The objective of this work is to introduce a prototype fan-beam optical computed tomography scanner for three-dimensional (3D) radiation dosimetry. Methods: Two techniques of fan-beam creation were evaluated: a helium-neon laser (HeNe, {lambda} = 543 nm) with line-generating lens, and a laser diode module (LDM, {lambda} = 635 nm) with line-creating head module. Two physical collimator designs were assessed: a single-slot collimator and a multihole collimator. Optimal collimator depth was determined by observing the signal of a single photodiode with varying collimator depths. A method of extending the dynamic range of the system is presented. Two sample types were used for evaluations: nondosimetric absorbent solutions and irradiated polymer gel dosimeters, each housed in 1 liter cylindrical plastic flasks. Imaging protocol investigations were performed to address ring artefacts and image noise. Two image artefact removal techniques were performed in sinogram space. Collimator efficacy was evaluated by imaging highly opaque samples of scatter-based and absorption-based solutions. A noise-based flask registration technique was developed. Two protocols for gel manufacture were examined. Results: The LDM proved advantageous over the HeNe laser due to its reduced noise. Also, the LDM uses a wavelength more suitable for the PRESAGE{sup TM} dosimeter. Collimator depth of 1.5 cm was found to be an optimal balance between scatter rejection, signal strength, and manufacture ease. The multihole collimator is capable of maintaining accurate scatter-rejection to high levels of opacity with scatter-based solutions (T < 0.015%). Imaging protocol investigations support the need for preirradiation and postirradiation scanning to reduce reflection-based ring artefacts and to accommodate flask imperfections and gel inhomogeneities. Artefact removal techniques in sinogram space eliminate streaking artefacts and reduce ring artefacts of up to {approx}40% in magnitude. The flask registration technique was shown to achieve submillimetre and subdegree placement accuracy. Dosimetry protocol investigations emphasize the need to allow gel dosimeters to cool gradually and to be scanned while at room temperature. Preliminary tests show that considerable noise reduction can be achieved with sinogram filtering and by binning image pixels into more clinically relevant grid sizes. Conclusions: This paper describes a new optical CT scanner for 3D radiation dosimetry. Tests demonstrate that it is capable of imaging both absorption-based and scatter-based samples of high opacities. Imaging protocol and gel dosimeter manufacture techniques have been adapted to produce optimal reconstruction results. These optimal results will require suitable filtering and binning techniques for noise reduction purposes.

  9. Stationary table CT dosimetry and anomalous scanner-reported values of CTDI{sub vol}

    SciTech Connect (OSTI)

    Dixon, Robert L., E-mail: rdixon@wfubmc.edu [Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 (United States); Boone, John M. [Departments of Radiology and Biomedical Engineering, University of California Davis, Sacramento, California 95817 (United States)] [Departments of Radiology and Biomedical Engineering, University of California Davis, Sacramento, California 95817 (United States)

    2014-01-15

    Purpose: Anomalous, scanner-reported values of CTDI{sub vol} for stationary phantom/table protocols (having elevated values of CTDI{sub vol} over 300% higher than the actual dose to the phantom) have been observed; which are well-beyond the typical accuracy expected of CTDI{sub vol} as a phantom dose. Recognition of these outliers as bad data is important to users of CT dose index tracking systems (e.g., ACR DIR), and a method for recognition and correction is provided. Methods: Rigorous methods and equations are presented which describe the dose distributions for stationary-table CT. A comparison with formulae for scanner-reported values of CTDI{sub vol} clearly identifies the source of these anomalies. Results: For the stationary table, use of the CTDI{sub 100} formula (applicable to a moving phantom only) overestimates the dose due to extra scatter and also includes an overbeaming correction, both of which are nonexistent when the phantom (or patient) is held stationary. The reported DLP remains robust for the stationary phantom. Conclusions: The CTDI-paradigm does not apply in the case of a stationary phantom and simpler nonintegral equations suffice. A method of correction of the currently reported CTDI{sub vol} using the approach-to-equilibrium formula H(a) and an overbeaming correction factor serves to scale the reported CTDI{sub vol} values to more accurate levels for stationary-table CT, as well as serving as an indicator in the detection of bad data..

  10. Experimental validation of a method characterizing bow tie filters in CT scanners using a real-time dose probe

    SciTech Connect (OSTI)

    McKenney, Sarah E.; Nosratieh, Anita; Gelskey, Dale; Yang Kai; Huang Shinying; Chen Lin; Boone, John M. [Department of Radiology, University of California, Davis Medical Center, Rm. 0505, ACC Ellison Bldg., 4860 Y St., Sacramento, California 95817 (United States) and Department of Biomedical Engineering, University of California, Davis, Rm. 2303, GBSF, 451 E. Health Science Dr., Davis, California 95616 (United States); Diagnostic Imaging Specialists Corporation (DISC), 163 St. Malo Street, St. Malo, Manitoba R0A 1T0 (Canada); Department of Radiology, University of California, Davis Medical Center, Rm. 0505, ACC Ellison Bldg., 4860 Y St., Sacramento, California 95817 (United States); Department of Radiology, University of California, Davis Medical Center, Rm. 0505, ACC Ellison Bldg., 4860 Y St., Sacramento, California 95817 (United States) and Department of Biomedical Engineering, University of California, Davis, Rm. 2303, GBSF, 451 E. Health Science Dr., Davis, California 95616 (United States)

    2011-03-15

    Purpose: Beam-shaping or ''bow tie'' (BT) filters are used to spatially modulate the x-ray beam in a CT scanner, but the conventional method of step-and-shoot measurement to characterize a beam's profile is tedious and time-consuming. The theory for characterization of bow tie relative attenuation (COBRA) method, which relies on a real-time dosimeter to address the issues of conventional measurement techniques, was previously demonstrated using computer simulations. In this study, the feasibility of the COBRA theory is further validated experimentally through the employment of a prototype real-time radiation meter and a known BT filter. Methods: The COBRA method consisted of four basic steps: (1) The probe was placed at the edge of a scanner's field of view; (2) a real-time signal train was collected as the scanner's gantry rotated with the x-ray beam on; (3) the signal train, without a BT filter, was modeled using peak values measured in the signal train of step 2; and (4) the relative attenuation of the BT filter was estimated from filtered and unfiltered data sets. The prototype probe was first verified to have an isotropic and linear response to incident x-rays. The COBRA method was then tested on a dedicated breast CT scanner with a custom-designed BT filter and compared to the conventional step-and-shoot characterization of the BT filter. Using basis decomposition of dual energy signal data, the thickness of the filter was estimated and compared to the BT filter's manufacturing specifications. The COBRA method was also demonstrated with a clinical whole body CT scanner using the body BT filter. The relative attenuation was calculated at four discrete x-ray tube potentials and used to estimate the thickness of the BT filter. Results: The prototype probe was found to have a linear and isotropic response to x-rays. The relative attenuation produced from the COBRA method fell within the error of the relative attenuation measured with the step-and-shoot method. The BT filter thickness estimates resulting from the dual energy scans on the breast CT system were equivalent to the manufacturing specifications. The clinical CT evaluation produced data conceptually similar to previous computer simulations and plausible relative attenuation profiles were observed. Conclusions: The COBRA method is a fast and accurate method for BT filter characterization, which requires a simple experimental setup in a clinical environment. Because of the ease of data acquisition, multienergy scans can be acquired which allow characterization of the BT filter thickness.

  11. Medical Imaging Process Accelerated in FPGA Hardware by 82x over Software Line of Reaction Estimation for a PET scanner Optimized using C to FPGA Methodology

    E-Print Network [OSTI]

    Hauck, Scott

    for a high-resolution Positron Emission Tomography (PET) scanner. The estimation algorithm provides Estimation for a PET scanner Optimized using C to FPGA Methodology Zhongho Chen Department of CSIE, National to the exact needs of a given computation. In previous work we have benchmarked a CT scanner backprojection

  12. Establishing a process of irradiating small animal brain using a CyberKnife and a microCT scanner

    SciTech Connect (OSTI)

    Kim, Haksoo; Welford, Scott; Fabien, Jeffrey; Zheng, Yiran; Yuan, Jake; Brindle, James; Yao, Min; Lo, Simon; Wessels, Barry; Machtay, Mitchell; Sohn, Jason W.; Sloan, Andrew

    2014-02-15

    Purpose: Establish and validate a process of accurately irradiating small animals using the CyberKnife G4 System (version 8.5) with treatment plans designed to irradiate a hemisphere of a mouse brain based on microCT scanner images. Methods: These experiments consisted of four parts: (1) building a mouse phantom for intensity modulated radiotherapy (IMRT) quality assurance (QA), (2) proving usability of a microCT for treatment planning, (3) fabricating a small animal positioning system for use with the CyberKnife's image guided radiotherapy (IGRT) system, and (4)in vivo verification of targeting accuracy. A set of solid water mouse phantoms was designed and fabricated, with radiochromic films (RCF) positioned in selected planes to measure delivered doses. After down-sampling for treatment planning compatibility, a CT image set of a phantom was imported into the CyberKnife treatment planning systemMultiPlan (ver. 3.5.2). A 0.5 cm diameter sphere was contoured within the phantom to represent a hemispherical section of a mouse brain. A nude mouse was scanned in an alpha cradle using a microCT scanner (cone-beam, 157 149 pixels slices, 0.2 mm longitudinal slice thickness). Based on the results of our positional accuracy study, a planning treatment volume (PTV) was created. A stereotactic body mold of the mouse was printed using a 3D printer laying UV curable acrylic plastic. Printer instructions were based on exported contours of the mouse's skin. Positional reproducibility in the mold was checked by measuring ten CT scans. To verify accurate dose delivery in vivo, six mice were irradiated in the mold with a 4 mm target contour and a 2 mm PTV margin to 3 Gy and sacrificed within 20 min to avoid DNA repair. The brain was sliced and stained for analysis. Results: For the IMRT QA using a set of phantoms, the planned dose (6 Gy to the calculation point) was compared to the delivered dose measured via film and analyzed using Gamma analysis (3% and 3 mm). A passing rate of 99% was measured in areas of above 40% of the prescription dose. The final inverse treatment plan was comprised of 43 beams ranging from 5 to 12.5 mm in diameter (2.5 mm size increments are available up to 15 mm in diameter collimation). Using the Xsight Spine Tracking module, the CyberKnife system could not reliably identify and track the tiny mouse spine; however, the CyberKnife system could identify and track the fiducial markers on the 3D mold.In vivo positional accuracy analysis using the 3D mold generated a mean error of 1.41 mm 0.73 mm when fiducial markers were used for position tracking. Analysis of the dissected brain confirmed the ability to target the correct brain volume. Conclusions: With the use of a stereotactic body mold with fiducial markers, microCT imaging, and resolution down-sampling, the CyberKnife system can successfully perform small-animal radiotherapy studies.

  13. SciThur PM: Imaging 06: Canada's National Computed Tomography (CT) Survey

    SciTech Connect (OSTI)

    Wardlaw, GM; Martel, N; Blackler, W; Asselin, J-F

    2014-08-15

    The value of computed tomography (CT) in medical imaging is reflected in its' increased use and availability since the early 1990's; however, given CT's relatively larger exposures (vs. planar x-ray) greater care must be taken to ensure that CT procedures are optimised in terms of providing the smallest dose possible while maintaining sufficient diagnostic image quality. The development of CT Diagnostic Reference Levels (DRLs) supports this process. DRLs have been suggested/supported by international/national bodies since the early 1990's and widely adopted elsewhere, but not on a national basis in Canada. Essentially, CT DRLs provide guidance on what is considered good practice for common CT exams, but require a representative sample of CT examination data to make any recommendations. Canada's National CT Survey project, in collaboration with provincial/territorial authorities, has collected a large national sample of CT practice data for 7 common examinations (with associated clinical indications) of both adult and pediatric patients. Following completion of data entry into a common database, a survey summary report and recommendations will be made on CT DRLs from this data. It is hoped that these can then be used by local regions to promote CT practice optimisation and support any dose reduction initiatives.

  14. Processing optimization with parallel computing for the J-PET tomography scanner

    E-Print Network [OSTI]

    Krzemie?, W; Bednarski, T; Bia?as, P; Czerwi?ski, E; Gajos, A; Gorgol, M; Jasi?ska, B; Kami?ska, D; Kap?on, ?; Korcyl, G; Kowalski, P; Kozik, T; Kubicz, E; Nied?wiecki, Sz; Pa?ka, M; Raczy?ski, L; Rudy, Z; Rundel, O; Sharma, N G; Silarski, M; S?omski, A; Stola, K; Strzelecki, A; Trybek, D; Wieczorek, Anna; Wi?licki, W; Zieli?ski, M; Zgardzi?ska, B K; Moskal, P

    2015-01-01

    The Jagiellonian-PET (J-PET) collaboration is developing a prototype TOF-PET detector based on long polymer scintillators. This novel approach exploits the excellent time properties of the plastic scintillators, which permit very precise time measurements. The very fast, FPGA-based front-end electronics and the data acquisition system, as well as, low- and high-level reconstruction algorithms were specially developed to be used with the J-PET scanner. The TOF-PET data processing and reconstruction are time and resource demanding operations, especially in case of a large acceptance detector, which works in triggerless data acquisition mode. In this article, we discuss the parallel computing methods applied to optimize the data processing for the J-PET detector. We begin with general concepts of parallel computing and then we discuss several applications of those techniques in the J-PET data processing.

  15. Abstract-Proton Computed Tomography (CT) has important implications for both image-guided diagnosis and radiation

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Abstract- Proton Computed Tomography (CT) has important implications for both image-guided diagnosis and radiation therapy. For diagnosis, the fact that the patient dose committed by proton CT and contrast, may be exploited in dose-critical clinical settings. Proton CT is also the most appropriate

  16. Pilot study for compact microbeam radiation therapy using a carbon nanotube field emission micro-CT scanner

    SciTech Connect (OSTI)

    Hadsell, Mike Cao, Guohua; Zhang, Jian; Burk, Laurel; Schreiber, Torsten; Lu, Jianping; Zhou, Otto; Schreiber, Eric; Chang, Sha

    2014-06-15

    Purpose: Microbeam radiation therapy (MRT) is defined as the use of parallel, microplanar x-ray beams with an energy spectrum between 50 and 300 keV for cancer treatment and brain radiosurgery. Up until now, the possibilities of MRT have mainly been studied using synchrotron sources due to their high flux (100s Gy/s) and approximately parallel x-ray paths. The authors have proposed a compact x-ray based MRT system capable of delivering MRT dose distributions at a high dose rate. This system would employ carbon nanotube (CNT) field emission technology to create an x-ray source array that surrounds the target of irradiation. Using such a geometry, multiple collimators would shape the irradiation from this array into multiple microbeams that would then overlap or interlace in the target region. This pilot study demonstrates the feasibility of attaining a high dose rate and parallel microbeam beams using such a system. Methods: The microbeam dose distribution was generated by our CNT micro-CT scanner (100?m focal spot) and a custom-made microbeam collimator. An alignment assembly was fabricated and attached to the scanner in order to collimate and superimpose beams coming from different gantry positions. The MRT dose distribution was measured using two orthogonal radiochromic films embedded inside a cylindrical phantom. This target was irradiated with microbeams incident from 44 different gantry angles to simulate an array of x-ray sources as in the proposed compact CNT-based MRT system. Finally, phantom translation in a direction perpendicular to the microplanar beams was used to simulate the use of multiple parallel microbeams. Results: Microbeams delivered from 44 gantry angles were superimposed to form a single microbeam dose distribution in the phantom with a FWHM of 300?m (calculated value was 290 ?m). Also, during the multiple beam simulation, a peak to valley dose ratio of ?10 was found when the phantom translation distance was roughly 4x the beam width. The first prototype CNT-based x-ray tube dedicated to the development of compact MRT technology development was proposed and planned based on the preliminary experimental results presented here and the previous corresponding Monte Carlo simulations. Conclusions: The authors have demonstrated the feasibility of creating microbeam dose distributions at a high dose rate using a proposed compact MRT system. The flexibility of CNT field emission x-ray sources could possibly bring compact and low cost MRT devices to the larger research community and assist in the translational research of this promising new approach to radiation therapy.

  17. Dose uncertainty due to computed tomography ,,CT... slice thickness in CT-based high dose rate brachytherapy of the prostate cancer

    E-Print Network [OSTI]

    Pouliot, Jean

    brachytherapy of the prostate cancer Yongbok Kim,a) I-Chow Joe Hsu, Etienne Lessard, and Jean Pouliot Department tomography CT -based high dose rate HDR brachytherapy, the uncertainty in the localization in Medicine. DOI: 10.1118/1.1785454 Key words: high dose rate brachytherapy, computed tomography, prostate

  18. for Proton CT R. P. Johnson, Member, IEEE, V. Bashkirov, V. Giacometti, R. F. Hurley, P. Piersimoni,

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    for Proton CT R. P. Johnson, Member, IEEE, V. Bashkirov, V. Giacometti, R. F. Hurley, P. Piersimoni beam test results with our pre-clinical (Phase-II) head scanner developed for proton computed tomography (pCT). After extensive preclinical testing, pCT will be employed in support of proton therapy

  19. SU-D-9A-04: Brain PET/CT Imaging On a Scanner with a Large Axial Field-Of-View

    SciTech Connect (OSTI)

    Park, M; Gerbaudo, V; Hamberg, L; Seaver, K; Kijewski, M

    2014-06-01

    Purpose: Large axial field-of-view (FOV) PET/CT scanners are valued for high sensitivity. Brain PET image quality may depend on the head position within the FOV. We investigated the precision of activity estimation for brain PET imaging when the brain was positioned at the end (END) and in the middle (CEN) of the FOV. The additional CT dose for the CEN position was recorded. Methods: An image quality (Jaszczak) phantom and a striatal phantom were filled with F-18 and positioned in END and CEN locations. For each phantom and each location, we acquired a ?1-hr listmode PET, rebinned the data into 10 frames with equal number of coincidence events, and reconstructed each frame using an iterative algorithm. For the striatal phantom, END and CEN were compared by drawing on each image three regions of interest (ROI) in axially separated uniform areas. The standard deviation of the activity estimation within each ROI was averaged over the 10 images. The coefficient of variation (CV) for activity estimation was calculated at each position. Image quality was assessed by inspecting the resolution bar pattern in the Jaszczak phantom at two different head positions. Results: The CV was the lowest for ROIs near the center of the FOV. For slices near the end, not only was the CV highest, but also the resolution pattern was degraded. CTDIvol summarized in the dose report indicated that the CT dose was ? 10% higher for CEN as compared to END position. Conclusion: Positioning the brain in the middle of the FOV in a large FOV PET/CT scanner allows more precise measurement of tracer uptake and better image quality at the cost of increased CT dose. For the end location longer scan times may minimize image quality degradation without any additional CT dose.

  20. NETL CT Imaging Facility

    ScienceCinema (OSTI)

    None

    2014-05-21

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  1. NETL CT Imaging Facility

    SciTech Connect (OSTI)

    2013-09-04

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  2. An Exact Modeling of Signal Statistics in Energy-integrating X-ray Computed Tomography

    E-Print Network [OSTI]

    used by modern computed tomography (CT) scanners and has been an interesting research topicAn Exact Modeling of Signal Statistics in Energy-integrating X-ray Computed Tomography Yi Fan1.i.d.), such as Gamma, Gaussian, etc, would be valid. A comparison study was performed to estimate the introduced errors

  3. Semi-resonant operation of a fiber-cantilever piezotube scanner for stable optical coherence tomography endoscope imaging

    E-Print Network [OSTI]

    Moon, Sucbei; Lee, Sang-Won; Rubinstein, Marc; Wong, Brian J. F; Chen, Zhongping

    2010-01-01

    of a rotational microelectromechanical system probe, Opt.tomography based on a microelectromechanical mirror, Opt.with a modified microelectromechanical systems mirror for

  4. Abstract--Proton computed tomography (pCT) has the potential to improve the accuracy of dose calculations for proton

    E-Print Network [OSTI]

    Mueller, Klaus

    Abstract--Proton computed tomography (pCT) has the potential to improve the accuracy of dose calculations for proton treatment planning, and will also be useful for pretreatment verification of patient positioning relative to the proton beam. A design study was performed to define the optimal approach to a p

  5. Chun Jiao, Dongming Wang, Hongbing Lu*, Member, IEEE, Zhu Zhang, Jerome Z. Liang, Fellow, IEEE AbstractLow-dose protocol for computed tomography (CT)

    E-Print Network [OSTI]

    higher risk of lung cancer, and that of children. To lower the radiation exposure, low-dose protocols AbstractLow-dose protocol for computed tomography (CT) scans has been gradually used in clinics to lower-stationary Gaussian noise in low-dose CT sinograms by wavelet analysis. To explore the noise property in wavelet

  6. SU-E-I-25: Determining Tube Current, Tube Voltage and Pitch Suitable for Low- Dose Lung Screening CT

    SciTech Connect (OSTI)

    Williams, K; Matthews, K

    2014-06-01

    Purpose: The quality of a computed tomography (CT) image and the dose delivered during its acquisition depend upon the acquisition parameters used. Tube current, tube voltage, and pitch are acquisition parameters that potentially affect image quality and dose. This study investigated physicians' abilities to characterize small, solid nodules in low-dose CT images for combinations of current, voltage and pitch, for three CT scanner models. Methods: Lung CT images was acquired of a Data Spectrum anthropomorphic torso phantom with various combinations of pitch, tube current, and tube voltage; this phantom was used because acrylic beads of various sizes could be placed within the lung compartments to simulate nodules. The phantom was imaged on two 16-slice scanners and a 64-slice scanner. The acquisition parameters spanned a range of estimated CTDI levels; the CTDI estimates from the acquisition software were verified by measurement. Several experienced radiologists viewed the phantom lung CT images and noted nodule location, size and shape, as well as the acceptability of overall image quality. Results: Image quality for assessment of nodules was deemed unsatisfactory for all scanners at 80 kV (any tube current) and at 35 mA (any tube voltage). Tube current of 50 mA or more at 120 kV resulted in similar assessments from all three scanners. Physician-measured sphere diameters were closer to actual diameters for larger spheres, higher tube current, and higher kV. Pitch influenced size measurements less for larger spheres than for smaller spheres. CTDI was typically overestimated by the scanner software compared to measurement. Conclusion: Based on this survey of acquisition parameters, a low-dose CT protocol of 120 kV, 50 mA, and pitch of 1.4 is recommended to balance patient dose and acceptable image quality. For three models of scanners, this protocol resulted in estimated CTDIs from 2.93.6 mGy.

  7. Implications of CT noise and artifacts for quantitative {sup 99m}Tc SPECT/CT imaging

    SciTech Connect (OSTI)

    Hulme, K. W.; Kappadath, S. C.

    2014-04-15

    Purpose: This paper evaluates the effects of computed tomography (CT) image noise and artifacts on quantitative single-photon emission computed-tomography (SPECT) imaging, with the aim of establishing an appropriate range of CT acquisition parameters for low-dose protocols with respect to accurate SPECT attenuation correction (AC). Methods: SPECT images of two geometric and one anthropomorphic phantom were reconstructed iteratively using CT scans acquired at a range of dose levels (CTDI{sub vol} = 0.4 to 46 mGy). Resultant SPECT image quality was evaluated by comparing mean signal, background noise, and artifacts to SPECT images reconstructed using the highest dose CT for AC. Noise injection was performed on linear-attenuation (?) maps to determine the CT noise threshold for accurate AC. Results: High levels of CT noise (? ? 200400 HU) resulted in low ?-maps noise (? ? 1%3%). Noise levels greater than ?10% in 140 keV ?-maps were required to produce visibly perceptible increases of ?15% in {sup 99m}Tc SPECT images. These noise levels would be achieved at low CT dose levels (CTDI{sub vol} = 4 ?Gy) that are over 2 orders of magnitude lower than the minimum dose for diagnostic CT scanners. CT noise could also lower (bias) the expected ? values. The relative error in reconstructed SPECT signal trended linearly with the relative shift in ?. SPECT signal was, on average, underestimated in regions corresponding with beam-hardening artifacts in CT images. Any process that has the potential to change the CT number of a region by ?100 HU (e.g., misregistration between CT images and SPECT images due to motion, the presence of contrast in CT images) could introduce errors in ?{sub 140} {sub keV} on the order of 10%, that in turn, could introduce errors on the order of ?10% into the reconstructed {sup 99m}Tc SPECT image. Conclusions: The impact of CT noise on SPECT noise was demonstrated to be negligible for clinically achievable CT parameters. Because CT dose levels that affect SPECT quantification is low (CTDI{sub vol} ? 4 ?Gy), the low dose limit for the CT exam as part of SPECT/CT will be guided by CT image quality requirements for anatomical localization and artifact reduction. A CT technique with higher kVp in combination with lower mAs is recommended when low-dose CT images are used for AC to minimize beam-hardening artifacts.

  8. Abstract --Four-dimensional dynamic computed tomography (4D-dCT) plays an important role in radiation treatment

    E-Print Network [OSTI]

    dose during a 4D-dCT procedure is much higher than a routine 3D CT study. Low-dose scans for 4D with low-dose dynamic CT scans. It first applies the Karhunen-Love (KL) transform to the neighboring-CT datasets are usually acquired in treatment planning for lung cancer [1]-[3]. Thus, the radiation dose of 4D

  9. Abstract ---Computed tomography colonography (CTC) or CT-based virtual colonoscopy (VC) is an emerging tool for detection

    E-Print Network [OSTI]

    . The radiation dose is a major concern for screening application of CTC. In this work, we performed a simulation study to demonstrate a possible ultra low-dose CT technique for VC. The ultra low-dose abdominal CT by a filtered backprojection algorithm for the ultra low-dose CT images. The patient-specific virtual colon

  10. CT Scans of Cores Metadata, Barrow, Alaska 2015

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Katie McKnight; Tim Kneafsey; Craig Ulrich

    2015-03-11

    Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

  11. CT Scans of Cores Metadata, Barrow, Alaska 2015

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Katie McKnight; Tim Kneafsey; Craig Ulrich

    Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

  12. Sample size requirements for estimating effective dose from computed tomography using solid-state metal-oxide-semiconductor field-effect transistor dosimetry

    SciTech Connect (OSTI)

    Trattner, Sigal; Cheng, Bin; Pieniazek, Radoslaw L.; Hoffmann, Udo; Douglas, Pamela S.; Einstein, Andrew J.

    2014-04-15

    Purpose: Effective dose (ED) is a widely used metric for comparing ionizing radiation burden between different imaging modalities, scanners, and scan protocols. In computed tomography (CT), ED can be estimated by performing scans on an anthropomorphic phantom in which metal-oxide-semiconductor field-effect transistor (MOSFET) solid-state dosimeters have been placed to enable organ dose measurements. Here a statistical framework is established to determine the sample size (number of scans) needed for estimating ED to a desired precision and confidence, for a particular scanner and scan protocol, subject to practical limitations. Methods: The statistical scheme involves solving equations which minimize the sample size required for estimating ED to desired precision and confidence. It is subject to a constrained variation of the estimated ED and solved using the Lagrange multiplier method. The scheme incorporates measurement variation introduced both by MOSFET calibration, and by variation in MOSFET readings between repeated CT scans. Sample size requirements are illustrated on cardiac, chest, and abdomenpelvis CT scans performed on a 320-row scanner and chest CT performed on a 16-row scanner. Results: Sample sizes for estimating ED vary considerably between scanners and protocols. Sample size increases as the required precision or confidence is higher and also as the anticipated ED is lower. For example, for a helical chest protocol, for 95% confidence and 5% precision for the ED, 30 measurements are required on the 320-row scanner and 11 on the 16-row scanner when the anticipated ED is 4 mSv; these sample sizes are 5 and 2, respectively, when the anticipated ED is 10 mSv. Conclusions: Applying the suggested scheme, it was found that even at modest sample sizes, it is feasible to estimate ED with high precision and a high degree of confidence. As CT technology develops enabling ED to be lowered, more MOSFET measurements are needed to estimate ED with the same precision and confidence.

  13. Characterizing properties of fractured porous media using x-ray computed tomography

    E-Print Network [OSTI]

    Mudra, James

    1990-01-01

    REFERENCES 270 APPENDIX 273 v i i VITA 277 v i i i LIST OF TABLES Table Page 1 Mineral Composition of the Devonian Shale 8 2 Operating Modes of the CT Scanner 41 3 CT Values f o r the Evacuated Berea Sandstone Sample . 64 4 Porosity Value... of Xenon i n the Perpendicular Devonian Shale Experiment 221 9 Movie Log 2 61 i x LIST OF FIGURES Figure Page 1 F i r s t Generation CT Scanner 22 2 Second Generation CT Scanner 23 3 Third Generation CT Scanner 25 4 Fourth Generation CT Scanner 2 6...

  14. Dual energy CT for attenuation correction with PET/CT

    SciTech Connect (OSTI)

    Xia, Ting; Alessio, Adam M.; Kinahan, Paul E.

    2014-01-15

    Purpose: The authors evaluate the energy dependent noise and bias properties of monoenergetic images synthesized from dual-energy CT (DECT) acquisitions. These monoenergetic images can be used to estimate attenuation coefficients at energies suitable for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging. This is becoming more relevant with the increased use of quantitative imaging by PET/CT and SPECT/CT scanners. There are, however, potential variations in the noise and bias of synthesized monoenergetic images as a function of energy. Methods: The authors used analytic approximations and simulations to estimate the noise and bias of synthesized monoenergetic images of water-filled cylinders with different shapes and the NURBS-based cardiac-torso (NCAT) phantom from 40 to 520 keV, the range of SPECT and PET energies. The dual-kVp spectra were based on the GE Lightspeed VCT scanner at 80 and 140 kVp with added filtration of 0.5 mm Cu. The authors evaluated strategies of noise suppression with sinogram smoothing and dose minimization with reduction of tube currents at the two kVp settings. The authors compared the impact of DECT-based attenuation correction with single-kVp CT-based attenuation correction on PET quantitation for the NCAT phantom for soft tissue and high-Z materials of bone and iodine contrast enhancement. Results: Both analytic calculations and simulations displayed the expected minimum noise value for a synthesized monoenergetic image at an energy between the mean energies of the two spectra. In addition the authors found that the normalized coefficient of variation in the synthesized attenuation map increased with energy but reached a plateau near 160 keV, and then remained constant with increasing energy up to 511 keV and beyond. The bias was minimal, as the linear attenuation coefficients of the synthesized monoenergetic images were within 2.4% of the known true values across the entire energy range. Compared with no sinogram smoothing, sinogram smoothing can dramatically reduce noise in the DECT-derived attenuation map. Through appropriate selection of tube currents for high and low kVp scans, DECT can deliver roughly the same amount of radiation dose as that of a single kVp CT scan, but could be used for PET attenuation correction with reduced bias in contrast agent regions by a factor of ?2.6 and slightly reduced RMSE for the total image. Conclusions: When DECT is used for attenuation correction at higher energies, there is a noise amplification that is dependent on the energy of the synthesized monoenergetic image of linear attenuation coefficients. Sinogram smoothing reduces the noise amplification in DECT-derived attenuation maps without increasing bias. With an appropriate selection of CT techniques, a DECT scan with the same radiation dose as a single CT scan can result in a PET image with improved quantitative accuracy.

  15. Artifact reduction in industrial computed tomography via data fusion

    SciTech Connect (OSTI)

    Schrapp, Michael; Goldammer, Matthias; Stephan, Jrgen

    2014-02-18

    As the most stressed part of a gas turbine the first row of turbine blades is not only a challenge for the materials used. Also the testing of these parts have to meet the highest standards. Computed tomography (CT) as the technique which could reveal the most details also provides the biggest challenges [1]: A full penetration of large sized turbine blades is often only possible at high X-ray voltages causing disproportional high costs. A reduction of the X-ray voltage is able to reduce these arising costs but yields non penetration artifacts in the reconstructed CT image. In most instances, these artifacts manifests itself as blurred and smeared regions at concave edges due to a reduced signal to noise ratio. In order to complement the missing information and to increase the overall image quality of our reconstruction, we use further imaging modalities such as a 3-D Scanner and ultrasonic imaging. A 3-D scanner is easy and cost effective to implement and is able to acquire all relevant data simultaneously with the CT projections. If, however, the interior structure is of supplemental interest, an ultrasonic imaging method is additionally used. We consider this data as a priori knowledge to employ them in an iterative reconstruction. To do so, standard iterative reconstruction methods are modified to incorporate the a priori data in a regularization approach in combination with minimizing the total variation of our image. Applying this procedure on turbine blades, we are able to reduce the apparent artifacts almost completely.

  16. Biochip scanner device

    DOE Patents [OSTI]

    Perov, Alexander (Troitsk, RU); Belgovskiy, Alexander I. (Mayfield Heights, OH); Mirzabekov, Andrei D. (Darien, IL)

    2001-01-01

    A biochip scanner device used to detect and acquire fluorescence signal data from biological microchips or biochips and method of use are provided. The biochip scanner device includes a laser for emitting a laser beam. A modulator, such as an optical chopper modulates the laser beam. A scanning head receives the modulated laser beam and a scanning mechanics coupled to the scanning head moves the scanning head relative to the biochip. An optical fiber delivers the modulated laser beam to the scanning head. The scanning head collects the fluorescence light from the biochip, launches it into the same optical fiber, which delivers the fluorescence into a photodetector, such as a photodiode. The biochip scanner device is used in a row scanning method to scan selected rows of the biochip with the laser beam size matching the size of the immobilization site.

  17. Performance characterization of a MVCT scanner using multislice thick, segmented cadmium tungstate-photodiode detectors

    SciTech Connect (OSTI)

    Kirvan, P. F.; Monajemi, T. T.; Fallone, B. G.; Rathee, S. [Department of Physics, University of Alberta, Edmonton, Alberta T6E 2E1 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Physics, University of Alberta, Edmonton, Alberta T6E 2E1 (Canada); Department of Medical Physics, Cross Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2010-01-15

    Purpose: Megavoltage computed tomography (MVCT) and megavoltage cone beam computed tomography (MVCBCT) can be used for visualizing anatomical structures prior to radiation therapy treatments to assist in patient setup and target localization. These systems are less susceptible to metal artifacts and provide better CT number linearity than conventional CT scanners. However, their contrast is limited by the properties of the megavoltage photons and the low detective quantum efficiency (DQE) of flat panel detector systems currently available. By using higher DQE, thick, segmented cadmium tungstate detectors, the authors can improve the low contrast detectability of a MVCT system. This in turn would permit greater soft tissue visualization for a given radiation dose, allowing MVCT to be used in more clinical situations. Methods: This article describes the evaluation of our prototype system that uses thick, segmented detectors. In order to create images using a dose that would be acceptable for day to day patient imaging, the authors evaluated their system using the low intensity bremsstrahlung component of a 6 MeV electron beam. The system was evaluated for its uniformity, high contrast resolution, low contrast detectability, signal to noise ratio, contrast to noise ratio, and CT number linearity. Results: The prototype system was found to have a high contrast spatial resolution of about 5 line pairs per cm, and to be able to visualize a 15 mm 1.5% contrast target with 2 cGy of radiation dose delivered. SNR{sup 2} vs radiation dose and mean pixel value vs electron density curves were linear. Conclusions: This prototype system shows a large improvement in low contrast detectability over current MVCBCT systems.

  18. Limited View Angle Iterative CT Reconstruction

    E-Print Network [OSTI]

    . Connelly, "CT Technologies," in Aspects of Explosives Detection, Elsevier 2009. Dual energy CT Z. Ying, R. Nam and C. R. Crawford, "Dual energy computed tomography for explosive detection," Journal of X

  19. Positron Emission Tomography Physics, Instrumentation, Data Analysis

    E-Print Network [OSTI]

    Liu, Thomas T.

    1 Positron Emission Tomography Physics, Instrumentation, Data Analysis Carl K. Hoh, MD Department PET Scanner Design Smaller individual crystal size = better spatial resolution Physical limit HR scanner = 24 elements in axial FOV.Axial FOV = 15 cm 2D and 3D Detector Configurations 2D mode

  20. High throughput optical scanner

    DOE Patents [OSTI]

    Basiji, David A. (Seattle, WA); van den Engh, Gerrit J. (Seattle, WA)

    2001-01-01

    A scanning apparatus is provided to obtain automated, rapid and sensitive scanning of substrate fluorescence, optical density or phosphorescence. The scanner uses a constant path length optical train, which enables the combination of a moving beam for high speed scanning with phase-sensitive detection for noise reduction, comprising a light source, a scanning mirror to receive light from the light source and sweep it across a steering mirror, a steering mirror to receive light from the scanning mirror and reflect it to the substrate, whereby it is swept across the substrate along a scan arc, and a photodetector to receive emitted or scattered light from the substrate, wherein the optical path length from the light source to the photodetector is substantially constant throughout the sweep across the substrate. The optical train can further include a waveguide or mirror to collect emitted or scattered light from the substrate and direct it to the photodetector. For phase-sensitive detection the light source is intensity modulated and the detector is connected to phase-sensitive detection electronics. A scanner using a substrate translator is also provided. For two dimensional imaging the substrate is translated in one dimension while the scanning mirror scans the beam in a second dimension. For a high throughput scanner, stacks of substrates are loaded onto a conveyor belt from a tray feeder.

  1. Modeling and simulation results on a new Compton scattering tomography modality

    E-Print Network [OSTI]

    Nguyen-Verger, Ma K.

    (X-ray scanner, Single Photon Emission Computed Tomography, Positron Emission Tomography, etcModeling and simulation results on a new Compton scattering tomography modality Gal Rigaud a Biomedical imaging Compton scattering tomography Image reconstruction a b s t r a c t Conventional tomography

  2. Metal Artifact Reduction in Computed Tomography /

    E-Print Network [OSTI]

    Karimi, Seemeen

    2014-01-01

    Monoenergetic imaging of dual-energy CT reduces artifactsartifact reduction by dual energy computed tomography usingimage re- construction for dual energy X-ray transmission

  3. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    SciTech Connect (OSTI)

    Alva-Snchez, Hctor

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  4. Medical Imaging Computed Tomography (CT)

    E-Print Network [OSTI]

    Massey, Thomas N.

    #12;LSO-APD Array Schematic #12;Time-of-Flight PET #12;Energy Spectrum with lutetium oxyorthosilicate

  5. Analysis framework for the J-PET scanner

    E-Print Network [OSTI]

    Krzemie?, W; Gruntowski, A; Stola, K; Trybek, D; Bednarski, T; Bia?as, P; Czerwi?ski, E; Kami?ska, D; Kap?on, L; Kochanowski, A; Korcyl, G; Kowal, J; Kowalski, P; Kozik, T; Kubicz, E; Moskal, P; Nied?wiecki, Sz; Pa?ka, M; Raczy?ski, L; Rudy, Z; Salabura, P; Sharma, N G; Silarski, M; S?omski, A; Smyrski, J; Strzelecki, A; Wieczorek, A; Wi?licki, W; Zieli?ski, M; Zo?, N

    2015-01-01

    J-PET analysis framework is a flexible, lightweight, ROOT-based software package which provides the tools to develop reconstruction and calibration procedures for PET tomography. In this article we present the implementation of the full data-processing chain in the J-PET framework which is used for the data analysis of the J-PET tomography scanner. The Framework incorporates automated handling of PET setup parameters' database as well as high level tools for building data reconstruction procedures. Each of these components is briefly discussed.

  6. MO-PIS-Exhibit Hall-01: Imaging: CT Dose Optimization Technologies I

    SciTech Connect (OSTI)

    Denison, K; Smith, S

    2014-06-15

    Partners in Solutions is an exciting new program in which AAPM partners with our vendors to present practical hands-on information about the equipment and software systems that we use in our clinics. The imaging topic this year is CT scanner dose optimization capabilities. Note that the sessions are being held in a special purpose room built on the Exhibit Hall Floor, to encourage further interaction with the vendors. Dose Optimization Capabilities of GE Computed Tomography Scanners Presentation Time: 11:15 11:45 AM GE Healthcare is dedicated to the delivery of high quality clinical images through the development of technologies, which optimize the application of ionizing radiation. In computed tomography, dose management solutions fall into four categories: employs projection data and statistical modeling to decrease noise in the reconstructed image - creating an opportunity for mA reduction in the acquisition of diagnostic images. Veo represents true Model Based Iterative Reconstruction (MBiR). Using high-level algorithms in tandem with advanced computing power, Veo enables lower pixel noise standard deviation and improved spatial resolution within a single image. Advanced Adaptive Image Filters allow for maintenance of spatial resolution while reducing image noise. Examples of adaptive image space filters include Neuro 3-D filters and Cardiac Noise Reduction Filters. AutomA adjusts mA along the z-axis and is the CT equivalent of auto exposure control in conventional x-ray systems. Dynamic Z-axis Tracking offers an additional opportunity for dose reduction in helical acquisitions while SmartTrack Z-axis Tracking serves to ensure beam, collimator and detector alignment during tube rotation. SmartmA provides angular mA modulation. ECG Helical Modulation reduces mA during the systolic phase of the heart cycle. SmartBeam optimization uses bowtie beam-shaping hardware and software to filter off-axis x-rays - minimizing dose and reducing x-ray scatter. The DICOM Radiation Dose Structured Report (RDSR) generates a dose report at the conclusion of every examination. Dose Check preemptively notifies CT operators when scan parameters exceed user-defined dose thresholds. DoseWatch is an information technology application providing vendor-agnostic dose tracking and analysis for CT (and all other diagnostic x-ray modalities) SnapShot Pulse improves coronary CTA dose management. VolumeShuttle uses two acquisitions to increase coverage, decrease dose, and conserve on contrast administration. Color-Coding for Kids applies the Broselow-Luten Pediatric System to facilitate pediatric emergency care and reduce medical errors. FeatherLight achieves dose optimization through pediatric procedure-based protocols. Adventure Series scanners provide a child-friendly imaging environment promoting patient cooperation with resultant reduction in retakes and patient motion. Philips CT Dose Optimization Tools and Advanced Reconstruction Presentation Time: 11:45 12:15 PM The first part of the talk will cover Dose Reduction and Dose Optimization Technologies present in Philips CT Scanners. The main Technologies to be presented include: DoseRight and tube current modulation (DoseRight, Z-DOM, 3D-DOM, DoseRight Cardiac) Special acquisition modes Beam filtration and beam shapers Eclipse collimator and ClearRay collimator NanoPanel detector DoseRight will cover automatic tube current selection that automatically adjusts the dose for the individual patient. The presentation will explore the modulation techniques currently employed in Philips CT scanners and will include the algorithmic concepts as well as illustrative examples. Modulation and current selection technologies to be covered include the Automatic Current Selection component of DoseRight, ZDOM longitudinal dose modulation, 3D-DOM (combination of longitudinal and rotational dose modulation), Cardiac Dose right (an ECG based dose modulation scheme), and the DoseRight Index (DRI) IQ index. The special acquisition modes covers acquisition techniques such as prospective gating that

  7. Respiratory correlated cone beam CT

    SciTech Connect (OSTI)

    Sonke, Jan-Jakob; Zijp, Lambert; Remeijer, Peter; Herk, Marcel van [Department of Radiation Oncology, Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)

    2005-04-01

    A cone beam computed tomography (CBCT) scanner integrated with a linear accelerator is a powerful tool for image guided radiotherapy. Respiratory motion, however, induces artifacts in CBCT, while the respiratory correlated procedures, developed to reduce motion artifacts in axial and helical CT are not suitable for such CBCT scanners. We have developed an alternative respiratory correlated procedure for CBCT and evaluated its performance. This respiratory correlated CBCT procedure consists of retrospective sorting in projection space, yielding subsets of projections that each corresponds to a certain breathing phase. Subsequently, these subsets are reconstructed into a four-dimensional (4D) CBCT dataset. The breathing signal, required for respiratory correlation, was directly extracted from the 2D projection data, removing the need for an additional respiratory monitor system. Due to the reduced number of projections per phase, the contrast-to-noise ratio in a 4D scan reduced by a factor 2.6-3.7 compared to a 3D scan based on all projections. Projection data of a spherical phantom moving with a 3 and 5 s period with and without simulated breathing irregularities were acquired and reconstructed into 3D and 4D CBCT datasets. The positional deviations of the phantoms center of gravity between 4D CBCT and fluoroscopy were small: 0.13{+-}0.09 mm for the regular motion and 0.39{+-}0.24 mm for the irregular motion. Motion artifacts, clearly present in the 3D CBCT datasets, were substantially reduced in the 4D datasets, even in the presence of breathing irregularities, such that the shape of the moving structures could be identified more accurately. Moreover, the 4D CBCT dataset provided information on the 3D trajectory of the moving structures, absent in the 3D data. Considerable breathing irregularities, however, substantially reduces the image quality. Data presented for three different lung cancer patients were in line with the results obtained from the phantom study. In conclusion, we have successfully implemented a respiratory correlated CBCT procedure yielding a 4D dataset. With respiratory correlated CBCT on a linear accelerator, the mean position, trajectory, and shape of a moving tumor can be verified just prior to treatment. Such verification reduces respiration induced geometrical uncertainties, enabling safe delivery of 4D radiotherapy such as gated radiotherapy with small margins.

  8. FPGA-Based Pulse Parameter Discovery for Positron Emission Tomography.

    E-Print Network [OSTI]

    Hauck, Scott

    technology for a data acquisition system for a positron emission tomography (PET) scanner. The University Programmable Gate Arrays (FPGAs) are capable of performing complex digital signal processing algorithms of Washington is producing a series of high-resolution, small-animal PET scanners that utilize FPGAs as the core

  9. CT head-scan dosimetry in an anthropomorphic phantom and associated measurement of ACR accreditation-phantom imaging metrics under clinically representative scan conditions

    SciTech Connect (OSTI)

    Brunner, Claudia C.; Stern, Stanley H.; Chakrabarti, Kish; Minniti, Ronaldo; Parry, Marie I.; Skopec, Marlene

    2013-08-15

    Purpose: To measure radiation absorbed dose and its distribution in an anthropomorphic head phantom under clinically representative scan conditions in three widely used computed tomography (CT) scanners, and to relate those dose values to metrics such as high-contrast resolution, noise, and contrast-to-noise ratio (CNR) in the American College of Radiology CT accreditation phantom.Methods: By inserting optically stimulated luminescence dosimeters (OSLDs) in the head of an anthropomorphic phantom specially developed for CT dosimetry (University of Florida, Gainesville), we measured dose with three commonly used scanners (GE Discovery CT750 HD, Siemens Definition, Philips Brilliance 64) at two different clinical sites (Walter Reed National Military Medical Center, National Institutes of Health). The scanners were set to operate with the same data-acquisition and image-reconstruction protocols as used clinically for typical head scans, respective of the practices of each facility for each scanner. We also analyzed images of the ACR CT accreditation phantom with the corresponding protocols. While the Siemens Definition and the Philips Brilliance protocols utilized only conventional, filtered back-projection (FBP) image-reconstruction methods, the GE Discovery also employed its particular version of an adaptive statistical iterative reconstruction (ASIR) algorithm that can be blended in desired proportions with the FBP algorithm. We did an objective image-metrics analysis evaluating the modulation transfer function (MTF), noise power spectrum (NPS), and CNR for images reconstructed with FBP. For images reconstructed with ASIR, we only analyzed the CNR, since MTF and NPS results are expected to depend on the object for iterative reconstruction algorithms.Results: The OSLD measurements showed that the Siemens Definition and the Philips Brilliance scanners (located at two different clinical facilities) yield average absorbed doses in tissue of 42.6 and 43.1 mGy, respectively. The GE Discovery delivers about the same amount of dose (43.7 mGy) when run under similar operating and image-reconstruction conditions, i.e., without tube current modulation and ASIR. The image-metrics analysis likewise showed that the MTF, NPS, and CNR associated with the reconstructed images are mutually comparable when the three scanners are run with similar settings, and differences can be attributed to different edge-enhancement properties of the applied reconstruction filters. Moreover, when the GE scanner was operated with the facility's scanner settings for routine head exams, which apply 50% ASIR and use only approximately half of the 100%-FBP dose, the CNR of the images showed no significant change. Even though the CNR alone is not sufficient to characterize the image quality and justify any dose reduction claims, it can be useful as a constancy test metric.Conclusions: This work presents a straightforward method to connect direct measurements of CT dose with objective image metrics such as high-contrast resolution, noise, and CNR. It demonstrates that OSLD measurements in an anthropomorphic head phantom allow a realistic and locally precise estimation of magnitude and spatial distribution of dose in tissue delivered during a typical CT head scan. Additional objective analysis of the images of the ACR accreditation phantom can be used to relate the measured doses to high contrast resolution, noise, and CNR.

  10. Improvements to Existing Jefferson Lab Wire Scanners

    SciTech Connect (OSTI)

    McCaughan, Michael D. [JLAB; Tiefenback, Michael G. [JLAB; Turner, Dennis L. [JLAB

    2013-06-01

    This poster will detail the augmentation of selected existing CEBAF wire scanners with commercially available hardware, PMTs, and self created software in order to improve the scanners both in function and utility.

  11. Using the Zeiss Phodis Scanner August 1988

    E-Print Network [OSTI]

    Baker, Timothy S.

    and blow them off with the canned air. The glass surfaces of the scanner should also be carefully brushed. Be careful about raising the top glass of the scanner. It is not hinged and it can easily drop. Place the negative emulsion side down on the glass in the center of the scanner. If you hold an EM negative

  12. Volumetric Reconstruction in the MicroCAT Tomography System

    E-Print Network [OSTI]

    Cates, Josh

    Volumetric Reconstruction in the MicroCAT Tomography System A Thesis Presented for the Master sustained me my entire academic career. ii #12; Abstract A new system for xray conebeam microtomography that is based on twodimensional (fanbeam) reconstruction techniques. The disparity between the actual scanner

  13. Combined PET/MRI scanner

    DOE Patents [OSTI]

    Schlyer, David (Bellport, NY); Woody, Craig L. (Setauket, NY); Rooney, William (Miller Place, NY); Vaska, Paul (Sound Beach, NY); Stoll, Sean (Wading River, NY); Pratte, Jean-Francois (Stony Brook, NY); O'Connor, Paul (Bellport, NY)

    2007-10-23

    A combined PET/MRI scanner generally includes a magnet for producing a magnetic field suitable for magnetic resonance imaging, a radiofrequency (RF) coil disposed within the magnetic field produced by the magnet and a ring tomograph disposed within the magnetic field produced by the magnet. The ring tomograph includes a scintillator layer for outputting at least one photon in response to an annihilation event, a detection array coupled to the scintillator layer for detecting the at least one photon outputted by the scintillator layer and for outputting a detection signal in response to the detected photon and a front-end electronic array coupled to the detection array for receiving the detection signal, wherein the front-end array has a preamplifier and a shaper network for conditioning the detection signal.

  14. Positron emission tomography wrist detector

    DOE Patents [OSTI]

    Schlyer, David J. (Bellport, NY); O'Connor, Paul (Bellport, NY); Woody, Craig (Setauket, NY); Junnarkar, Sachin Shrirang (Sound Beach, NY); Radeka, Veljko (Bellport, NY); Vaska, Paul (Sound Beach, NY); Pratte, Jean-Francois (Stony Brook, NY)

    2006-08-15

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal representing a time-of-occurrence of an annihilation event, generating an address signal representing a channel detecting the annihilation event, and generating a channel signal including the time and address signals. The method also includes generating a composite signal including the channel signal and another similarly generated channel signal concerning another annihilation event. An apparatus that serially transfers annihilation information includes a time signal generator, address signal generator, channel signal generator, and composite signal generator. The time signal is asynchronous and the address signal is synchronous to a clock signal. A PET scanner includes a scintillation array, detection array, front-end array, and a serial encoder. The serial encoders include the time signal generator, address signal generator, channel signal generator, and composite signal generator.

  15. Development of a dynamic quality assurance testing protocol for multisite clinical trial DCE-CT accreditation

    SciTech Connect (OSTI)

    Driscoll, B.; Keller, H.; Jaffray, D.; Coolens, C.; Department of Radiation Oncology, University of Toronto, 150 College Street, Toronto, Ontario M5S 3E2; Techna Institute, University Health Network, 124-100 College Street, Toronto, Ontario M5G 1L5

    2013-08-15

    Purpose: Credentialing can have an impact on whether or not a clinical trial produces useful quality data that is comparable between various institutions and scanners. With the recent increase of dynamic contrast enhanced-computed tomography (DCE-CT) usage as a companion biomarker in clinical trials, effective quality assurance, and control methods are required to ensure there is minimal deviation in the results between different scanners and protocols at various institutions. This paper attempts to address this problem by utilizing a dynamic flow imaging phantom to develop and evaluate a DCE-CT quality assurance (QA) protocol.Methods: A previously designed flow phantom, capable of producing predictable and reproducible time concentration curves from contrast injection was fully validated and then utilized to design a DCE-CT QA protocol. The QA protocol involved a set of quantitative metrics including injected and total mass error, as well as goodness of fit comparison to the known truth concentration curves. An additional region of interest (ROI) sensitivity analysis was also developed to provide additional details on intrascanner variability and determine appropriate ROI sizes for quantitative analysis. Both the QA protocol and ROI sensitivity analysis were utilized to test variations in DCE-CT results using different imaging parameters (tube voltage and current) as well as alternate reconstruction methods and imaging techniques. The developed QA protocol and ROI sensitivity analysis was then applied at three institutions that were part of clinical trial involving DCE-CT and results were compared.Results: The inherent specificity of robustness of the phantom was determined through calculation of the total intraday variability and determined to be less than 2.2 1.1% (total calculated output contrast mass error) with a goodness of fit (R{sup 2}) of greater than 0.99 0.0035 (n= 10). The DCE-CT QA protocol was capable of detecting significant deviations from the expected phantom result when scanning at low mAs and low kVp in terms of quantitative metrics (Injected Mass Error 15.4%), goodness of fit (R{sup 2}) of 0.91, and ROI sensitivity (increase in minimum input function ROI radius by 146 86%). These tests also confirmed that the ASIR reconstruction process was beneficial in reducing noise without substantially increasing partial volume effects and that vendor specific modes (e.g., axial shuttle) did not significantly affect the phantom results. The phantom and QA protocol were finally able to quickly (<90 min) and successfully validate the DCE-CT imaging protocol utilized at the three separate institutions of a multicenter clinical trial; thereby enhancing the confidence in the patient data collected.Conclusions: A DCE QA protocol was developed that, in combination with a dynamic multimodality flow phantom, allows the intrascanner variability to be separated from other sources of variability such as the impact of injection protocol and ROI selection. This provides a valuable resource that can be utilized at various clinical trial institutions to test conformance with imaging protocols and accuracy requirements as well as ensure that the scanners are performing as expected for dynamic scans.

  16. Hand-held optical fuel pin scanner

    DOE Patents [OSTI]

    Kirchner, T.L.; Powers, H.G.

    1980-12-07

    An optical scanner for indicia arranged in a focal plane perpendicular to an optical system including a rotatable dove prism. The dove prism transmits a rotating image to a stationary photodiode array.

  17. (to appear in 1998 IEEE MIC) Joint-MAP Reconstruction/Segmentation for Transmission Tomography

    E-Print Network [OSTI]

    . In addition, the geometry of fan beam scanners for transmission tomography in SPECT with line sources can(to appear in 1998 IEEE MIC) Joint-MAP Reconstruction/Segmentation for Transmission Tomography A Bayesian method, including a pointwise prior comprising mixtures of gamma distributions, is applied

  18. AUTOMATED DETECTION OF STABLE FRACTURE POINTS IN COMPUTED TOMOGRAPHY IMAGE SEQUENCES

    E-Print Network [OSTI]

    Bhandarkar, Suchendra "Suchi" M.

    AUTOMATED DETECTION OF STABLE FRACTURE POINTS IN COMPUTED TOMOGRAPHY IMAGE SEQUENCES A.S. Chowdhury fracture points in a sequence of Computed Tomography (CT) images is found to be a challenging task. In this paper, an innovative scheme for automatic fracture detection in CT images is presented. The input

  19. SU-E-I-98: Dose Comparison for Pulmonary Embolism CT Studies: Single Energy Vs. Dual Energy

    SciTech Connect (OSTI)

    Mahmood, U; Erdi, Y

    2014-06-01

    Purpose: The purpose of this study was to assess and compare the size specific dose estimate (SSDE), dose length product (DLP) and noise relationship for pulmonary embolism studies evaluated by single source dual energy computed tomography (DECT) against conventional CT (CCT) studies in a busy cancer center and to determine the dose savings provided by DECT. Methods: An IRB-approved retrospective study was performed to determine the CTDIvol and DLP from a subset of patients scanned with both DECT and CCT over the past five years. We were able to identify 30 breast cancer patients (6 male, 24 female, age range 24 to 81) who had both DECT and CCT studies performed. DECT scans were performed with a GE HD 750 scanner (140/80 kVp, 480 mAs and 40 mm) and CCT scans were performed with a GE Lightspeed 16 slice scanner (120 kVp, 352 mAs, 20 mm). Image noise was measured by placing an ROI and recording the standard deviation of the mean HU along the descending aorta. Results: The average DECT patient size specific dose estimate was to be 14.2 1.7 mGy as compared to 22.4 2.7 mGy from CCT PE studies, which is a 37% reduction in the SSDE. The average DECT DLP was 721.8 84.6 mGy-cm as compared to 981.8 106.1 mGy-cm for CCT, which is a 26% decrease. Compared to CCT the image noise was found to decrease by 19% when using DECT for PE studies. Conclusion: DECT SSDE and DLP measurements indicate dose savings and image noise reduction when compared to CCT. In an environment that heavily debates CT patient doses, this study confirms the effectiveness of DECT in PE imaging.

  20. Lung Nodule Detection in Screening Computed Tomography

    E-Print Network [OSTI]

    Gori, I; Cerello, P; Cheran, S C; De Nunzio, G; Fantacci, M E; Kasae, P; Masala, G L; Prez-Martnez, A; Retico, A

    2007-01-01

    A computer-aided detection (CAD) system for the identification of pulmonary nodules in low-dose multi-detector helical Computed Tomography (CT) images with 1.25 mm slice thickness is presented. The basic modules of our lung-CAD system, a dot-enhancement filter for nodule candidate selection and a neural classifier for false-positive finding reduction, are described. The results obtained on the collected database of lung CT scans are discussed.

  1. Soft Classification with Gaussian Mixture Model for Clinical Dual-Energy CT Reconstructions

    E-Print Network [OSTI]

    1 Soft Classification with Gaussian Mixture Model for Clinical Dual-Energy CT Reconstructions, and Ken D. Sauer, Member, IEEE Abstract--We study the distribution of the clinical dual-energy CT (DECT material separation. Index Terms--Computed tomography (CT), dual energy, sta- tistical method, Gaussian

  2. Augmenting CT Cardiac Roadmaps with Segmented Streaming Qi Duan a,b

    E-Print Network [OSTI]

    Augmenting CT Cardiac Roadmaps with Segmented Streaming Ultrasound Qi Duan a,b , Guy Shechter Static X-ray computed tomography (CT) volumes are often used as anatomic roadmaps during catheter. Augmenting these static CT roadmaps with segmented myocardial borders extracted from live ultrasound (US

  3. RESOLUTION IN DYNAMIC EMISSION TOMOGRAPHY JEAN MAEGHT AND DOMINIKUS NOLL

    E-Print Network [OSTI]

    Noll, Dominikus

    . Introduction. Current state-of-the-art medical imaging technologies provide extremely detailed and accurate. It is not possible, as yet, to measure absolute metabolic rates from the different bio- logical processes, nor, in positron emission tomography (PET), and in computed tomography (CT), where an elaborate Fourier analysis

  4. Miniature 'Wearable' PET Scanner Ready for Use

    ScienceCinema (OSTI)

    Paul Vaska

    2013-07-22

    Scientists from BNL, Stony Brook University, and collaborators have demonstrated the efficacy of a "wearable," portable PET scanner they've developed for rats. The device will give neuroscientists a new tool for simultaneously studying brain function and behavior in fully awake, moving animals.

  5. Neutron Tomography and Space

    E-Print Network [OSTI]

    Egbert, Hal; Walker, Ronald; Flocchini, R.

    2007-01-01

    Kevin Shields, Optimization of neutron tomography for rapidNEUTRON TOMOGRAPHY AND SPACE Hal Egbert, Ronald Walker, R.industrial applications[1]. Neutron Computed Tomography was

  6. MagViz Bottled Liquid Scanner at Albuquerque International Sunport

    ScienceCinema (OSTI)

    Surko, Stephen; Dennis, Steve; Espy, Michelle

    2014-08-12

    The next-generation bottled liquid scanner, MagViz BLS, is demonstrated at the Albuquerque International Sunport, New Mexico

  7. Noise Analysis and Synthesis for 3D Laser Depth Scanners

    E-Print Network [OSTI]

    Martin, Ralph R.

    Noise Analysis and Synthesis for 3D Laser Depth Scanners Xianfang Sun a,b,, Paul L. Rosin a , Ralph the noise present in range data measured by a Konica Minolta Vivid 910 scanner, in order to better characterise real scanner noise. Methods for denoising 3D mesh data have often assumed the noise to be Gaussian

  8. Addressing the risks of diagnostic radiology : what should be done about the increasing use of computed tomography in the United States

    E-Print Network [OSTI]

    Eastwick, Gary (Gary A.)

    2010-01-01

    Computed tomography (CT) is a prominent procedure in the US with larger radiation doses than traditional radiology. CT is a powerful tool in the diagnosis of a wide variety of conditions and its use has grown quickly because ...

  9. Radiation-induced refraction artifacts in the optical CT readout of polymer gel dosimeters

    SciTech Connect (OSTI)

    Campbell, Warren G.; Jirasek, Andrew; Wells, Derek M.

    2014-11-01

    Purpose: The objective of this work is to demonstrate imaging artifacts that can occur during the optical computed tomography (CT) scanning of polymer gel dosimeters due to radiation-induced refractive index (RI) changes in polyacrylamide gels. Methods: A 1 L cylindrical polyacrylamide gel dosimeter was irradiated with 3 3 cm{sup 2} square beams of 6 MV photons. A prototype fan-beam optical CT scanner was used to image the dosimeter. Investigative optical CT scans were performed to examine two types of rayline bending: (i) bending within the plane of the fan-beam and (ii) bending out the plane of the fan-beam. To address structured errors, an iterative SavitzkyGolay (ISG) filtering routine was designed to filter 2D projections in sinogram space. For comparison, 2D projections were alternatively filtered using an adaptive-mean (AM) filter. Results: In-plane rayline bending was most notably observed in optical CT projections where rays of the fan-beam confronted a sustained dose gradient that was perpendicular to their trajectory but within the fan-beam plane. These errors caused distinct streaking artifacts in image reconstructions due to the refraction of higher intensity rays toward more opaque regions of the dosimeter. Out-of-plane rayline bending was observed in slices of the dosimeter that featured dose gradients perpendicular to the plane of the fan-beam. These errors caused widespread, severe overestimations of dose in image reconstructions due to the higher-than-actual opacity that is perceived by the scanner when light is bent off of the detector array. The ISG filtering routine outperformed AM filtering for both in-plane and out-of-plane rayline errors caused by radiation-induced RI changes. For in-plane rayline errors, streaks in an irradiated region (>7 Gy) were as high as 49% for unfiltered data, 14% for AM, and 6% for ISG. For out-of-plane rayline errors, overestimations of dose in a low-dose region (?50 cGy) were as high as 13 Gy for unfiltered data, 10 Gy for AM, and 3.1 Gy for ISG. The ISG routine also addressed unrelated artifacts that previously needed to be manually removed in sinogram space. However, the ISG routine blurred reconstructions, causing losses in spatial resolution of ?5 mm in the plane of the fan-beam and ?8 mm perpendicular to the fan-beam. Conclusions: This paper reveals a new category of imaging artifacts that can affect the optical CT readout of polyacrylamide gel dosimeters. Investigative scans show that radiation-induced RI changes can cause significant rayline errors when rays confront a prolonged dose gradient that runs perpendicular to their trajectory. In fan-beam optical CT, these errors manifested in two ways: (1) distinct streaking artifacts caused by in-plane rayline bending and (2) severe overestimations of opacity caused by rays bending out of the fan-beam plane and missing the detector array. Although the ISG filtering routine mitigated these errors better than an adaptive-mean filtering routine, it caused unacceptable losses in spatial resolution.

  10. Kilovoltage Rotational External Beam Radiotherapy on a Breast Computed Tomography Platform: A Feasibility Study

    SciTech Connect (OSTI)

    Prionas, Nicolas D.; McKenney, Sarah E. [Department of Radiology, University of California, Davis, Medical Center, Sacramento, California (United States)] [Department of Radiology, University of California, Davis, Medical Center, Sacramento, California (United States); Stern, Robin L. [Department of Radiation Oncology, University of California, Davis, Medical Center, Sacramento, California (United States)] [Department of Radiation Oncology, University of California, Davis, Medical Center, Sacramento, California (United States); Boone, John M., E-mail: jmboone@ucdavis.edu [Department of Radiology, University of California, Davis, Medical Center, Sacramento, California (United States)

    2012-10-01

    Purpose: To demonstrate the feasibility of a dedicated breast computed tomography (bCT) platform to deliver rotational kilovoltage (kV) external beam radiotherapy (RT) for partial breast irradiation, whole breast irradiation, and dose painting. Methods and Materials: Rotational kV-external beam RT using the geometry of a prototype bCT platform was evaluated using a Monte Carlo simulator. A point source emitting 178 keV photons (approximating a 320-kVp spectrum with 4-mm copper filtration) was rotated around a 14-cm voxelized polyethylene disk (0.1 cm tall) or cylinder (9 cm tall) to simulate primary and primary plus scattered photon interactions, respectively. Simulations were also performed using voxelized bCT patient images. Beam collimation was varied in the x-y plane (1-14 cm) and in the z-direction (0.1-10 cm). Dose painting for multiple foci, line, and ring distributions was demonstrated using multiple rotations with varying beam collimation. Simulations using the scanner's native hardware (120 kVp filtered by 0.2-mm copper) were validated experimentally. Results: As the x-y collimator was narrowed, the two-dimensional dose profiles shifted from a cupped profile with a high edge dose to an increasingly peaked central dose distribution with a sharp dose falloff. Using a 1-cm beam, the cylinder edge dose was <7% of the dose deposition at the cylinder center. Simulations using 120-kVp X-rays showed distributions similar to the experimental measurements. A homogeneous dose distribution (<2.5% dose fluctuation) with a 20% decrease in dose deposition at the cylinder edge (i.e., skin sparing) was demonstrated by weighted summation of four dose profiles using different collimation widths. Simulations using patient bCT images demonstrated the potential for treatment planning and image-guided RT. Conclusions: Rotational kV-external beam RT for partial breast irradiation, dose painting, and whole breast irradiation with skin sparing is feasible on a bCT platform with the potential for high-resolution image-guided RT.

  11. SU-E-I-28: Evaluating the Organ Dose From Computed Tomography Using Monte Carlo Calculations

    SciTech Connect (OSTI)

    Ono, T; Araki, F

    2014-06-01

    Purpose: To evaluate organ doses from computed tomography (CT) using Monte Carlo (MC) calculations. Methods: A Philips Brilliance CT scanner (64 slice) was simulated using the GMctdospp (IMPS, Germany) based on the EGSnrc user code. The X-ray spectra and a bowtie filter for MC simulations were determined to coincide with measurements of half-value layer (HVL) and off-center ratio (OCR) profile in air. The MC dose was calibrated from absorbed dose measurements using a Farmer chamber and a cylindrical water phantom. The dose distribution from CT was calculated using patient CT images and organ doses were evaluated from dose volume histograms. Results: The HVLs of Al at 80, 100, and 120 kV were 6.3, 7.7, and 8.7 mm, respectively. The calculated HVLs agreed with measurements within 0.3%. The calculated and measured OCR profiles agreed within 3%. For adult head scans (CTDIvol) =51.4 mGy), mean doses for brain stem, eye, and eye lens were 23.2, 34.2, and 37.6 mGy, respectively. For pediatric head scans (CTDIvol =35.6 mGy), mean doses for brain stem, eye, and eye lens were 19.3, 24.5, and 26.8 mGy, respectively. For adult chest scans (CTDIvol=19.0 mGy), mean doses for lung, heart, and spinal cord were 21.1, 22.0, and 15.5 mGy, respectively. For adult abdominal scans (CTDIvol=14.4 mGy), the mean doses for kidney, liver, pancreas, spleen, and spinal cord were 17.4, 16.5, 16.8, 16.8, and 13.1 mGy, respectively. For pediatric abdominal scans (CTDIvol=6.76 mGy), mean doses for kidney, liver, pancreas, spleen, and spinal cord were 8.24, 8.90, 8.17, 8.31, and 6.73 mGy, respectively. In head scan, organ doses were considerably different from CTDIvol values. Conclusion: MC dose distributions calculated by using patient CT images are useful to evaluate organ doses absorbed to individual patients.

  12. Pseudolocal tomography

    DOE Patents [OSTI]

    Katsevich, A.J.; Ramm, A.G.

    1996-07-23

    Local tomographic data is used to determine the location and value of a discontinuity between a first internal density of an object and a second density of a region within the object. A beam of radiation is directed in a predetermined pattern through the region of the object containing the discontinuity. Relative attenuation data of the beam is determined within the predetermined pattern having a first data component that includes attenuation data through the region. The relative attenuation data is input to a pseudo-local tomography function, where the difference between the internal density and the pseudo-local tomography function is computed across the discontinuity. The pseudo-local tomography function outputs the location of the discontinuity and the difference in density between the first density and the second density. 7 figs.

  13. Doppler Tomography

    E-Print Network [OSTI]

    T. R. Marsh

    2000-11-01

    I review the method of Doppler tomography which translates binary-star line profiles taken at a series of orbital phases into a distribution of emission over the binary. I begin with a discussion of the basic principles behind Doppler tomography, including a comparison of the relative merits of maximum entropy regularisation versus filtered back-projection for implementing the inversion. Following this I discuss the issue of noise in Doppler images and possible methods for coping with it. Then I move on to look at the results of Doppler Tomography applied to cataclysmic variable stars. Outstanding successes to date are the discovery of two-arm spiral shocks in cataclysmic variable accretion discs and the probing of the stream/magnetospheric interaction in magnetic cataclysmic variable stars. Doppler tomography has also told us much about the stream/disc interaction in non-magnetic systems and the irradiation of the secondary star in all systems. The latter indirectly reveals such effects as shadowing by the accretion disc or stream. I discuss all of these and finish with some musings on possible future directions for the method. At the end I include a tabulation of Doppler maps published in refereed journals.

  14. Low-Dose Spiral CT Scans for Early Lung Cancer Detection

    Broader source: Energy.gov [DOE]

    Low-dose spiral computed tomography (CT) scanning is a noninvasive medical imaging test that has been used for the early detection of lung cancer for over 16 years (Sone et al. 1998; Henschke et.al. 1999).

  15. Surface Extraction from Multi-Material Components for Metrology using Dual Energy CT

    E-Print Network [OSTI]

    Surface Extraction from Multi-Material Components for Metrology using Dual Energy CT Christoph surface models of multi-material components using dual energy com- puted tomography (DECT exposure scans was facilitated. Index Terms--DECT image fusion, local surface extraction, Dual Energy CT

  16. Automated segmentation of lungs with severe interstitial lung disease in CT

    E-Print Network [OSTI]

    Automated segmentation of lungs with severe interstitial lung disease in CT Jiahui Wang Department: Accurate segmentation of lungs with severe interstitial lung disease ILD in thoracic computed tomography CT developed in this study a texture analysis-based method for accurate segmentation of lungs with severe ILD

  17. Multi-level Ground Glass Nodule Detection and Segmentation in CT Lung Images

    E-Print Network [OSTI]

    Corso, Jason J.

    Multi-level Ground Glass Nodule Detection and Segmentation in CT Lung Images Yimo Tao1,2 , Le Lu1. Early detection of Ground Glass Nodule (GGN) in lung Computed Tomography (CT) images is important for lung cancer prog- nosis. Due to its indistinct boundaries, manual detection and segmenta- tion of GGN

  18. Plastic scintillators for positron emission tomography obtained by the bulk polymerization method

    E-Print Network [OSTI]

    Kap?on, ?ukasz; Molenda, Marcin; Moskal, Pawe?; Wieczorek, Anna; Bednarski, Tomasz; Bia?as, Piotr; Czerwi?ski, Eryk; Korcyl, Grzegorz; Kowal, Jakub; Kowalski, Pawe?; Kozik, Tomasz; Krzemie?, Wojciech; Nied?wiecki, Szymon; Pa?ka, Marek; Pawlik, Monika; Raczy?ski, Lech; Rudy, Zbigniew; Salabura, Piotr; Gupta-Sharma, Neha; Silarski, Micha?; S?omski, Artur; Smyrski, Jerzy; Strzelecki, Adam; Wi?licki, Wojciech; Zieli?ski, Marcin; Zo?, Natalia

    2015-01-01

    This paper describes three methods regarding the production of plastic scintillators. One method appears to be suitable for the manufacturing of plastic scintillator, revealing properties which fulfill the requirements of novel positron emission tomography scanners based on plastic scintillators. The key parameters of the manufacturing process are determined and discussed.

  19. FPGA-Based Front-End Electronics for Positron Emission Tomography

    E-Print Network [OSTI]

    Hauck, Scott

    technology for a data acquisition system for positron emission tomography (PET) scanners. Our laboratory, Design, Verification Keywords PET, FPGA, Digital Signal Processing, Pulse Timing, Event Localization 1 to process the incoming data without the complexity of an application-specific circuit. Technology advances

  20. Laser excited confocal microscope fluorescence scanner and method

    DOE Patents [OSTI]

    Mathies, R.A.; Peck, K.

    1992-02-25

    A fluorescent scanner is designed for scanning the fluorescence from a fluorescence labeled separated sample on a sample carrier. The scanner includes a confocal microscope for illuminating a predetermined volume of the sample carrier and/or receiving and processing fluorescence emissions from the volume to provide a display of the separated sample. 8 figs.

  1. Test of 3D CT reconstructions by EM + TV algorithm from undersampled data

    SciTech Connect (OSTI)

    Evseev, Ivan; Ahmann, Francielle; Silva, Hamilton P. da

    2013-05-06

    Computerized tomography (CT) plays an important role in medical imaging for diagnosis and therapy. However, CT imaging is connected with ionization radiation exposure of patients. Therefore, the dose reduction is an essential issue in CT. In 2011, the Expectation Maximization and Total Variation Based Model for CT Reconstruction (EM+TV) was proposed. This method can reconstruct a better image using less CT projections in comparison with the usual filtered back projection (FBP) technique. Thus, it could significantly reduce the overall dose of radiation in CT. This work reports the results of an independent numerical simulation for cone beam CT geometry with alternative virtual phantoms. As in the original report, the 3D CT images of 128 Multiplication-Sign 128 Multiplication-Sign 128 virtual phantoms were reconstructed. It was not possible to implement phantoms with lager dimensions because of the slowness of code execution even by the CORE i7 CPU.

  2. A Laser Range Scanner Designed for Minimum Calibration Complexity James Davis, Xing Chen

    E-Print Network [OSTI]

    Stanford University

    A Laser Range Scanner Designed for Minimum Calibration Complexity James Davis, Xing Chen Computer Graphics Lab, Stanford University {jedavis, xcchen}@graphics.stanford.edu Abstract Laser range scanners reduce the costs associated with calibration. 1 Introduction Laser triangulation scanners

  3. Radiologic Sciences BS, Computed Tomography Emphasis, 2015-2016 Name ID# Date

    E-Print Network [OSTI]

    Barrash, Warren

    Radiologic Sciences BS, Computed Tomography Emphasis, 2015-2016 Name ID# Date Course Number with Computers 3 DLS PSYC 101 or SOC 101 3 DLS Social Sciences course in a second field 3 MATH 143 or MATH 170 Imaging 3 RADSCI 431 CT Radiation Dose and Risk Analysis 1 RADSCI 450 Principles of Computed Tomography 3

  4. Knowledge-Based Dynamic Volumetric Cardiac Computed Tomography With Saddle Curve Trajectory

    E-Print Network [OSTI]

    Wang, Ge

    Knowledge-Based Dynamic Volumetric Cardiac Computed Tomography With Saddle Curve Trajectory Deepak simulations with the dynamic thorax phantom. Key Words: X-ray computed tomography, dynamic volumetric cardiac. In 2002, Wang et al10 proposed a dynamic knowledge-based cardiac volumetric CT for the circular trajectory

  5. Experiments and simulations on a metamaterial based ultrasonic scanner

    E-Print Network [OSTI]

    Hizir, Fahri Erinc

    2013-01-01

    Fingerprint scanning is one form of biometrics used to identify individuals. Ultrasonic fingerprint scanners use acoustic waves to obtain the fingerprint image and their performance is invariant to the surface conditions ...

  6. An improved analytical detector response function model for multilayer small-diameter PET scanners

    E-Print Network [OSTI]

    Strul, D; Slates, R B; Dahlbom, M; Cherry, Simon R; Marsden, P K

    2003-01-01

    of microPET: a high-resolution lutetium oxyorthosilicate PETlayer, scanners employing lutetium oxyorthosilicate (LSO)

  7. Manifold Learning for 4D CT Reconstruction of the Lung Manfred Georg*, Richard Souvenir, Andrew Hope, Robert Pless*

    E-Print Network [OSTI]

    Pless, Robert

    Manifold Learning for 4D CT Reconstruction of the Lung Manfred Georg*, Richard Souvenir, Andrew, Canada Andrew.Hope@rmp.uhn.on.ca Abstract Computed Tomography is used to create models of lung dynamics because it provides high contrast images of lung tissue. Creating 4D CT models which capture dynamics

  8. The Welfare Analysis of Product Innovations, with an Application to Computed Tomography Author(s): Manuel Trajtenberg

    E-Print Network [OSTI]

    Crowther, Paul

    The Welfare Analysis of Product Innovations, with an Application to Computed Tomography Scanners to The Journal of Political Economy. http://www.jstor.org #12;The Welfare Analysis of Product Innovations is to put forward a methodology for the measurement of product innovations using a value metric, that is

  9. Mathematics of thermoacoustic tomography

    E-Print Network [OSTI]

    Peter Kuchment; Leonid Kunyansky

    2007-10-21

    The paper presents a survey of mathematical problems, techniques, and challenges arising in the Thermoacoustic and Photoacoustic Tomography.

  10. An RF dosimeter for independent SAR measurement in MRI scanners

    SciTech Connect (OSTI)

    Qian, Di; Bottomley, Paul A.; El-Sharkawy, AbdEl-Monem M.; Edelstein, William A.

    2013-12-15

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ?3%. With the torso landmarked at the xiphoid, human adult whole?body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. Conclusions: Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.

  11. Development of a lab-scale, high-resolution, tube-generated X-ray computed-tomography system for three-dimensional (3D) materials characterization

    SciTech Connect (OSTI)

    Mertens, J.C.E. Williams, J.J. Chawla, Nikhilesh

    2014-06-01

    The design and construction of a modular high resolution X-ray computed tomography (XCT) system is highlighted in this paper. The design approach is detailed for meeting a specified set of instrument performance goals tailored towards experimental versatility and high resolution imaging. The XCT tool is unique in the detector and X-ray source design configuration, enabling control in the balance between detection efficiency and spatial resolution. The system package is also unique: The sample manipulation approach implemented enables a wide gamut of in situ experimentation to analyze structure evolution under applied stimulus, by optimizing scan conditions through a high degree of controllability. The component selection and design process is detailed: Incorporated components are specified, custom designs are shared, and the approach for their integration into a fully functional XCT scanner is provided. Custom designs discussed include the dual-target X-ray source cradle which maintains position and trajectory of the beam between the two X-ray target configurations with respect to a scintillator mounting and positioning assembly and the imaging sensor, as well as a novel large-format X-ray detector with enhanced adaptability. The instrument is discussed from an operational point of view, including the details of data acquisition and processing implemented for 3D imaging via micro-CT. The performance of the instrument is demonstrated on a silica-glass particle/hydroxyl-terminated-polybutadiene (HTPB) matrix binder PBX simulant. Post-scan data processing, specifically segmentation of the sample's relevant microstructure from the 3D reconstruction, is provided to demonstrate the utility of the instrument. - Highlights: Custom built X-ray tomography system for microstructural characterization Detector design for maximizing polychromatic X-ray detection efficiency X-ray design offered for maximizing X-ray flux with respect to imaging resolution Novel lab-scale XCT data acquisition and data processing methods 3D characterization of glass-bead mock plastic-bonded-explosive stimulant.

  12. A Detector for Proton Computed Tomography

    SciTech Connect (OSTI)

    Blazey, G.; et al.,

    2013-12-06

    Radiation therapy is a widely recognized treatment for cancer. Energetic protons have distinct features that set them apart from photons and make them desirable for cancer therapy as well as medical imaging. The clinical interest in heavy ion therapy is due to the fact that ions deposit almost all of their energy in a sharp peak the Bragg peak- at the very end of their path. Proton beams can be used to precisely localize a tumor and deliver an exact dose to the tumor with small doses to the surrounding tissue. Proton computed tomography (pCT) provides direct information on the location on the target tumor, and avoids position uncertainty caused by treatment planning based on imaging with X-ray CT. The pCT project goal is to measure and reconstruct the proton relative stopping power distribution directly in situ. To ensure the full advantage of cancer treatment with 200 MeV proton beams, pCT must be realized.

  13. Turbocharging Quantum Tomography.

    SciTech Connect (OSTI)

    Blume-Kohout, Robin J; Gamble, John King,; Nielsen, Erik; Maunz, Peter Lukas Wilhelm; Scholten, Travis L.; Rudinger, Kenneth Michael

    2015-01-01

    Quantum tomography is used to characterize quantum operations implemented in quantum information processing (QIP) hardware. Traditionally, state tomography has been used to characterize the quantum state prepared in an initialization procedure, while quantum process tomography is used to characterize dynamical operations on a QIP system. As such, tomography is critical to the development of QIP hardware (since it is necessary both for debugging and validating as-built devices, and its results are used to influence the next generation of devices). But tomography su %7C ers from several critical drawbacks. In this report, we present new research that resolves several of these flaws. We describe a new form of tomography called gate set tomography (GST), which unifies state and process tomography, avoids prior methods critical reliance on precalibrated operations that are not generally available, and can achieve unprecedented accuracies. We report on theory and experimental development of adaptive tomography protocols that achieve far higher fidelity in state reconstruction than non-adaptive methods. Finally, we present a new theoretical and experimental analysis of process tomography on multispin systems, and demonstrate how to more e %7C ectively detect and characterize quantum noise using carefully tailored ensembles of input states.

  14. Relationship of computed tomography perfusion and positron emission tomography to tumour progression in malignant glioma

    SciTech Connect (OSTI)

    Yeung, Timothy P C; Yartsev, Slav; Lee, Ting-Yim; Wong, Eugene; He, Wenqing; Fisher, Barbara; VanderSpek, Lauren L; Macdonald, David; Bauman, Glenn

    2014-02-15

    Introduction: This study aimed to explore the potential for computed tomography (CT) perfusion and 18-Fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting sites of future progressive tumour on a voxel-by-voxel basis after radiotherapy and chemotherapy. Methods: Ten patients underwent pre-radiotherapy magnetic resonance (MR), FDG-PET and CT perfusion near the end of radiotherapy and repeated post-radiotherapy follow-up MR scans. The relationships between these images and tumour progression were assessed using logistic regression. Cross-validation with receiver operating characteristic (ROC) analysis was used to assess the value of these images in predicting sites of tumour progression. Results: Pre-radiotherapy MR-defined gross tumour; near-end-of-radiotherapy CT-defined enhancing lesion; CT perfusion blood flow (BF), blood volume (BV) and permeability-surface area (PS) product; FDG-PET standard uptake value (SUV); and SUV:BF showed significant associations with tumour progression on follow-up MR imaging (P < 0.0001). The mean sensitivity (standard deviation), specificity and area under the ROC curve (AUC) of PS were 0.64 0.15, 0.74 0.07 and 0.72 0.12 respectively. This mean AUC was higher than that of the pre-radiotherapy MR-defined gross tumour and near-end-of-radiotherapy CT-defined enhancing lesion (both AUCs = 0.6 0.1, P ? 0.03). The multivariate model using BF, BV, PS and SUV had a mean AUC of 0.8 0.1, but this was not significantly higher than the PS only model. Conclusion: PS is the single best predictor of tumour progression when compared to other parameters, but voxel-based prediction based on logistic regression had modest sensitivity and specificity.

  15. Multi-scale analysis of lung computed tomography images

    E-Print Network [OSTI]

    Gori, I; Fantacci, M E; Martinez, A Preite; Retico, A; De Mitri, I; Donadio, S; Fulcheri, C; Gargano, G; Magro, R; Santoro, M; Stumbo, S; 10.1088/1748-0221/2/09/P09007

    2009-01-01

    A computer-aided detection (CAD) system for the identification of lung internal nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 project. The three modules of our lung CAD system, a segmentation algorithm for lung internal region identification, a multi-scale dot-enhancement filter for nodule candidate selection and a multi-scale neural technique for false positive finding reduction, are described. The results obtained on a dataset of low-dose and thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.

  16. Steps towards Quality Improvement of Airborne Laser Scanner Data

    E-Print Network [OSTI]

    Vosselman, George

    , and forestry management. However, to guarantee this level of data quality the measurements must be as closeSteps towards Quality Improvement of Airborne Laser Scanner Data A Behan1 , H-G Maas2 and G for the acquisition of 2.5D data, mainly for use in topographic and mapping operations. In recent years, however

  17. Noise in 3D Laser Range Scanner Data Xianfang Sun

    E-Print Network [OSTI]

    Martin, Ralph R.

    Noise in 3D Laser Range Scanner Data Xianfang Sun Cardiff University, UK Beihang University, China University, UK Abstract This paper discusses noise in range data measured by a Konica Mi- nolta Vivid 910 Gaussian noise, which is independently distributed at each mesh point. Measure- ments of an accurately

  18. SCIENTIFIC NOTE Scanner uniformity improvements for radiochromic film analysis

    E-Print Network [OSTI]

    Yu, Peter K.N.

    and Medical Research Institute and the Centre for Medical Radiation Physics, University of Wollongong and normally corrections need to be applied. These corrections are dependant on scanner coordinates and dose for dosimetry in radiotherapy and medical imaging. The low X-ray energy dependence of radiochromic films [1, 2

  19. First Test Results of the New LANSCE Wire Scanner

    SciTech Connect (OSTI)

    Sedillo, James Daniel

    2011-01-01

    The Beam Diagnostics and Instrumentation Team (BDIT) at Los Alamos National Laboratory's LANSCE facility is presently developing a new and improved wire scanner diagnostics system controlled by National Instrument's cRIO platform. This paper describes the current state of development of the control system along with the results gathered from the latest actuator motion performance and accelerator-beam data acquisition tests.

  20. Scanners and drillers: Characterizing expert visual search through volumetric images

    E-Print Network [OSTI]

    Scanners and drillers: Characterizing expert visual search through volumetric images Trafton Drew in 2-D, relatively little is known about search in volumetric space. In recent years, with the ever-increasing popularity of volumetric medical imaging, this question has taken on increased importance as we try

  1. CT Solar Lease

    Broader source: Energy.gov [DOE]

    CT Solar Lease allows homeowners to lease a photovoltaic (PV) or solar thermal system, with fixed monthly payments, for a term of 20 years, at no upfront down payment.* This program, which takes...

  2. A micron resolution optical scanner for characterization of silicon detectors

    SciTech Connect (OSTI)

    Shukla, R. A.; Dugad, S. R. Gopal, A. V.; Gupta, S. K.; Prabhu, S. S.; Garde, C. S.

    2014-02-15

    The emergence of high position resolution (?10 ?m) silicon detectors in recent times have highlighted the urgent need for the development of new automated optical scanners of micron level resolution suited for characterizing microscopic features of these detectors. More specifically, for the newly developed silicon photo-multipliers (SiPM) that are compact, possessing excellent photon detection efficiency with gain comparable to photo-multiplier tube. In a short time, since their invention the SiPMs are already being widely used in several high-energy physics and astrophysics experiments as the photon readout element. The SiPM is a high quantum efficiency, multi-pixel photon counting detector with fast timing and high gain. The presence of a wide variety of photo sensitive silicon detectors with high spatial resolution requires their performance evaluation to be carried out by photon beams of very compact spot size. We have designed a high resolution optical scanner that provides a monochromatic focused beam on a target plane. The transverse size of the beam was measured by the knife-edge method to be 1.7 ?m at 1 ? ? level. Since the beam size was an order of magnitude smaller than the typical feature size of silicon detectors, this optical scanner can be used for selective excitation of these detectors. The design and operational details of the optical scanner, high precision programmed movement of target plane (0.1 ?m) integrated with general purpose data acquisition system developed for recording static and transient response photo sensitive silicon detector are reported in this paper. Entire functionality of scanner is validated by using it for selective excitation of individual pixels in a SiPM and identifying response of active and dead regions within SiPM. Results from these studies are presented in this paper.

  3. Two-axis MEMS scanner with transfer-printed high-reflectivity, broadband monolithic silicon

    E-Print Network [OSTI]

    Rogers, John A.

    Two-axis MEMS scanner with transfer-printed high-reflectivity, broadband monolithic silicon@illinois.edu Abstract: We present a two-axis electrostatic MEMS scanner with high- reflectivity monolithic. The reflective surfaces of the MEMS scanner are transfer-printed PC mirrors with low polarization dependence, low

  4. THERMOACOUSTIC TOMOGRAPHY WITH VARIABLE SOUND ...

    E-Print Network [OSTI]

    2009-10-26

    We study the mathematical model of thermoacoustic tomography in media with a ... In thermoacoustic tomography, a short electro-magnetic pulse is sent through...

  5. Utilizing a simple CT dosimetry phantom for the comprehension of the operational characteristics of CT AEC systems

    SciTech Connect (OSTI)

    Tsalafoutas, Ioannis A.; Varsamidis, Athanasios; Thalassinou, Stella; Efstathopoulos, Efstathios P.

    2013-11-15

    Purpose: To investigate the utility of the nested polymethylacrylate (PMMA) phantom (which is available in many CT facilities for CTDI measurements), as a tool for the presentation and comparison of the ways that two different CT automatic exposure control (AEC) systems respond to a phantom when various scan parameters and AEC protocols are modified.Methods: By offsetting the two phantom's components (the head phantom and the body ring) half-way along their longitudinal axis, a phantom with three sections of different x-ray attenuation was created. Scan projection radiographs (SPRs) and helical scans of the three-section phantom were performed on a Toshiba Aquilion 64 and a Philips Brilliance 64 CT scanners, with different scan parameter selections [scan direction, pitch factor, slice thickness, and reconstruction interval (ST/RI), AEC protocol, and tube potential used for the SPRs]. The dose length product (DLP) values of each scan were recorded and the tube current (mA) values of the reconstructed CT images were plotted against the respective Z-axis positions on the phantom. Furthermore, measurements of the noise levels at the center of each phantom section were performed to assess the impact of mA modulation on image quality.Results: The mA modulation patterns of the two CT scanners were very dissimilar. The mA variations were more pronounced for Aquilion 64, where changes in any of the aforementioned scan parameters affected both the mA modulations curves and DLP values. However, the noise levels were affected only by changes in pitch, ST/RI, and AEC protocol selections. For Brilliance 64, changes in pitch affected the mA modulation curves but not the DLP values, whereas only AEC protocol and SPR tube potential selection variations affected both the mA modulation curves and DLP values. The noise levels increased for smaller ST/RI, larger weight category AEC protocol, and larger SPR tube potential selection.Conclusions: The nested PMMA dosimetry phantom can be effectively utilized for the comprehension of CT AEC systems performance and the way that different scan conditions affect the mA modulation patterns, DLP values, and image noise. However, in depth analysis of the reasons why these two systems exhibited such different behaviors in response to the same phantom requires further investigation which is beyond the scope of this study.

  6. Test of a single module of the J-PET scanner based on plastic scintillators

    E-Print Network [OSTI]

    P. Moskal; Sz. Nied?wiecki; T. Bednarski; E. Czerwi?ski; ?. Kap?on; E. Kubicz; I. Moskal; M. Pawlik-Nied?wiecka; N. G. Sharma; M. Silarski; M. Zieli?ski; N. Zo?; P. Bia?as; A. Gajos; A. Kochanowski; G. Korcyl; J. Kowal; P. Kowalski; T. Kozik; W. Krzemie?; M. Molenda; M. Pa?ka; L. Raczy?ski; Z. Rudy; P. Salabura; A. S?omski; J. Smyrski; A. Strzelecki; A. Wieczorek; W. Wi?licki

    2014-08-29

    Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this article we report on tests of a single detection module built out from BC-420 plastic scintillator strip (with dimensions of 5x19x300mm^3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50ps intervals. The time resolution of the prototype module was established to be better than 80ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93cm (sigma) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to sigma(E)/E = 0.044/sqrt(E[MeV]) and corresponds to the sigma(E)/E of 7.5% at the Compton edge.

  7. Test of a single module of the J-PET scanner based on plastic scintillators

    E-Print Network [OSTI]

    Moskal, P; Bednarski, T; Czerwi?ski, E; Kap?on, ?; Kubicz, E; Moskal, I; Pawlik-Nied?wiecka, M; Sharma, N G; Silarski, M; Zieli?ski, M; Zo?, N; Bia?as, P; Gajos, A; Kochanowski, A; Korcyl, G; Kowal, J; Kowalski, P; Kozik, T; Krzemie?, W; Molenda, M; Pa?ka, M; Raczy?ski, L; Rudy, Z; Salabura, P; S?omski, A; Smyrski, J; Strzelecki, A; Wieczorek, A; Wi?licki, W

    2014-01-01

    Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this article we report on tests of a single detection module built out from BC-420 plastic scintillator strip (with dimensions of 5x19x300mm^3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50ps intervals. The time resolution of the prototype module was established to be better than 80ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93cm (sigma) for the annihilation quanta...

  8. NFolkstoneCt PepperPikeRd

    E-Print Network [OSTI]

    Kamat, Vineet R.

    Sturbridge Ct Paisley Ct CedarBendDr Stanton Ct BonisteelBlvd Middleton Dr Pointe Ln Charter Pl Larchmont Dr

  9. SCIPP 06/04 1 Prototype Tracking Studies for Proton CT

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    SCIPP 06/04 1 Prototype Tracking Studies for Proton CT Nate Blumenkrantz, Jason Feldt, Jason the feasibility of proton computed tomography, the most likely path (MLP) of protons inside an absorber resolution. The locations of 200 MeV protons were measured at three different absorber depth of PMMA (3.75, 6

  10. Automatic Lung Segmentation of Volumetric Low-Dose CT Scans Using Graph Cuts

    E-Print Network [OSTI]

    Louisville, University of

    Automatic Lung Segmentation of Volumetric Low-Dose CT Scans Using Graph Cuts Asem M. Ali and Aly A for unsupervised segmentation of the lung region from low dose computed tomography (LDCT) images. We follow distribution model. To better spec- ify region borders between lung and chest, each empirical distribution

  11. SU-E-I-60: The Correct Selection of Pitch and Rotation Time for Optimal CT Scanning : The Big Misconception

    SciTech Connect (OSTI)

    Ranallo, F; Szczykutowicz, T

    2014-06-01

    Purpose: To provide correct guidance in the proper selection of pitch and rotation time for optimal CT imaging with multi-slice scanners. Methods: There exists a widespread misconception concerning the role of pitch in patient dose with modern multi-slice scanners, particularly with the use of mA modulation techniques. We investigated the relationship of pitch and rotation time to image quality, dose, and scan duration, with CT scanners from different manufacturers in a way that clarifies this misconception. This source of this misconception may concern the role of pitch in single slice CT scanners. Results: We found that the image noise and dose are generally independent of the selected effective mAs (mA*time/ pitch) with manual mA technique settings and are generally independent of the selected pitch and /or rotation time with automatic mA modulation techniques. However we did find that on certain scanners the use of a pitch just above 0.5 provided images of equal image noise at a lower dose compared to the use of a pitch just below 1.0. Conclusion: The misconception that the use of a lower pitch over-irradiates patients by wasting dose is clearly false. The use of a lower pitch provides images of equal or better image quality at the same patient dose, whether using manual mA or automatic mA modulation techniques. By decreasing the pitch and the rotation times by equal amounts, both helical and patient motion artifacts can be reduced without affecting the exam time. The use of lower helical pitch also allows better scanning of larger patients by allowing a greater scan effective mAs, if the exam time can be extended. The one caution with the use of low pitch is not related to patient dose, but to the length of the scan time if the rotation time is not set short enough. Partial Research funding from GE HealthCare.

  12. Data fusion in neutron and X-ray computed tomography

    SciTech Connect (OSTI)

    Schrapp, Michael J.; Goldammer, Matthias; Schulz, Michael; Issani, Siraj; Bhamidipati, Suryanarayana; Bni, Peter

    2014-10-28

    We present a fusion methodology between neutron and X-ray computed tomography (CT). On the one hand, the inspection by X-ray CT of a wide class of multimaterials in non-destructive testing applications suffers from limited information of object features. On the other hand, neutron imaging can provide complementary data in such a way that the combination of both data sets fully characterizes the object. In this contribution, a novel data fusion procedure, called Fusion Regularized Simultaneous Algebraic Reconstruction Technique, is developed where the X-ray reconstruction is modified to fulfill the available data from the imaging with neutrons. The experiments, which were obtained from an aluminum profile containing a steel screw, and attached carbon fiber plates demonstrate that the image quality in CT can be significantly improved when the proposed fusion method is used.

  13. Quantum Tomography twenty years later

    E-Print Network [OSTI]

    M. Asorey; A. Ibort; G. Marmo; F. Ventriglia

    2015-10-28

    A sample of some relevant developments that have taken place during the last twenty years in classical and quantum tomography are displayed. We will present a general conceptual framework that provides a simple unifying mathematical picture for all of them and, as an effective use of it, three subjects have been chosen that offer a wide panorama of the scope of classical and quantum tomography: tomography along lines and submanifolds, coherent state tomography and tomography in the abstract algebraic setting of quantum systems.

  14. Radiation dose reduction in computed tomography perfusion using spatial-temporal Bayesian methods

    E-Print Network [OSTI]

    Chen, Tsuhan

    in mean-square-error (MSE) of 40% at low dose radiation of 43mA. Keywords: spatial-temporal, BayesianRadiation dose reduction in computed tomography perfusion using spatial-temporal Bayesian methods-ray radiation dose is of significant concern to patients and operators, especially CT perfusion (CTP) imaging

  15. STATISTICAL MODELING OF THE LUNG NODULES IN LOW DOSE COMPUTED TOMOGRAPHY SCANS OF THE CHEST

    E-Print Network [OSTI]

    Louisville, University of

    STATISTICAL MODELING OF THE LUNG NODULES IN LOW DOSE COMPUTED TOMOGRAPHY SCANS OF THE CHEST Amal in automatic detection of the lung nodules and is compared with respect to parametric nodule models in terms appearing in low dose CT (LDCT) scans of the human chest. Four types of common lung nodules are analyzed

  16. Pretreatment Staging Positron Emission Tomography/Computed Tomography in Patients With Inflammatory Breast Cancer Influences Radiation Treatment Field Designs

    SciTech Connect (OSTI)

    Walker, Gary V.; Niikura, Naoki; Yang Wei; Rohren, Eric; Valero, Vicente; Woodward, Wendy A.; Alvarez, Ricardo H.; Lucci, Anthony; Ueno, Naoto T.; Buchholz, Thomas A.

    2012-08-01

    Purpose: Positron emission tomography/computed tomography (PET/CT) is increasingly being utilized for staging of inflammatory breast cancer (IBC). The purpose of this study was to define how pretreatment PET/CT studies affected postmastectomy radiation treatment (PMRT) planning decisions for IBC. Methods and Materials: We performed a retrospective analysis of 62 patients diagnosed with IBC between 2004 and 2009, who were treated with PMRT in our institution and who had a staging PET/CT within 3 months of diagnosis. Patients received a baseline physical examination, staging mammography, ultrasonographic examination of breast and draining lymphatics, and chest radiography; most patients also had a bone scan (55 patients), liver imaging (52 patients), breast MRI (46 patients), and chest CT (25 patients). We compared how PET/CT findings affected PMRT, assuming that standard PMRT would target the chest wall, level III axilla, supraclavicular fossa, and internal mammary chain (IMC). Any modification of target volumes, field borders, or dose prescriptions was considered a change. Results: PET/CT detected new areas of disease in 27 of the 62 patients (44%). The areas of additional disease included the breast (1 patient), ipsilateral axilla (1 patient), ipsilateral supraclavicular (4 patients), ipsilateral infraclavicular (1 patient), ipsilateral IMC (5 patients), ipsilateral subpectoral (3 patients), mediastinal (8 patients), other distant/contralateral lymph nodes (15 patients), or bone (6 patients). One patient was found to have a non-breast second primary tumor. The findings of the PET/CT led to changes in PMRT in 11 of 62 patients (17.7%). These changes included additional fields in 5 patients, adjustment of fields in 2 patients, and higher doses to the supraclavicular fossa (2 patients) and IMC (5 patients). Conclusions: For patients with newly diagnosed IBC, pretreatment PET/CT provides important information concerning involvement of locoregional lymph nodes, mediastinal lymph nodes, and unsuspected sites of distant metastasis. This information is important in the design of radiotherapy treatment fields and, therefore, we recommend that PET/CT be a component of initial staging for IBC.

  17. Frequency and patterns of abnormality detected by iodine-123 amine emission CT after cerebral infarction

    SciTech Connect (OSTI)

    Brott, T.G.; Gelfand, M.J.; Williams, C.C.; Spilker, J.A.; Hertzberg, V.S.

    1986-03-01

    Single photon emission computed tomography (SPECT) was performed in 31 patients with cerebral infarction and 13 who had had transient ischemic attacks, using iodine-123-labeled N,N,N'-trimethyl-N'-(2-hydroxyl-3-methyl-5-iodobenzyl)-1,3-propanediamin e (I-123-HIPDM) as the radiopharmaceutical. SPECT scans were compared with computed tomographic (CT) scans. SPECT was as sensitive as CT in detecting cerebral infarction (94% vs. 84%). The abnormalities were larger on the SPECT scans than on the CT scans in 19 cases, equal in seven, and smaller in five (SPECT abnormalities greater than or equal to CT abnormalities in 86% of cases). Fifteen of 30 patients with hemispheric infarction had decreased perfusion (decreased uptake of I-123-HIPDM) to the cerebellar hemisphere contralateral to the cerebral hemisphere involved by the infarction (crossed cerebellar diaschisis). Nine of these 15 patients had major motor deficits, while only one of the 15 without crossed cerebellar diaschisis had a major motor deficit.

  18. X-ray Computed Tomography of coal: Final report

    SciTech Connect (OSTI)

    Maylotte, D.H.; Spiro, C.L.; Kosky, P.G.; Lamby, E.J.

    1986-12-01

    X-ray Computed Tomography (CT) is a method of mapping with x-rays the internal structures of coal. The technique normally produces 2-D images of the internal structures of an object. These images can be recast to create pseudo 3-D representations. CT of coal has been explored for a variety of different applications to coal and coal processing technology. In a comparison of CT data with conventional coal analyses and petrography, CT was found to offer a good indication of the total ash content of the coal. The spatial distribution of the coal mineral matter as seen with CT has been suggested as an indicator of coal washability. Studies of gas flow through coal using xenon gas as a tracer have shown the extremely complicated nature of the modes of penetration of gas through coal, with significant differences in the rates at which the gas can pass along and across the bedding planes of coal. In a special furnace designed to allow CT images to be taken while the coal was being heated, the pyrolysis and gasification of coal have been studied. Gasification rates with steam and CO/sub 2/ for a range of coal ranks have been obtained, and the location of the gasification reactions within the piece of coal can be seen. Coal drying and the progress of the pyrolysis wave into coal have been examined when the coal was subjected to the kind of sudden temperature jump that it might experience in fixed bed gasifier applications. CT has also been used to examine stable flow structures within model fluidized beds and the accessibility of lump coal to microbial desulfurization. 53 refs., 242 figs., 26 tabs.

  19. Pre-processing methods for nodule detection in lung CT

    E-Print Network [OSTI]

    Cheran, S C; De Mitri, I; De Nunzio, G; Fantacci, M E; Fauci, F; Gargano, G; Torres, E L; Massafra, R; Oliva, P; Prez-Martnez, A; Raso, G; Retico, A; Stumbo, S; Tata, A

    2005-01-01

    The use of automatic systems in the analysis of medical images has proven to be very useful to radiologists, especially in the framework of screening programs, in which radiologists make their first diagnosis on the basis of images only, most of those corresponding to healthy patients, and have to distinguish pathological findings from non-pathological ones at an early stage. In particular, we are developing preprocessing methods to be applied for pulmonary nodule Computer Aided Detection in low-dose lung Multi Slice CT (Computed Tomography) images.

  20. Introduction to Positron Emission Tomography

    E-Print Network [OSTI]

    Oakes, Terry

    range: 1-10 mm Gamma-Ray range: 10 mm - 8 positron annihilation #12;Positron Emission TomographyIntroduction to Positron Emission Tomography Positron Annihilation 180 o #1 #2 with your host detector #2 detector #1 #2 #1 detector ring #12;Positron Emission Tomography detector #2 detector #1 #2

  1. CT NC0

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth DakotaRobbins and Myers Co -VANaval ,, *' ;x-L* d! CT NC0 - i , ,.

  2. 200 MeV Proton Radiography Studies with a Hand Phantom Using a Prototype Proton CT Scanner

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    of becoming a new, potentially low-dose medical imaging modality. The experiment used the current first radiation therapy for cancer patients, research into new imaging methods that can improve the accuracy of damaging otherwise healthy tissue. Most importantly, the greatest radiation dose occurs only in the last 2

  3. Evaluation of Biomaterials Using Micro-Computerized Tomography

    SciTech Connect (OSTI)

    Torris, A. T. Arun; Columbus, K. C. Soumya; Saaj, U. S.; Krishnan, Kalliyana V. [Dental Products Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala-695012 (India); Nair, Manitha B. [Transmission Electron Microscopy Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala-695012 (India)

    2008-09-26

    Micro-computed tomography or Micro-CT is a high resolution, non-invasive, x-ray scanning technique that allows precise three-dimensional imaging and quantification of micro-architectural and structural parameters of objects. Tomographic reconstruction is based on a cone-beam convolution-back-projection algorithm. Micro-architectural and structural parameters such as porosity, surface area to volume ratio, interconnectivity, pore size, wall thickness, anisotropy and cross-section area of biomaterials and bio-specimens such as trabecular bone, polymer scaffold, bio-ceramics and dental restorative were evaluated through imaging and computer aided manipulation of the object scan data sets.

  4. Insights into manufacturing techniques of archaeological pottery: Industrial X-ray computed tomography as a tool in the examination of

    E-Print Network [OSTI]

    Gertz, Michael

    -ray computed tomography (CT) for non-destructive testing as an archaeometric or archaeological method-invasive archaeology. 1. Introduction For as long as archaeometric methods have been well established in the study of manufacturing details and to provide more accurate vessel profiles, particularly of closed shapes. The further

  5. Finite quantum tomography via semidefinite programming

    E-Print Network [OSTI]

    M. A. Jafarizadeh; M. Mirzaee; M. Rezaee

    2007-07-26

    Using the the convex semidefinite programming method and superoperator formalism we obtain the finite quantum tomography of some mixed quantum states such as: qudit tomography, N-qubit tomography, phase tomography and coherent spin state tomography, where that obtained results are in agreement with those of References \\cite{schack,Pegg,Barnett,Buzek,Weigert}.

  6. Compact cold stage for micro-computerized tomography imaging of chilled or frozen samples

    SciTech Connect (OSTI)

    Hullar, Ted; Anastasio, Cort; Paige, David F.; Rowland, Douglas J.

    2014-04-15

    High resolution X-ray microCT (computerized tomography) can be used to image a variety of objects, including temperature-sensitive materials. In cases where the sample must be chilled or frozen to maintain sample integrity, either the microCT machine itself must be placed in a refrigerated chamber, or a relatively expensive commercial cold stage must be purchased. We describe here the design and construction of a low-cost custom cold stage suitable for use in a microCT imaging system. Our device uses a boron nitride sample holder, two-stage Peltier cooler, fan-cooled heat sink, and electronic controller to maintain sample temperatures as low as ?25?C 0.2?C for the duration of a tomography acquisition. The design does not require modification to the microCT machine, and is easily installed and removed. Our custom cold stage represents a cost-effective solution for refrigerating CT samples for imaging, and is especially useful for shared equipment or machines unsuitable for cold room use.

  7. CT reconstruction techniques for improved accuracy of lung CT airway measurement

    SciTech Connect (OSTI)

    Rodriguez, A.; Ranallo, F. N.; Judy, P. F.; Gierada, D. S.; Fain, S. B.

    2014-11-01

    Purpose: To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose. Methods: Measurement of small airways with qCT remains a challenge, especially for low x-ray dose protocols. Images of the COPDGene quality assurance phantom (CTP698, The Phantom Laboratory, Salem, NY) were obtained using a GE discovery CT750 HD scanner for helical scans at x-ray radiation dose-equivalents ranging from 1 to 4.12 mSv (12100 mA s currenttime product). Other parameters were 40 mm collimation, 0.984 pitch, 0.5 s rotation, and 0.625 mm thickness. The phantom was sandwiched between 7.5 cm thick water attenuating phantoms for a total length of 20 cm to better simulate the scatter conditions of patient scans. Image data sets were reconstructed using STANDARD (STD), DETAIL, BONE, and EDGE algorithms for filtered back projection (FBP), 100% adaptive statistical iterative reconstruction (ASIR), and Veo reconstructions. Reduced (half) display field of view (DFOV) was used to increase sampling across airway phantom structures. Inner diameter (ID), wall area percent (WA%), and wall thickness (WT) measurements of eight airway mimicking tubes in the phantom, including a 2.5 mm ID (42.6 WA%, 0.4 mm WT), 3 mm ID (49.0 WA%, 0.6 mm WT), and 6 mm ID (49.0 WA%, 1.2 mm WT) were performed with Airway Inspector (Surgical Planning Laboratory, Brigham and Womens Hospital, Boston, MA) using the phase congruency edge detection method. The average of individual measures at five central slices of the phantom was taken to reduce measurement error. Results: WA% measures were greatly overestimated while IDs were underestimated for the smaller airways, especially for reconstructions at full DFOV (36 cm) using the STD kernel, due to poor sampling and spatial resolution (0.7 mm pixel size). Despite low radiation dose, the ID of the 6 mm ID airway was consistently measured accurately for all methods other than STD FBP. Veo reconstructions showed slight improvement over STD FBP reconstructions (4%9% increase in accuracy). The most improved ID and WA% measures were for the smaller airways, especially for low dose scans reconstructed at half DFOV (18 cm) with the EDGE algorithm in combination with 100% ASIR to mitigate noise. Using the BONE + ASIR at half BONE technique, measures improved by a factor of 2 over STD FBP even at a quarter of the x-ray dose. Conclusions: The flexibility of ASIR in combination with higher frequency algorithms, such as BONE, provided the greatest accuracy for conventional and low x-ray dose relative to FBP. Veo provided more modest improvement in qCT measures, likely due to its compatibility only with the smoother STD kernel.

  8. Data fusion in X-ray computed tomography using a superiorization approach

    SciTech Connect (OSTI)

    Schrapp, Michael J.; Herman, Gabor T.

    2014-05-15

    X-ray computed tomography (CT) is an important and widespread inspection technique in industrial non-destructive testing. However, large-sized and heavily absorbing objects cause artifacts due to either the lack of penetration of the specimen in specific directions or by having data from only a limited angular range of views. In such cases, valuable information about the specimen is not revealed by the CT measurements alone. Further imaging modalities, such as optical scanning and ultrasonic testing, are able to provide data (such as an edge map) that are complementary to the CT acquisition. In this paper, a superiorization approach (a newly developed method for constrained optimization) is used to incorporate the complementary data into the CT reconstruction; this allows precise localization of edges that are not resolvable from the CT data by itself. Superiorization, as presented in this paper, exploits the fact that the simultaneous algebraic reconstruction technique (SART), often used for CT reconstruction, is resilient to perturbations; i.e., it can be modified to produce an output that is as consistent with the CT measurements as the output of unmodified SART, but is more consistent with the complementary data. The application of this superiorized SART method to measured data of a turbine blade demonstrates a clear improvement in the quality of the reconstructed image.

  9. Transhepatic Approach for Percutaneous Computed-Tomography-Guided Radiofrequency Ablation of Renal Cell Carcinoma

    SciTech Connect (OSTI)

    Iguchi, Toshihiro, E-mail: iguchi@cc.okayama-u.ac.jp; Hiraki, Takao; Gobara, Hideo; Mukai, Takashi; Hase, Soichiro; Fujiwara, Hiroyasu; Tajiri, Nobuhisa; Sakurai, Jun; Mimura, Hidefumi [Okayama University Medical School, Department of Radiology (Japan); Saika, Takashi; Kumon, Hiromi [Okayama University Medical School, Department of Urology (Japan); Kanazawa, Susumu [Okayama University Medical School, Department of Radiology (Japan)

    2007-07-15

    We performed percutaneously radiofrequency (RF) ablation of 5 renal cell carcinomas (mean diameter 26 {+-} 15 mm) with computed-tomography (CT) fluoroscopic guidance using the transhepatic route. The RF electrode was successfully advanced into all tumors. RF ablation caused one minor complication (small asymptomatic perirenal hematoma); no major complications occurred. The follow-up contrast-enhanced CT images showed no local tumor progression of any tumors in a median period of 10 months (range 3-14 months). In conclusion, it seems that this transhepatic approach is safe and can be an alternative method for electrode insertion during RF ablation of selected renal tumors.

  10. Thermoacoustic tomography, variable sound speed

    E-Print Network [OSTI]

    Plamen Stefanov

    2009-10-26

    In thermoacoustic tomography, a short electro-magnetic pulse is sent through a patient's body. The tissue reacts and emits an ultrasound wave form any point,...

  11. Semi-resonant operation of a fiber-cantilever piezotube scanner for stable optical coherence tomography endoscope imaging

    E-Print Network [OSTI]

    Moon, Sucbei; Lee, Sang-Won; Rubinstein, Marc; Wong, Brian J. F; Chen, Zhongping

    2010-01-01

    of a rotational microelectromechanical system probe, Opt.with a modified microelectromechanical systems mirror for

  12. Wire Scanner Beam Profile Measurements for the LANSCE Facility

    SciTech Connect (OSTI)

    Gilpatrick, John D. [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; Pillai, Chandra [Los Alamos National Laboratory; Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory

    2012-05-15

    The Los Alamos Neutron Science Center (LANSCE) is replacing beam profile measurement systems, commonly known as Wire Scanners (WS). Using the principal of secondary electron emission, the WS measurement system moves a wire or fiber across an impinging particle beam, sampling a projected transverse-beam distribution. Because existing WS actuators and electronic components are either no longer manufactured or home-built with antiquated parts, a new WS beam profile measurement is being designed, fabricated, and tested. The goals for these new WS's include using off-the-shelf components while eliminating antiquated components, providing quick operation while allowing for easy maintainability, and tolerating external radioactivation. The WS measurement system consists of beam line actuators, a cable plant, an electronics processor chassis, and software located both in the electronics chassis (National Instruments LabVIEW) and in the Central Control Room (EPICS-based client software). This WS measurement system will measure Hand H{sup +} LANSCE-facility beams and will also measure less common beams. This paper describes these WS measurement systems.

  13. Semi-automatic delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer

    SciTech Connect (OSTI)

    Fitton, I. [European Georges Pompidou Hospital, Department of Radiology, 20 rue Leblanc, 75015, Paris (France); Cornelissen, S. A. P. [Image Sciences Institute, UMC, Department of Radiology, P.O. Box 85500, 3508 GA Utrecht (Netherlands); Duppen, J. C.; Rasch, C. R. N.; Herk, M. van [The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Department of Radiotherapy, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Steenbakkers, R. J. H. M. [University Medical Center Groningen, Department of Radiation Oncology, Hanzeplein 1, 9713 GZ Groningen (Netherlands); Peeters, S. T. H. [UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgique (Belgium); Hoebers, F. J. P. [Maastricht University Medical Center, Department of Radiation Oncology (MAASTRO clinic), GROW School for Oncology and Development Biology Maastricht, 6229 ET Maastricht (Netherlands); Kaanders, J. H. A. M. [UMC St-Radboud, Department of Radiotherapy, Geert Grooteplein 32, 6525 GA Nijmegen (Netherlands); Nowak, P. J. C. M. [ERASMUS University Medical Center, Department of Radiation Oncology,Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands)

    2011-08-15

    Purpose: To develop a delineation tool that refines physician-drawn contours of the gross tumor volume (GTV) in nasopharynx cancer, using combined pixel value information from x-ray computed tomography (CT) and magnetic resonance imaging (MRI) during delineation. Methods: Operator-guided delineation assisted by a so-called ''snake'' algorithm was applied on weighted CT-MRI registered images. The physician delineates a rough tumor contour that is continuously adjusted by the snake algorithm using the underlying image characteristics. The algorithm was evaluated on five nasopharyngeal cancer patients. Different linear weightings CT and MRI were tested as input for the snake algorithm and compared according to contrast and tumor to noise ratio (TNR). The semi-automatic delineation was compared with manual contouring by seven experienced radiation oncologists. Results: A good compromise for TNR and contrast was obtained by weighing CT twice as strong as MRI. The new algorithm did not notably reduce interobserver variability, it did however, reduce the average delineation time by 6 min per case. Conclusions: The authors developed a user-driven tool for delineation and correction based a snake algorithm and registered weighted CT image and MRI. The algorithm adds morphological information from CT during the delineation on MRI and accelerates the delineation task.

  14. Computer modeling of the spatial resolution properties of a dedicated breast CT system

    SciTech Connect (OSTI)

    Yang Kai; Kwan, Alexander L. C.; Boone, John M. [Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100 Ellison Building, Sacramento, California 95817 (United States) and Department of Biomedical Engineering, University of California, Davis, California, 95616 (United States); Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100 Ellison Building, Sacramento, California 95817 (United States); Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100 Ellison Building, Sacramento, California 95817 (United States) and Department of Biomedical Engineering, University of California, Davis, California 95616 (United States)

    2007-06-15

    Computer simulation methods were used to evaluate the spatial resolution properties of a dedicated cone-beam breast CT system. x-ray projection data of a 70 {mu}m nickel-chromium wire were simulated. The modulation transfer function (MTF) was calculated from the reconstructed axial images at different radial positions from the isocenter to study the spatial dependency of the spatial resolution of the breast CT scanner. The MTF was also calculated in both the radial and azimuthal directions. Subcomponents of the cone beam CT system that affect the MTF were modeled in the computer simulation in a serial manner, including the x-ray focal spot distribution, gantry rotation under the condition of continuous fluoroscopy, detector lag, and detector spatial resolution. Comparison between the computer simulated and physically measured MTF values demonstrates reasonable accuracy in the simulation process, with a small systematic difference ({approx}9.5{+-}6.4% difference, due to unavoidable uncertainties from physical measurement and system calibration). The intrinsic resolution in the radial direction determined by simulation was about 2.0 mm{sup -1} uniformly through the field of view. The intrinsic resolution in the azimuthal direction degrades from 2.0 mm{sup -1} at the isocenter to 1.0 mm{sup -1} at the periphery with 76.9 mm from the isocenter. The results elucidate the intrinsic spatial resolution properties of the prototype breast CT system, and suggest ways in which spatial resolution can be improved with system modification.

  15. Automatic CT simulation optimization for radiation therapy: A general strategy

    SciTech Connect (OSTI)

    Li, Hua, E-mail: huli@radonc.wustl.edu; Chen, Hsin-Chen; Tan, Jun; Gay, Hiram; Michalski, Jeff M.; Mutic, Sasa [Department of Radiation Oncology, Washington University, St. Louis, Missouri 63110 (United States)] [Department of Radiation Oncology, Washington University, St. Louis, Missouri 63110 (United States); Yu, Lifeng [Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States)] [Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Anastasio, Mark A. [Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110 (United States)] [Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110 (United States); Low, Daniel A. [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California 90095 (United States)] [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2014-03-15

    Purpose: In radiation therapy, x-ray computed tomography (CT) simulation protocol specifications should be driven by the treatment planning requirements in lieu of duplicating diagnostic CT screening protocols. The purpose of this study was to develop a general strategy that allows for automatically, prospectively, and objectively determining the optimal patient-specific CT simulation protocols based on radiation-therapy goals, namely, maintenance of contouring quality and integrity while minimizing patient CT simulation dose. Methods: The authors proposed a general prediction strategy that provides automatic optimal CT simulation protocol selection as a function of patient size and treatment planning task. The optimal protocol is the one that delivers the minimum dose required to provide a CT simulation scan that yields accurate contours. Accurate treatment plans depend on accurate contours in order to conform the dose to actual tumor and normal organ positions. An image quality index, defined to characterize how simulation scan quality affects contour delineation, was developed and used to benchmark the contouring accuracy and treatment plan quality within the predication strategy. A clinical workflow was developed to select the optimal CT simulation protocols incorporating patient size, target delineation, and radiation dose efficiency. An experimental study using an anthropomorphic pelvis phantom with added-bolus layers was used to demonstrate how the proposed prediction strategy could be implemented and how the optimal CT simulation protocols could be selected for prostate cancer patients based on patient size and treatment planning task. Clinical IMRT prostate treatment plans for seven CT scans with varied image quality indices were separately optimized and compared to verify the trace of target and organ dosimetry coverage. Results: Based on the phantom study, the optimal image quality index for accurate manual prostate contouring was 4.4. The optimal tube potentials for patient sizes of 38, 43, 48, 53, and 58 cm were 120, 140, 140, 140, and 140 kVp, respectively, and the corresponding minimum CTDIvol for achieving the optimal image quality index 4.4 were 9.8, 32.2, 100.9, 241.4, and 274.1 mGy, respectively. For patients with lateral sizes of 4358 cm, 120-kVp scan protocols yielded up to 165% greater radiation dose relative to 140-kVp protocols, and 140-kVp protocols always yielded a greater image quality index compared to the same dose-level 120-kVp protocols. The trace of target and organ dosimetry coverage and the ? passing rates of seven IMRT dose distribution pairs indicated the feasibility of the proposed image quality index for the predication strategy. Conclusions: A general strategy to predict the optimal CT simulation protocols in a flexible and quantitative way was developed that takes into account patient size, treatment planning task, and radiation dose. The experimental study indicated that the optimal CT simulation protocol and the corresponding radiation dose varied significantly for different patient sizes, contouring accuracy, and radiation treatment planning tasks.

  16. IEEE Transactions on Automation Science and Engineering Compensation of Scanner Creep and Hysteresis

    E-Print Network [OSTI]

    Southern California, University of

    IEEE Transactions on Automation Science and Engineering Compensation of Scanner Creep and Hysteresis for AFM Nanomanipulation Babak Mokaberi Student Member, IEEE, and Aristides A. G. Requicha, Life Fellow, IEEE Abstract--Nanomanipulation with Atomic Force Microscopes (AFMs) for nanoparticles

  17. SU-E-I-62: Assessing Radiation Dose Reduction and CT Image Optimization Through the Measurement and Analysis of the Detector Quantum Efficiency (DQE) of CT Images Using Different Beam Hardening Filters

    SciTech Connect (OSTI)

    Collier, J; Aldoohan, S; Gill, K

    2014-06-01

    Purpose: Reducing patient dose while maintaining (or even improving) image quality is one of the foremost goals in CT imaging. To this end, we consider the feasibility of optimizing CT scan protocols in conjunction with the application of different beam-hardening filtrations and assess this augmentation through noise-power spectrum (NPS) and detector quantum efficiency (DQE) analysis. Methods: American College of Radiology (ACR) and Catphan phantoms (The Phantom Laboratory) were scanned with a 64 slice CT scanner when additional filtration of thickness and composition (e.g., copper, nickel, tantalum, titanium, and tungsten) had been applied. A MATLAB-based code was employed to calculate the image of noise NPS. The Catphan Image Owl software suite was then used to compute the modulated transfer function (MTF) responses of the scanner. The DQE for each additional filter, including the inherent filtration, was then computed from these values. Finally, CT dose index (CTDIvol) values were obtained for each applied filtration through the use of a 100 mm pencil ionization chamber and CT dose phantom. Results: NPS, MTF, and DQE values were computed for each applied filtration and compared to the reference case of inherent beam-hardening filtration only. Results showed that the NPS values were reduced between 5 and 12% compared to inherent filtration case. Additionally, CTDIvol values were reduced between 15 and 27% depending on the composition of filtration applied. However, no noticeable changes in image contrast-to-noise ratios were noted. Conclusion: The reduction in the quanta noise section of the NPS profile found in this phantom-based study is encouraging. The reduction in both noise and dose through the application of beam-hardening filters is reflected in our phantom image quality. However, further investigation is needed to ascertain the applicability of this approach to reducing patient dose while maintaining diagnostically acceptable image qualities in a clinical setting.

  18. SU-E-I-68: Practical Considerations On Implementation of the Image Gently Pediatric CT Protocols

    SciTech Connect (OSTI)

    Zhang, J; Adams, C; Lumby, C; Dillon, J [University of Kentucky, Lexington, KY (United States); Woods, E [University of kentucky, Lexington, KY (United States); Richer, E [University of Kentucky, Lexington, Lexington (United States)

    2014-06-01

    Purpose: One limitation associated with the Image Gently pediatric CT protocols is practical implementation of the recommended manual techniques. Inconsistency as a result of different practice is a possibility among technologist. An additional concern is the added risk of data error that would result in over or underexposure. The Automatic Exposure Control (AEC) features automatically reduce radiation for children. However, they do not work efficiently for the patients of very small size and relative large size. This study aims to implement the Image Gently pediatric CT protocols in the practical setting while maintaining the use of AEC features for pediatric patients of varying size. Methods: Anthropomorphological abdomen phantoms were scanned in a CT scanner using the Image Gently pediatric protocols, the AEC technique with a fixed adult baseline, and automatic protocols with various baselines. The baselines were adjusted corresponding to patient age, weight and posterioranterior thickness to match the Image Gently pediatric CT manual techniques. CTDIvol was recorded for each examination. Image noise was measured and recorded for image quality comparison. Clinical images were evaluated by pediatric radiologists. Results: By adjusting vendor default baselines used in the automatic techniques, radiation dose and image quality can match those of the Image Gently manual techniques. In practice, this can be achieved by dividing pediatric patients into three major groups for technologist reference: infant, small child, and large child. Further division can be done but will increase the number of CT protocols. For each group, AEC can efficiently adjust acquisition techniques for children. This implementation significantly overcomes the limitation of the Image Gently manual techniques. Conclusion: Considering the effectiveness in clinical practice, Image Gently Pediatric CT protocols can be implemented in accordance with AEC techniques, with adjusted baselines, to achieve the goal of providing the most appropriate radiation dose for pediatric patients of varying sizes.

  19. Positron Emission Tomography (PET)

    DOE R&D Accomplishments [OSTI]

    Welch, M. J.

    1990-01-00

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET.

  20. Radial reflection diffraction tomography

    DOE Patents [OSTI]

    Lehman, Sean K.

    2012-12-18

    A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a "pitch/catch" operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes.

  1. Introduction to Positron Emission Tomography

    E-Print Network [OSTI]

    Oakes, Terry

    Introduction to Positron Emission Tomography with your host, Terry Oakes Positron Annihilation #1 neighboring atom Positron range: 1-10 mm Gamma-Ray range: 10 mm - 8 positron annihilation #2 #1 T.R.Oakes Univ. WI-Madison #12;Positron Emission Tomography detector #2 detector #1 #2 #1 detector ring T

  2. Electrical Impedance Tomography Liliana Borcea

    E-Print Network [OSTI]

    Borcea, Liliana

    Electrical Impedance Tomography Liliana Borcea #3; September 3, 2002 Abstract We review theoretical and numerical studies of the inverse problem of electrical impedance tomography which seeks the electrical conductivity and permittivity inside a body, given simul- taneous measurements of electrical currents

  3. X-Ray Digital Radiography and Computed Tomography Characterization of Targets

    SciTech Connect (OSTI)

    Sain, J D; Brown, W D; Chinn, D J; Martz Jr., H E; Morales, K E; Schneberk, D J; Updike, E O

    2008-04-16

    The summary of this report is: (1) The Xradia Micro XCT and LLNL CCAT x-ray systems are used to nondestructively characterize a variety of materials, assemblies, and reference standard components; (2) The digital radiograph (DR) and computed tomography (CT) image data may be used for metrology, quality control, and defect detection; and (3) The ability to detect and characterize imperfections leads to improvements in the manufacturing processes for assemblies.

  4. Upright cone beam CT imaging using the onboard imager

    SciTech Connect (OSTI)

    Fave, Xenia Martin, Rachael; Yang, Jinzhong; Balter, Peter; Court, Laurence; Carvalho, Luis; Pan, Tinsu

    2014-06-15

    Purpose: Many patients could benefit from being treated in an upright position. The objectives of this study were to determine whether cone beam computed tomography (CBCT) could be used to acquire upright images for treatment planning and to demonstrate whether reconstruction of upright images maintained accurate geometry and Hounsfield units (HUs). Methods: A TrueBeam linac was programmed in developer mode to take upright CBCT images. The gantry head was positioned at 0, and the couch was rotated to 270. The x-ray source and detector arms were extended to their lateral positions. The x-ray source and gantry remained stationary as fluoroscopic projections were taken and the couch was rotated from 270 to 90. The x-ray tube current was normalized to deposit the same dose (measured using a calibrated Farmer ion chamber) as that received during a clinical helical CT scan to the center of a cylindrical, polyethylene phantom. To extend the field of view, two couch rotation scans were taken with the detector offset 15 cm superiorly and then 15 cm inferiorly. The images from these two scans were stitched together before reconstruction. Upright reconstructions were compared to reconstructions from simulation CT scans of the same phantoms. Two methods were investigated for correcting the HUs, including direct calibration and mapping the values from a simulation CT. Results: Overall geometry, spatial linearity, and high contrast resolution were maintained in upright reconstructions. Some artifacts were created and HU accuracy was compromised; however, these limitations could be removed by mapping the HUs from a simulation CT to the upright reconstruction for treatment planning. Conclusions: The feasibility of using the TrueBeam linac to take upright CBCT images was demonstrated. This technique is straightforward to implement and could be of enormous benefit to patients with thoracic tumors or those who find a supine position difficult to endure.

  5. An automated system for lung nodule detection in low-dose computed tomography

    E-Print Network [OSTI]

    Gori, I; Martinez, A Preite; Retico, A

    2007-01-01

    A computer-aided detection (CAD) system for the identification of pulmonary nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 Italian project. One of the main goals of this project is to build a distributed database of lung CT scans in order to enable automated image analysis through a data and cpu GRID infrastructure. The basic modules of our lung-CAD system, a dot-enhancement filter for nodule candidate selection and a neural classifier for false-positive finding reduction, are described. The system was designed and tested for both internal and sub-pleural nodules. The results obtained on the collected database of low-dose thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.

  6. THERMOACOUSTIC TOMOGRAPHY ARISING IN BRAIN IMAGING ...

    E-Print Network [OSTI]

    2011-02-21

    THERMOACOUSTIC TOMOGRAPHY ARISING IN BRAIN IMAGING. PLAMEN STEFANOV AND GUNTHER UHLMANN. ABSTRACT. We study the mathematical...

  7. Preventive maintenance system for the photomultiplier detector blocks of pet scanners

    DOE Patents [OSTI]

    Levy, Alejandro V. (Center Moriches, NY); Warner, Donald (Shirley, NY)

    1995-01-24

    A system including a method and apparatus for preventive maintenance of PET scanner photomultiplier detector blocks is disclosed. The quantitive comparisons used in the method of the present invention to provide an indication in the form of a display or printout advising the user that the photomultiplier block is stable, intermittently unstable, or drifting unstable, and also advising of the expected date of failure of a photomultiplier block in the PET scanner. The system alerts the user to replace the defective photomultiplier block prior to catastrophic failure in a scheduled preventative maintenance program, thus eliminating expensive and unscheduled downtime of the PET scanner due to photomultiplier failure. The apparatus for carrying out the method of the present invention preferably resides in the host computer controlling a PET scanner. It includes a memory adapted for storing a record of a number of iterative adjustments that are necessary to calibrate the gain of a photomultiplier detector block i at a time t.sub.0, a time t.sub.1 and a time T, where T>t.sub.1 >t.sub.0, which is designated as Histo(i,j(t)). The apparatus also includes a processor configured by a software program or a combination of programmed RAM and ROM devices to perform a number of calculations and operations on these values, and also includes a counter for analyzing each photomultiplier detector block i=1 through I of a PET scanner.

  8. Preventive maintenance system for the photomultiplier detector blocks of PET scanners

    DOE Patents [OSTI]

    Levy, A.V.; Warner, D.

    1995-01-24

    A system including a method and apparatus for preventive maintenance of PET scanner photomultiplier detector blocks is disclosed. The qualitative comparisons used in the method of the present invention to provide an indication in the form of a display or printout advising the user that the photomultiplier block is stable, intermittently unstable, or drifting unstable, and also advising of the expected date of failure of a photomultiplier block in the PET scanner. The system alerts the user to replace the defective photomultiplier block prior to catastrophic failure in a scheduled preventative maintenance program, thus eliminating expensive and unscheduled downtime of the PET scanner due to photomultiplier failure. The apparatus for carrying out the method of the present invention preferably resides in the host computer controlling a PET scanner. It includes a memory adapted for storing a record of a number of iterative adjustments that are necessary to calibrate the gain of a photomultiplier detector block i at a time t[sub 0], a time t[sub 1] and a time T, where T>t[sub 1]>t[sub 0], which is designated as Histo(i,j(t)). The apparatus also includes a processor configured by a software program or a combination of programmed RAM and ROM devices to perform a number of calculations and operations on these values, and also includes a counter for analyzing each photomultiplier detector block i=1 through I of a PET scanner. 40 figures.

  9. Mathematical Problems of Thermoacoustic Tomography

    E-Print Network [OSTI]

    Nguyen, Linh V.

    2010-10-12

    Thermoacoustic tomography (TAT) is a newly emerging modality in biomedical imaging. It combines the good contrast of electromagnetic and good resolution of ultrasound imaging. The mathematical model of TAT is the observability problem for the wave...

  10. SU-E-I-57: Evaluation and Optimization of Effective-Dose Using Different Beam-Hardening Filters in Clinical Pediatric Shunt CT Protocol

    SciTech Connect (OSTI)

    Gill, K; Aldoohan, S; Collier, J

    2014-06-01

    Purpose: Study image optimization and radiation dose reduction in pediatric shunt CT scanning protocol through the use of different beam-hardening filters Methods: A 64-slice CT scanner at OU Childrens Hospital has been used to evaluate CT image contrast-to-noise ratio (CNR) and measure effective-doses based on the concept of CT dose index (CTDIvol) using the pediatric head shunt scanning protocol. The routine axial pediatric head shunt scanning protocol that has been optimized for the intrinsic x-ray tube filter has been used to evaluate CNR by acquiring images using the ACR approved CT-phantom and radiation dose CTphantom, which was used to measure CTDIvol. These results were set as reference points to study and evaluate the effects of adding different filtering materials (i.e. Tungsten, Tantalum, Titanium, Nickel and Copper filters) to the existing filter on image quality and radiation dose. To ensure optimal image quality, the scanner routine air calibration was run for each added filter. The image CNR was evaluated for different kVps and wide range of mAs values using above mentioned beam-hardening filters. These scanning protocols were run under axial as well as under helical techniques. The CTDIvol and the effective-dose were measured and calculated for all scanning protocols and added filtration, including the intrinsic x-ray tube filter. Results: Beam-hardening filter shapes energy spectrum, which reduces the dose by 27%. No noticeable changes in image low contrast detectability Conclusion: Effective-dose is very much dependent on the CTDIVol, which is further very much dependent on beam-hardening filters. Substantial reduction in effective-dose is realized using beam-hardening filters as compare to the intrinsic filter. This phantom study showed that significant radiation dose reduction could be achieved in CT pediatric shunt scanning protocols without compromising in diagnostic value of image quality.

  11. A wire scanner system for characterizing the BNL energy recovery LINAC beam position monitor system

    SciTech Connect (OSTI)

    Michnoff R.; Biscardi, C.; Cerniglia, P.; Degen, C.; Gassner, D.; Hoff, L.; Hulsart, R.

    2012-04-15

    A stepper motor controlled wire scanner system has recently been modified to support testing of the Brookhaven National Laboratory (BNL) Collider-Accelerator department's Energy Recovery Linac (ERL) beam position monitor (BPM) system. The ERL BPM consists of four 9.33 mm diameter buttons mounted at 90 degree spacing in a cube with 1.875 inch inside diameter. The buttons were designed by BNL and fabricated by Times Microwave Systems. Libera brilliance single pass BPM electronic modules with 700 MHz bandpass filter, manufactured by Instrumentation Technologies, will be used to measure the transverse beam positions at 14 locations around the ERL. The wire scanner assembly provides the ability to measure the BPM button response to a pulsed wire, and evaluate and calibrate the Libera position measurement electronics. A description of the wire scanner system and test result data will be presented.

  12. SU-E-J-218: Evaluation of CT Images Created Using a New Metal Artifact Reduction Reconstruction Algorithm for Radiation Therapy Treatment Planning

    SciTech Connect (OSTI)

    Niemkiewicz, J; Palmiotti, A; Miner, M; Stunja, L; Bergene, J [Lehigh Valley Health Network, Allentown, PA (United States)

    2014-06-01

    Purpose: Metal in patients creates streak artifacts in CT images. When used for radiation treatment planning, these artifacts make it difficult to identify internal structures and affects radiation dose calculations, which depend on HU numbers for inhomogeneity correction. This work quantitatively evaluates a new metal artifact reduction (MAR) CT image reconstruction algorithm (GE Healthcare CT-0521-04.13-EN-US DOC1381483) when metal is present. Methods: A Gammex Model 467 Tissue Characterization phantom was used. CT images were taken of this phantom on a GE Optima580RT CT scanner with and without steel and titanium plugs using both the standard and MAR reconstruction algorithms. HU values were compared pixel by pixel to determine if the MAR algorithm altered the HUs of normal tissues when no metal is present, and to evaluate the effect of using the MAR algorithm when metal is present. Also, CT images of patients with internal metal objects using standard and MAR reconstruction algorithms were compared. Results: Comparing the standard and MAR reconstructed images of the phantom without metal, 95.0% of pixels were within 35 HU and 98.0% of pixels were within 85 HU. Also, the MAR reconstruction algorithm showed significant improvement in maintaining HUs of non-metallic regions in the images taken of the phantom with metal. HU Gamma analysis (2%, 2mm) of metal vs. non-metal phantom imaging using standard reconstruction resulted in an 84.8% pass rate compared to 96.6% for the MAR reconstructed images. CT images of patients with metal show significant artifact reduction when reconstructed with the MAR algorithm. Conclusion: CT imaging using the MAR reconstruction algorithm provides improved visualization of internal anatomy and more accurate HUs when metal is present compared to the standard reconstruction algorithm. MAR reconstructed CT images provide qualitative and quantitative improvements over current reconstruction algorithms, thus improving radiation treatment planning accuracy.

  13. Quantum field tomography

    E-Print Network [OSTI]

    A. Steffens; C. A. Riofro; R. Hbener; J. Eisert

    2014-11-06

    We introduce the concept of quantum field tomography, the efficient and reliable reconstruction of unknown quantum fields based on data of correlation functions. At the basis of the analysis is the concept of continuous matrix product states, a complete set of variational states grasping states in quantum field theory. We innovate a practical method, making use of and developing tools in estimation theory used in the context of compressed sensing such as Prony methods and matrix pencils, allowing us to faithfully reconstruct quantum field states based on low-order correlation functions. In the absence of a phase reference, we highlight how specific higher order correlation functions can still be predicted. We exemplify the functioning of the approach by reconstructing randomised continuous matrix product states from their correlation data and study the robustness of the reconstruction for different noise models. We also apply the method to data generated by simulations based on continuous matrix product states and using the time-dependent variational principle. The presented approach is expected to open up a new window into experimentally studying continuous quantum systems, such as encountered in experiments with ultra-cold atoms on top of atom chips. By virtue of the analogy with the input-output formalism in quantum optics, it also allows for studying open quantum systems.

  14. COMPARISON OF DSMS GENERATED FROM MINI UAV IMAGERY AND TERRESTRIAL LASER SCANNER IN A CULTURAL HERITAGE APPLICATION

    E-Print Network [OSTI]

    COMPARISON OF DSMS GENERATED FROM MINI UAV IMAGERY AND TERRESTRIAL LASER SCANNER IN A CULTURAL Navigation KEY WORDS: UAV, Laser scanning, DEM/DTM, Comparison, Analysis, Accuracy, Archaeology ABSTRACT was recorded using a terrestrial laser scanner (Riegl LMS-Z420i) and a mini UAV-system (Unmanned Aerial Vehicle

  15. Effect of the static magnetic field of the MR-scanner on ERPs: Evaluation of visual, cognitive and motor potentials

    E-Print Network [OSTI]

    Effect of the static magnetic field of the MR-scanner on ERPs: Evaluation of visual, cognitive December 2009 Available online 25 January 2010 Keywords: ERP EEGfMRI 3 T static magnetic field of the static magnetic field of the MR-scanner on ERPs extracted from simultaneous EEGfMRI recordings

  16. Teaching geometric modeling algorithms and data structures through laser scanner acquisition pipeline

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    measurements and finally its instantiation through 3D printing, are presented. Laser scanner acquisition, reconstruction and 3D printing lend well to teaching general concepts in geometric modeling for several reasons. First, starting and ending with real physical 3D objects (the talus and its 3D print) provide

  17. 2D X-ray scanner and its uses in laboratory reservoir characterization measurements

    SciTech Connect (OSTI)

    Maloney, D.; Doggett, K.

    1997-08-01

    X-ray techniques are used in petroleum laboratories for a variety of reservoir characterization measurements. This paper describes the configuration of a 2D X-ray scanner and many of the ways in which it simplifies and improves accuracy`s of laboratory measurements. Linear X-ray scanners are most often used to provide descriptions of fluid saturations within core plugs during flow tests. We configured our linear scanner for both horizontal and vertical movement. Samples can be scanned horizontally, vertically, or according to horizontal and vertical grids. X-ray measurements are fast, allowing measurements of two- and three-phase fluid saturations during both steady- and unsteady-state flow processes. Rock samples can be scanned while they are subjected to stress, pore pressure, and temperature conditions simulating those of a petroleum reservoir. Many types of measurements are possible by selecting appropriate X-ray power settings, dopes, filters, and collimator configurations. The scanner has been used for a variety of applications besides fluid saturation measurements. It is useful for measuring porosity distributions in rocks, concentrations of X-ray dopes within flow streams during tracer tests, gap widths in fracture flow cells, fluid interface levels in PVT cells and fluid separators, and other features and phenomena.

  18. LOW POWER SCANNER FOR HIGH-DENSITY ELECTRODE ARRAY NEURAL RECORDING

    E-Print Network [OSTI]

    Mahmoodi, Hamid

    of this research is to design a low power integrated system that can be used in vivo for scanning the electrode. A model created in Python provides input vectors and output comparison for the verification processLOW POWER SCANNER FOR HIGH-DENSITY ELECTRODE ARRAY NEURAL RECORDING A Thesis work submitted

  19. System for Prostate Brachytherapy and Biopsy in a Standard 1.5 T MRI Scanner

    E-Print Network [OSTI]

    Atalar, Ergin

    System for Prostate Brachytherapy and Biopsy in a Standard 1.5 T MRI Scanner Robert C. Susil,1-dose-rate (HDR) prostate brachytherapy and needle biopsy in a standard 1.5 T MRI scan- ner is demonstrated transperineal catheters for HDR brachytherapy. Mean needle-placement accuracy was 2.1 mm, 95% of needle

  20. USER-ASSISTED OBJECT DETECTION BY SEGMENT BASED SIMILARITY MEASURES IN MOBILE LASER SCANNER DATA

    E-Print Network [OSTI]

    USER-ASSISTED OBJECT DETECTION BY SEGMENT BASED SIMILARITY MEASURES IN MOBILE LASER SCANNER DATA S WORDS: Segmentation, Object Detection, Semi-Automatic, Mobile Mapping Systems, Segment based in fields related to urban safety analyses and/or asset management. Many MMS systems carry video cameras

  1. Development of a Compact Optical-MEMS Scanner with Integrated VCSEL Light Source and Diffractive Optics

    SciTech Connect (OSTI)

    Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven; Smith, James H.; Warren, Mial; Sweatt, William; Blum-Spahn, Olga; Wendt, Joel R.; Asbill, Randy

    1999-06-30

    In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOEs) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysilicon gold-coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 500 {micro}m x 1000 {micro}m shuttle is extremely low, with a maximum deflection of only 0.18{micro}m over an 800 {micro}m span for an unmetallized case and a deflection of 0.56{micro}m for the metallized case. A conservative estimate for the scan range is {approximately}{+-}4{degree}, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.

  2. NREL Develops High-Speed Scanner to Monitor Fuel Cell Material Defects

    SciTech Connect (OSTI)

    2015-09-01

    This highlight describes results of recent work in which polymer electrolyte membrane fuel cell electrodes with intentionally introduced known defects were imaged and analyzed using a fuel cell scanner recently developed at NREL. The highlight is being developed for the September 2015 Alliance S&T Board meeting.

  3. Reconstruction in tomography with diffracting sources

    E-Print Network [OSTI]

    Xu, Yuan

    2005-02-17

    In this dissertation, we ?rst derive exact reconstuction algorithms for thermoacoustic tomography (TAT) and broadband di?raction tomography (a linearized inverse scattering problem) using derived time-reversal formulas. Then we focus...

  4. Thermoacoustic and Photoacoustic Tomography with a variable ...

    E-Print Network [OSTI]

    Plamen Stefanov

    2010-11-09

    ... a joint work with. Jianliang Qian, Gunther Uhlmann and Hongkai Zhao. Plamen Stefanov (Purdue University ). Thermoacoustic Tomography, Variable Speed.

  5. Mathematics of Thermoacoustic and Photoacoustic Tomography

    E-Print Network [OSTI]

    Kuchment, Peter

    2007-01-01

    The paper presents a survey of mathematical problems, techniques, and challenges arising in the Thermoacoustic and Photoacoustic Tomography.

  6. MULTIWAVE TOMOGRAPHY IN A CLOSED DOMAIN: AVERAGED ...

    E-Print Network [OSTI]

    2015-05-03

    Mathematics of photoacoustic and thermoacoustic tomography. In O. Scherzer, editor ... An efficient Neumann series-based algorithm for thermoacoustic.

  7. Cholecystokinin-Assisted Hydrodissection of the Gallbladder Fossa during FDG PET/CT-guided Liver Ablation

    SciTech Connect (OSTI)

    Tewari, Sanjit O.; Petre, Elena N.; Osborne, Joseph; Sofocleous, Constantinos T.

    2013-12-15

    A 68-year-old female with colorectal cancer developed a metachronous isolated fluorodeoxyglucose-avid (FDG-avid) segment 5/6 gallbladder fossa hepatic lesion and was referred for percutaneous ablation. Pre-procedure computed tomography (CT) images demonstrated a distended gallbladder abutting the segment 5/6 hepatic metastasis. In order to perform ablation with clear margins and avoid direct puncture and aspiration of the gallbladder, cholecystokinin was administered intravenously to stimulate gallbladder contraction before hydrodissection. Subsequently, the lesion was ablated successfully with sufficient margins, of greater than 1.0 cm, using microwave with ultrasound and FDG PET/CT guidance. The patient tolerated the procedure very well and was discharged home the next day.

  8. Hybrid tomography for conductivity imaging

    E-Print Network [OSTI]

    T. Widlak; O. Scherzer

    2012-03-20

    Hybrid imaging techniques utilize couplings of physical modalities -- they are called hybrid, because, typically, the excitation and measurement quantities belong to different modalities. Recently there has been an enormous research interest in this area because these methods promise very high resolution. In this paper we give a review on hybrid tomography methods for \\emph{electrical conductivity} imaging. The reviewed imaging methods utilize couplings between electric, magnetic and ultrasound modalities. By this it is possible to perform high-resolution electrical impedance imaging and to overcome the low-resolution problem of electric impedance tomography.

  9. Resolution enhancement of lung 4D-CT data using multiscale interphase iterative nonlocal means

    SciTech Connect (OSTI)

    Zhang Yu [School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China and Department of Radiology and BRIC, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Yap, Pew-Thian; Wu Guorong [Department of Radiology and BRIC, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Feng Qianjin; Chen Wufan [School of Biomedical Engineering, Southern Medical University, Guangzhou 510515 (China); Lian Jun [Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Shen Dinggang [Department of Radiology and BRIC, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Department of Brain and Cognitive Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2013-05-15

    Purpose: Four-dimensional computer tomography (4D-CT) has been widely used in lung cancer radiotherapy due to its capability in providing important tumor motion information. However, the prolonged scanning duration required by 4D-CT causes considerable increase in radiation dose. To minimize the radiation-related health risk, radiation dose is often reduced at the expense of interslice spatial resolution. However, inadequate resolution in 4D-CT causes artifacts and increases uncertainty in tumor localization, which eventually results in extra damages of healthy tissues during radiotherapy. In this paper, the authors propose a novel postprocessing algorithm to enhance the resolution of lung 4D-CT data. Methods: The authors' premise is that anatomical information missing in one phase can be recovered from the complementary information embedded in other phases. The authors employ a patch-based mechanism to propagate information across phases for the reconstruction of intermediate slices in the longitudinal direction, where resolution is normally the lowest. Specifically, the structurally matching and spatially nearby patches are combined for reconstruction of each patch. For greater sensitivity to anatomical details, the authors employ a quad-tree technique to adaptively partition the image for more fine-grained refinement. The authors further devise an iterative strategy for significant enhancement of anatomical details. Results: The authors evaluated their algorithm using a publicly available lung data that consist of 10 4D-CT cases. The authors' algorithm gives very promising results with significantly enhanced image structures and much less artifacts. Quantitative analysis shows that the authors' algorithm increases peak signal-to-noise ratio by 3-4 dB and the structural similarity index by 3%-5% when compared with the standard interpolation-based algorithms. Conclusions: The authors have developed a new algorithm to improve the resolution of 4D-CT. It outperforms the conventional interpolation-based approaches by producing images with the markedly improved structural clarity and greatly reduced artifacts.

  10. SU-E-P-03: Implementing a Low Dose Lung Screening CT Program Meeting Regulatory Requirements

    SciTech Connect (OSTI)

    LaFrance, M; Marsh, S; O'Donnell, G

    2014-06-01

    Purpose: To provide information pertaining to IROC Houston QA Center's (RPC) credentialing process for institutions participating in NCI-sponsored clinical trials. Purpose: Provide guidance to the Radiology Departments with the intent of implementing a Low Dose CT Screening Program using different CT Scanners with multiple techniques within the framework of the required state regulations. Method: State Requirements for the purpose of implementing a Low Dose CT Lung Protocol required working with the Radiology and Pulmonary Department in setting up a Low Dose Screening Protocol designed to reduce the radiation burden to the patients enrolled. Radiation dose measurements (CTDIvol) for various CT manufacturers (Siemens16, Siemens 64, Philips 64, and Neusoft128) for three different weight based protocols. All scans were reviewed by the Radiologist. Prior to starting a low dose lung screening protocol, information had to be submitted to the state for approval. Performing a Healing Arts protocol requires extensive information. This not only includes name and address of the applicant but a detailed description of the disease, the x-ray examination and the population to be examined. The unit had to be tested by a qualified expert using the technique charts. The credentials of all the operators, the supervisors and the Radiologists had to be submitted to the state. Results: All the appropriate documentation was sent to the state for review. The measured results between the Low Dose Protocol versus the default Adult Chest Protocol showed that there was a dose reduction of 65% for small (100-150 lb.) patient, 75% for the Medium patient (151-250 lbs.), and a 55% reduction for the Large patient ( over 250 lbs.). Conclusion: Measured results indicated that the Low Dose Protocol indeed lowered the screening patient's radiation dose and the institution was able to submit the protocol to the State's regulators.

  11. Mathematics of thermoacoustic and photoacoustic tomography

    E-Print Network [OSTI]

    Mathematics of thermoacoustic and photoacoustic tomography Peter Kuchment and Leonid Kunyansky in the Thermoacoustic and Photoacoustic To- mography. 1 Introduction Medical tomography has had a huge impact on medical succesfull example of such a combination is the Thermoacoustic Tomography (TAT) (also abbreviated as TCT) [50

  12. Fuzzy Modeling of Electrical Impedance Tomography Image of the Lungs

    E-Print Network [OSTI]

    Tanaka, Harki; Galizia, Mauricio Stanzione; Sobrinho, Joao Batista Borges; Amato, Marcelo Britto Passos

    2007-01-01

    Electrical Impedance Tomography (EIT) is a functional imaging method that is being developed for bedside use in critical care medicine. Aiming at improving the chest anatomical resolution of EIT images we developed a fuzzy model based on EIT high temporal resolution and the functional information contained in the pulmonary perfusion and ventilation signals. EIT data from an experimental animal model were collected during normal ventilation and apnea while an injection of hypertonic saline was used as a reference . The fuzzy model was elaborated in three parts: a modeling of the heart, a pulmonary map from ventilation images and, a pulmonary map from perfusion images. Image segmentation was performed using a threshold method and a ventilation/perfusion map was generated. EIT images treated by the fuzzy model were compared with the hypertonic saline injection method and CT-scan images, presenting good results in both qualitative (the image obtained by the model was very similar to that of the CT-scan) and quant...

  13. FMTOMOFMTOMO Fast Marching Tomography Package

    E-Print Network [OSTI]

    Rawlinson, Nick

    FMTOMOFMTOMO Fast Marching Tomography Package: Instruction Manual by Nick Rawlinson Research School;1 Introduction This document describes how to use the Fortran software package FMTOMO to perform 3-D traveltime to be reconciled. The long term goal of the FMTOMO project is to produce a comprehensive package for carrying out

  14. Iterative reconstruction using a Monte Carlo based system transfer matrix for dedicated breast positron emission tomography

    SciTech Connect (OSTI)

    Saha, Krishnendu; Straus, Kenneth J.; Glick, Stephen J.; Chen, Yu.

    2014-08-28

    To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.

  15. A One-Step Cone-Beam CT-Enabled Planning-to-Treatment Model for Palliative Radiotherapy-From Development to Implementation

    SciTech Connect (OSTI)

    Wong, Rebecca K.S.; Letourneau, Daniel; Varma, Anita; Department of Radiation Oncology, University of Toronto, Toronto, Ontario ; Bissonnette, Jean Pierre; Fitzpatrick, David; Grabarz, Daniel; Elder, Christine; Martin, Melanie; Bezjak, Andrea; Department of Radiation Oncology, University of Toronto, Toronto, Ontario ; Panzarella, Tony; Gospodarowicz, Mary; Department of Radiation Oncology, University of Toronto, Toronto, Ontario ; Jaffray, David A.; Department of Radiation Oncology, University of Toronto, Toronto, Ontario; Department of Medical Biophysics, University of Toronto, Toronto, Ontario

    2012-11-01

    Purpose: To develop a cone-beam computed tomography (CT)-enabled one-step simulation-to-treatment process for the treatment of bone metastases. Methods and Materials: A three-phase prospective study was conducted. Patients requiring palliative radiotherapy to the spine, mediastinum, or abdomen/pelvis suitable for treatment with simple beam geometry ({<=}2 beams) were accrued. Phase A established the accuracy of cone-beam CT images for the purpose of gross tumor target volume (GTV) definition. Phase B evaluated the feasibility of implementing the cone-beam CT-enabled planning process at the treatment unit. Phase C evaluated the online cone-beam CT-enabled process for the planning and treatment of patients requiring radiotherapy for bone metastases. Results: Eighty-four patients participated in this study. Phase A (n = 9) established the adequacy of cone-beam CT images for target definition. Phase B (n = 45) established the quality of treatment plans to be adequate for clinical implementation for bone metastases. When the process was applied clinically in bone metastases (Phase C), the degree of overlap between planning computed tomography (PCT) and cone-beam CT for GTV and between PCT and cone-beam CT for treatment field was 82% {+-} 11% and 97% {+-} 4%, respectively. The oncologist's decision to accept the plan under a time-pressured environment remained of high quality, with the cone-beam CT-generated treatment plan delivering at least 90% of the prescribed dose to 100% {+-} 0% of the cone-beam CT planning target volume (PTV). With the assumption that the PCT PTV is the gold-standard target, the cone-beam CT-generated treatment plan delivered at least 90% and at least 95% of dose to 98% {+-} 2% and 97% {+-} 5% of the PCT PTV, respectively. The mean time for the online planning and treatment process was 32.7 {+-} 4.0 minutes. Patient satisfaction was high, with a trend for superior satisfaction with the cone-beam CT-enabled process. Conclusions: The cone-beam CT-enabled palliative treatment process is feasible and is ready for clinical implementation for the treatment of bone metastases using simple beam geometry, providing a streamlined one-step process toward palliative radiotherapy.

  16. Statistical model based iterative reconstruction (MBIR) in clinical CT systems: Experimental assessment of noise performance

    SciTech Connect (OSTI)

    Li, Ke; Tang, Jie; Chen, Guang-Hong

    2014-04-15

    Purpose: To reduce radiation dose in CT imaging, the statistical model based iterative reconstruction (MBIR) method has been introduced for clinical use. Based on the principle of MBIR and its nonlinear nature, the noise performance of MBIR is expected to be different from that of the well-understood filtered backprojection (FBP) reconstruction method. The purpose of this work is to experimentally assess the unique noise characteristics of MBIR using a state-of-the-art clinical CT system. Methods: Three physical phantoms, including a water cylinder and two pediatric head phantoms, were scanned in axial scanning mode using a 64-slice CT scanner (Discovery CT750 HD, GE Healthcare, Waukesha, WI) at seven different mAs levels (5, 12.5, 25, 50, 100, 200, 300). At each mAs level, each phantom was repeatedly scanned 50 times to generate an image ensemble for noise analysis. Both the FBP method with a standard kernel and the MBIR method (Veo{sup }, GE Healthcare, Waukesha, WI) were used for CT image reconstruction. Three-dimensional (3D) noise power spectrum (NPS), two-dimensional (2D) NPS, and zero-dimensional NPS (noise variance) were assessed both globally and locally. Noise magnitude, noise spatial correlation, noise spatial uniformity and their dose dependence were examined for the two reconstruction methods. Results: (1) At each dose level and at each frequency, the magnitude of the NPS of MBIR was smaller than that of FBP. (2) While the shape of the NPS of FBP was dose-independent, the shape of the NPS of MBIR was strongly dose-dependent; lower dose lead to a redder NPS with a lower mean frequency value. (3) The noise standard deviation (?) of MBIR and dose were found to be related through a power law of ????(dose){sup ??} with the component ? ? 0.25, which violated the classical ????(dose){sup ?0.5} power law in FBP. (4) With MBIR, noise reduction was most prominent for thin image slices. (5) MBIR lead to better noise spatial uniformity when compared with FBP. (6) A composite image generated from two MBIR images acquired at two different dose levels (D1 and D2) demonstrated lower noise than that of an image acquired at a dose level of D1+D2. Conclusions: The noise characteristics of the MBIR method are significantly different from those of the FBP method. The well known tradeoff relationship between CT image noise and radiation dose has been modified by MBIR to establish a more gradual dependence of noise on dose. Additionally, some other CT noise properties that had been well understood based on the linear system theory have also been altered by MBIR. Clinical CT scan protocols that had been optimized based on the classical CT noise properties need to be carefully re-evaluated for systems equipped with MBIR in order to maximize the method's potential clinical benefits in dose reduction and/or in CT image quality improvement.

  17. Synchrotron-based X-ray computed tomography during compression loading of cellular materials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cordes, Nikolaus L.; Henderson, Kevin; Stannard, Tyler; Williams, Jason J.; Xiao, Xianghui; Robinson, Mathew W. C.; Schaedler, Tobias A.; Chawla, Nikhilesh; Patterson, Brian M.

    2015-04-29

    Three-dimensional X-ray computed tomography (CT) of in situ dynamic processes provides internal snapshot images as a function of time. Tomograms are mathematically reconstructed from a series of radiographs taken in rapid succession as the specimen is rotated in small angular increments. In addition to spatial resolution, temporal resolution is important. Thus temporal resolution indicates how close together in time two distinct tomograms can be acquired. Tomograms taken in rapid succession allow detailed analyses of internal processes that cannot be obtained by other means. This article describes the state-of-the-art for such measurements acquired using synchrotron radiation as the X-ray source.

  18. STRIP-PET: a novel detector concept for the TOF-PET scanner

    E-Print Network [OSTI]

    Moskal, P; Bia?as, P; Ciszewska, M; Czerwi?ski, E; Heczko, A; Kajetanowicz, M; Kap?on, ?; Kochanowski, A; Konopka-Cupia?, G; Korcyl, G; Krzemie?, W; ?ojek, K; Majewski, J; Migda?, W; Molenda, M; Nied?wiecki, Sz; Pa?ka, M; Rudy, Z; Salabura, P; Silarski, M; S?omski, A; Smyrski, J; Zdebik, J; Zieli?ski, M

    2013-01-01

    We briefly present a design of a new PET scanner based on strips of polymer scintillators arranged in a barrel constituting a large acceptance detector. The solution proposed is based on the superior timing properties of the polymer scintillators. The position and time of the reaction of the gamma quanta in the detector material will be determined based on the time of arrival of light signals to the edges of the scintillator strips.

  19. Leanness and Convenience Dimensions of Beef Products: an Exploratory Analysis Using Scanner Data.

    E-Print Network [OSTI]

    Capps, Oral Jr; Nayga, Rodolfo M. Jr.

    1991-01-01

    and the likelihood of buying lean meat products. Furthermore, no statistically significant elationship was evident between price consciousness and the likelihood of buying lean meat products. The National Academy of Sciences (Lemieux and Wohlgenant, 1988...I., 1982). Except for the work by Jourdan (1981) as well as the work by McLaughlin and Lesser (1986), few analyses of consumer demand have been conducted using scanner data. Jourdan (1981) estimated own-price and cross price elasticities of demand...

  20. The use of wavelet filters for reducing noise in posterior fossa Computed Tomography images

    SciTech Connect (OSTI)

    Pita-Machado, Reinado; Perez-Diaz, Marlen Lorenzo-Ginori, Juan V. Bravo-Pino, Rolando

    2014-11-07

    Wavelet transform based de-noising like wavelet shrinkage, gives the good results in CT. This procedure affects very little the spatial resolution. Some applications are reconstruction methods, while others are a posteriori de-noising methods. De-noising after reconstruction is very difficult because the noise is non-stationary and has unknown distribution. Therefore, methods which work on the sinogram-space dont have this problem, because they always work over a known noise distribution at this point. On the other hand, the posterior fossa in a head CT is a very complex region for physicians, because it is commonly affected by artifacts and noise which are not eliminated during the reconstruction procedure. This can leads to some false positive evaluations. The purpose of our present work is to compare different wavelet shrinkage de-noising filters to reduce noise, particularly in images of the posterior fossa within CT scans in the sinogram-space. This work describes an experimental search for the best wavelets, to reduce Poisson noise in Computed Tomography (CT) scans. Results showed that de-noising with wavelet filters improved the quality of posterior fossa region in terms of an increased CNR, without noticeable structural distortions.

  1. A multispectral scanner survey of the United States Department of Energy's Paducah Gaseous Diffusion Plant

    SciTech Connect (OSTI)

    Not Available

    1991-06-01

    Airborne multispectral scanner data of the Paducah Gaseous Diffusion Plant (PGDP) and surrounding area were acquired during late spring 1990. This survey was conducted by the Remote Sensing Laboratory (RSL) which is operated by EG G Energy Measurements (EG G/EM) for the US Department of Energy (DOE) Nevada Operations Office. It was requested by the US Department of Energy (DOE) Environmental Audit Team which was reviewing environmental conditions at the facility. The objectives of this survey were to: (1) Acquire 12-channel, multispectral scanner data of the PGDP from an altitude of 3000 feet above ground level (AGL); (2) Acquire predawn, digital thermal infrared (TIR) data of the site from the same altitude; (3) Collect color and color-infrared (CIR) aerial photographs over the facilities; and (4) Illustrate how the analyses of these data could benefit environmental monitoring at the PGDP. This report summarizes the two multispectral scanner and aerial photographic missions at the Paducah Gaseous Diffusion Plant. Selected examples of the multispectral data are presented to illustrate its potential for aiding environmental management at the site. 4 refs., 1 fig., 2 tabs.

  2. Earthquake Forecast via Neutrino Tomography

    E-Print Network [OSTI]

    Bin Wang; Ya-Zheng Chen; Xue-Qian Li

    2011-03-29

    We discuss the possibility of forecasting earthquakes by means of (anti)neutrino tomography. Antineutrinos emitted from reactors are used as a probe. As the antineutrinos traverse through a region prone to earthquakes, observable variations in the matter effect on the antineutrino oscillation would provide a tomography of the vicinity of the region. In this preliminary work, we adopt a simplified model for the geometrical profile and matter density in a fault zone. We calculate the survival probability of electron antineutrinos for cases without and with an anomalous accumulation of electrons which can be considered as a clear signal of the coming earthquake, at the geological region with a fault zone, and find that the variation may reach as much as 3% for $\\bar \

  3. Computed tomography image using sub-terahertz waves generated from a high-T{sub c} superconducting intrinsic Josephson junction oscillator

    SciTech Connect (OSTI)

    Kashiwagi, T., E-mail: kashiwagi@ims.tsukuba.ac.jp; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Markovi?, B. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Mirkovi?, J. [Faculty of Science, University of Montenegro, and CETI, Put Radomira Ivanovica, 81000 Podgorica (Montenegro); Klemm, R. A. [Department of Physics, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816-2385 (United States)

    2014-02-24

    A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-T{sub c} superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?} was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications.

  4. Non-medical Uses of Computed Tomography (CT) and Nuclear Magnetic Resonance

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJessework usesofPublications64Newsroom NewsroomNomination &ofdefault

  5. Algorithm for Rapid Tomography of Gas Concentrations

    E-Print Network [OSTI]

    Price, P.N.

    2008-01-01

    sensing and computed tomography in industrial hygiene.American Industrial Hygiene Association Journal 51: 1165-indoor air. American Industrial Hygiene Association Journal

  6. On reconstruction and time reversal in thermoacoustic tomography in acoustically

    E-Print Network [OSTI]

    Kuchment, Peter

    On reconstruction and time reversal in thermoacoustic tomography in acoustically homogeneous of recent approaches to the reconstruction in thermoacoustic/photoacoustic tomography: backprojection of the problem of sound speed recovery is also provided. Keywords: Tomography, thermoacoustic, wave equation. AMS

  7. Fourier Transform Quantum State Tomography

    E-Print Network [OSTI]

    Mohammadreza Mohammadi; Agata M. Branczyk; Daniel F. V. James

    2013-01-17

    We propose a technique for performing quantum state tomography of photonic polarization-encoded multi-qubit states. Our method uses a single rotating wave plate, a polarizing beam splitter and two photon-counting detectors per photon mode. As the wave plate rotates, the photon counters measure a pseudo-continuous signal which is then Fourier transformed. The density matrix of the state is reconstructed using the relationship between the Fourier coefficients of the signal and the Stokes' parameters that represent the state. The experimental complexity, i.e. different wave plate rotation frequencies, scales linearly with the number of qubits.

  8. Thermoacoustic Tomography in Elastic Media

    E-Print Network [OSTI]

    Justin Tittelfitz

    2011-10-11

    We investigate the problem of recovering the initial displacement f for a solution u of a linear, isotropic, non-homogeneous elastic wave equation, given measurements of u on [0,T] x \\partial \\Omega, where \\Omega\\subset\\R^3 is some bounded domain containing the support of f. For the acoustic wave equation, this problem is known as thermoacoustic tomography (TAT), and has been well-studied; for the elastic wave equation, the situation is somewhat more subtle, and we give sufficient conditions on the Lam\\'e parameters to ensure that recovery is possible.

  9. NEUTRON IMAGING, RADIOGRAPHY AND TOMOGRAPHY.

    SciTech Connect (OSTI)

    SMITH,G.C.

    2002-03-01

    Neutrons are an invaluable probe in a wide range of scientific, medical and commercial endeavors. Many of these applications require the recording of an image of the neutron signal, either in one-dimension or in two-dimensions. We summarize the reactions of neutrons with the most important elements that are used for their detection. A description is then given of the major techniques used in neutron imaging, with emphasis on the detection media and position readout principle. Important characteristics such as position resolution, linearity, counting rate capability and sensitivity to gamma-background are discussed. Finally, the application of a subset of these instruments in radiology and tomography is described.

  10. ADAPTIVE AND ROBUST TECHNIQUES (ART) FOR THERMOACOUSTIC TOMOGRAPHY

    E-Print Network [OSTI]

    Xie, Yao

    ADAPTIVE AND ROBUST TECHNIQUES (ART) FOR THERMOACOUSTIC TOMOGRAPHY By YAO XIE A DISSERTATION.1 Thermoacoustic Tomography . . . . . . . . . . . . . . . . . . . . . 1 1.2 Image Reconstruction Algorithms for TAT

  11. Lung Tumors Treated With Percutaneous Radiofrequency Ablation: Computed Tomography Imaging Follow-Up

    SciTech Connect (OSTI)

    Palussiere, Jean, E-mail: palussiere@bergonie.org; Marcet, Benjamin; Descat, Edouard [Institut Bergonie, Regional Cancer Center, Department of Interventional Radiology (France); Deschamps, Frederic; Rao, Pramod [Institut Gustave Roussy, Department of Interventional Radiology (France); Ravaud, Alain [Hopital Saint-Andre, Department of Medical Oncology (France); Brouste, Veronique [Institut Bergonie, Department of Biostatistics (France); Baere, Thierry de [Institut Gustave Roussy, Department of Interventional Radiology (France)

    2011-10-15

    Purpose: To describe the morphologic evolution of lung tumors treated with radiofrequency ablation (RFA) by way of computed tomography (CT) images and to investigate patterns of incomplete RFA at the site of ablation. Materials and Methods: One hundred eighty-nine patients with 350 lung tumors treated with RFA underwent CT imaging at 2, 4, 6, and 12 months. CT findings were interpreted separately by two reviewers with consensus. Five different radiologic patterns were predefined: fibrosis, cavitation, nodule, atelectasis, and disappearance. The appearance of the treated area was evaluated at each follow-up CT using the predefined patterns. Results: At 1 year after treatment, the most common evolutions were fibrosis (50.5%) or nodules (44.8%). Differences were noted depending on the initial size of the tumor, with fibrosis occurring more frequently for tumors <2 cm (58.6% vs. 22.9%, P = 1 Multiplication-Sign 10{sup -5}). Cavitation and atelectasis were less frequent patterns (2.4% and 1.4%, respectively, at 1 year). Tumor location (intraparenchymatous, with pleural contact <50% or >50%) was not significantly correlated with follow-up image pattern. Local tumor progressions were observed with each type of evolution. At 1 year, 12 local recurrences were noted: 2 cavitations, which represented 40% of the cavitations noted at 1 year; 2 fibroses (1.9%); 7 nodules (7.4%); and 1 atelectasis (33.3%). Conclusion: After RFA of lung tumors, follow-up CT scans show that the shape of the treatment zone can evolve in five different patterns. None of these patterns, however, can confirm the absence of further local tumor progression at subsequent follow-up.

  12. Efficiency of quantum state tomography for qubits

    E-Print Network [OSTI]

    Koichi Yamagata

    2011-05-19

    The efficiency of quantum state tomography is discussed from the point of view of quantum parameter estimation theory, in which the trace of the weighted covariance is to be minimized. It is shown that tomography is optimal only when a special weight is adopted.

  13. SU-E-I-82: Improving CT Image Quality for Radiation Therapy Using Iterative Reconstruction Algorithms and Slightly Increasing Imaging Doses

    SciTech Connect (OSTI)

    Noid, G; Chen, G; Tai, A; Li, X

    2014-06-01

    Purpose: Iterative reconstruction (IR) algorithms are developed to improve CT image quality (IQ) by reducing noise without diminishing spatial resolution or contrast. For CT in radiation therapy (RT), slightly increasing imaging dose to improve IQ may be justified if it can substantially enhance structure delineation. The purpose of this study is to investigate and to quantify the IQ enhancement as a result of increasing imaging doses and using IR algorithms. Methods: CT images were acquired for phantoms, built to evaluate IQ metrics including spatial resolution, contrast and noise, with a variety of imaging protocols using a CT scanner (Definition AS Open, Siemens) installed inside a Linac room. Representative patients were scanned once the protocols were optimized. Both phantom and patient scans were reconstructed using the Sinogram Affirmed Iterative Reconstruction (SAFIRE) and the Filtered Back Projection (FBP) methods. IQ metrics of the obtained CTs were compared. Results: IR techniques are demonstrated to preserve spatial resolution as measured by the point spread function and reduce noise in comparison to traditional FBP. Driven by the reduction in noise, the contrast to noise ratio is doubled by adopting the highest SAFIRE strength. As expected, increasing imaging dose reduces noise for both SAFIRE and FBP reconstructions. The contrast to noise increases from 3 to 5 by increasing the dose by a factor of 4. Similar IQ improvement was observed on the CTs for selected patients with pancreas and prostrate cancers. Conclusion: The IR techniques produce a measurable enhancement to CT IQ by reducing the noise. Increasing imaging dose further reduces noise independent of the IR techniques. The improved CT enables more accurate delineation of tumors and/or organs at risk during RT planning and delivery guidance.

  14. Noise variance analysis using a flat panel x-ray detector: A method for additive noise assessment with application to breast CT applications

    SciTech Connect (OSTI)

    Yang Kai; Huang, Shih-Ying; Packard, Nathan J.; Boone, John M. [Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100 Ellison Building, Sacramento, California 95817 (United States); Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100 Ellison Building, Sacramento, California 95817 (United States) and Department of Biomedical Engineering, University of California, Davis, Davis, California, 95616 (United States)

    2010-07-15

    Purpose: A simplified linear model approach was proposed to accurately model the response of a flat panel detector used for breast CT (bCT). Methods: Individual detector pixel mean and variance were measured from bCT projection images acquired both in air and with a polyethylene cylinder, with the detector operating in both fixed low gain and dynamic gain mode. Once the coefficients of the linear model are determined, the fractional additive noise can be used as a quantitative metric to evaluate the system's efficiency in utilizing x-ray photons, including the performance of different gain modes of the detector. Results: Fractional additive noise increases as the object thickness increases or as the radiation dose to the detector decreases. For bCT scan techniques on the UC Davis prototype scanner (80 kVp, 500 views total, 30 frames/s), in the low gain mode, additive noise contributes 21% of the total pixel noise variance for a 10 cm object and 44% for a 17 cm object. With the dynamic gain mode, additive noise only represents approximately 2.6% of the total pixel noise variance for a 10 cm object and 7.3% for a 17 cm object. Conclusions: The existence of the signal-independent additive noise is the primary cause for a quadratic relationship between bCT noise variance and the inverse of radiation dose at the detector. With the knowledge of the additive noise contribution to experimentally acquired images, system modifications can be made to reduce the impact of additive noise and improve the quantum noise efficiency of the bCT system.

  15. Dose reconstruction for real-time patient-specific dose estimation in CT

    SciTech Connect (OSTI)

    De Man, Bruno Yin, Zhye; Wu, Mingye; FitzGerald, Paul; Kalra, Mannudeep

    2015-05-15

    Purpose: Many recent computed tomography (CT) dose reduction approaches belong to one of three categories: statistical reconstruction algorithms, efficient x-ray detectors, and optimized CT acquisition schemes with precise control over the x-ray distribution. The latter category could greatly benefit from fast and accurate methods for dose estimation, which would enable real-time patient-specific protocol optimization. Methods: The authors present a new method for volumetrically reconstructing absorbed dose on a per-voxel basis, directly from the actual CT images. The authors specific implementation combines a distance-driven pencil-beam approach to model the first-order x-ray interactions with a set of Gaussian convolution kernels to model the higher-order x-ray interactions. The authors performed a number of 3D simulation experiments comparing the proposed method to a Monte Carlo based ground truth. Results: The authors results indicate that the proposed approach offers a good trade-off between accuracy and computational efficiency. The images show a good qualitative correspondence to Monte Carlo estimates. Preliminary quantitative results show errors below 10%, except in bone regions, where the authors see a bigger model mismatch. The computational complexity is similar to that of a low-resolution filtered-backprojection algorithm. Conclusions: The authors present a method for analytic dose reconstruction in CT, similar to the techniques used in radiation therapy planning with megavoltage energies. Future work will include refinements of the proposed method to improve the accuracy as well as a more extensive validation study. The proposed method is not intended to replace methods that track individual x-ray photons, but the authors expect that it may prove useful in applications where real-time patient-specific dose estimation is required.

  16. Computer assisted gamma and X-ray tomography: Applications to multiphase flow systems

    SciTech Connect (OSTI)

    Kumar, S.B.; Dudukovic, M.

    1998-01-01

    In process vessels, involving two or three phases it is often important not only to know the volume fraction (holdup) of each phase but also the spatial distribution of such holdups. This information is needed in control, trouble shooting and assessment of flow patterns and can be observed noninvasively by the application of Computed Tomography (CT). This report presents a complete overview of X-ray and gamma ray transmission tomography principles, equipment design to specific tasks and application in process industry. The fundamental principles of tomography, the algorithms for image reconstruction, the measurement method and the possible sources of error are discussed in detail. A case study highlights the methodology involved in designing a scanning system for the study of a given process unit, e.g., reactor, separations column etc. Results obtained in the authors` laboratory for the gas holdup distribution in bubble columns are also presented. Recommendations are made for the Advanced Fuels Development Unit (AFDU) in LaPorte, TX.

  17. Compensator models for fluence field modulated computed tomography

    SciTech Connect (OSTI)

    Bartolac, Steven; Jaffray, David; Radiation Medicine Program, Princess Margaret Hospital Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9

    2013-12-15

    Purpose: Fluence field modulated computed tomography (FFMCT) presents a novel approach for acquiring CT images, whereby a patient model guides dynamically changing fluence patterns in an attempt to achieve task-based, user-prescribed, regional variations in image quality, while also controlling dose to the patient. This work aims to compare the relative effectiveness of FFMCT applied to different thoracic imaging tasks (routine diagnostic CT, lung cancer screening, and cardiac CT) when the modulator is subject to limiting constraints, such as might be present in realistic implementations.Methods: An image quality plan was defined for a simulated anthropomorphic chest slice, including regions of high and low image quality, for each of the thoracic imaging tasks. Modulated fluence patterns were generated using a simulated annealing optimization script, which attempts to achieve the image quality plan under a global dosimetric constraint. Optimization was repeated under different types of modulation constraints (e.g., fixed or gantry angle dependent patterns, continuous or comprised of discrete apertures) with the most limiting case being a fixed conventional bowtie filter. For each thoracic imaging task, an image quality map (IQM{sub sd}) representing the regionally varying standard deviation is predicted for each modulation method and compared to the prescribed image quality plan as well as against results from uniform fluence fields. Relative integral dose measures were also compared.Results: Each IQM{sub sd} resulting from FFMCT showed improved agreement with planned objectives compared to those from uniform fluence fields for all cases. Dynamically changing modulation patterns yielded better uniformity, improved image quality, and lower dose compared to fixed filter patterns with optimized tube current. For the latter fixed filter cases, the optimal choice of tube current modulation was found to depend heavily on the task. Average integral dose reduction compared to a uniform fluence field ranged from 10% using a bowtie filter to 40% or greater using an idealized modulator.Conclusions: The results support that FFMCT may achieve regionally varying image quality distributions in good agreement with user-prescribed values, while limiting dose. The imposition of constraints inhibits dose reduction capacity and agreement with image quality plans but still yields significant improvement over what is afforded by conventional dose minimization techniques. These results suggest that FFMCT can be implemented effectively even when the modulator has limited modulation capabilities.

  18. Automated detection of lung nodules in low-dose computed tomography

    E-Print Network [OSTI]

    Cascio, D; Chincarini, A; De Nunzio, G; Delogu, P; Fantacci, M E; Gargano, G; Gori, I; Masala, G L; Martinez, A Preite; Retico, A; Santoro, M; Spinelli, C; Tarantino, T

    2007-01-01

    A computer-aided detection (CAD) system for the identification of pulmonary nodules in low-dose multi-detector computed-tomography (CT) images has been developed in the framework of the MAGIC-5 Italian project. One of the main goals of this project is to build a distributed database of lung CT scans in order to enable automated image analysis through a data and cpu GRID infrastructure. The basic modules of our lung-CAD system, consisting in a 3D dot-enhancement filter for nodule detection and a neural classifier for false-positive finding reduction, are described. The system was designed and tested for both internal and sub-pleural nodules. The database used in this study consists of 17 low-dose CT scans reconstructed with thin slice thickness (~300 slices/scan). The preliminary results are shown in terms of the FROC analysis reporting a good sensitivity (85% range) for both internal and sub-pleural nodules at an acceptable level of false positive findings (1-9 FP/scan); the sensitivity value remains very hig...

  19. Implementation and commissioning of an integrated micro-CT/RT system with computerized independent jaw collimation

    SciTech Connect (OSTI)

    Jensen, Michael D.; Hrinivich, W. Thomas; Jung, Jongho A.; Holdsworth, David W.; Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7; Department of Surgery, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 ; Drangova, Maria; Chen, Jeff; Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7; Department of Oncology, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 ; Wong, Eugene; Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7; Department of Oncology, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7; Department of Physics and Engineering, London Regional Cancer Program, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario N6A 5W9

    2013-08-15

    Purpose: To design, construct, and commission a set of computer-controlled motorized jaws for a micro-CT/RT system to perform conformal image-guided small animal radiotherapy.Methods: The authors designed and evaluated a system of custom-built motorized orthogonal jaws, which allows the delivery of off-axis rectangular fields on a GE eXplore CT 120 preclinical imaging system. The jaws in the x direction are independently driven, while the y-direction jaws are symmetric. All motors have backup encoders, verifying jaw positions. Mechanical performance of the jaws was characterized. Square beam profiles ranging from 2 2 to 60 60 mm{sup 2} were measured using EBT2 film in the center of a 70 70 22 mm{sup 3} solid water block. Similarly, absolute depth dose was measured in a solid water and EBT2 film stack 50 50 50 mm{sup 3}. A calibrated Farmer ion chamber in a 70 70 20 mm{sup 3} solid water block was used to measure the output of three field sizes: 50 50, 40 40, and 30 30 mm{sup 2}. Elliptical target plans were delivered to films to assess overall system performance. Respiratory-gated treatment was implemented on the system and initially proved using a simple sinusoidal motion phantom. All films were scanned on a flatbed scanner (Epson 1000XL) and converted to dose using a fitted calibration curve. A Monte Carlo beam model of the micro-CT with the jaws has been created using BEAMnrc for comparison with the measurements. An example image-guided partial lung irradiation in a rat is demonstrated.Results: The averaged random error of positioning each jaw is less than 0.1 mm. Relative output factors measured with the ion chamber agree with Monte Carlo simulations within 2%. Beam profiles and absolute depth dose curves measured from the films agree with simulations within measurement uncertainty. Respiratory-gated treatments applied to a phantom moving with a peak-to-peak amplitude of 5 mm showed improved beam penumbra (80%20%) from 3.9 to 0.8 mm.Conclusions: A set of computer-controlled motorized jaws for a micro-CT/RT system were constructed with position reliably better than a tenth of a millimeter. The hardware system is ready for image-guided conformal radiotherapy for small animals with capability of respiratory-gated delivery.

  20. Model-based PSF and MTF estimation and validation from skeletal clinical CT images

    SciTech Connect (OSTI)

    Pakdel, Amirreza; Mainprize, James G.; Robert, Normand; Fialkov, Jeffery; Whyne, Cari M.

    2014-01-15

    Purpose: A method was developed to correct for systematic errors in estimating the thickness of thin bones due to image blurring in CT images using bone interfaces to estimate the point-spread-function (PSF). This study validates the accuracy of the PSFs estimated using said method from various clinical CT images featuring cortical bones. Methods: Gaussian PSFs, characterized by a different extent in the z (scan) direction than in the x and y directions were obtained using our method from 11 clinical CT scans of a cadaveric craniofacial skeleton. These PSFs were estimated for multiple combinations of scanning parameters and reconstruction methods. The actual PSF for each scan setting was measured using the slanted-slit technique within the image slice plane and the longitudinal axis. The Gaussian PSF and the corresponding modulation transfer function (MTF) are compared against the actual PSF and MTF for validation. Results: The differences (errors) between the actual and estimated full-width half-max (FWHM) of the PSFs were 0.09 0.05 and 0.14 0.11 mm for the xy and z axes, respectively. The overall errors in the predicted frequencies measured at 75%, 50%, 25%, 10%, and 5% MTF levels were 0.06 0.07 and 0.06 0.04 cycles/mm for the xy and z axes, respectively. The accuracy of the estimates was dependent on whether they were reconstructed with a standard kernel (Toshiba's FC68, mean error of 0.06 0.05 mm, MTF mean error 0.02 0.02 cycles/mm) or a high resolution bone kernel (Toshiba's FC81, PSF FWHM error 0.12 0.03 mm, MTF mean error 0.09 0.08 cycles/mm). Conclusions: The method is accurate in 3D for an image reconstructed using a standard reconstruction kernel, which conforms to the Gaussian PSF assumption but less accurate when using a high resolution bone kernel. The method is a practical and self-contained means of estimating the PSF in clinical CT images featuring cortical bones, without the need phantoms or any prior knowledge about the scanner-specific parameters.

  1. Wireless Tomography, Part II: A System Engineering Approach

    E-Print Network [OSTI]

    Qiu, Robert Caiming

    Wireless Tomography, Part II: A System Engineering Approach R. C. Qiu, Z. Hu, M. C. Wicks, S. J.Wicks@rl.af.mil Abstract--This is the second paper in a series on a new initiative of wireless tomography. The goal is to combine two areas: wireless communication and radio tomography. This paper studies wireless tomography

  2. Diffraction tomography with Fourier ptychography

    E-Print Network [OSTI]

    Horstmeyer, Roarke

    2015-01-01

    This article presents a method to perform diffraction tomography in a standard microscope that includes an LED array for illumination. After acquiring a sequence of intensity-only images of a thick sample, a ptychography-based reconstruction algorithm solves for its unknown complex index of refraction across three dimensions. The experimental microscope demonstrates a spatial resolution of 0.39 $\\mu$m and an axial resolution of 3.7 $\\mu$m at the Nyquist-Shannon sampling limit (0.54 $\\mu$m and 5.0 $\\mu$m at the Sparrow limit, respectively), across a total imaging volume of 2.2 mm $\\times$ 2.2 mm $\\times$ 110 $\\mu$m. Unlike competing methods, the 3D tomograms presented in this article are continuous, quantitative, and formed without the need for interferometry or any moving parts. Wide field-of-view reconstructions of thick biological specimens demonstrate potential applications in pathology and developmental biology.

  3. Collimator-free photon tomography

    DOE Patents [OSTI]

    Dilmanian, F. Avraham (Yaphank, NY); Barbour, Randall L. (Westbury, NY)

    1998-10-06

    A method of uncollimated single photon emission computed tomography includes administering a radioisotope to a patient for producing gamma ray photons from a source inside the patient. Emissivity of the photons is measured externally of the patient with an uncollimated gamma camera at a plurality of measurement positions surrounding the patient for obtaining corresponding energy spectrums thereat. Photon emissivity at the plurality of measurement positions is predicted using an initial prediction of an image of the source. The predicted and measured photon emissivities are compared to obtain differences therebetween. Prediction and comparison is iterated by updating the image prediction until the differences are below a threshold for obtaining a final prediction of the source image.

  4. Collimator-free photon tomography

    DOE Patents [OSTI]

    Dilmanian, F.A.; Barbour, R.L.

    1998-10-06

    A method of uncollimated single photon emission computed tomography includes administering a radioisotope to a patient for producing gamma ray photons from a source inside the patient. Emissivity of the photons is measured externally of the patient with an uncollimated gamma camera at a plurality of measurement positions surrounding the patient for obtaining corresponding energy spectrums thereat. Photon emissivity at the plurality of measurement positions is predicted using an initial prediction of an image of the source. The predicted and measured photon emissivities are compared to obtain differences therebetween. Prediction and comparison is iterated by updating the image prediction until the differences are below a threshold for obtaining a final prediction of the source image. 6 figs.

  5. Evaluation of pore structures and cracking in cement paste exposed to elevated temperatures by X-ray computed tomography

    SciTech Connect (OSTI)

    Kim, Kwang Yeom, E-mail: kimky@kict.re.kr [Korea Institute of Construction Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang 411-712 (Korea, Republic of); Yun, Tae Sup, E-mail: taesup@yonsei.ac.kr [School of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Park, Kwang Pil, E-mail: bamtol97@kict.re.kr [Korea Institute of Construction Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang 411-712 (Korea, Republic of)

    2013-08-15

    When cement-based materials are exposed to the high temperatures induced by fire, which can rapidly cause temperatures of over 1000 C, the changes in pore structure and density prevail. In the present study, mortar specimens were subjected to a series of increasing temperatures to explore the temperature-dependent evolution of internal pore structure. High-performance X-ray computed tomography (CT) was used to observe the evolution of temperature-induced discontinuities at the sub-millimeter level. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate the cause of physical changes in the heated mortar specimens. Results exhibit the changes in pore structure caused by elevated temperatures, and thermally induced fractures. We discuss the progressive formation of thermally induced fracture networks, which is a prerequisite for spalling failure of cement-based materials by fire, based on visual observations of the 3D internal structures revealed by X-ray CT.

  6. Computed tomography and optical remote sensing: Development for the study of indoor air pollutant transport and dispersion

    SciTech Connect (OSTI)

    Drescher, A.C.

    1995-06-01

    This thesis investigates the mixing and dispersion of indoor air pollutants under a variety of conditions using standard experimental methods. It also extensively tests and improves a novel technique for measuring contaminant concentrations that has the potential for more rapid, non-intrusive measurements with higher spatial resolution than previously possible. Experiments conducted in a sealed room support the hypothesis that the mixing time of an instantaneously released tracer gas is inversely proportional to the cube root of the mechanical power transferred to the room air. One table-top and several room-scale experiments are performed to test the concept of employing optical remote sensing (ORS) and computed tomography (CT) to measure steady-state gas concentrations in a horizontal plane. Various remote sensing instruments, scanning geometries and reconstruction algorithms are employed. Reconstructed concentration distributions based on existing iterative CT techniques contain a high degree of unrealistic spatial variability and do not agree well with simultaneously gathered point-sample data.

  7. Dual-Energy Micro-Computed Tomography Imaging of Radiation-Induced Vascular Changes in Primary Mouse Sarcomas

    SciTech Connect (OSTI)

    Moding, Everett J. [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States)] [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States); Clark, Darin P.; Qi, Yi [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States)] [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Li, Yifan; Ma, Yan [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)] [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Ghaghada, Ketan [The Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston, Texas (United States)] [The Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston, Texas (United States); Johnson, G. Allan [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States)] [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Kirsch, David G. [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States) [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Badea, Cristian T., E-mail: cristian.badea@duke.edu [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States)

    2013-04-01

    Purpose: To evaluate the effects of radiation therapy on primary tumor vasculature using dual-energy (DE) micro-computed tomography (micro-CT). Methods and Materials: Primary sarcomas were generated with mutant Kras and p53. Unirradiated tumors were compared with tumors irradiated with 20 Gy. A liposomal-iodinated contrast agent was administered 1 day after treatment, and mice were imaged immediately after injection (day 1) and 3 days later (day 4) with DE micro-CT. CT-derived tumor sizes were used to assess tumor growth. After DE decomposition, iodine maps were used to assess tumor fractional blood volume (FBV) at day 1 and tumor vascular permeability at day 4. For comparison, tumor vascularity and vascular permeability were also evaluated histologically by use of CD31 immunofluorescence and fluorescently-labeled dextrans. Results: Radiation treatment significantly decreased tumor growth from day 1 to day 4 (P<.05). There was a positive correlation between CT measurement of tumor FBV on day 1 and extravasated iodine on day 4 with microvascular density (MVD) on day 4 (R{sup 2}=0.53) and dextran accumulation (R{sup 2}=0.63) on day 4, respectively. Despite no change in MVD measured by histology, tumor FBV significantly increased after irradiation as measured by DE micro-CT (0.070 vs 0.091, P<.05). Both dextran and liposomal-iodine accumulation in tumors increased significantly after irradiation, with dextran fractional area increasing 5.2-fold and liposomal-iodine concentration increasing 4.0-fold. Conclusions: DE micro-CT is an effective tool for noninvasive assessment of vascular changes in primary tumors. Tumor blood volume and vascular permeability increased after a single therapeutic dose of radiation treatment.

  8. Tomography of lensing cross power spectra

    E-Print Network [OSTI]

    Masahiro Takada; Martin White

    2004-09-14

    By obtaining photometric redshift information, tomography allows us to cross-correlate galaxy ellipticities in different source redshift bins. The cross-correlation is non-vanishing because the different bins share much of the foreground mass distribution from which, over Gpc scales, the lensing signal is built. If the redshift bins are thick enough however, the cross-correlations are insensitive to contamination from the intrinsic alignments of galaxies since these fall off rapidly on scales larger than a few tens of Mpc. We forecast how lensing tomography using only the cross-power spectra can constrain cosmological parameters compared to tomography including the auto-spectra. It is shown that the parameter errors are degraded by only O(10%) for 5 or more source redshift bins. Thus, the cross-power spectrum tomography can be a simple, model-independent means of reducing the intrinsic alignment contamination while retaining most of the constraints on cosmology.

  9. Quantile tomography: using quantiles with multivariate data,

    E-Print Network [OSTI]

    Jin, Jiashun

    Quantile tomography: using quantiles with multivariate data, with applications to multivariate at smooth boundary points. They can be viewed as a natural, nonparametric extension of "multivariate quantiles" yielded by fitted multivariate normal distribution, and, as illustrated on data examples

  10. Seismic interferometry and non-linear tomography

    E-Print Network [OSTI]

    Galetti, Erica

    2015-06-30

    Seismic records contain information that allows geoscientists to make inferences about the structure and properties of the Earths interior. Traditionally, seismic imaging and tomography methods require wavefields to be ...

  11. Level-set segmentation of pulmonary nodules in megavolt electronic portal images using a CT prior

    SciTech Connect (OSTI)

    Schildkraut, J. S.; Prosser, N.; Savakis, A.; Gomez, J.; Nazareth, D.; Singh, A. K.; Malhotra, H. K.

    2010-11-15

    Purpose: Pulmonary nodules present unique problems during radiation treatment due to nodule position uncertainty that is caused by respiration. The radiation field has to be enlarged to account for nodule motion during treatment. The purpose of this work is to provide a method of locating a pulmonary nodule in a megavolt portal image that can be used to reduce the internal target volume (ITV) during radiation therapy. A reduction in the ITV would result in a decrease in radiation toxicity to healthy tissue. Methods: Eight patients with nonsmall cell lung cancer were used in this study. CT scans that include the pulmonary nodule were captured with a GE Healthcare LightSpeed RT 16 scanner. Megavolt portal images were acquired with a Varian Trilogy unit equipped with an AS1000 electronic portal imaging device. The nodule localization method uses grayscale morphological filtering and level-set segmentation with a prior. The treatment-time portion of the algorithm is implemented on a graphical processing unit. Results: The method was retrospectively tested on eight cases that include a total of 151 megavolt portal image frames. The method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases. The treatment phase portion of the method has a subsecond execution time that makes it suitable for near-real-time nodule localization. Conclusions: A method was developed to localize a pulmonary nodule in a megavolt portal image. The method uses the characteristics of the nodule in a prior CT scan to enhance the nodule in the portal image and to identify the nodule region by level-set segmentation. In a retrospective study, the method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases studied.

  12. Regularized Equally Sloped Tomography Algorithm for Low Dose X-Ray Computed Tomography

    E-Print Network [OSTI]

    Zhao, Yunzhe

    2012-01-01

    benefits most for the low dose radiation CT protocols, whenet al. Exposure to low-dose ionizing radiation from medicalobtained from low radiation dose. In theory, radiation dose

  13. Studying Brazil-Nut Effect History Line using Disk-Formed Objects, Scanner, and Web Browser

    E-Print Network [OSTI]

    Sparisoma Viridi; Siti Nurul Khotimah; Novitrian; Widayani; Luman Haris; Dimas Praja Purwa Aji

    2014-08-07

    Grains configuration snapshots of Brazil-nut effect (BNE) in two-dimension are physically modeled using disk-formed objects, e.g., buttons and magnetic pin. These BNE configurations are artificially designed to mimic the real ones observed in experiments. A computer scanner is used to capture the configurations. Obtained images are then digitized using web browser running a HTML equipped with a JavaScript code, which is built mainly only for this work. From digitization process all grains positions (granular bed and intruder) are obtained, which is later analyzed using the simplest model, i.e., potential energy. Since the minimum energy principle (MEP) suggests that a closed system should go to its state with minimum internal energy, our BNE system must also obey it. Evolution of only the intruder seems to violate MEP but not for the whole system. Grains compaction plays important role, so that the system can achieve its configuration with minimum potential energy.

  14. Ionisation losses and wire scanner heating evaluation, possible solutions, application to the LHC

    E-Print Network [OSTI]

    Fischer, C

    2000-01-01

    Harmful heating mechanisms, resulting in wire breakage, limit the utilisation of wire scanner monitors to below a given beam intensity. This threshold depends on the accelerator design parameters. In lepton colliders, the short beam bunches generate strong wake-fields inside the vacuum pipe which are sensed by the wire and are the predominant current limit. These effects can be minimised by a smooth design of the monitor cross section and by choosing a wire made of an insulating material [1]. A second source of energy deposition inside the wire, also present in hadron machines, and even when the wire material is insulating, results from collision and ionisation of the wire material atoms by the incident beam particles. Calculations are presented to evaluate the efficiency of this process and a possible solution is suggested which may reduce this limitation. An example is given for the case of the LHC.

  15. Wind Scanner: A full-scale Laser Facility for Wind and Turbulence Measurements around large Wind Turbines

    E-Print Network [OSTI]

    Wind Scanner: A full-scale Laser Facility for Wind and Turbulence Measurements around large Wind Turbines Torben Mikkelsen, Jakob Mann and Michael Courtney Wind Energy Department, Ris National Laboratory:Torben.Mikkelsen@Risoe.dk Summary RIS DTU has started to build a newly designed laser-based lidar scanning facility for remote wind

  16. Real-Time, Non-Contact Plant Growth Monitoring at Microscopic Levels using 3D Laser Scanner.

    E-Print Network [OSTI]

    Barron, John

    Real-Time, Non-Contact Plant Growth Monitoring at Microscopic Levels using 3D Laser Scanner. M differential inspection techniques applied to plant growth monitoring. Experimental results shows growth rate of detailed plants and leaves motion. Such studies have been made on single or few leaves at a time

  17. Sensor Fusion for Improved Control of Piezoelectric Tube Scanners Andrew J. Fleming Adrian Wills S. O. Reza Moheimani

    E-Print Network [OSTI]

    Fleming, Andrew J.

    lateral deflection of the tube tip. Piezoelectric tubes are used extensively in applications requiring1 Sensor Fusion for Improved Control of Piezoelectric Tube Scanners Andrew J. Fleming Adrian Wills is augmented with the high dynamic sensitivity of piezoelectric transducers. By combining the low- frequency

  18. Title: NMR scanner with motion zeugmatography Patent Number: 04516075 (U.S. patents which cite this patent)

    E-Print Network [OSTI]

    Walker, Thad G.

    Title: NMR scanner with motion zeugmatography Patent Number: 04516075 (U.S. patents which cite this patent) Issue Date: 05-07-1985 Application Date: 01-04-1983 Application Number: 455596 Inventor(s): Name Patents Number Date Inventor 04015196 1977-03 Moore et al. 04021726 1977-05 Garroway et al. 04070611 1978

  19. Dealing with Laser Scanner Failure: Mirrors and Windows Shao-Wen Yang and Chieh-Chih Wang

    E-Print Network [OSTI]

    Wang, Chieh-Chih "Bob"

    such as mirror reflection and glass transparency. We introduce a sensor fusion technique to detect the potential the round-trip time of a pulse of light. Laser scanners can send light photons toward an object and only and a black surface will reflect only a small amount of light. Transparent objects such as glasses will only

  20. 263 Farmington Avenue, Farmington, CT 06030 Confidential Health Information Enclosed

    E-Print Network [OSTI]

    Oliver, Douglas L.

    263 Farmington Avenue, Farmington, CT 06030 Confidential Health Information Enclosed Sender Information: Date: ________________________________ Time: ________________________ From: ________________________ Recipient Information: To: ________________________________ Phone: ________________________ Organization

  1. Inter-slice bidirectional registration-based segmentation of the prostate gland in MR and CT image sequences

    SciTech Connect (OSTI)

    Khalvati, Farzad Tizhoosh, Hamid R.; Salmanpour, Aryan; Rahnamayan, Shahryar; Rodrigues, George

    2013-12-15

    Purpose: Accurate segmentation and volume estimation of the prostate gland in magnetic resonance (MR) and computed tomography (CT) images are necessary steps in diagnosis, treatment, and monitoring of prostate cancer. This paper presents an algorithm for the prostate gland volume estimation based on the semiautomated segmentation of individual slices in T2-weighted MR and CT image sequences. Methods: The proposedInter-Slice Bidirectional Registration-based Segmentation (iBRS) algorithm relies on interslice image registration of volume data to segment the prostate gland without the use of an anatomical atlas. It requires the user to mark only three slices in a given volume dataset, i.e., the first, middle, and last slices. Next, the proposed algorithm uses a registration algorithm to autosegment the remaining slices. We conducted comprehensive experiments to measure the performance of the proposed algorithm using three registration methods (i.e., rigid, affine, and nonrigid techniques). Results: The results with the proposed technique were compared with manual marking using prostate MR and CT images from 117 patients. Manual marking was performed by an expert user for all 117 patients. The median accuracies for individual slices measured using the Dice similarity coefficient (DSC) were 92% and 91% for MR and CT images, respectively. The iBRS algorithm was also evaluated regarding user variability, which confirmed that the algorithm was robust to interuser variability when marking the prostate gland. Conclusions: The proposed algorithm exploits the interslice data redundancy of the images in a volume dataset of MR and CT images and eliminates the need for an atlas, minimizing the computational cost while producing highly accurate results which are robust to interuser variability.

  2. Economical standard quantum process tomography

    E-Print Network [OSTI]

    Xiaohua Wu; Ke Xu

    2011-05-12

    Recently, Bendersky \\emph{et al.} developed a method to complete the task of characterizing an arbitrary $\\chi$ matrix element in a scalable way, Phys. Rev. Lett. Vol. \\textbf{100}, 190403(2008), where an auxiliary system was needed. In present work, we shall show that the same task can also be completed within the scheme of standard quantum process tomography (SQPT) where there is no requirement for ancilla. Our method depends on two observations: With the elaborately chosen operators basis, the SQPT may have an economical form where a single run of experiment, in which we measure the expectation value of a chosen operator in the outport of the quantum channel with a known input, is sufficient to characterize a selected $\\chi$ matrix element; With the progress recently achieved in quantum entanglement detection, we also find that the number of the experimental settings to realize the experiment for the selected $\\chi$ matrix element does not exceed 2N for the N-qubits system. For practice, our scheme can be applied for the cases where the controlled two-body interaction is neither available nor desirable.

  3. PET/CT shielding design comparisons

    E-Print Network [OSTI]

    Coker, Audra Lee

    2007-09-17

    used to calculate unattenuated radiation through existing lead walls. The computer code MCNPX was used to simulate the leaded walls of the PET/CT suite and provide another set of results. These two sets of results were compared to doses gathered from...

  4. Introduction of heat map to fidelity assessment of compressed CT images

    SciTech Connect (OSTI)

    Lee, Hyunna; Kim, Bohyoung; Seo, Jinwook; Park, Seongjin; Shin, Yeong-Gil; Kim, Kil Joong; Lee, Kyoung Ho

    2011-08-15

    Purpose: This study aimed to introduce heat map, a graphical data presentation method widely used in gene expression experiments, to the presentation and interpretation of image fidelity assessment data of compressed computed tomography (CT) images. Methods: The authors used actual assessment data that consisted of five radiologists' responses to 720 computed tomography images compressed using both Joint Photographic Experts Group 2000 (JPEG2000) 2D and JPEG2000 3D compressions. They additionally created data of two artificial radiologists, which were generated by partly modifying the data from two human radiologists. Results: For each compression, the entire data set, including the variations among radiologists and among images, could be compacted into a small color-coded grid matrix of the heat map. A difference heat map depicted the advantage of 3D compression over 2D compression. Dendrograms showing hierarchical agglomerative clustering results were added to the heat maps to illustrate the similarities in the data patterns among radiologists and among images. The dendrograms were used to identify two artificial radiologists as outliers, whose data were created by partly modifying the responses of two human radiologists. Conclusions: The heat map can illustrate a quick visual extract of the overall data as well as the entirety of large complex data in a compact space while visualizing the variations among observers and among images. The heat map with the dendrograms can be used to identify outliers or to classify observers and images based on the degree of similarity in the response patterns.

  5. Percutaneous Extraction of Cement Leakage After Vertebroplasty Under CT and Fluoroscopy Guidance: A New Technique

    SciTech Connect (OSTI)

    Amoretti, Nicolas Huwart, Laurent

    2012-12-15

    Purpose: We report a new minimally invasive technique of extraction of cement leakage following percutaneous vertebroplasty in adults. Methods: Seven adult patients (five women, two men; mean age: 81 years) treated for vertebral compression fractures by percutaneous vertebroplasty had cement leakage into perivertebral soft tissues along the needle route. Immediately after vertebroplasty, the procedure of extraction was performed under computed tomography (CT) and fluoroscopy guidance: a Chiba needle was first inserted using the same route as the vertebroplasty until contact was obtained with the cement fragment. This needle was then used as a guide for an 11-gauge Trocar t'am (Thiebaud, France). After needle withdrawal, a 13-gauge endoscopy clamp was inserted through the cannula to extract the cement fragments. The whole procedure was performed under local anesthesia. Results: In each patient, all cement fragments were withdrawn within 10 min, without complication. Conclusions: This report suggests that this CT- and fluoroscopy-guided percutaneous technique of extraction could reduce the rate of cement leakage-related complications.

  6. Sparse signal reconstruction from polychromatic X-ray CT measurements via mass attenuation discretization

    SciTech Connect (OSTI)

    Gu, Renliang; Dogandi?, Aleksandar [Iowa State University, Center for Nondestructive Evaluation, 1915 Scholl Road, Ames, IA 50011 (United States)

    2014-02-18

    We propose a method for reconstructing sparse images from polychromatic x-ray computed tomography (ct) measurements via mass attenuation coefficient discretization. The material of the inspected object and the incident spectrum are assumed to be unknown. We rewrite the Lambert-Beers law in terms of integral expressions of mass attenuation and discretize the resulting integrals. We then present a penalized constrained least-squares optimization approach for reconstructing the underlying object from log-domain measurements, where an active set approach is employed to estimate incident energy density parameters and the nonnegativity and sparsity of the image density map are imposed using negative-energy and smooth ?{sub 1}-norm penalty terms. We propose a two-step scheme for refining the mass attenuation discretization grid by using higher sampling rate over the range with higher photon energy, and eliminating the discretization points that have little effect on accuracy of the forward projection model. This refinement allows us to successfully handle the characteristic lines (Dirac impulses) in the incident energy density spectrum. We compare the proposed method with the standard filtered backprojection, which ignores the polychromatic nature of the measurements and sparsity of the image density map. Numerical simulations using both realistic simulated and real x-ray ct data are presented.

  7. Does Preinterventional Flat-Panel Computer Tomography Pooled Blood Volume Mapping Predict Final Infarct Volume After Mechanical Thrombectomy in Acute Cerebral Artery Occlusion?

    SciTech Connect (OSTI)

    Wagner, Marlies, E-mail: marlies.wagner@kgu.de [Hospital of Goethe University, Institute of Neuroradiology (Germany); Kyriakou, Yiannis, E-mail: yiannis.kyriakou@siemens.com [Siemens AG, Health Care Sector (Germany); Mesnil de Rochemont, Richard du, E-mail: mesnil@em.uni-frankfurt.de [Hospital of Goethe University, Institute of Neuroradiology (Germany); Singer, Oliver C., E-mail: o.singer@em.uni-frankfurt.de [Hospital of Goethe University, Department of Neurology (Germany); Berkefeld, Joachim, E-mail: berkefeld@em.uni-frankfurt.de [Hospital of Goethe University, Institute of Neuroradiology (Germany)

    2013-08-01

    PurposeDecreased cerebral blood volume is known to be a predictor for final infarct volume in acute cerebral artery occlusion. To evaluate the predictability of final infarct volume in patients with acute occlusion of the middle cerebral artery (MCA) or the distal internal carotid artery (ICA) and successful endovascular recanalization, pooled blood volume (PBV) was measured using flat-panel detector computed tomography (FPD CT).Materials and MethodsTwenty patients with acute unilateral occlusion of the MCA or distal ACI without demarcated infarction, as proven by CT at admission, and successful Thrombolysis in cerebral infarction score (TICI 2b or 3) endovascular thrombectomy were included. Cerebral PBV maps were acquired from each patient immediately before endovascular thrombectomy. Twenty-four hours after recanalization, each patient underwent multislice CT to visualize final infarct volume. Extent of the areas of decreased PBV was compared with the final infarct volume proven by follow-up CT the next day.ResultsIn 15 of 20 patients, areas of distinct PBV decrease corresponded to final infarct volume. In 5 patients, areas of decreased PBV overestimated final extension of ischemia probably due to inappropriate timing of data acquisition and misery perfusion.ConclusionPBV mapping using FPD CT is a promising tool to predict areas of irrecoverable brain parenchyma in acute thromboembolic stroke. Further validation is necessary before routine use for decision making for interventional thrombectomy.

  8. On two-parameter models of photon cross sections: Application to dual-energy CT imaging

    SciTech Connect (OSTI)

    Williamson, Jeffrey F.; Li Sicong; Devic, Slobodan; Whiting, Bruce R.; Lerma, Fritz A.

    2006-11-15

    The goal of this study is to evaluate the theoretically achievable accuracy in estimating photon cross sections at low energies (20-1000 keV) from idealized dual-energy x-ray computed tomography (CT) images. Cross-section estimation from dual-energy measurements requires a model that can accurately represent photon cross sections of any biological material as a function of energy by specifying only two characteristic parameters of the underlying material, e.g., effective atomic number and density. This paper evaluates the accuracy of two commonly used two-parameter cross-section models for postprocessing idealized measurements derived from dual-energy CT images. The parametric fit model (PFM) accounts for electron-binding effects and photoelectric absorption by power functions in atomic number and energy and scattering by the Klein-Nishina cross section. The basis-vector model (BVM) assumes that attenuation coefficients of any biological substance can be approximated by a linear combination of mass attenuation coefficients of two dissimilar basis substances. Both PFM and BVM were fit to a modern cross-section library for a range of elements and mixtures representative of naturally occurring biological materials (Z=2-20). The PFM model, in conjunction with the effective atomic number approximation, yields estimated the total linear cross-section estimates with mean absolute and maximum error ranges of 0.6%-2.2% and 1%-6%, respectively. The corresponding error ranges for BVM estimates were 0.02%-0.15% and 0.1%-0.5%. However, for photoelectric absorption frequency, the PFM absolute mean and maximum errors were 10.8%-22.4% and 29%-50%, compared with corresponding BVM errors of 0.4%-11.3% and 0.5%-17.0%, respectively. Both models were found to exhibit similar sensitivities to image-intensity measurement uncertainties. Of the two models, BVM is the most promising approach for realizing dual-energy CT cross-section measurement.

  9. Allan Cormack, Computerized Axial Tomography (CAT), and Magnetic...

    Office of Scientific and Technical Information (OSTI)

    energy physicist at Tufts University, shared the 1979 Nobel Prize in Physiology and Medicine for his key work in developing the methods for CAT scanners. At the time of...

  10. Photoacoustic and thermoacoustic tomography: system development for biomedical applications

    E-Print Network [OSTI]

    Ku, Geng

    2006-04-12

    Photoacoustic tomography (PAT), as well as thermoacoustic tomography (TAT), utilize electromagnetic radiation in its visible, near infrared, microwave, and radiofrequency forms, respectively, to induce acoustic waves in biological tissues...

  11. Scanning microwave-induced thermoacoustic tomography: Signal, resolution, and contrast

    E-Print Network [OSTI]

    Wang, Lihong

    Scanning microwave-induced thermoacoustic tomography: Signal, resolution, and contrast Geng Ku Scanning thermoacoustic tomography was explored in the microwave region of the electromagnetic spectrum ultrasonic transducer detected the time-resolved thermoacoustic signals. Based on the microwave

  12. Measuring the efficacy of a root biobarrier with x-ray computed tomography

    SciTech Connect (OSTI)

    Tollner, E.W.; Murphy, C.E. Jr. . Dept. of Agricultural Engineering)

    1990-08-16

    X-ray computed tomography is a useful tool for investigating soil physical properties nondestructively. There is a need to develop proper calibration relationships between soil properties and the x-ray absorption coefficient. The objective of the work was to evaluate soil factors affecting the x-ray absorption coefficient. Based on a theoretical analysis, experimental data from five soils and on results of several other investigators, it was concluded that for many applications, one calibration relationship is applicable to a wide range of soils. The montmorillinitic clay used in the study required special handling due to the extreme shrinkage of this soil upon drying. Knowledge of chemical composition enables approximations but not exact predictions of the x-ray absorption coefficient. The results suggested some reasonable alternative to exhaustive calibration for each anticipated soil condition. Quantification of root activity in terms of root growth and indirectly through water uptake is necessary for understanding plant growth dynamics. X-ray computed tomography (CT) enables qualitative as well as two quantitative outputs, one of which can lead to conclusions regarding root activity. A greenhouse study involving soil columns (Lakeland sand, bulk density 1.4 Mg/m{sup 3}) planted to soybean, Bahiagras, and control (no vegetation) was conducted in 1989. A treflan based on chemical barrier was placed in half of the soil column of each species. The mean x-ray absorption correlated to water content. Results suggested that root presence can also be indirectly inferred based on water content drawn down during planned stress events. It was concluded that x-ray CT may have a niche in soil-water-plant relation studies, particularly when plant species have large roots. 35 refs., 13 figs., 8 tabs.

  13. Siemens Corporate Technology CT | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Information Serbia-Enhancing Capacity for LowInformationShoshone County,SiCorporate Technology CT

  14. Microlocal Analysis of Thermoacoustic (or Multiwave) Tomography, III

    E-Print Network [OSTI]

    Plamen Stefanov

    2012-07-20

    Microlocal Analysis of Thermoacoustic (or Multiwave). Tomography, III. Plamen Stefanov. Purdue University. TAT of brain imaging (discontinuous wave speed).

  15. FIONDA (Filtering Images of Niobium Disks Application): Filter application for Eddy Current Scanner data analysis

    SciTech Connect (OSTI)

    Boffo, C.; Bauer, P.; /Fermilab

    2005-05-01

    As part of the material QC process, each Niobium disk from which a superconducting RF cavity is built must undergo an eddy current scan [1]. This process allows to discover embedded defects in the material that are not visible to the naked eye because too small or under the surface. Moreover, during the production process of SC cavities the outer layer of Nb is removed via chemical or electro-chemical etching, thus it is important to evaluate the quality of the subsurface layer (in the order of 100nm) where superconductivity will happen. The reference eddy current scanning machine is operated at DESY; at Fermilab we are using the SNS eddy current scanner on loan, courtesy of SNS. In the past year, several upgrades were implemented aiming at raising the SNS machine performance to that of the DESY reference machine [2]. As part of this effort an algorithm that enables the filtering of the results of the scans and thus improves the resolution of the process was developed. The description of the algorithm and of the software used to filter the scan results is presented in this note.

  16. Fabrication of Diffractive Optical Elements for an Integrated Compact Optical-MEMS Laser Scanner

    SciTech Connect (OSTI)

    WENDT,JOEL R.; KRYGOWSKI,T.W.; VAWTER,GREGORY A.; SPAHN,OLGA B.; SWEATT,WILLIAM C.; WARREN,MIAL E.; REYES,DAVID NMN

    2000-07-13

    The authors describe the microfabrication of a multi-level diffractive optical element (DOE) onto a micro-electromechanical system (MEMS) as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive ion beam etching. The DOE was fabricated on two generations of MEMS components. The first generation design uses a shuttle suspended on springs and displaced by a linear rack. The second generation design uses a shuttle guided by roller bearings and driven by a single reciprocating gear. Both the linear rack and the reciprocating gear are driven by a microengine assembly. The compact design is based on mounting the MEMS module and a vertical cavity surface emitting laser (VCSEL) onto a fused silica substrate that contains the rest of the optical system. The estimated scan range of the system is {+-}4{degree} with a spot size of 0.5 mm.

  17. Microlocal Analysis of Thermoacoustic (or Multiwave) Tomography, I

    E-Print Network [OSTI]

    Stefanov, Plamen

    Microlocal Analysis of Thermoacoustic (or Multiwave) Tomography, I Plamen Stefanov Purdue. They are available at my web page. Thermoacoustic tomography with variable sound speed (with Gunther Uhlmann), Inverse Prob. 25(2009), 075011. Thermoacoustic tomography arising in brain imaging (with Gunther Uhlmann

  18. THERMOACOUSTIC TOMOGRAPHY WITH AN ARBITRARY ELLIPTIC OPERATOR MICHAEL V. KLIBANOV

    E-Print Network [OSTI]

    1 THERMOACOUSTIC TOMOGRAPHY WITH AN ARBITRARY ELLIPTIC OPERATOR MICHAEL V. KLIBANOV Abstract. Thermoacoustic tomography is a term for the inverse problem of determining of one of initial conditions. In thermoacoustic tomography (TAT) a short radio frequency pulse is sent in a biological tissue [1, 9]. Some energy

  19. PHOTOACOUSTIC AND THERMOACOUSTIC TOMOGRAPHY WITH AN UNCERTAIN WAVE SPEED

    E-Print Network [OSTI]

    Uhlmann, Gunther

    PHOTOACOUSTIC AND THERMOACOUSTIC TOMOGRAPHY WITH AN UNCERTAIN WAVE SPEED LAURI OKSANEN AND GUNTHER UHLMANN Abstract. We consider the mathematical model of photoacoustic and thermoacoustic tomography. In Thermoacoustic tomography (TAT), see e.g. [8], low frequency microwaves, with wavelengths on the order of 1m

  20. Wireless Tomography, Part I: A Novel Approach to Remote Sensing

    E-Print Network [OSTI]

    Qiu, Robert Caiming

    Wireless Tomography, Part I: A Novel Approach to Remote Sensing R. C. Qiu, M. C. Wicks, L. Li, Z. Browning.12@us.af.mil Abstract--Wireless tomography, a novel approach to remote sensing, is proposed--radio frequency tomography, remote sensing, cognitive radar, cognitive radio. I. INTRODUCTION The ever increasing

  1. Application of a nudging technique to thermoacoustic tomography

    E-Print Network [OSTI]

    Boyer, Edmond

    Application of a nudging technique to thermoacoustic tomography Xavier Bonnefond and Sbastien Marinesque December 3, 2011 Abstract ThermoAcoustic Tomography (TAT) is a promising, non invasive, medical inversion method. 1 Introduction ThermoAcoustic Tomography (TAT) is a hybrid imaging technique that uses

  2. Seismic Tomography: Definitions Lapo Boschi (lapo@erdw.ethz.ch)

    E-Print Network [OSTI]

    Boschi, Lapo

    Seismic Tomography: Definitions Lapo Boschi (lapo@erdw.ethz.ch) September 14, 2009 Seismic Tomography Seismic tomography is the science of interpreting seismic measurements (seismograms) to derive information about the structure of the Earth. This course does not cover the techniques of seismic observation

  3. Three-dimensional fluorescence lifetime tomography

    SciTech Connect (OSTI)

    Godavarty, Anuradha; Sevick-Muraca, Eva M.; Eppstein, Margaret J. [327 Votey Building, Department of Computer Science, University of Vermont, Burlington, Vermont 05405 (United States); 1011 Richardson Building, Photon Migration Laboratories, Texas A and M University, College Station, Texas 77843 (United States); 327 Votey Building, Department of Computer Science, University of Vermont, Burlington, Vermont 05405 (United States)

    2005-04-01

    Near-infrared fluorescence tomography using molecularly targeted lifetime-sensitive, fluorescent contrast agents have applications for early-stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two-dimensional studies. Herein, the feasibility of three-dimensional fluorescence-lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain-modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3-3'-Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4-2 cm. The Bayesian tomography algorithm was employed to obtain three-dimensional images of lifetime and absorption owing to the fluorophores.

  4. High performance graphics processor based computed tomography reconstruction algorithms for nuclear and other large scale applications.

    SciTech Connect (OSTI)

    Jimenez, Edward Steven,

    2013-09-01

    The goal of this work is to develop a fast computed tomography (CT) reconstruction algorithm based on graphics processing units (GPU) that achieves significant improvement over traditional central processing unit (CPU) based implementations. The main challenge in developing a CT algorithm that is capable of handling very large datasets is parallelizing the algorithm in such a way that data transfer does not hinder performance of the reconstruction algorithm. General Purpose Graphics Processing (GPGPU) is a new technology that the Science and Technology (S&T) community is starting to adopt in many fields where CPU-based computing is the norm. GPGPU programming requires a new approach to algorithm development that utilizes massively multi-threaded environments. Multi-threaded algorithms in general are difficult to optimize since performance bottlenecks occur that are non-existent in single-threaded algorithms such as memory latencies. If an efficient GPU-based CT reconstruction algorithm can be developed; computational times could be improved by a factor of 20. Additionally, cost benefits will be realized as commodity graphics hardware could potentially replace expensive supercomputers and high-end workstations. This project will take advantage of the CUDA programming environment and attempt to parallelize the task in such a way that multiple slices of the reconstruction volume are computed simultaneously. This work will also take advantage of the GPU memory by utilizing asynchronous memory transfers, GPU texture memory, and (when possible) pinned host memory so that the memory transfer bottleneck inherent to GPGPU is amortized. Additionally, this work will take advantage of GPU-specific hardware (i.e. fast texture memory, pixel-pipelines, hardware interpolators, and varying memory hierarchy) that will allow for additional performance improvements.

  5. Segmentation of artifacts and anatomy in CT metal artifact reduction

    E-Print Network [OSTI]

    Karimi, Seemeen; Cosman, Pamela; Wald, Christoph; Martz, Harry

    2012-01-01

    Maximum- likelihood dual-energy tomographic imageartifact reduction by dual energy CT using monoenergetictive reconstruction of dual energy data 21 has the potential

  6. CT. L-2 United States Government

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth DakotaRobbins and Myers Co -VANaval ,, *' ;x-L* d! CT NC0 - i ,

  7. CT Investment Partners LLP | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoopButte County, California: Energy ResourcesCRED: A New Model of ClimateOpenCT

  8. Dose equations for shift-variant CT acquisition modes using variable pitch, tube current, and aperture, and the meaning of their associated CTDI{sub vol}

    SciTech Connect (OSTI)

    Dixon, Robert L.; Boone, John M.; Kraft, Robert A.

    2014-11-01

    Purpose: With the increasing clinical use of shift-variant CT protocols involving tube current modulation (TCM), variable pitch or pitch modulation (PM), and variable aperture a(t), the interpretation of the scanner-reported CTDI{sub vol} is called into question. This was addressed for TCM in their previous paper published by Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)] and is extended to PM and concurrent TCM/PM as well as variable aperture in this work. Methods: Rigorous convolution equations are derived to describe the accumulated dose distributions for TCM, PM, and concurrent TCM/PM. A comparison with scanner-reported CTDI{sub vol} formulae clearly identifies the source of their differences with the traditional CTDI{sub vol}. Dose distribution simulations using the convolution are provided for a variety of TCM and PM scenarios including a helical shuttle used for perfusion studies (as well as constant mA)all having the same scanner-reported CTDI{sub vol}. These new convolution simulations for TCM are validated by comparison with their previous discrete summations. Results: These equations show that PM is equivalent to TCM if the pitch variation p(z) is proportional to 1/i(z), where i(z) is the local tube current. The simulations show that the local dose at z depends only weakly on the local tube current i(z) or local pitch p(z) due to scatter from all other locations along z, and that the local CTDI{sub vol}(z) or CTDI{sub vol} per slice do not represent a local dose but rather only a relative i(z) or p(z). The CTDI-paradigm does not apply to shift-variant techniques and the scanner-reported CTDI{sub vol} for the same lacks physical significance and relevance. Conclusions: While the traditional CTDI{sub vol} at constant tube current and pitch conveys useful information (the peak dose at the center of the scan length), CTDI{sub vol} for shift-variant techniques (TCM or PM) conveys no useful information about the associated dose distribution it purportedly represents. On the other hand, the total energy absorbed E (integral dose) as well as its surrogate DLP remain robust (invariant) with respect to shift-variance, depending only on the total mAs = ?i?t{sub 0} accumulated during the total beam-on time t{sub 0} and aperture a, where ?i? is the average current.

  9. A general framework and review of scatter correction methods in x-ray cone-beam computerized tomography. Part 1: Scatter compensation approaches

    SciTech Connect (OSTI)

    Ruehrnschopf, Ernst-Peter; Klingenbeck, Klaus

    2011-07-15

    Since scattered radiation in cone-beam volume CT implies severe degradation of CT images by quantification errors, artifacts, and noise increase, scatter suppression is one of the main issues related to image quality in CBCT imaging. The aim of this review is to structurize the variety of scatter suppression methods, to analyze the common structure, and to develop a general framework for scatter correction procedures. In general, scatter suppression combines hardware techniques of scatter rejection and software methods of scatter correction. The authors emphasize that scatter correction procedures consist of the main components scatter estimation (by measurement or mathematical modeling) and scatter compensation (deterministic or statistical methods). The framework comprises most scatter correction approaches and its validity also goes beyond transmission CT. Before the advent of cone-beam CT, a lot of papers on scatter correction approaches in x-ray radiography, mammography, emission tomography, and in Megavolt CT had been published. The opportunity to avail from research in those other fields of medical imaging has not yet been sufficiently exploited. Therefore additional references are included when ever it seems pertinent. Scatter estimation and scatter compensation are typically intertwined in iterative procedures. It makes sense to recognize iterative approaches in the light of the concept of self-consistency. The importance of incorporating scatter compensation approaches into a statistical framework for noise minimization has to be underscored. Signal and noise propagation analysis is presented. A main result is the preservation of differential-signal-to-noise-ratio (dSNR) in CT projection data by ideal scatter correction. The objective of scatter compensation methods is the restoration of quantitative accuracy and a balance between low-contrast restoration and noise reduction. In a synopsis section, the different deterministic and statistical methods are discussed with respect to their properties and applications. The current paper is focused on scatter compensation algorithms. The multitude of scatter estimation models will be dealt with in a separate paper.

  10. Coronary CT angiography offers further risk stratification in the management of patients with normal SPECT results

    E-Print Network [OSTI]

    Budoff, Matthew J.; Hacioglu, Yalcin

    2010-01-01

    Coronary CT angiography offers further risk strati?cation inCoronary CT angiography offers further risk strati?cationCoronary CT angiography offers further risk strati?cation

  11. Process tomography for unitary quantum channels

    SciTech Connect (OSTI)

    Gutoski, Gus; Johnston, Nathaniel

    2014-03-15

    We study the number of measurements required for quantum process tomography under prior information, such as a promise that the unknown channel is unitary. We introduce the notion of an interactive observable and we show that any unitary channel acting on a d-level quantum system can be uniquely identified among all other channels (unitary or otherwise) with only O(d{sup 2}) interactive observables, as opposed to the O(d{sup 4}) required for tomography of arbitrary channels. This result generalizes to the problem of identifying channels with at most q Kraus operators, and slight improvements can be obtained if we wish to identify such a channel only among unital channels or among other channels with q Kraus operators. These results are proven via explicit construction of large subspaces of Hermitian matrices with various conditions on rank, eigenvalues, and partial trace. Our constructions are built upon various forms of totally nonsingular matrices.

  12. Thermoacoustic tomography arising in brain imaging

    E-Print Network [OSTI]

    Plamen Stefanov; Gunther Uhlmann

    2010-09-09

    We study the mathematical model of thermoacoustic and photoacoustic tomography when the sound speed has a jump across a smooth surface. This models the change of the sound speed in the skull when trying to image the human brain. We derive an explicit inversion formula in the form of a convergent Neumann series under the assumptions that all singularities from the support of the source reach the boundary.

  13. Thermoacoustic tomography arising in brain imaging

    E-Print Network [OSTI]

    Stefanov, Plamen

    2010-01-01

    We study the mathematical model of thermoacoustic and photoacoustic tomography when the sound speed has a jump across a smooth surface. This models the change of the sound speed in the skull when trying to image the human brain. We derive an explicit inversion formula in the form of a convergent Neumann series under the assumptions that all singularities from the support of the source reach the boundary.

  14. Thermoacoustic tomography with variable sound speed

    E-Print Network [OSTI]

    Plamen Stefanov; Gunther Uhlmann

    2009-05-30

    We study the mathematical model of thermoacoustic tomography in media with a variable speed for a fixed time interval, greater than the diameter of the domain. In case of measurements on the whole boundary, we give an explicit solution in terms of a Neumann series expansion. We give necessary and sufficient conditions for uniqueness and stability when the measurements are taken on a part of the boundary.

  15. Thermoacoustic tomography with variable sound speed

    E-Print Network [OSTI]

    Stefanov, Plamen

    2009-01-01

    We study the mathematical model of thermoacoustic tomography in media with a variable speed for a fixed time interval, greater than the diameter of the domain. In case of measurements on the whole boundary, we give an explicit solution in terms of a Neumann series expansion. We give necessary and sufficient conditions for uniqueness and stability when the measurements are taken on a part of the boundary.

  16. Functional photoacoustic tomography of animal brains

    E-Print Network [OSTI]

    Wang, Xueding

    2005-11-01

    by the ultrasonic signals. In other words, these techniques combine the high-contrast advantage of optical imaging while also utilizing the high-resolution advantage of ultrasonic imaging. PAT (also referred to as optoacoustic tomography or thermoacoustic... pulse is very short, as in our experiments, the time required for thermal diffusion is much greater than the time for the thermoacoustic transition. Consequently, the effect of heat conduction in the thermoacoustic wave equations can be ignored. 38...

  17. Lung Segmentation from CT with Severe Pathologies Using Anatomical Constraints

    E-Print Network [OSTI]

    Lung Segmentation from CT with Severe Pathologies Using Anatomical Constraints Neil Birkbeck Healthcare, Oxford, UK Abstract. The diversity in appearance of diseased lung tissue makes automatic segmentation of lungs from CT with severe pathologies chal- lenging. To overcome this challenge, we rely

  18. Automatic Labeling and Segmentation of Vertebrae in CT Images

    E-Print Network [OSTI]

    Freitas, Nando de

    vertebral column. I validate my technique in terms of accuracy of the labeling and segmentation of CT images handled labeling of the vertebral column in arbitrary scans [3, 4]. Klinder et al. build a template (mean(s) Affiliation Address email Abstract Detection, Labeling, and segmentation of the spinal column from CT images

  19. A low dose simulation tool for CT systems with energy integrating detectors

    SciTech Connect (OSTI)

    Zabic, Stanislav; Morton, Thomas; Brown, Kevin M.; Wang Qiu

    2013-03-15

    Purpose: This paper introduces a new strategy for simulating low-dose computed tomography (CT) scans using real scans of a higher dose as an input. The tool is verified against simulations and real scans and compared to other approaches found in the literature. Methods: The conditional variance identity is used to properly account for the variance of the input high-dose data, and a formula is derived for generating a new Poisson noise realization which has the same mean and variance as the true low-dose data. The authors also derive a formula for the inclusion of real samples of detector noise, properly scaled according to the level of the simulated x-ray signals. Results: The proposed method is shown to match real scans in number of experiments. Noise standard deviation measurements in simulated low-dose reconstructions of a 35 cm water phantom match real scans in a range from 500 to 10 mA with less than 5% error. Mean and variance of individual detector channels are shown to match closely across the detector array. Finally, the visual appearance of noise and streak artifacts is shown to match in real scans even under conditions of photon-starvation (with tube currents as low as 10 and 80 mA). Additionally, the proposed method is shown to be more accurate than previous approaches (1) in achieving the correct mean and variance in reconstructed images from pure-Poisson noise simulations (with no detector noise) under photon-starvation conditions, and (2) in simulating the correct noise level and detector noise artifacts in real low-dose scans. Conclusions: The proposed method can accurately simulate low-dose CT data starting from high-dose data, including effects from photon starvation and detector noise. This is potentially a very useful tool in helping to determine minimum dose requirements for a wide range of clinical protocols and advanced reconstruction algorithms.

  20. CT imaging during microwave ablation: Analysis of spatial and temporal tissue contraction

    SciTech Connect (OSTI)

    Liu, Dong; Brace, Christopher L., E-mail: clbrace@wisc.edu [Departments of Radiology and Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53705 (United States)

    2014-11-01

    Purpose: To analyze the spatial distribution and temporal development of liver tissue contraction during high-temperature ablation by using intraprocedural computed tomography (CT) imaging. Methods: A total of 46 aluminum fiducial markers were positioned in a 60 45 mm grid, in a single plane, around a microwave ablation antenna in each of six ex vivo bovine liver samples. Ablations were performed for 10 min at 100 W. CT data of the liver sample were acquired every 30 s during ablation. Fiducial motion between acquisitions was tracked in postprocessing and used to calculate measures of tissue contraction and contraction rates. The spatial distribution and temporal evolution of contraction were analyzed. Results: Fiducial displacement indicated that the zone measured postablation was 8.2 1.8 mm (?20%) smaller in the radial direction and 7.1 1.0 mm (?10%) shorter in the longitudinal direction than the preablation tissue dimension. Therefore, the total ablation volume was reduced from its preablation value by approximately 45%. Very little longitudinal contraction was noted in the distal portion of the ablation zone. Central tissues contracted more than 60%, which was near an estimated limit of ?70% based on initial water content. More peripheral tissues contracted only 15% in any direction. Contraction rates peaked during the first 60 s of heating with a roughly exponential decay over time. Conclusions: Ablation zones measured posttreatment are significantly smaller than the pretreatment tissue dimensions. Tissue contraction is spatially dependent, with the greatest effect occurring in the central ablation zone. Contraction rate peaks early and decays over time.

  1. MicroCT: Semi-Automated Analysis of CT Reconstructed Data of Home Made Explosive Materials Using the Matlab MicroCT Analysis GUI

    SciTech Connect (OSTI)

    Seetho, I M; Brown, W D; Kallman, J S; Martz, H E; White, W T

    2011-09-22

    This Standard Operating Procedure (SOP) provides the specific procedural steps for analyzing reconstructed CT images obtained under the IDD Standard Operating Procedures for data acquisition [1] and MicroCT image reconstruction [2], per the IDD Quality Assurance Plan for MicroCT Scanning [3]. Although intended to apply primarily to MicroCT data acquired in the HEAFCAT Facility at LLNL, these procedures may also be applied to data acquired at Tyndall from the YXLON cabinet and at TSL from the HEXCAT system. This SOP also provides the procedural steps for preparing the tables and graphs to be used in the reporting of analytical results. This SOP applies to R and D work - for production applications, use [4].

  2. MicroCT: Automated Analysis of CT Reconstructed Data of Home Made Explosive Materials Using the Matlab MicroCT Analysis GUI

    SciTech Connect (OSTI)

    Seetho, I M; Brown, W D; Kallman, J S; Martz, H E; White, W T

    2011-09-22

    This Standard Operating Procedure (SOP) provides the specific procedural steps for analyzing reconstructed CT images obtained under the IDD Standard Operating Procedures for data acquisition [1] and MicroCT image reconstruction [2], per the IDD Quality Assurance Plan for MicroCT Scanning [3]. Although intended to apply primarily to MicroCT data acquired in the HEAFCAT Facility at LLNL, these procedures may also be applied to data acquired at Tyndall from the YXLON cabinet and at TSL from the HEXCAT system. This SOP also provides the procedural steps for preparing the tables and graphs to be used in the reporting of analytical results. This SOP applies to production work - for R and D there are two other semi-automated methods as given in [4, 5].

  3. Cone Beam Computed Tomography Image Guidance System for a Dedicated Intracranial Radiosurgery Treatment Unit

    SciTech Connect (OSTI)

    Ruschin, Mark; Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario ; Komljenovic, Philip T.; Ansell, Steve; Menard, Cynthia; Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario ; Bootsma, Gregory; Cho, Young-Bin; Chung, Caroline; Jaffray, David; Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario

    2013-01-01

    Purpose: Image guidance has improved the precision of fractionated radiation treatment delivery on linear accelerators. Precise radiation delivery is particularly critical when high doses are delivered to complex shapes with steep dose gradients near critical structures, as is the case for intracranial radiosurgery. To reduce potential geometric uncertainties, a cone beam computed tomography (CT) image guidance system was developed in-house to generate high-resolution images of the head at the time of treatment, using a dedicated radiosurgery unit. The performance and initial clinical use of this imaging system are described. Methods and Materials: A kilovoltage cone beam CT system was integrated with a Leksell Gamma Knife Perfexion radiosurgery unit. The X-ray tube and flat-panel detector are mounted on a translational arm, which is parked above the treatment unit when not in use. Upon descent, a rotational axis provides 210 Degree-Sign of rotation for cone beam CT scans. Mechanical integrity of the system was evaluated over a 6-month period. Subsequent clinical commissioning included end-to-end testing of targeting performance and subjective image quality performance in phantoms. The system has been used to image 2 patients, 1 of whom received single-fraction radiosurgery and 1 who received 3 fractions, using a relocatable head frame. Results: Images of phantoms demonstrated soft tissue contrast visibility and submillimeter spatial resolution. A contrast difference of 35 HU was easily detected at a calibration dose of 1.2 cGy (center of head phantom). The shape of the mechanical flex vs scan angle was highly reproducible and exhibited <0.2 mm peak-to-peak variation. With a 0.5-mm voxel pitch, the maximum targeting error was 0.4 mm. Images of 2 patients were analyzed offline and submillimeter agreement was confirmed with conventional frame. Conclusions: A cone beam CT image guidance system was successfully adapted to a radiosurgery unit. The system is capable of producing high-resolution images of bone and soft tissue. The system is in clinical use and provides excellent image guidance without invasive frames.

  4. Multi-energy CT Based on a Prior Rank, Intensity and Sparsity Model (PRISM)

    E-Print Network [OSTI]

    Soatto, Stefano

    -color, as a natural extension of dual energy CT [1], the future of CT will be multi-energy, generating much richer

  5. Compressed Sensing Quantum Process Tomography for Superconducting Quantum Gates

    E-Print Network [OSTI]

    Rodionov, Andrey

    2014-01-01

    2.2 Review of superconducting qubits . . . . . .State Tomography for superconducting qubits 3.1 The idea ofPossible new effects in superconductive tunnelling, Physics

  6. Probabilistic electrical resistivity tomography of a CO2 sequestration analog

    E-Print Network [OSTI]

    Lochbhler, T; Breen, SJ; Detwiler, RL; Vrugt, JA; Linde, N

    2014-01-01

    Archie, G.E. , 1942. The electrical resistivity log as anexperiments to evaluate electrical resistivity tomography asmodel- ing and inversion of electrical resistance and gas

  7. Three-Dimensional Thermal Tomography Advances Cancer Treatment...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Three-Dimensional Thermal Tomography Advances Cancer Treatment Technology available for licensing: A 3D technique to detect early skin changes due to radiation treatment in breast...

  8. Body Wave Tomography For Regional Scale Assessment Of Geothermal...

    Open Energy Info (EERE)

    wave tomography are two of the primary methods for estimation of regional scale seismic velocity variations. Seismic velocity is affected by temperature and rock composition...

  9. Minimally invasive diagnostic imaging using high resolution Optical Coherence Tomography

    E-Print Network [OSTI]

    Herz, Paul Richard, 1972-

    2004-01-01

    Advances in medical imaging have given researchers unprecedented capabilities to visualize, characterize and understand biological systems. Optical Coherence Tomography (OCT) is a high speed, high resolution imaging technique ...

  10. Early prediction of tumor recurrence based on CT texture changes after stereotactic ablative radiotherapy (SABR) for lung cancer

    SciTech Connect (OSTI)

    Mattonen, Sarah A.; Palma, David A.; Department of Oncology, The University of Western Ontario, London, Ontario N6A 4L6; Division of Radiation Oncology, London Regional Cancer Program, London, Ontario N6A 4L6 ; Haasbeek, Cornelis J. A.; Senan, Suresh; Ward, Aaron D.

    2014-03-15

    Purpose: Benign computed tomography (CT) changes due to radiation induced lung injury (RILI) are common following stereotactic ablative radiotherapy (SABR) and can be difficult to differentiate from tumor recurrence. The authors measured the ability of CT image texture analysis, compared to more traditional measures of response, to predict eventual cancer recurrence based on CT images acquired within 5 months of treatment. Methods: A total of 24 lesions from 22 patients treated with SABR were selected for this study: 13 with moderate to severe benign RILI, and 11 with recurrence. Three-dimensional (3D) consolidative and ground-glass opacity (GGO) changes were manually delineated on all follow-up CT scans. Two size measures of the consolidation regions (longest axial diameter and 3D volume) and nine appearance features of the GGO were calculated: 2 first-order features [mean density and standard deviation of density (first-order texture)], and 7 second-order texture features [energy, entropy, correlation, inverse difference moment (IDM), inertia, cluster shade, and cluster prominence]. For comparison, the corresponding response evaluation criteria in solid tumors measures were also taken for the consolidation regions. Prediction accuracy was determined using the area under the receiver operating characteristic curve (AUC) and two-fold cross validation (CV). Results: For this analysis, 46 diagnostic CT scans scheduled for approximately 3 and 6 months post-treatment were binned based on their recorded scan dates into 25 month and 58 month follow-up time ranges. At 25 months post-treatment, first-order texture, energy, and entropy provided AUCs of 0.790.81 using a linear classifier. On two-fold CV, first-order texture yielded 73% accuracy versus 76%77% with the second-order features. The size measures of the consolidative region, longest axial diameter and 3D volume, gave two-fold CV accuracies of 60% and 57%, and AUCs of 0.72 and 0.65, respectively. Conclusions: Texture measures of the GGO appearance following SABR demonstrated the ability to predict recurrence in individual patients within 5 months of SABR treatment. Appearance changes were also shown to be more accurately predictive of recurrence, as compared to size measures within the same time period. With further validation, these results could form the substrate for a clinically useful computer-aided diagnosis tool which could provide earlier salvage of patients with recurrence.

  11. A New Numerical Algorithm for Thermoacoustic and Photoacoustic Tomography with Variable Sound Speed

    E-Print Network [OSTI]

    Ferguson, Thomas S.

    A New Numerical Algorithm for Thermoacoustic and Photoacoustic Tomography with Variable Sound Speed algorithm for reconstructing an unknown source in Thermoacoustic and Photoacoustic Tomography based Thermoacoustic (TAT) and Photoacoustic (PAT) Tomography are emerging medical imaging modal- ities [32, 30

  12. Electrical impedance tomography using level set representation and total variational regularization

    E-Print Network [OSTI]

    Tai, Xue-Cheng

    Electrical impedance tomography using level set representation and total variational regularization electrical impedance tomography. The key feature of the scheme is the use of level set method. Introduction Electrical impedance tomography is a widely investigated problem with many applications

  13. Radiofrequency Ablation of Non-Small-Cell Carcinoma of the Lung Under Real-Time FDG PET CT Guidance

    SciTech Connect (OSTI)

    Schoellnast, Helmut; Larson, Steven M. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Nehmeh, Sadek A. [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics (United States); Carrasquillo, Jorge A.; Thornton, Raymond H.; Solomon, Stephen B., E-mail: solomons@mskcc.org [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States)

    2011-02-15

    Radiofrequency ablation (RFA) is a well-established method in treatment of patients with lung carcinomas who are not candidates for surgical resection. Usually computed tomographic (CT) guidance is used for the procedure, thus enabling needle placement and permitting evaluation of complications such as pneumothorax and bleeding. {sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is generally used for tumor activity assessment and is therefore useful in follow-up after tumor treatment. A method that provides real-time image-based monitoring of RFA to ensure complete tumor ablation would be a valuable tool. In this report, we describe the behavior of preinjected FDG during PET CT-guided RFA of a non-small-cell lung carcinoma and discuss the value of FDG as a tool to provide intraprocedure monitor ablation. The size and the form of the activity changed during ablation. Ablation led to increase of the size and blurring and irregularity of the contour compared to pretreatment imaging. The maximal standardized uptake value decreased only slightly during the procedure. Therefore, before RFA, FDG PET can guide initial needle placement, but it does not serve as a monitoring tool to evaluate residual viable tissue during the procedure.

  14. A hybrid approach for rapid, accurate, and direct kilovoltage radiation dose calculations in CT voxel space

    SciTech Connect (OSTI)

    Kouznetsov, Alexei; Tambasco, Mauro

    2011-03-15

    Purpose: To develop and validate a fast and accurate method that uses computed tomography (CT) voxel data to estimate absorbed radiation dose at a point of interest (POI) or series of POIs from a kilovoltage (kV) imaging procedure. Methods: The authors developed an approach that computes absorbed radiation dose at a POI by numerically evaluating the linear Boltzmann transport equation (LBTE) using a combination of deterministic and Monte Carlo (MC) techniques. This hybrid approach accounts for material heterogeneity with a level of accuracy comparable to the general MC algorithms. Also, the dose at a POI is computed within seconds using the Intel Core i7 CPU 920 2.67 GHz quad core architecture, and the calculations are performed using CT voxel data, making it flexible and feasible for clinical applications. To validate the method, the authors constructed and acquired a CT scan of a heterogeneous block phantom consisting of a succession of slab densities: Tissue (1.29 cm), bone (2.42 cm), lung (4.84 cm), bone (1.37 cm), and tissue (4.84 cm). Using the hybrid transport method, the authors computed the absorbed doses at a set of points along the central axis and x direction of the phantom for an isotropic 125 kVp photon spectral point source located along the central axis 92.7 cm above the phantom surface. The accuracy of the results was compared to those computed with MCNP, which was cross-validated with EGSnrc, and served as the benchmark for validation. Results: The error in the depth dose ranged from -1.45% to +1.39% with a mean and standard deviation of -0.12% and 0.66%, respectively. The error in the x profile ranged from -1.3% to +0.9%, with standard deviations of -0.3% and 0.5%, respectively. The number of photons required to achieve these results was 1x10{sup 6}. Conclusions: The voxel-based hybrid method evaluates the LBTE rapidly and accurately to estimate the absorbed x-ray dose at any POI or series of POIs from a kV imaging procedure.

  15. A Bone Density Based Finite Element Study of the Efficacy of Maxillary Protraction Protocols With and Without Mini-Implants

    E-Print Network [OSTI]

    Chu, Howard

    2015-01-01

    Materials and Methods 11 Computed Tomography (CT) RawMaterials and Methods A. Computed Tomography (CT) Raw Data

  16. Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Converse, Alexander K.; Ahlers, Elizabeth O.; Bryan, Tom W.; Hetue, Jackson D.; Lake, Katherine A.; Ellison, Paul A.; Engle, Jonathan W.; Barnhart, Todd E.; Nickles, Robert J.; Williams, Paul H.; et al

    2015-03-15

    Background: Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [?F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modelingmoreof fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. Results: After initiation of administration at the bisected leaf stalk, [?F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. Conclusion: Quantitative assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.less

  17. Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration

    SciTech Connect (OSTI)

    Converse, Alexander K. [Univ. of Wisconsin, Madison, WI (United States); Ahlers, Elizabeth O. [Univ. of Wisconsin, Madison, WI (United States); Bryan, Tom W. [Univ. of Wisconsin, Madison, WI (United States); Hetue, Jackson D. [Univ. of Wisconsin, Madison, WI (United States); Lake, Katherine A. [Univ. of Wisconsin, Madison, WI (United States); Ellison, Paul A. [Univ. of Wisconsin, Madison, WI (United States); Engle, Jonathan W. [Univ. of Wisconsin, Madison, WI (United States); Barnhart, Todd E. [Univ. of Wisconsin, Madison, WI (United States); Nickles, Robert J. [Univ. of Wisconsin, Madison, WI (United States); Williams, Paul H. [Univ. of Wisconsin, Madison, WI (United States); DeJesus, Onofre T. [Univ. of Wisconsin, Madison, WI (United States)

    2015-01-01

    Background: Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [?F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modeling of fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. Results: After initiation of administration at the bisected leaf stalk, [?F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. Conclusion: Quantitative assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.

  18. Radiation doses in cone-beam breast computed tomography: A Monte Carlo simulation study

    SciTech Connect (OSTI)

    Yi Ying; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Shen Youtao; Liu Xinming; Ge Shuaiping; You Zhicheng; Wang Tianpeng; Shaw, Chris C.

    2011-02-15

    Purpose: In this article, we describe a method to estimate the spatial dose variation, average dose and mean glandular dose (MGD) for a real breast using Monte Carlo simulation based on cone beam breast computed tomography (CBBCT) images. We present and discuss the dose estimation results for 19 mastectomy breast specimens, 4 homogeneous breast models, 6 ellipsoidal phantoms, and 6 cylindrical phantoms. Methods: To validate the Monte Carlo method for dose estimation in CBBCT, we compared the Monte Carlo dose estimates with the thermoluminescent dosimeter measurements at various radial positions in two polycarbonate cylinders (11- and 15-cm in diameter). Cone-beam computed tomography (CBCT) images of 19 mastectomy breast specimens, obtained with a bench-top experimental scanner, were segmented and used to construct 19 structured breast models. Monte Carlo simulation of CBBCT with these models was performed and used to estimate the point doses, average doses, and mean glandular doses for unit open air exposure at the iso-center. Mass based glandularity values were computed and used to investigate their effects on the average doses as well as the mean glandular doses. Average doses for 4 homogeneous breast models were estimated and compared to those of the corresponding structured breast models to investigate the effect of tissue structures. Average doses for ellipsoidal and cylindrical digital phantoms of identical diameter and height were also estimated for various glandularity values and compared with those for the structured breast models. Results: The absorbed dose maps for structured breast models show that doses in the glandular tissue were higher than those in the nearby adipose tissue. Estimated average doses for the homogeneous breast models were almost identical to those for the structured breast models (p=1). Normalized average doses estimated for the ellipsoidal phantoms were similar to those for the structured breast models (root mean square (rms) percentage difference=1.7%; p=0.01), whereas those for the cylindrical phantoms were significantly lower (rms percentage difference=7.7%; p<0.01). Normalized MGDs were found to decrease with increasing glandularity. Conclusions: Our results indicate that it is sufficient to use homogeneous breast models derived from CBCT generated structured breast models to estimate the average dose. This investigation also shows that ellipsoidal digital phantoms of similar dimensions (diameter and height) and glandularity to actual breasts may be used to represent a real breast to estimate the average breast dose with Monte Carlo simulation. We have also successfully demonstrated the use of structured breast models to estimate the true MGDs and shown that the normalized MGDs decreased with the glandularity as previously reported by other researchers for CBBCT or mammography.

  19. A Fully Automated Method for CT-on-Rails-Guided Online Adaptive Planning for Prostate Cancer Intensity Modulated Radiation Therapy

    SciTech Connect (OSTI)

    Li, Xiaoqiang; Quan, Enzhuo M.; Li, Yupeng; Pan, Xiaoning; Zhou, Yin; Wang, Xiaochun; Du, Weiliang; Kudchadker, Rajat J.; Johnson, Jennifer L.; Kuban, Deborah A.; Lee, Andrew K.; Zhang, Xiaodong

    2013-08-01

    Purpose: This study was designed to validate a fully automated adaptive planning (AAP) method which integrates automated recontouring and automated replanning to account for interfractional anatomical changes in prostate cancer patients receiving adaptive intensity modulated radiation therapy (IMRT) based on daily repeated computed tomography (CT)-on-rails images. Methods and Materials: Nine prostate cancer patients treated at our institution were randomly selected. For the AAP method, contours on each repeat CT image were automatically generated by mapping the contours from the simulation CT image using deformable image registration. An in-house automated planning tool incorporated into the Pinnacle treatment planning system was used to generate the original and the adapted IMRT plans. The cumulative dosevolume histograms (DVHs) of the target and critical structures were calculated based on the manual contours for all plans and compared with those of plans generated by the conventional method, that is, shifting the isocenters by aligning the images based on the center of the volume (COV) of prostate (prostate COV-aligned). Results: The target coverage from our AAP method for every patient was acceptable, while 1 of the 9 patients showed target underdosing from prostate COV-aligned plans. The normalized volume receiving at least 70 Gy (V{sub 70}), and the mean dose of the rectum and bladder were reduced by 8.9%, 6.4 Gy and 4.3%, 5.3 Gy, respectively, for the AAP method compared with the values obtained from prostate COV-aligned plans. Conclusions: The AAP method, which is fully automated, is effective for online replanning to compensate for target dose deficits and critical organ overdosing caused by interfractional anatomical changes in prostate cancer.

  20. Mathematics of Photoacoustic and Thermoacoustic Tomography

    E-Print Network [OSTI]

    Peter Kuchment; Leonid Kunyansky

    2009-12-10

    This is the manuscript of the chapter for a planned Handbook of Mathematical Methods in Imaging that surveys the mathematical models, problems, and algorithms of the Thermoacoustic (TAT) and Photoacoustic (PAT) Tomography. TAT and PAT represent probably the most developed of the several novel ``hybrid'' methods of medical imaging. These new modalities combine different physical types of waves (electromagnetic and acoustic in case of TAT and PAT) in such a way that the resolution and contrast of the resulting method are much higher than those achievable using only acoustic or electromagnetic measurements.

  1. Mathematics of Photoacoustic and Thermoacoustic Tomography

    E-Print Network [OSTI]

    Kuchment, Peter

    2009-01-01

    This is the manuscript of the chapter for a planned Handbook of Mathematical Methods in Imaging that surveys the mathematical models, problems, and algorithms of the Thermoacoustic (TAT) and Photoacoustic (PAT) Tomography. TAT and PAT represent probably the most developed of the several novel ``hybrid'' methods of medical imaging. These new modalities combine different physical types of waves (electromagnetic and acoustic in case of TAT and PAT) in such a way that the resolution and contrast of the resulting method are much higher than those achievable using only acoustic or electromagnetic measurements.

  2. Thermoacoustic tomography with an arbitrary elliptic operator

    E-Print Network [OSTI]

    Michael V. Klibanov

    2012-08-26

    Thermoacoustic tomography is a term for the inverse problem of determining of one of initial conditions of a hyperbolic equation from boundary measurements. In the past publications both stability estimates and convergent numerical methods for this problem were obtained only under some restrictive conditions imposed on the principal part of the elliptic operator. In this paper logarithmic stability estimates are obatined for an arbitrary variable principal part of that operator. Convergence of the Quasi-Reversibility Method to the exact solution is also established for this case. Both complete and incomplete data collection cases are considered.

  3. High energy neutron Computed Tomography developed

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (JournalvivoHigh energy neutron Computed Tomography developed High energy

  4. CT-scan-monitored electrical-resistivity measurements show problems achieving homogeneous saturation

    SciTech Connect (OSTI)

    Sprunt, E.S.; Davis, R.M.; Muegge, E.L. (Mobil R and D Corp. (US)); Desai, K.P. (Saudi Aramco (SA))

    1991-06-01

    This paper reports on x-ray computerized tomography (CT) scans obtained during measurement of the electrical resistivity of core samples which revealed some problems in obtaining uniform saturation along the lengths of the samples. The electrical resistivity of core samples is measured as a function of water saturation to determine the saturation exponent used in electric-log interpretation. An assumption in such tests is that the water saturation is uniformly distributed. Failure of this assumption can result in errors in the determination of the saturation exponent. Three problems were identified in obtaining homogeneous water saturation in two samples of a Middle Eastern carbonate grainstone: a stationary front formed in one sample at 1-psi oil/brine capillary pressure, a moving front formed at oil/brine capillary pressure {le}4 psi in samples tested in fresh mixed-wettability and cleaned water-wet states, and the heterogeneous fluid distribution caused by a rapidly moving front did not dissipate when the capillary pressure was eliminated in the samples.

  5. The Role of Computed Tomography in the Management of the Neck After Chemoradiotherapy in Patients With Head-and-Neck Cancer

    SciTech Connect (OSTI)

    Clavel, Sebastien, E-mail: sebastien.clavel@umontreal.ca [Department of Radiation Oncology, Centre hospitalier de l'Universite de Montreal, Montreal, Quebec (Canada); Charron, Marie-Pierre [Faculte de medicine, Universite de Montreal, Montreal, Quebec (Canada); Belair, Manon [Department of Radiology, Centre hospitalier de l'Universite de Montreal, Montreal, Quebec (Canada); Delouya, Guila; Fortin, Bernard; Despres, Philippe [Department of Radiation Oncology, Centre hospitalier de l'Universite de Montreal, Montreal, Quebec (Canada); Soulieres, Denis [Department of Medical Oncology, Centre hospitalier de l'Universite de Montreal, Montreal, Quebec (Canada); Filion, Edith [Department of Radiation Oncology, Centre hospitalier de l'Universite de Montreal, Montreal, Quebec (Canada); Guertin, Louis [Department of Head and Neck Surgery, Centre hospitalier de l'Universite de Montreal, Montreal, Quebec (Canada); and others

    2012-02-01

    Purpose: The aim of this study was to describe the outcome in patients with head-and neck-squamous cell carcinoma (HNSCC) followed up without neck dissection (ND) after concomitant chemoradiotherapy (CRT) based on computed tomography (CT) response. The second objective was to establish CT characteristics that can predict which patients can safely avoid ND. Methods and Materials: Between 1998 and 2007, 369 patients with node-positive HNSCC were treated with primary CRT at our institution. After a clinical and a radiologic evaluation based on CT done 6 to 8 weeks after CRT, patients were labeled with a complete neck response (CR) or with a partial neck response (PR). Results: The median follow-up was 44 months. The number of patients presenting with N3, N2, or N1 disease were 54 (15%), 268 (72%), and 47 (13%), respectively. After CRT, 263 (71%) patients reached a CR, and 253 of them did not undergo ND. Ninety-six patients reached a PR and underwent ND. Of those, 34 (35%) had residual disease on pathologic evaluation. A regression of the diameter of {>=}80% and a residual largest diameter of 15 mm of nodes had negative pathologic predictive values of 100% and 86%, respectively. The 3-year regional control and survival rates were not different between patients with CR who had no ND and patients with PR followed by ND. Conclusion: Node-positive patients presenting a CR as determined by CT evaluation 6 to 8 weeks after CRT had a low rate of regional recurrence without ND. This study also suggests that lymph node residual size and percentage of regression on CT after CRT may be useful criteria to guide clinical decisions regarding neck surgery. Those results can help diminish the number of ND procedures with negative results and their associated surgical complications.

  6. Measuring the Kuroshio Current with ocean acoustic tomography Naokazu Taniguchia)

    E-Print Network [OSTI]

    Frandsen, Jannette B.

    Measuring the Kuroshio Current with ocean acoustic tomography Naokazu Taniguchia) Graduate School 29 April 2013) Ocean current profiling using ocean acoustic tomography (OAT) was conducted proportional to temperature) and current in the ocean (Munk et al., 1995). Other than coastal sea studies (e

  7. An interactive Bayesian geostatistical inverse protocol for hydraulic tomography

    E-Print Network [OSTI]

    Barrash, Warren

    An interactive Bayesian geostatistical inverse protocol for hydraulic tomography Michael N. Fienen April 2008; published 25 July 2008. [1] Hydraulic tomography is a powerful technique for characterizing, necessitate subdivision into zones across which there is no correlation among hydraulic parameters. We propose

  8. ELECTRICAL IMPEDANCE TOMOGRAPHY Margaret Cheney, David Isaacson, and Jonathan Newell

    E-Print Network [OSTI]

    Cheney, Margaret

    ELECTRICAL IMPEDANCE TOMOGRAPHY Margaret Cheney, David Isaacson, and Jonathan Newell Rensselaer in electrical impedance tomography. 1. INTRODUCTION There are a variety of medical problems for which it would be useful to know the timevarying distribution of electrical properties inside the body. By ``electrical

  9. USING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF

    E-Print Network [OSTI]

    Barton, Jennifer K.

    ), a new method for ceramics research, is a non-destructive, three-dimensional tomography system, which;However, optical coherence tomography (OCT) provides a non-destructive, three-dimensional technique and atmosphere controlled, cooling rates modified, additive experimental testing and other parameters measured

  10. Optimal control techniques for thermo-acoustic tomography Maitine Bergounioux

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    . These hybrid systems use an electromagnetic pulse as an input and record ultrasound waves as an output-acoustic tomography (TAT) when the heating is realized by means of microwaves, and of photo-acoustic tomography (PAT) when optical heating is used. While in TAT waves of radio frequency range are used to trigger

  11. Waveform tomography at a groundwater contamination site: Surface reflection data

    E-Print Network [OSTI]

    Pratt, R. Gerhard

    acoustic-waveform tomography to 45 2D seismic profiles to image the 3D geometry of a buried pale- ochannel the shallowest groundwater system in the study area. The 2D profiles were extracted from a 3D surface reflection the channel showed marked vertical and lat- eral velocity heterogeneity. Traveltime tomography and waveform

  12. Signal processing in scanning thermoacoustic tomography in biological tissues

    E-Print Network [OSTI]

    Wang, Lihong

    Signal processing in scanning thermoacoustic tomography in biological tissues Yuan Xu and Lihong V Microwave-induced thermoacoustic tomography was explored to image biological tissues. Short microwave pulses-induced thermoacoustic waves were detected with a focused ultrasonic transducer to obtain two-dimensional tomographic

  13. Microwave-induced thermoacoustic tomography: Reconstruction by synthetic aperture

    E-Print Network [OSTI]

    Wang, Lihong

    Microwave-induced thermoacoustic tomography: Reconstruction by synthetic aperture Dazi Feng, Yuan thermoacoustic signals, to which the delay-and-sum algorithm was applied for image reconstruc- tion. We greatly-induced thermoacoustic tomography based on focused transducers. Two mi- crowave sources, which had frequencies of 9 and 3

  14. Double-Difference Tomography for Sequestration MVA

    SciTech Connect (OSTI)

    Westman, Erik

    2008-12-31

    Analysis of synthetic data was performed to determine the most cost-effective tomographic monitoring system for a geologic carbon sequestration injection site. Double-difference tomographic inversion was performed on 125 synthetic data sets: five stages of CO2 plume growth, five seismic event regions, and five geophone arrays. Each resulting velocity model was compared quantitatively to its respective synthetic velocity model to determine an accuracy value. The results were examined to determine a relationship between cost and accuracy in monitoring, verification, and accounting applications using double-difference tomography. The geophone arrays with widely-varying geophone locations, both laterally and vertically, performed best. Additionally, double difference seismic tomography was performed using travel time data from a carbon sequestration site at the Aneth oil field in southeast Utah as part of a Department of Energy initiative on monitoring, verification, and accounting (MVA) of sequestered CO2. A total of 1,211 seismic events were recorded from a borehole array consisting of 22 geophones. Artificial velocity models were created to determine the ease with which different CO2 plume locations and sizes can be detected. Most likely because of the poor geophone arrangement, a low velocity zone in the Desert Creek reservoir can only be detected when regions of test site containing the highest ray path coverage are considered. MVA accuracy and precision may be improved through the use of a receiver array that provides more comprehensive ray path coverage.

  15. Shape Filtering for False Positive Reduction at Computed Tomography Colonography

    E-Print Network [OSTI]

    Whelan, Paul F.

    with standard and low radiation dose) and real CT datasets (scanned at a standard radiation dose). This paper of 100% for polyps greater than 10mm when it was applied to standard and low dose CT data. 1 Introduction to follow a low-residue diet for 48 hours, followed by the ingestion of clear fluids for 24 hours. Before

  16. Note: Reliable and non-contact 6D motion tracking system based on 2D laser scanners for cargo transportation

    SciTech Connect (OSTI)

    Kim, Young-Keun, E-mail: ykkim@handong.edu [Department of Mechanical and Control Engineering, Handong Global University, Pohang (Korea, Republic of); Kim, Kyung-Soo [Department of Mechanical Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2014-10-15

    Maritime transportation demands an accurate measurement system to track the motion of oscillating container boxes in real time. However, it is a challenge to design a sensor system that can provide both reliable and non-contact methods of 6-DOF motion measurements of a remote object for outdoor applications. In the paper, a sensor system based on two 2D laser scanners is proposed for detecting the relative 6-DOF motion of a crane load in real time. Even without implementing a camera, the proposed system can detect the motion of a remote object using four laser beam points. Because it is a laser-based sensor, the system is expected to be highly robust to sea weather conditions.

  17. Permeability of laboratory-formed methane-hydrate-bearing sand: Measurements and observations using x-ray computed tomography

    SciTech Connect (OSTI)

    Kneafsey, T. J.; Seol, Y.; Gupta, A.; Tomutsa, L.

    2010-09-15

    Methane hydrate was formed in two moist sands and a sand/silt mixture under a confining stress in an X-ray-transparent pressure vessel. Three initial water saturations were used to form three different methane-hydrate saturations in each medium. X-ray computed tomography (CT) was used to observe location-specific density changes caused by hydrate formation and flowing water. Gas-permeability measurements in each test for the dry, moist, frozen, and hydrate-bearing states are presented. As expected, the effective permeabilities (intrinsic permeability of the medium multiplied by the relative permeability) of the moist sands decreased with increasing moisture content. In a series of tests on a single sample, the effective permeability typically decreased as the pore space became more filled, in the order of dry, moist, frozen, and hydrate-bearing. In each test, water was flowed through the hydrate-bearing medium and we observed the location-specific changes in water saturation using CT scanning. We compared our data to a number of models, and our relative permeability data compare most favorably with models in which hydrate occupies the pore bodies rather than the pore throats. Inverse modeling (using the data collected from the tests) will be performed to extend the relative permeability measurements.

  18. X-ray computed-tomography observations of water flow through anisotropic methane hydrate-bearing sand

    SciTech Connect (OSTI)

    Seol, Yongkoo; Kneafsey, Timothy J.

    2009-06-01

    We used X-ray computed tomography (CT) to image and quantify the effect of a heterogeneous sand grain-size distribution on the formation and dissociation of methane hydrate, as well as the effect on water flow through the heterogeneous hydrate-bearing sand. A 28 cm long sand column was packed with several segments having vertical and horizontal layers with sands of different grain-size distributions. During the hydrate formation, water redistribution occurred. Observations of water flow through the hydrate-bearing sands showed that water was imbibed more readily into the fine sand, and that higher hydrate saturation increased water imbibition in the coarse sand due to increased capillary strength. Hydrate dissociation induced by depressurization resulted in different flow patterns with the different grain sizes and hydrate saturations, but the relationships between dissociation rates and the grain sizes could not be identified using the CT images. The formation, presence, and dissociation of hydrate in the pore space dramatically impact water saturation and flow in the system.

  19. 9.1 Introduction A scanner is a device that looks and works much like a xerox machine except that the

    E-Print Network [OSTI]

    Boyd, John P.

    are the most common. They vary in price, but a decent scanner is only $100. Many home computers now have a laser as the light source; xerox machines also employ laser light sources, and indeed the mechanics and electronics of the moving laser is very similar in both types of equipment. The reflected or transmitted light

  20. SU-D-12A-07: Optimization of a Moving Blocker System for Cone-Beam Computed Tomography Scatter Correction

    SciTech Connect (OSTI)

    Ouyang, L; Yan, H; Jia, X; Jiang, S; Wang, J [UT Southwestern Medical Center, Dallas, TX (United States); Zhang, H [Southern Medical University, Guangzhou, Guang Dong (China)

    2014-06-01

    Purpose: A moving blocker based strategy has shown promising results for scatter correction in cone-beam computed tomography (CBCT). Different parameters of the system design affect its performance in scatter estimation and image reconstruction accuracy. The goal of this work is to optimize the geometric design of the moving block system. Methods: In the moving blocker system, a blocker consisting of lead strips is inserted between the x-ray source and imaging object and moving back and forth along rotation axis during CBCT acquisition. CT image of an anthropomorphic pelvic phantom was used in the simulation study. Scatter signal was simulated by Monte Carlo calculation with various combinations of the lead strip width and the gap between neighboring lead strips, ranging from 4 mm to 80 mm (projected at the detector plane). Scatter signal in the unblocked region was estimated by cubic B-spline interpolation from the blocked region. Scatter estimation accuracy was quantified as relative root mean squared error by comparing the interpolated scatter to the Monte Carlo simulated scatter. CBCT was reconstructed by total variation minimization from the unblocked region, under various combinations of the lead strip width and gap. Reconstruction accuracy in each condition is quantified by CT number error as comparing to a CBCT reconstructed from unblocked full projection data. Results: Scatter estimation error varied from 0.5% to 2.6% as the lead strip width and the gap varied from 4mm to 80mm. CT number error in the reconstructed CBCT images varied from 12 to 44. Highest reconstruction accuracy is achieved when the blocker lead strip width is 8 mm and the gap is 48 mm. Conclusions: Accurate scatter estimation can be achieved in large range of combinations of lead strip width and gap. However, image reconstruction accuracy is greatly affected by the geometry design of the blocker.

  1. Utility of Megavoltage Fan-Beam CT for Treatment Planning in a Head-And-Neck Cancer Patient with Extensive Dental Fillings Undergoing Helical Tomotherapy

    SciTech Connect (OSTI)

    Yang, Claus; Liu Tianxiao; Jennelle, Richard L.; Ryu, Janice K.; Vijayakumar, Srinivasan; Purdy, James A. [Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA (United States); Chen, Allen M. [Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA (United States)], E-mail: allen.chen@ucdmc.ucdavis.edu

    2010-07-01

    The purpose of this study was to demonstrate the potential utility of megavoltage fan-beam computed tomography (MV-FBCT) for treatment planning in a patient undergoing helical tomotherapy for nasopharyngeal carcinoma in the presence of extensive dental artifact. A 28-year-old female with locally advanced nasopharyngeal carcinoma presented for radiation therapy. Due to the extensiveness of the dental artifact present in the oral cavity kV-CT scan acquired at simulation, which made treatment planning impossible on tomotherapy planning system, MV-FBCT imaging was obtained using the HI-ART tomotherapy treatment machine, with the patient in the treatment position, and this information was registered with her original kV-CT scan for the purposes of structure delineation, dose calculation, and treatment planning. To validate the feasibility of the MV-FBCT-generated treatment plan, an electron density CT phantom (model 465, Gammex Inc., Middleton, WI) was scanned using MV-FBCT to obtain CT number to density table. Additionally, both a 'cheese' phantom (which came with the tomotherapy treatment machine) with 2 inserted ion chambers and a generic phantom called Quasar phantom (Modus Medical Devices Inc., London, ON, Canada) with one inserted chamber were used to confirm dosimetric accuracy. The MV-FBCT could be used to clearly visualize anatomy in the region of the dental artifact and provide sufficient soft-tissue contrast to assist in the delineation of normal tissue structures and fat planes. With the elimination of the dental artifact, the MV-FBCT images allowed more accurate dose calculation by the tomotherapy system. It was confirmed that the phantom material density was determined correctly by the tomotherapy MV-FBCT number to density table. The ion chamber measurements agreed with the calculations from the MV-FBCT generated phantom plan within 2%. MV-FBCT may be useful in radiation treatment planning for nasopharyngeal cancer patients in the setting of extensive dental artifacts.

  2. Influence of radiation therapy on the lung-tissue in breast cancer patients: CT-assessed density changes and associated symptoms

    SciTech Connect (OSTI)

    Rotstein, S.; Lax, I.; Svane, G. )

    1990-01-01

    The relative electron density of lung tissue was measured from computer tomography (CT) slices in 33 breast cancer patients treated by various techniques of adjuvant radiotherapy. The measurements were made before radiotherapy, 3 months and 9 months after completion of radiation therapy. The changes in lung densities at 3 months and 9 months were compared to radiation induced radiological (CT) findings. In addition, subjective symptoms such as cough and dyspnoea were assessed before and after radiotherapy. It was observed that the mean of the relative electron density of lung tissue varied from 0.25 when the whole lung was considered to 0.17 when only the anterior lateral quarter of the lung was taken into account. In patients with positive radiological (CT) findings the mean lung density of the anterior lateral quarter increased 2.1 times 3 months after radiotherapy and was still increased 1.6 times 6 months later. For those patients without findings, in the CT pictures the corresponding values were 1.2 and 1.1, respectively. The standard deviation of the pixel values within the anterior lateral quarter of the lung increased 3.8 times and 3.2 times at 3 months and 9 months, respectively, in the former group, as opposed to 1.2 and 1.1 in the latter group. Thirteen patients had an increase in either cough or dyspnoea as observed 3 months after completion of radiotherapy. In eleven patients these symptoms persisted 6 months later. No significant correlation was found between radiological findings and subjective symptoms. However, when three different treatment techniques were compared among 29 patients the highest rate of radiological findings was observed in patients in which the largest lung volumes received the target dose. A tendency towards an increased rate of subjective symptoms was also found in this group.

  3. Use of spheroidal models in gravitational tomography

    E-Print Network [OSTI]

    Sizikov, Valery

    2015-01-01

    The direct gravimetry problem is solved using the subdivision of each body of a deposit into a set of vertical adjoining bars, and in the inverse problem each body of a deposit is modeled by a uniform ellipsoid of revolution (spheroid). Well-known formulas for z-component of gravitational intensity of a spheroid are transformed to a convenient form. Parameters of a spheroid are determined by minimizing the Tikhonov smoothing functional using constraints on the parameters. This makes the ill-posed inverse problem by unique and stable. The Bulakh algorithm for initial estimating the depth and mass of a deposit is modified. The technique is illustrated by numerical model examples of deposits in the form of two and five bodies. The inverse gravimetry problem is interpreted as a gravitational tomography problem or the intravision of the Earth's crust and mantle.

  4. Magnified Weak Lensing Cross Correlation Tomography

    SciTech Connect (OSTI)

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    This project carried out a weak lensing tomography (WLT) measurement around rich clusters of galaxies. This project used ground based photometric redshift data combined with HST archived cluster images that provide the WLT and cluster mass modeling. The technique has already produced interesting results (Guennou et al, 2010,Astronomy & Astrophysics Vol 523, page 21, and Clowe et al, 2011 to be submitted). Guennou et al have validated that the necessary accuracy can be achieved with photometric redshifts for our purposes. Clowe et al titled "The DAFT/FADA survey. II. Tomographic weak lensing signal from 10 high redshift clusters," have shown that for the **first time** via this purely geometrical technique, which does not assume a standard rod or candle, that a cosmological constant is **required** for flat cosmologies. The intent of this project is not to produce the best constraint on the value of the dark energy equation of state, w. Rather, this project is to carry out a sustained effort of weak lensing tomography that will naturally feed into the near term Dark Energy Survey (DES) and to provide invaluable mass calibration for that project. These results will greatly advance a key cosmological method which will be applied to the top-rated ground-based project in the Astro2020 decadal survey, LSST. Weak lensing tomography is one of the key science drivers behind LSST. CO-I Clowe is on the weak lensing LSST committee, and senior scientist on this project, at FNAL James Annis, plays a leading role in the DES. This project has built on successful proposals to obtain ground-based imaging for the cluster sample. By 1 Jan, it is anticipated the project will have accumulated complete 5-color photometry on 30 (or about 1/3) of the targeted cluster sample (public webpage for the survey is available at http://cencos.oamp.fr/DAFT/ and has a current summary of the observational status of various clusters). In all, the project has now been awarded the equivalent of over 60 nights on 4-m class telescopes, which gives concrete evidence of strong community support for this project. The WLT technique is based on the dependence of the gravitational shear signal on the angular diameter distances between the observer, the lens, and the lensed galaxy to measure cosmological parameters. By taking the ratio of measured shears of galaxies with different redshifts around the same lens, one obtains a measurement of the ratios of the angular diameter distances involved. Making these observations over a large range of lenses and background galaxy redshifts will measure the history of the expansion rate of the universe. Because this is a purely geometric measurement, it is insensitive to any form of evolution of objects or the necessity to understand the physics in the early universe. Thus, WLT was identified by the Dark Energy Task Force as perhaps the best method to measure the evolution of DE. To date, however, the conjecture of the DETF has not been experimentally verified, but will be by the proposed project. The primary reason for the lack of tomography measurements is that one must have an exceptional data-set to attempt the measurement. One needs both extremely good seeing (or space observations) in order to minimize the point spread function smearing corrections on weak lensing shear measurements and deep, multi-color data, from B to z, to measure reliable photometric redshifts of the background galaxies being lensed (which are typically too faint to obtain spectroscopic redshifts). Because the entire process from multi-drizzling the HST images, and then creating shear maps, to gathering the necessary ground based observations, to generating photo-zs and then carrying out the tomography is a complicated task, until the creation of our team, nobody has taken the time to connect all the levels of expertise necessary to carry out this project based on HST archival data. Our data are being used in 2 Ph.D. theses. Kellen Murphy, at Ohio University, is using the tomography data along with simulations in a thesis expected to be completed in Jun

  5. Ultrahigh speed optical coherence tomography for ophthalmic imaging applications

    E-Print Network [OSTI]

    Liu, Jonathan Jaoshin

    2014-01-01

    Optical coherence tomography (OCT) is a non-contact, non-invasive, micron-scale optical imaging technology that has become a standard clinical tool in ophthalmology. Fourier domain OCT detection methods have enabled higher ...

  6. High speed handheld instrument for ophthalmic optical coherence tomography

    E-Print Network [OSTI]

    Lu, Chen David

    2013-01-01

    Optical coherence tomography (OCT) is a non-contact, high resolution biomedical imaging technique that uses low coherence interferometry to generate cross-sectional images of tissue. OCT has become a standard tool in ...

  7. Spherical radon transforms and mathematical problems of thermoacoustic tomography

    E-Print Network [OSTI]

    Ambartsoumian, Gaik

    2009-06-02

    including approximation theory, integral geometry, inverse problems for PDEs, etc. In Chapter I we give a brief description of thermoacoustic tomography (TAT or TCT) and introduce the SRT. In Chapter II we consider the injectivity problem for SRT. A major...

  8. Iron oxide nanoparticles as a contrast agent for thermoacoustic tomography

    E-Print Network [OSTI]

    Keho, Aaron Lopez

    2009-06-02

    An exogenous contrast agent has been developed to enhance the contrast achievable in Thermoacoustic Tomography (TAT). TAT utilizes the penetration depth of microwave energy while producing high resolution images through acoustic waves. A sample...

  9. Microwave-induced thermoacoustic tomography: reconstruction by synthetic aperture

    E-Print Network [OSTI]

    Feng, Dazi

    2001-01-01

    We have applied the synthetic-aperture method to linear-scanning microwave-induced thermoacoustic tomography in biological tissues. A non-focused ultrasonic transducer was used to receive thermoacoustic signals, to which the delay-and-sum algorithm...

  10. 3D optical tomography in the presence of void regions

    E-Print Network [OSTI]

    Lorenzo, Jorge Ripoll

    reconstruction scheme for optical tomography based on the equation of radiative transfer," Med. Phys. 26 1698 and F. Wubbeling, Mathematical Methods in Image Reconstruction (SIAM, Philadel- phia, 2001). 15. J. Sch

  11. Functional lung imaging in humans using Positron Emission Tomography

    E-Print Network [OSTI]

    Layfield, Dominick, 1971-

    2003-01-01

    This thesis deals with a method of functional lung imaging using Positron Emission Tomography (PET). In this technique, a radioactive tracer, nitrogen-13, is dissolved in saline solution, and injected into a peripheral ...

  12. Development of a proton Computed Tomography Detector System

    E-Print Network [OSTI]

    Naimuddin, Md; Blazey, G; Boi, S; Dyshkant, A; Erdelyi, B; Hedin, D; Johnson, E; Krider, J; Rukalin, V; Uzunyan, S A; Zutshi, V; Fordt, R; Sellberg, G; Rauch, J E; Roman, M; Rubinov, P; Wilson, P

    2015-01-01

    Computer tomography is one of the most promising new methods to image abnormal tissues inside the human body. Tomography is also used to position the patient accurately before radiation therapy. Hadron therapy for treating cancer has become one of the most advantageous and safe options. In order to fully utilize the advantages of hadron therapy, there is a necessity of performing radiography with hadrons as well. In this paper we present the development of a proton computed tomography system. Our second-generation proton tomography system consists of two upstream and two downstream trackers made up of fibers as active material and a range detector consisting of plastic scintillators. We present details of the detector system, readout electronics, and data acquisition system as well as the commissioning of the entire system. We also present preliminary results from the test beam of the range detector.

  13. Applicability of moire deflection tomography for diagnosing arc plasmas

    SciTech Connect (OSTI)

    Chen Yunyun; Song Yang; He Anzhi; Li Zhenhua

    2009-01-20

    The argon arc plasma whose central temperature, 1.90x10{sup 4} K, is used as a practical example for an experiment to research the applicability of moire deflection tomography in arc plasma flow-field diagnosis. The experimental result indicates that moire deflection of the measured argon arc plasma is very small, even smaller than that of a common flame with the maximal temperature of nearly 1.80x10{sup 3} K. The refractive-index gradient in moire deflection tomography mainly contributes to the temperature gradient in essence when the probe wavelength and pressure are certain in plasma diagnosis. The applicable temperature ranges of moire deflection tomography in the argon arc plasma diagnosis are given with the probe wavelength 532 nm at 1 atm in certain measuring error requirements. In a word, the applicable temperature range of moire deflection tomography for arc plasma diagnosis is intimately related to the probe wavelength and the practical measuring requirements.

  14. Nitride semiconductors studied by atom probe tomography and correlative techniques

    E-Print Network [OSTI]

    Bennett, Samantha

    2011-02-08

    , as well as atom probe tomography (APT), a technique more usually applied to metals that provides three-dimensional (3D) compositional information at the atomic scale. By using both APT and correlative microscopy techniques, a more complete understanding...

  15. Quantum-optical coherence tomography with collinear entangled photons

    E-Print Network [OSTI]

    Novotny, Lukas

    Quantum-optical coherence tomography with collinear entangled photons Dorilian Lopez-Mago1 Photonics and Mathematical Optics Group, Tecnolgico de Monterrey, Monterrey, Nuevo Len 64849, Mexico 3 ETH Zrich, Photonics Laboratory, 8093 Zrich, Switzerland *Corresponding author: novotny

  16. Ultrasound-modulated optical tomography for biomedical applications

    E-Print Network [OSTI]

    Li, Jun

    2004-11-15

    I experimentally studied ultrasound-modulated optical tomography, which holds the promise for biomedical diagnosis. I measured the degree of polarization of laser speckles generated by scattered light transmitted through ...

  17. Time-dependent seismic tomography and its application to the...

    Open Energy Info (EERE)

    Time-dependent seismic tomography and its application to the Coso geothermal area, 1996-2006 Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference...

  18. Volumetric quantification of lung nodules in CT with iterative reconstruction (ASiR and MBIR)

    SciTech Connect (OSTI)

    Chen, Baiyu [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States)] [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Barnhart, Huiman [Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina 27705 (United States)] [Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina 27705 (United States); Richard, Samuel [Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke University, Durham, North Carolina 27705 (United States)] [Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Robins, Marthony [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States)] [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Colsher, James [Department of Radiology, Duke University, Durham, North Carolina 27705 (United States)] [Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Samei, Ehsan [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States) [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Department of Biomedical Engineering, and Department of Electronic and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States)

    2013-11-15

    Purpose: Volume quantifications of lung nodules with multidetector computed tomography (CT) images provide useful information for monitoring nodule developments. The accuracy and precision of the volume quantification, however, can be impacted by imaging and reconstruction parameters. This study aimed to investigate the impact of iterative reconstruction algorithms on the accuracy and precision of volume quantification with dose and slice thickness as additional variables.Methods: Repeated CT images were acquired from an anthropomorphic chest phantom with synthetic nodules (9.5 and 4.8 mm) at six dose levels, and reconstructed with three reconstruction algorithms [filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASiR), and model based iterative reconstruction (MBIR)] into three slice thicknesses. The nodule volumes were measured with two clinical software (A: Lung VCAR, B: iNtuition), and analyzed for accuracy and precision.Results: Precision was found to be generally comparable between FBP and iterative reconstruction with no statistically significant difference noted for different dose levels, slice thickness, and segmentation software. Accuracy was found to be more variable. For large nodules, the accuracy was significantly different between ASiR and FBP for all slice thicknesses with both software, and significantly different between MBIR and FBP for 0.625 mm slice thickness with Software A and for all slice thicknesses with Software B. For small nodules, the accuracy was more similar between FBP and iterative reconstruction, with the exception of ASIR vs FBP at 1.25 mm with Software A and MBIR vs FBP at 0.625 mm with Software A.Conclusions: The systematic difference between the accuracy of FBP and iterative reconstructions highlights the importance of extending current segmentation software to accommodate the image characteristics of iterative reconstructions. In addition, a calibration process may help reduce the dependency of accuracy on reconstruction algorithms, such that volumes quantified from scans of different reconstruction algorithms can be compared. The little difference found between the precision of FBP and iterative reconstructions could be a result of both iterative reconstruction's diminished noise reduction at the edge of the nodules as well as the loss of resolution at high noise levels with iterative reconstruction. The findings do not rule out potential advantage of IR that might be evident in a study that uses a larger number of nodules or repeated scans.

  19. Realistic simulation of reduced-dose CT with noise modeling and sinogram synthesis using DICOM CT images

    SciTech Connect (OSTI)

    Won Kim, Chang; Kim, Jong Hyo

    2014-01-15

    Purpose: Reducing the patient dose while maintaining the diagnostic image quality during CT exams is the subject of a growing number of studies, in which simulations of reduced-dose CT with patient data have been used as an effective technique when exploring the potential of various dose reduction techniques. Difficulties in accessing raw sinogram data, however, have restricted the use of this technique to a limited number of institutions. Here, we present a novel reduced-dose CT simulation technique which provides realistic low-dose images without the requirement of raw sinogram data. Methods: Two key characteristics of CT systems, the noise equivalent quanta (NEQ) and the algorithmic modulation transfer function (MTF), were measured for various combinations of object attenuation and tube currents by analyzing the noise power spectrum (NPS) of CT images obtained with a set of phantoms. Those measurements were used to develop a comprehensive CT noise model covering the reduced x-ray photon flux, object attenuation, system noise, and bow-tie filter, which was then employed to generate a simulated noise sinogram for the reduced-dose condition with the use of a synthetic sinogram generated from a reference CT image. The simulated noise sinogram was filtered with the algorithmic MTF and back-projected to create a noise CT image, which was then added to the reference CT image, finally providing a simulated reduced-dose CT image. The simulation performance was evaluated in terms of the degree of NPS similarity, the noise magnitude, the bow-tie filter effect, and the streak noise pattern at photon starvation sites with the set of phantom images. Results: The simulation results showed good agreement with actual low-dose CT images in terms of their visual appearance and in a quantitative evaluation test. The magnitude and shape of the NPS curves of the simulated low-dose images agreed well with those of real low-dose images, showing discrepancies of less than +/?3.2% in terms of the noise power at the peak height and +/?1.2% in terms of the spatial frequency at the peak height. The magnitudes of the noise measured for 12 different combinations the phantom size, tube current, and reconstruction kernel for the simulated and real low-dose images were very similar, with differences of 0.1 to 4.7%. Thep value for a statistical testing of the difference in the noise magnitude ranged from 0.99 to 0.11, showing that there was no difference statistically between the noise magnitudes of the real and simulated low-dose images using our method. The strength and pattern of the streak noise in an anthropomorphic phantom was also consistent with expectations. Conclusions: A novel reduced-dose CT simulation technique was developed which uses only CT images while not requiring raw sinogram data. Our method can provide realistic simulation results under reduced-dose conditions both in terms of the noise magnitude and the textual appearance. This technique has the potential to promote clinical research for patient dose reductions.

  20. Advances in Inverse Transport Methods and Applications to Neutron Tomography

    E-Print Network [OSTI]

    Wu, Zeyun

    2011-02-22

    ) tomography method [5?7], which mainly involves the following principles: (1) Radon transform and inverse Radon transform, which maps and anti-maps a transmission line set to a projected point set; (2) Fourier projection-slice theorem (also referred... of the Radon Transform [5,6,59], e.g., line integrals along projection trajectories. With some in- version techniques such as filtered back projection (FBP) applied to the projections, analytic tomography methods are capable of reconstructing material...

  1. A Compact Torus Fusion Reactor Utilizing a Continuously Generated Strings of CT's. The CT String Reactor, CTSR.

    SciTech Connect (OSTI)

    Hartman, C W; Reisman, D B; McLean, H S; Thomas, J

    2007-05-30

    A fusion reactor is described in which a moving string of mutually repelling compact toruses (alternating helicity, unidirectional Btheta) is generated by repetitive injection using a magnetized coaxial gun driven by continuous gun current with alternating poloidal field. An injected CT relaxes to a minimum magnetic energy equilibrium, moves into a compression cone, and enters a conducting cylinder where the plasma is heated to fusion-producing temperature. The CT then passes into a blanketed region where fusion energy is produced and, on emergence from the fusion region, the CT undergoes controlled expansion in an exit cone where an alternating poloidal field opens the flux surfaces to directly recover the CT magnetic energy as current which is returned to the formation gun. The CT String Reactor (CTSTR) reactor satisfies all the necessary MHD stability requirements and is based on extrapolation of experimentally achieved formation, stability, and plasma confinement. It is supported by extensive 2D, MHD calculations. CTSTR employs minimal external fields supplied by normal conductors, and can produce high fusion power density with uniform wall loading. The geometric simplicity of CTSTR acts to minimize initial and maintenance costs, including periodic replacement of the reactor first wall.

  2. Measurement Variation and Robustness in Quantitative Thoracic Computed Tomography

    E-Print Network [OSTI]

    Chong, Daniel Y.

    2015-01-01

    were calibrated for air and water, as per site protocols. CTwere calibrated for air and water, as per site protocols.water corresponds to a CT value of 0 HU, while air

  3. Comparison of Repositioning Accuracy of Two Commercially Available Immobilization Systems for Treatment of Head-and-Neck Tumors Using Simulation Computed Tomography Imaging

    SciTech Connect (OSTI)

    Rotondo, Ronny L. [Department of Oncology, Division of Radiation Oncology, McGill University, Montreal, Quebec (Canada); Sultanem, Khalil [Department of Oncology, Division of Radiation Oncology, McGill University, Montreal, Quebec (Canada)], E-mail: ksultane@roc.jgh.mcgill.ca; Lavoie, Isabelle; Skelly, Julie; Raymond, Luc [Department of Oncology, Division of Radiation Oncology, McGill University, Montreal, Quebec (Canada)

    2008-04-01

    Purpose: To compare the setup accuracy, comfort level, and setup time of two immobilization systems used in head-and-neck radiotherapy. Methods and Materials: Between February 2004 and January 2005, 21 patients undergoing radiotherapy for head-and-neck tumors were assigned to one of two immobilization devices: a standard thermoplastic head-and-shoulder mask fixed to a carbon fiber base (Type S) or a thermoplastic head mask fixed to the Accufix cantilever board equipped with the shoulder depression system. All patients underwent planning computed tomography (CT) followed by repeated control CT under simulation conditions during the course of therapy. The CT images were subsequently co-registered and setup accuracy was examined by recording displacement in the three cartesian planes at six anatomic landmarks and calculating the three-dimensional vector errors. In addition, the setup time and comfort of the two systems were compared. Results: A total of 64 CT data sets were analyzed. No difference was found in the cartesian total displacement errors or total vector displacement errors between the two populations at any landmark considered. A trend was noted toward a smaller mean systemic error for the upper landmarks favoring the Accufix system. No difference was noted in the setup time or comfort level between the two systems. Conclusion: No significant difference in the three-dimensional setup accuracy was identified between the two immobilization systems compared. The data from this study reassure us that our technique provides accurate patient immobilization, allowing us to limit our planning target volume to <4 mm when treating head-and-neck tumors.

  4. Four-Dimensional Measurement of the Displacement of Internal Fiducial and Skin Markers During 320-Multislice Computed Tomography Scanning of Breast Cancer

    SciTech Connect (OSTI)

    Yamashita, Hideomi; Okuma, Kae; Tada, Keiichiro; Shiraishi, Kenshiro; Takahashi, Wataru; Shibata-Mobayashi, Shino; Sakumi, Akira; Saotome, Naoya; Haga, Akihiro; Onoe, Tsuyoshi; Ino, Kenji; Akahane, Masaaki; Ohtomo, Kuni; Nakagawa, Keiichi

    2012-10-01

    Purpose: To study the three-dimensional movement of internal tumor bed fiducial and breast skin markers, using 320-multislice computed tomography (CT); and to analyze intrafractional errors for breast cancer patients undergoing breast irradiation. Methods and Materials: This study examined 280 markers on the skin of the breast (200 markers) and on the primary tumor bed (80 markers) of 20 patients treated by external-beam photon radiotherapy. Motion assessment was analyzed in 41 respiratory phases during 20 s of cine CT in the radiotherapy position. To assess intrafractional errors resulting from respiratory motion, four-dimensional CT scans were acquired for 20 patients. Results: Motion in the anterior-posterior (A/P) and superior-inferior (S/I) directions showed a strong correlation (|r| > 0.7) with the respiratory curve for most markers (79% and 70%, respectively). The average marker displacements between maximum and minimum value during 20 s for the 200 breast skin metal markers were 1.1 {+-} 0.3 mm, 2.1 {+-} 0.6 mm, and 1.6 {+-} 0.4 mm in the left-right, A/P, and S/I directions, respectively. For the 80 tumor bed clips, displacements were 0.9 {+-} 0.2 mm in left-right, 1.7 {+-} 0.5 mm in A/P, and 1.1 {+-} 0.3 mm in S/I. There was no significant difference in the motion between breast quadrant regions or between the primary site and the other regions. Conclusions: Motion in primary breast tumors was evaluated with 320-multislice CT. Very little change was detected during individual radiation treatment fractions.

  5. Amorphous silicon detectors in positron emission tomography

    SciTech Connect (OSTI)

    Conti, M. (Istituto Nazionale di Fisica Nucleare, Pisa (Italy) Lawrence Berkeley Lab., CA (USA)); Perez-Mendez, V. (Lawrence Berkeley Lab., CA (USA))

    1989-12-01

    The physics of the detection process is studied and the performances of different Positron Emission Tomography (PET) system are evaluated by theoretical calculation and/or Monte Carlo Simulation (using the EGS code) in this paper, whose table of contents can be summarized as follows: a brief introduction to amorphous silicon detectors and some useful equation is presented; a Tantalum/Amorphous Silicon PET project is studied and the efficiency of the systems is studied by Monte Carlo Simulation; two similar CsI/Amorphous Silicon PET projects are presented and their efficiency and spatial resolution are studied by Monte Carlo Simulation, light yield and time characteristics of the scintillation light are discussed for different scintillators; some experimental result on light yield measurements are presented; a Xenon/Amorphous Silicon PET is presented, the physical mechanism of scintillation in Xenon is explained, a theoretical estimation of total light yield in Xenon and the resulting efficiency is discussed altogether with some consideration of the time resolution of the system; the amorphous silicon integrated electronics is presented, total noise and time resolution are evaluated in each of our applications; the merit parameters {epsilon}{sup 2}{tau}'s are evaluated and compared with other PET systems and conclusions are drawn; and a complete reference list for Xenon scintillation light physics and its applications is presented altogether with the listing of the developed simulation programs.

  6. Simultaneous Detection and Registration for Ileo-Cecal Valve Detection in 3D CT Colonography

    E-Print Network [OSTI]

    Barbu, Adrian

    Simultaneous Detection and Registration for Ileo-Cecal Valve Detection in 3D CT Colonography Le Lu1-Cecal Valve (ICV) detection in both clean and tagged 3D CT colonography scans. Our final ICV detection system

  7. Prostate CT segmentation method based on nonrigid registration in ultrasound-guided CT-based HDR prostate brachytherapy

    SciTech Connect (OSTI)

    Yang, Xiaofeng Rossi, Peter; Ogunleye, Tomi; Marcus, David M.; Jani, Ashesh B.; Curran, Walter J.; Liu, Tian; Mao, Hui

    2014-11-01

    Purpose: The technological advances in real-time ultrasound image guidance for high-dose-rate (HDR) prostate brachytherapy have placed this treatment modality at the forefront of innovation in cancer radiotherapy. Prostate HDR treatment often involves placing the HDR catheters (needles) into the prostate gland under the transrectal ultrasound (TRUS) guidance, then generating a radiation treatment plan based on CT prostate images, and subsequently delivering high dose of radiation through these catheters. The main challenge for this HDR procedure is to accurately segment the prostate volume in the CT images for the radiation treatment planning. In this study, the authors propose a novel approach that integrates the prostate volume from 3D TRUS images into the treatment planning CT images to provide an accurate prostate delineation for prostate HDR treatment. Methods: The authors approach requires acquisition of 3D TRUS prostate images in the operating room right after the HDR catheters are inserted, which takes 13 min. These TRUS images are used to create prostate contours. The HDR catheters are reconstructed from the intraoperative TRUS and postoperative CT images, and subsequently used as landmarks for the TRUSCT image fusion. After TRUSCT fusion, the TRUS-based prostate volume is deformed to the CT images for treatment planning. This method was first validated with a prostate-phantom study. In addition, a pilot study of ten patients undergoing HDR prostate brachytherapy was conducted to test its clinical feasibility. The accuracy of their approach was assessed through the locations of three implanted fiducial (gold) markers, as well as T2-weighted MR prostate images of patients. Results: For the phantom study, the target registration error (TRE) of gold-markers was 0.41 0.11 mm. For the ten patients, the TRE of gold markers was 1.18 0.26 mm; the prostate volume difference between the authors approach and the MRI-based volume was 7.28% 0.86%, and the prostate volume Dice overlap coefficient was 91.89% 1.19%. Conclusions: The authors have developed a novel approach to improve prostate contour utilizing intraoperative TRUS-based prostate volume in the CT-based prostate HDR treatment planning, demonstrated its clinical feasibility, and validated its accuracy with MRIs. The proposed segmentation method would improve prostate delineations, enable accurate dose planning and treatment delivery, and potentially enhance the treatment outcome of prostate HDR brachytherapy.

  8. Slowing the Increase in the Population Dose Resulting from CT Scans D. J. Brenner

    E-Print Network [OSTI]

    Brenner, David Jonathan

    is by far in the patient's favor. Nevertheless, CT should operate under the ALARA (As Low As Reasonably

  9. The San Francisco Consortium CT Host, CE Home

    E-Print Network [OSTI]

    Ovchinnikov, Sergei

    The San Francisco Consortium CT Host, CE Home me l r Student: Complete Sections 1 through 5. Print Campus Campus California College of Podiatric Medicine City College of San Francisco Cogswell College Golden Gate University Tuition Required Hastings College of the Law San Francisco State University

  10. CT Poison Control Center 2014 Video Contest Rules

    E-Print Network [OSTI]

    Kim, Duck O.

    CT Poison Control Center 2014 Video Contest Rules To Enter: 1) Record and upload a video to your an immediate family member who is an employee of the Connecticut Poison Control Center. Video Requirements: DO NOT HANDLE, INGEST OR USE ANY ACTUAL POISONOUS OR HAZARDOUSSUBSTANCES. IF YOU HAVE QUESTIONS ABOUT

  11. Collapsibility of Lung Volume by Paired Inspiratory and Expiratory CT

    E-Print Network [OSTI]

    Collapsibility of Lung Volume by Paired Inspiratory and Expiratory CT Scans: Correlations with Lung Function and Mean Lung Density Tsuneo Yamashiro, MD, Shin Matsuoka, MD, PhD, Brian J. Bartholmai, MD, Rau: To evaluate the relationship between measurements of lung volume (LV) on inspiratory/expiratory computed

  12. Targeted CT Screening for Lung Cancer using Absolute Risk Prediction

    E-Print Network [OSTI]

    Brent, Roger

    Targeted CT Screening for Lung Cancer using Absolute Risk Prediction Stephanie A. Kovalchik skovalch@rand.org FHCRC 2014 Risk Prediction Symposium June 11, 2014 1 #12;Outline Lung Cancer Epidemiology and Screening Screening Benefit and Absolute Risk Absolute Risk Model for Lung Cancer

  13. Fractional scan algorithms for low-dose perfusion CT Jiang Hsieha)

    E-Print Network [OSTI]

    Wang, Ge

    Fractional scan algorithms for low-dose perfusion CT Jiang Hsieha) GE Medical Systems, Milwaukee be reconstructed at a fraction of the nominal radiation dose. 2004 American Asso- ciation of Physicists to perform perfusion CT at a significantly reduced x-ray dose. One method to achieve low-dose CT is to reduce

  14. Automatic Lung Nodule Detection from Chest CT Data Using Geometrical Features: Initial Results

    E-Print Network [OSTI]

    Whelan, Paul F.

    Automatic Lung Nodule Detection from Chest CT Data Using Geometrical Features: Initial Results for automatic lung nodule detection from Chest CT data is proposed. The proposed system includes the methods of lung segmentation and nodule detection from CT data. The algorithm for lung segmentation consists

  15. Robust Segmentation of Challenging Lungs in CT using Multi-Stage Learning

    E-Print Network [OSTI]

    Robust Segmentation of Challenging Lungs in CT using Multi-Stage Learning and Level Set.Kevin Zhou1 Abstract Automatic segmentation of lung tissue in thoracic CT scans is useful for diagnosis and treatment planning of pulmonary diseases. Unlike healthy lung tissue that is easily identifiable in CT scans

  16. The effect of head size/shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256-slice CT: How can we minimize the risk for deterministic effects?

    SciTech Connect (OSTI)

    Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis; Papadakis, Antonios E.; Damilakis, John

    2013-01-15

    Purpose: To determine patient-specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low-dose brain perfusion CT studies on a 256-slice CT scanner, and investigate the effect of patient head size/shape, head position during the examination and bowtie filter used on peak tissue doses. Methods: The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual-specific adult head phantoms subjected to the standard low-dose brain perfusion CT on a 256-slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peak tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size/shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye-lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed. Results: The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye-lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x-ray beam. Positioning head phantom off-isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of signal-to-noise ratio mainly to the peripheral region of the phantom. Conclusions: Despite typical peak doses to skin, eye lens, brain, and RBM from the standard low-dose brain perfusion 256-slice CT protocol are well below the corresponding thresholds for the induction of erythema, cataract, cerebrovascular disease, and depression of hematopoiesis, respectively, every effort should be made toward optimization of the procedure and minimization of dose received by these tissues. The current study provides evidence that the use of the narrower bowtie filter available may considerably reduce peak absorbed dose to all above radiosensitive tissues with minimal deterioration in image quality. Considerable reduction in peak eye-lens dose may also be achieved by positioning patient head center a few centimeters above isocenter during the exposure.

  17. Computerized assessment of motion-contaminated calcified plaques in cardiac multidetector CT

    SciTech Connect (OSTI)

    King, Martin; Giger, Maryellen L.; Suzuki, Kenji; Bardo, Dianna M. E.; Greenberg, Brent; Lan Li; Pan Xiaochuan [Department of Radiology, Committee on Medical Physics, University of Chicago, Chicago, Illinois 60637 (United States)

    2007-12-15

    An automated method for evaluating the image quality of calcified plaques with respect to motion artifacts in noncontrast-enhanced cardiac computed tomography (CT) images is introduced. This method involves using linear regression (LR) and artificial neural network (ANN) regression models for predicting two patient-specific, region-of-interest-specific, reconstruction-specific and temporal phase-specific image quality indices. The first is a plaque motion index, which is derived from the actual trajectory of the calcified plaque and is represented on a continuous scale. The second is an assessability index, which reflects the degree to which a calcified plaque is affected by motion artifacts, and is represented on an ordinal five-point scale. Two sets of assessability indices were provided independently by two radiologists experienced in evaluating cardiac CT images. Inputs for the regression models were selected from 12 features characterizing the dynamic, morphological, and intensity-based properties of the calcified plaques. Whereas LR-velocity (LR-V) used only a single feature (three-dimensional velocity), the LR-multiple (LR-M) and ANN regression models used the same subset of these 12 features selected through stepwise regression. The regression models were parameterized and evaluated using a database of simulated calcified plaque images from the dynamic NCAT phantom involving nine heart rate/multi-sector gating combinations and 40 cardiac phases covering two cardiac cycles. Six calcified plaques were used for the plaque motion indices and three calcified plaques were used for both sets of assessability indices. In one configuration, images from the second cardiac cycle were used for feature selection and regression model parameterization, whereas images from the first cardiac cycle were used for testing. With this configuration, repeated measures concordance correlation coefficients (CCCs) and associated 95% confidence intervals for the LR-V, LR-M, and ANN were 0.817 [0.785, 0.848], 0.894 [0.869, 0.916], and 0.917 [0.892, 0.936] for the plaque motion indices. For the two sets of assessability indices, CCC values for the ANN model were 0.843 [0.791, 0.877] and 0.793 [0.747, 0.828]. These two CCC values were statistically greater than the CCC value of 0.689 [0.648, 0.727], which was obtained by comparing the two sets of assessability indices with each other. These preliminary results suggest that the variabilities of assessability indices provided by regression models can lie within the variabilities of the indices assigned by independent observers. Thus, the potential exists for using regression models and assessability indices for determining optimal phases for cardiac CT image interpretation.

  18. State Waste Discharge Permit Application: Electric resistance tomography testing

    SciTech Connect (OSTI)

    Not Available

    1994-04-01

    This permit application documentation is for a State Waste Discharge Permit issued in accordance with requirements of Washington Administrative Code 173-216. The activity being permitted is a technology test using electrical resistance tomography. The electrical resistance tomography technology was developed at Lawrence Livermore National Laboratory and has been used at other waste sites to track underground contamination plumes. The electrical resistance tomography technology measures soil electrical resistance between two electrodes. If a fluid contaminated with electrolytes is introduced into the soil, the soil resistance is expected to drop. By using an array of measurement electrodes in several boreholes, the areal extent of contamination can be estimated. At the Hanford Site, the purpose of the testing is to determine if the electrical resistance tomography technology can be used in the vicinity of large underground metal tanks without the metal tank interfering with the test. It is anticipated that the electrical resistance tomography technology will provide a method for accurately detecting leaks from the bottom of underground tanks, such as the Hanford Site single-shell tanks.

  19. Investigation of the Feasibility of Utilizing Gamma Emission Computed Tomography in Evaluating Fission Product Migration in Irradiated TRISO Fuel Experiments

    SciTech Connect (OSTI)

    Jason M. Harp; Paul A. Demkowicz

    2014-10-01

    In the High Temperature Gas-Cooled Reactor (HTGR) the TRISO particle fuel serves as the primary fission product containment. However the large number of TRISO particles present in proposed HTGRs dictates that there will be a small fraction (~10-4 to 10-5) of as manufactured and in-pile particle failures that will lead to some fission product release. The matrix material surrounding the TRISO particles in fuel compacts and the structural graphite holding the TRISO particles in place can also serve as sinks for containing any released fission products. However data on the migration of solid fission products through these materials is lacking. One of the primary goals of the AGR-3/4 experiment is to study fission product migration from failed TRISO particles in prototypic HTGR components such as structural graphite and compact matrix material. In this work, the potential for a Gamma Emission Computed Tomography (GECT) technique to non-destructively examine the fission product distribution in AGR-3/4 components and other irradiation experiments is explored. Specifically, the feasibility of using the Idaho National Laboratory (INL) Hot Fuels Examination Facility (HFEF) Precision Gamma Scanner (PGS) system for this GECT application is considered. To test the feasibility, the response of the PGS system to idealized fission product distributions has been simulated using Monte Carlo radiation transport simulations. Previous work that applied similar techniques during the AGR-1 experiment will also be discussed as well as planned uses for the GECT technique during the post irradiation examination of the AGR-2 experiment. The GECT technique has also been applied to other irradiated nuclear fuel systems that were currently available in the HFEF hot cell including oxide fuel pins, metallic fuel pins, and monolithic plate fuel.

  20. Quantitative cone-beam CT imaging in radiation therapy using planning CT as a prior: First patient studies

    SciTech Connect (OSTI)

    Niu Tianye; Al-Basheer, Ahmad; Zhu Lei [Nuclear and Radiological Engineering and Medical Physics Programs, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Georgia Radiation Therapy Center, Department of Radiology, Georgia Health Sciences University, Augusta, Georgia 30912 (United States); Nuclear and Radiological Engineering and Medical Physics Programs, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2012-04-15

    Purpose: Quantitative cone-beam CT (CBCT) imaging is on increasing demand for high-performance image guided radiation therapy (IGRT). However, the current CBCT has poor image qualities mainly due to scatter contamination. Its current clinical application is therefore limited to patient setup based on only bony structures. To improve CBCT imaging for quantitative use, we recently proposed a correction method using planning CT (pCT) as the prior knowledge. Promising phantom results have been obtained on a tabletop CBCT system, using a correction scheme with rigid registration and without iterations. More challenges arise in clinical implementations of our method, especially because patients have large organ deformation in different scans. In this paper, we propose an improved framework to extend our method from bench to bedside by including several new components. Methods: The basic principle of our correction algorithm is to estimate the primary signals of CBCT projections via forward projection on the pCT image, and then to obtain the low-frequency errors in CBCT raw projections by subtracting the estimated primary signals and low-pass filtering. We improve the algorithm by using deformable registration to minimize the geometry difference between the pCT and the CBCT images. Since the registration performance relies on the accuracy of the CBCT image, we design an optional iterative scheme to update the CBCT image used in the registration. Large correction errors result from the mismatched objects in the pCT and the CBCT scans. Another optional step of gas pocket and couch matching is added into the framework to reduce these effects. Results: The proposed method is evaluated on four prostate patients, of which two cases are presented in detail to investigate the method performance for a large variety of patient geometry in clinical practice. The first patient has small anatomical changes from the planning to the treatment room. Our algorithm works well even without the optional iterations and the gas pocket and couch matching. The image correction on the second patient is more challenging due to the effects of gas pockets and attenuating couch. The improved framework with all new components is used to fully evaluate the correction performance. The enhanced image quality has been evaluated using mean CT number and spatial nonuniformity (SNU) error as well as contrast improvement factor. If the pCT image is considered as the ground truth, on the four patients, the overall mean CT number error is reduced from over 300 HU to below 16 HU in the selected regions of interest (ROIs), and the SNU error is suppressed from over 18% to below 2%. The average soft-tissue contrast is improved by an average factor of 2.6. Conclusions: We further improve our pCT-based CBCT correction algorithm for clinical use. Superior correction performance has been demonstrated on four patient studies. By providing quantitative CBCT images, our approach significantly increases the accuracy of advanced CBCT-based clinical applications for IGRT.

  1. Automated aortic calcium scoring on low-dose chest computed tomography

    SciTech Connect (OSTI)

    Isgum, Ivana; Rutten, Annemarieke; Prokop, Mathias; Staring, Marius; Klein, Stefan; Pluim, Josien P. W.; Viergever, Max A.; Ginneken, Bram van [Image Sciences Institute, University Medical Center Utrecht, Utrecht 3584 CX (Netherlands); Department of Radiology, University Medical Center Utrecht, Utrecht 3584 CX (Netherlands); Image Sciences Institute, University Medical Center Utrecht, Utrecht 3584 (Netherlands)

    2010-02-15

    Purpose: Thoracic computed tomography (CT) scans provide information about cardiovascular risk status. These scans are non-ECG synchronized, thus precise quantification of coronary calcifications is difficult. Aortic calcium scoring is less sensitive to cardiac motion, so it is an alternative to coronary calcium scoring as an indicator of cardiovascular risk. The authors developed and evaluated a computer-aided system for automatic detection and quantification of aortic calcifications in low-dose noncontrast-enhanced chest CT. Methods: The system was trained and tested on scans from participants of a lung cancer screening trial. A total of 433 low-dose, non-ECG-synchronized, noncontrast-enhanced 16 detector row examinations of the chest was randomly divided into 340 training and 93 test data sets. A first observer manually identified aortic calcifications on training and test scans. A second observer did the same on the test scans only. First, a multiatlas-based segmentation method was developed to delineate the aorta. Segmented volume was thresholded and potential calcifications (candidate objects) were extracted by three-dimensional connected component labeling. Due to image resolution and noise, in rare cases extracted candidate objects were connected to the spine. They were separated into a part outside and parts inside the aorta, and only the latter was further analyzed. All candidate objects were represented by 63 features describing their size, position, and texture. Subsequently, a two-stage classification with a selection of features and k-nearest neighbor classifiers was performed. Based on the detected aortic calcifications, total calcium volume score was determined for each subject. Results: The computer system correctly detected, on the average, 945 mm{sup 3} out of 965 mm{sup 3} (97.9%) calcified plaque volume in the aorta with an average of 64 mm{sup 3} of false positive volume per scan. Spearman rank correlation coefficient was {rho}=0.960 between the system and the first observer compared to {rho}=0.961 between the two observers. Conclusions: Automatic calcium scoring in the aorta thus appears feasible with good correlation between manual and automatic scoring.

  2. Overview of the software architecture and data flow for the J-PET tomography device

    E-Print Network [OSTI]

    Krzemien, W; Bialas, P; Czerwinski, E; Gajos, A; Gruntowski, A; Gruntowski, T; Kaplon, L; Kochanowski, A; Korcyl, G; Kowal, J; Kowalski, P; Kozik, T; Kubicz, E; Moskal, P; Niedzwiecki, Sz; Palka, M; Raczynski, L; Rudy, Z; Sharma, N G; Silarski, M; Slomski, A; Stola, K; Strzelecki, A; Trybek, D; Wieczorek, A; Zielinski, M; Wislicki, W; Zon, N

    2015-01-01

    Modern TOF-PET scanner systems require high-speed computing resources for efficient data processing, monitoring and image reconstruction. In this article we present the data flow and software architecture for the novel TOF-PET scanner developed by the J-PET collaboration. We discuss the data acquisition system, reconstruction framework and some image reconstruction issues. Also, the concept of computing outside hospitals in the remote centers such as \\'Swierk Computing Centre in Poland is presented.

  3. GRIN lens rod based probe for endoscopic spectral domain optical coherence tomography with fast dynamic focus tracking

    E-Print Network [OSTI]

    Xie, Tuqiang; Guo, Shuguang; Chen, Zhongping; Mukai, David; Brenner, Matthew

    2006-01-01

    tomography based on a microelectromechanical mirror, Opt.tomography based on a microelectromechanical mirror, Opt.of a rotational microelectromechanical system probe, Opt.

  4. An Efficient Neumann-Series Based Algorithm for Thermoacoustic and Photoacoustic Tomography with Variable Sound Speed

    E-Print Network [OSTI]

    Stefanov, Plamen

    An Efficient Neumann-Series Based Algorithm for Thermoacoustic and Photoacoustic Tomography present an efficient algorithm for reconstructing an unknown source in Thermoacoustic and Photoacoustic of the Neumann-series based algorithm. 1 Introduction Thermoacoustic (TAT) and Photoacoustic (PAT) Tomography

  5. Microwave-induced thermoacoustic tomography: applications and corrections for the effects of acoustic heterogeneities

    E-Print Network [OSTI]

    Jin, Xing

    2009-05-15

    This research is primarily focused on developing potential applications for microwaveinduced thermoacoustic tomography and correcting for image degradations caused by acoustic heterogeneities. Microwave-induced thermoacoustic tomography was first...

  6. AMP-activated protein kinase phosphorylates CtBP1 and down-regulates its activity

    SciTech Connect (OSTI)

    Kim, Jae-Hwan; Choi, Soo-Youn; Kang, Byung-Hee; Lee, Soon-Min [National Creative Research Center for Epigenome Reprogramming Network, Departments of Biomedical Sciences and Biochemistry and Molecular Biology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of)] [National Creative Research Center for Epigenome Reprogramming Network, Departments of Biomedical Sciences and Biochemistry and Molecular Biology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Park, Hyung Soon; Kang, Gum-Yong; Bang, Joo Young [Center for Biomedical Mass Spectrometry, Diatech Korea Co., Ltd., Seoul (Korea, Republic of)] [Center for Biomedical Mass Spectrometry, Diatech Korea Co., Ltd., Seoul (Korea, Republic of); Cho, Eun-Jung [National Research Laboratory for Chromatin Dynamics, College of Pharmacy, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)] [National Research Laboratory for Chromatin Dynamics, College of Pharmacy, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Youn, Hong-Duk, E-mail: hdyoun@snu.ac.kr [National Creative Research Center for Epigenome Reprogramming Network, Departments of Biomedical Sciences and Biochemistry and Molecular Biology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of) [National Creative Research Center for Epigenome Reprogramming Network, Departments of Biomedical Sciences and Biochemistry and Molecular Biology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); WCU Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence and Technology, Seoul National University, Seoul (Korea, Republic of)

    2013-02-01

    Highlights: ? AMPK phosphorylates CtBP1 on serine 158. ? AMPK-mediated phosphorylation of CtBP1 causes the ubiquitination and nuclear export of CtBP1. ? AMPK downregulates the CtBP1-mediated repression of Bax transcription. -- Abstract: CtBP is a transcriptional repressor which plays a significant role in the regulation of cell proliferation and tumor progression. It was reported that glucose withdrawal causes induction of Bax due to the dissociation of CtBP from the Bax promoter. However, the precise mechanism involved in the regulation of CtBP still remains unclear. In this study, we found that an activated AMP-activated protein kinase (AMPK) phosphorylates CtBP1 on Ser-158 upon metabolic stresses. Moreover, AMPK-mediated phosphorylation of CtBP1 (S158) attenuates the repressive function of CtBP1. We also confirmed that triggering activation of AMPK by various factors resulted in an increase of Bax gene expression. These findings provide connections of AMPK with CtBP1-mediated regulation of Bax expression for cell death under metabolic stresses.

  7. Reconstructions for continuous-wave diffuse optical tomography by a globally convergent

    E-Print Network [OSTI]

    approximation and analysis; (110.6960) Tomography; (110.7050) Turbid media; (170.3880) Medical and biological

  8. Computer tomography of large dust clouds in complex plasmas

    SciTech Connect (OSTI)

    Killer, Carsten; Himpel, Michael; Melzer, Andr

    2014-10-15

    The dust density is a central parameter of a dusty plasma. Here, a tomography setup for the determination of the three-dimensionally resolved density distribution of spatially extended dust clouds is presented. The dust clouds consist of micron-sized particles confined in a radio frequency argon plasma, where they fill almost the entire discharge volume. First, a line-of-sight integrated dust density is obtained from extinction measurements, where the incident light from an LED panel is scattered and absorbed by the dust. Performing these extinction measurements from many different angles allows the reconstruction of the 3D dust density distribution, analogous to a computer tomography in medical applications.

  9. Some Remarks on Quantum Tomography in Laser Cooling

    E-Print Network [OSTI]

    Artur Czerwi?ski

    2015-04-16

    In this article we take into consideration the evolution model of 3-level quantum systems known as \\textit{laser cooling}. The evolution in this model is given by an equation which is a special case of the general Kossakowski-Lindblad master equation. The explicit knowledge about the evolution makes it possible to apply the stroboscopic tomography to laser cooling. In this article we present some remarks concerning the minimal number of observables and moments of measurement for quantum tomography in laser cooling.

  10. THERMOACOUSTIC TOMOGRAPHY WITH VARIABLE SOUND SPEED PLAMEN STEFANOV AND GUNTHER UHLMANN

    E-Print Network [OSTI]

    Uhlmann, Gunther

    THERMOACOUSTIC TOMOGRAPHY WITH VARIABLE SOUND SPEED PLAMEN STEFANOV AND GUNTHER UHLMANN ABSTRACT. We study the mathematical model of thermoacoustic tomography in media with a variable speed are taken on a part of the boundary. 1. INTRODUCTION In thermoacoustic tomography, a short electro

  11. THERMOACOUSTIC TOMOGRAPHY ARISING IN BRAIN IMAGING PLAMEN STEFANOV AND GUNTHER UHLMANN

    E-Print Network [OSTI]

    Uhlmann, Gunther

    THERMOACOUSTIC TOMOGRAPHY ARISING IN BRAIN IMAGING PLAMEN STEFANOV AND GUNTHER UHLMANN Abstract. We study the mathematical model of thermoacoustic and photoacoustic tomography when the sound speed has. Introduction In this paper, we study the mathematical model of thermoacoustic and photoacoustic tomography

  12. Reconstructions in limited-view thermoacoustic tomography Yuan Xu and Lihong V. Wanga)

    E-Print Network [OSTI]

    Kuchment, Peter

    Reconstructions in limited-view thermoacoustic tomography Yuan Xu and Lihong V. Wanga) Optical for publication 9 December 2003; published 11 March 2004 The limited-view problem is studied for thermoacoustic of Physicists in Medicine. DOI: 10.1118/1.1644531 Key words: thermoacoustic tomography, photoacoustic tomography

  13. Gradual time reversal in thermo-and photo-acoustic tomography within a resonant

    E-Print Network [OSTI]

    Kunyansky, Leonid

    , thermoacoustic tomography, time reversal, resonant cavity, reflecting walls, wave equation 1. Introduction Thermoacoustic tomography (TAT) [23, 44] and photoacoustic (or optoacoustic) tomography (PAT/OAT) [9, 22, 33] are based on the thermoacoustic effect: when a material is heated it expands. To perform measurements

  14. THERMOACOUSTIC TOMOGRAPHY ARISING IN BRAIN IMAGING PLAMEN STEFANOV AND GUNTHER UHLMANN

    E-Print Network [OSTI]

    Stefanov, Plamen

    THERMOACOUSTIC TOMOGRAPHY ARISING IN BRAIN IMAGING PLAMEN STEFANOV AND GUNTHER UHLMANN ABSTRACT. We study the mathematical model of thermoacoustic and photoacoustic tomography when the sound speed has. INTRODUCTION In this paper, we study the mathematical model of thermoacoustic and photoacoustic tomography

  15. Radio Science, Volume ???, Number , Pages 131, Radio tomography of the ionosphere: Analysis

    E-Print Network [OSTI]

    Garcia, Raphal

    Radio Science, Volume ???, Number , Pages 131, Radio tomography of the ionosphere: Analysis AND CRESPON: 4D IONOSPHERE TOMOGRAPHY After analysing the forward and inverse problems of radio tomography, the development of Faraday rotation measurements on-board satellites opens the way to magnetospheric radio

  16. LEVEL SET REGULARIZATION IN POSITRON EMISSION TOMOGRAPHY 1 Level Set Method for Positron Emission

    E-Print Network [OSTI]

    Ferguson, Thomas S.

    LEVEL SET REGULARIZATION IN POSITRON EMISSION TOMOGRAPHY 1 Level Set Method for Positron Emission for integrated Petroleum Research). #12;LEVEL SET REGULARIZATION IN POSITRON EMISSION TOMOGRAPHY 2 Abstract In positron emission tomography (PET) a radioactive compound is injected into the body to promote a tissue

  17. Effects of acoustic heterogeneities on transcranial brain imaging with microwave-induced thermoacoustic tomography

    E-Print Network [OSTI]

    Wang, Lihong

    -induced thermoacoustic tomography Xing Jin Department of Biomedical Engineering, Texas A&M University, 3120 TAMU, College: thermoacoustic tomography, transcranial brain imaging, acoustic heterogeneities I. INTRODUCTION Microwave-induced thermoacoustic tomography TAT is a noninvasive and nonionizing imaging modality that can dif- ferentiate

  18. Image distortion in thermoacoustic tomography caused by microwave diffraction Changhui Li,* Manojit Pramanik,

    E-Print Network [OSTI]

    Wang, Lihong

    Image distortion in thermoacoustic tomography caused by microwave diffraction Changhui Li,* Manojit-induced thermoacoustic tomography. The distortion, due to microwave diffraction in the object to be imaged, leads Thermoacoustic TA tomography TAT in biological tis- sue reconstructs the TA source distribution from the acoustic

  19. Tangential resolution improvement in thermoacoustic and photoacoustic tomography using a negative

    E-Print Network [OSTI]

    Wang, Lihong

    Tangential resolution improvement in thermoacoustic and photoacoustic tomography using a negative improve- ment of the tangential resolution in both thermoacoustic and photoa- coustic tomography. In both thermoacoustic and photoacoustic tomography, for a given transducer bandwidth, the aperture size of the detector

  20. 1116 IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 30, NO. 5, MAY 2011 Statistical Interior Tomography

    E-Print Network [OSTI]

    Wang, Ge

    -known as-low-as- reasonably-achievable (ALARA) principle is widely accepted in the medical CT community

  1. Practical Vessel Imaging by Computed Tomography in Live Transgenic Mouse Models for Human Tumors

    E-Print Network [OSTI]

    Capecchi, Mario R.

    delivered by a generic fish tank pump. Volumetric CT of anesthetized mice was per- formed at 93 mm3 voxel

  2. X-ray micro-tomography investigation of the foaming process in the system of waste glasssilica mudMnO{sub 2}

    SciTech Connect (OSTI)

    Ducman, V., E-mail: vilma.ducman@zag.si [ZAG Ljubljana, Dimi?eva 12, 1000 Ljubljana (Slovenia); Korat, L.; Legat, A. [ZAG Ljubljana, Dimi?eva 12, 1000 Ljubljana (Slovenia); Mirti?, B. [NTF, Aker?eva 12, 1000 Ljubljana (Slovenia)

    2013-12-15

    In case of foamed lightweight aggregates (LWAs), porosity is introduced by the addition of a foaming agent to the glassy matrix, which degasses at an elevated temperature, so that the resulting gases remain trapped inside the glassy structure. The efficiency of action of MnO{sub 2} as a foaming agent in waste glass and waste glass/silica mud systems was studied. Samples were fired at different temperatures and with different dwelling times at a certain temperature, and the development of porosity was investigated by means of X-ray micro-tomography. It was found that, with the prolongation in dwelling times, the number of pores decreased, while, on the other hand, the volume of these pores increased, and that the addition of silica mud increases the foaming temperature and slows down the foaming process. - Highlights: Preparation of lightweight aggregate from waste glass, silica sludge, and MnO{sub 2} DTA/TG investigation of MnO{sub 2} Characterization of pore-forming process by means of X-ray micro-tomography (?cT)

  3. The CT14 Global Analysis of Quantum Chromodynamics

    E-Print Network [OSTI]

    Dulat, Sayipjamal; Gao, Jun; Guzzi, Marco; Huston, Joey; Nadolsky, Pavel; Pumplin, Jon; Schmidt, Carl; Stump, Daniel; Yuan, C P

    2015-01-01

    We present new parton distribution functions (PDFs) up to next-to-next-to-leading order (NNLO) from the CTEQ-TEA global analysis of quantum chromodynamics. These differ from previous CT PDFs in several respects, including the use of data from LHC experiments and the new D0 charged lepton rapidity asymmetry data, as well as the use of more flexible parametrization of PDFs that, in particular, allows a better fit to different combinations of quark flavors. Predictions for important LHC processes, especially Higgs boson production at 13 TeV, are presented. These CT14 PDFs include a central set and error sets in the Hessian representation. For completeness, we also present the CT14 PDFs determined at the leading order (LO) and the next-to-leading order (NLO) in QCD. Besides these general-purpose PDF sets, we provide a series of (N)NLO sets with various $\\alpha_s$ values and additional sets in heavy-quark scheme with up to 3, 4, and 6 active flavors.

  4. The CT14 Global Analysis of Quantum Chromodynamics

    E-Print Network [OSTI]

    Sayipjamal Dulat; Tie Jiun Hou; Jun Gao; Marco Guzzi; Joey Huston; Pavel Nadolsky; Jon Pumplin; Carl Schmidt; Daniel Stump; C. P. Yuan

    2015-08-02

    We present new parton distribution functions (PDFs) up to next-to-next-to-leading order (NNLO) from the CTEQ-TEA global analysis of quantum chromodynamics. These differ from previous CT PDFs in several respects, including the use of data from LHC experiments and the new D0 charged lepton rapidity asymmetry data, as well as the use of more flexible parametrization of PDFs that, in particular, allows a better fit to different combinations of quark flavors. Predictions for important LHC processes, especially Higgs boson production at 13 TeV, are presented. These CT14 PDFs include a central set and error sets in the Hessian representation. For completeness, we also present the CT14 PDFs determined at the leading order (LO) and the next-to-leading order (NLO) in QCD. Besides these general-purpose PDF sets, we provide a series of (N)NLO sets with various $\\alpha_s$ values and additional sets in general-mass variable flavor number (GM-VFN) schemes, to deal with heavy partons, with up to 3, 4, and 6 active flavors.

  5. Tomography of high harmonic generation in a cluster jet

    E-Print Network [OSTI]

    . In this Letter, we present a tomographic tech- nique for studying high harmonic generation in cluster jetsTomography of high harmonic generation in a cluster jet Chih-Hao Pai Department of Physics; accepted December 21, 2005; posted January 4, 2006 (Doc. ID 66558) Tomographic measurement of high harmonic

  6. Neutron Stimulated Emission Computed Tomography of Stable Isotopes

    E-Print Network [OSTI]

    on the development of a new molecular imaging technique using inelastic scattering of fast neutrons. Earlier studies characteristic gamma photons through inelastic scattering of an external neutron beam. These stable isotopes canNeutron Stimulated Emission Computed Tomography of Stable Isotopes Carey E. Floyd Jr.*ab , Calvin

  7. Electrical Impedance Tomography in geophysics, application of EIDORS

    E-Print Network [OSTI]

    Adler, Andy

    Electrical Impedance Tomography in geophysics, application of EIDORS Lesparre N., Adler A., Gibert to adapt EIDORS for applications in geophysics. In geophysics, we apply EIT in order to image inner. The spatial resolution of the method in geophysics is of the order of meters and the penetration depth can

  8. Time reversal in thermoacoustic tomography - an error estimate

    E-Print Network [OSTI]

    Hristova, Yulia

    2008-01-01

    The time reversal method in thermoacoustic tomography is used for approximating the initial pressure inside a biological object using measurements of the pressure wave made outside the object. This article presents error estimates for the time reversal method in the cases of variable, non-trapping sound speeds.

  9. A family of inversion formulas in Thermoacoustic Tomography

    E-Print Network [OSTI]

    Nguyen, Linh V

    2009-01-01

    We present a family of closed form inversion formulas in thermoacoustic tomography in the case of a constant sound speed. The formulas are presented in both time-domain and frequency-domain versions. As special cases, they imply most of the previously known filtered backprojection type formulas.

  10. rf testbed for thermoacoustic tomography D. Fallon,1

    E-Print Network [OSTI]

    Hanson, George

    rf testbed for thermoacoustic tomography D. Fallon,1 L. Yan,2 G. W. Hanson,3 and S. K. Patch4,a 1 Received 28 October 2008; accepted 22 April 2009; published online 9 June 2009 Thermoacoustic signal is a preferred acoustic coupling medium for thermoacoustics because acoustic and electromagnetic waves propagate

  11. On singularities and instability of reconstruction in thermoacoustic tomography

    E-Print Network [OSTI]

    Nguyen, Linh V

    2009-01-01

    We consider the problem of thermoacoustic tomography (TAT), in which one needs to reconstruct the initial value of a solution of the wave equation from its value on an observation surface. We show that if some geometric rays for the equation do not intersect the observation surface, the reconstruction in TAT is not H\\"{o}lder stable.

  12. Adaptive optics enhanced simultaneous en-face optical coherence tomography

    E-Print Network [OSTI]

    Dainty, Chris

    Adaptive optics enhanced simultaneous en-face optical coherence tomography and scanning laser ophthalmoscopy David Merino and Chris Dainty Applied Optics Group, Department of Experimental Physics, National and Adrian Gh. Podoleanu Applied Optics Group, School of Physical Sciences, University of Kent at Canterbury

  13. Development of ultrafast computed tomography of highly transient fuel sprays

    E-Print Network [OSTI]

    Gruner, Sol M.

    Development of ultrafast computed tomography of highly transient fuel sprays Xin Liu, Jinyuan Liu University, Ithaca, NY, USA 14853 ABSTRACT The detailed analysis of the fuel sprays has been well recognized emissions. However, the structure and dynamics of highly transient fuel sprays have never been visualized

  14. Cardiac Computed Tomography Radiation Dose Reduction Using Interior Reconstruction Algorithm

    E-Print Network [OSTI]

    Wang, Ge

    recommendations are to use radiation dose as low as possible while satisfying the diagnosis requirement. ThereforeCardiac Computed Tomography Radiation Dose Reduction Using Interior Reconstruction Algorithm. Jeffrey Carr, MD, and Ge Wang, PhD,* Abstract: High x-ray radiation dose is a major public concern

  15. Parallel Adaptive Mesh Coarsening for Seismic Tomography Marc Grunberg

    E-Print Network [OSTI]

    Genaud, Stphane

    . For instance, our case study process the seismic data set ac- quired by the ISC for year 1999 which represents the seismic ray, can be com- puted. Computing the ray paths from the records is called the ray-tracing process. Seismic tomography is a three-phases process : The space of study (either the whole globe or just a re

  16. Plane-wave fluorescence tomography with adaptive finite elements

    E-Print Network [OSTI]

    Bangerth, Wolfgang

    Plane-wave fluorescence tomography with adaptive finite elements Amit Joshi Photon Migration reflectance imaging setup. The method employs planar illumination with modulated light and frequency domain fluo- rescence measurements made on the illumination plane. An adaptive finite-element algorithm

  17. Wireless Tomography in Noisy Environments using Machine Learning

    E-Print Network [OSTI]

    Qiu, Robert Caiming

    1 Wireless Tomography in Noisy Environments using Machine Learning Z. Hu, S. J. Hou, M. C. Wicks, and R. C. Qiu Cognitive Radio Insitute Department of Electrical and Computer Engineering Center. Noise reduction, modified standard phase reconstruction, and imaging are exploited sequentially

  18. Automated robust test framework for electrical impedance tomography

    E-Print Network [OSTI]

    Adler, Andy

    impedance tomography (EIT) devices. The system is designed to calculate reliable, repeatable and accurate system by testing the overall effect of design changes. Test object Saline tank 9 g NaCl per liter H2 O 6. An automated test system and procedure is proposed, designed to enable systematic testing of electrical

  19. Internet Tomography Mark Coates Alfred Hero Robert Nowak Bin Yu

    E-Print Network [OSTI]

    Yu, Bin

    Internet Tomography Mark Coates Alfred Hero Robert Nowak Bin Yu January, 2002 ABSTRACT Today's Internet is a massive, distributed network which continues to explode in size as e- commerce and related activities grow. The heterogeneous and largely unregulated structure of the Internet renders tasks

  20. Asymmetries in Electrical Impedance Tomography Lung Images Bartlomiej Grychtol1

    E-Print Network [OSTI]

    Adler, Andy

    Asymmetries in Electrical Impedance Tomography Lung Images Bartlomiej Grychtol1 and Andy Adler2 1, it has been used to image the thorax, to monitor the movement of blood and gas in the heart and lungs. One key application of EIT is to determine the distribution of ventilation within the lungs

  1. OPTICAL COHERENCE TOMOGRAPHY PRINCIPLES, INSTRUMENTATION, AND BIOLOGICAL APPLICATONS

    E-Print Network [OSTI]

    Boppart, Stephen

    OPTICAL COHERENCE TOMOGRAPHY PRINCIPLES, INSTRUMENTATION, AND BIOLOGICAL APPLICATONS E.A. SW ANSON powerful medical diagnostic techniques,they are invasive and can be time consuming and costly. Furthermore. MIT has designed,developed,and fielded a clinical instrument that is now operating at the New England

  2. Digital optical tomography system for dynamic breast imaging

    E-Print Network [OSTI]

    Hielscher, Andreas

    Columbia University, Department of Electrical Engineering, 1300 S.W. Mudd, 500 West 120th Street, New York, New York be used to detect tumors. We present a new digital continuous-wave optical tomography system designed imaging (MRI) has proven to be a powerful tool in monitoring high-risk women; but its high cost

  3. NREL Develops High Speed Scanner to Monitor Fuel Cell Material Defects (Fact Sheet), Highlights in Research & Development, NREL (National Renewable Energy Laboratory)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJessework usesof EnergyY-12 NationalNO FEAR Act Noticefuel cell scanner

  4. 1st World Congress on Industrial Process Tomography, Buxton, Greater Manchester 1417 April 1999. Eddy Current Tomography for Metal

    E-Print Network [OSTI]

    Hua, Yingbo

    . 451 Eddy Current Tomography for Metal Solidification Imaging Minh H. Pham* , Yingbo Hua* , Neil B of molten metal inside a pipe by eddy currents. A complete mathematical model is developed which reveals computation, solidification 1. INTRODUCTION Electronic control system of molten metal flow is currently

  5. Pretreatment [{sup 18}F]-fluoro-2-deoxy-glucose Positron Emission Tomography Maximum Standardized Uptake Value as Predictor of Distant Metastasis in Early-Stage Non-Small Cell Lung Cancer Treated With Definitive Radiation Therapy: Rethinking the Role of Positron Emission Tomography in Personalizing Treatment Based on Risk Status

    SciTech Connect (OSTI)

    Nair, Vimoj J.; MacRae, Robert; Sirisegaram, Abby; Pantarotto, Jason R.

    2014-02-01

    Purpose: The aim of this study was to determine whether the preradiation maximum standardized uptake value (SUV{sub max}) of the primary tumor for [{sup 18}F]-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) has a prognostic significance in patients with Stage T1 or T2N0 non-small cell lung cancer (NSCLC) treated with curative radiation therapy, whether conventional or stereotactic body radiation therapy (SBRT). Methods and Materials: Between January 2007 and December 2011, a total of 163 patients (180 tumors) with medically inoperable histologically proven Stage T1 or T2N0 NSCLC and treated with radiation therapy (both conventional and SBRT) were entered in a research ethics board approved database. All patients received pretreatment FDG-PET / computed tomography (CT) at 1 institution with consistent acquisition technique. The medical records and radiologic images of these patients were analyzed. Results: The overall survival at 2 years and 3 years for the whole group was 76% and 67%, respectively. The mean and median SUV{sub max} were 8.1 and 7, respectively. Progression-free survival at 2 years with SUV{sub max} <7 was better than that of the patients with tumor SUV{sub max} ?7 (67% vs 51%; P=.0096). Tumors with SUV{sub max} ?7 were associated with a worse regional recurrence-free survival and distant metastasis-free survival. In the multivariate analysis, SUV{sub max} ?7 was an independent prognostic factor for distant metastasis-free survival. Conclusion: In early-stage NSCLC managed with radiation alone, patients with SUV{sub max} ?7 on FDG-PET / CT scan have poorer outcomes and high risk of progression, possibly because of aggressive biology. There is a potential role for adjuvant therapies for these high-risk patients with intent to improve outcomes.

  6. Pancreas imaging by computed tomography after endoscopic retrograde pancreatography. [Dogs; patients

    SciTech Connect (OSTI)

    Frick, M.P.; O'Leary, J.F.; Salomonowitz, E.; Stoltenberg, E.; Hutton, S.; Gedgaudas, E.

    1984-01-01

    A method using CT after endoscopic retrograde pancreatography (CT-ERP) is described for pancreatic imaging. When using an ERP technique in the canine model comparable to that used in humans, small amounts of contrast material in peripheral pancreatic radicles resulted in enhancement of the pancreas on CT scans. Nine patients were also studied by CT-ERP images. The main pancreatic duct was seen on delayed images. In cases of chronic pancreatitis (n = 2), pancreatic opacification was patchy and heterogeneous. There was no contrast-material enhancement in areas of pancreatic carcimomas (n = 2). CT-ERP showed the true extent of carcinoma better than ERP alone.

  7. Accelerated Aging of BKC 44306-10 Rigid Polyurethane Foam: FT-IR Spectroscopy, Dimensional Analysis, and Micro Computed Tomography

    SciTech Connect (OSTI)

    Gilbertson, Robert D.; Patterson, Brian M.; Smith, Zachary

    2014-01-02

    An accelerated aging study of BKC 44306-10 rigid polyurethane foam was carried out. Foam samples were aged in a nitrogen atmosphere at three different temperatures: 50 C, 65 C, and 80 C. Foam samples were periodically removed from the aging canisters at 1, 3, 6, 9, 12, and 15 month intervals when FT-IR spectroscopy, dimensional analysis, and mechanical testing experiments were performed. Micro Computed Tomography imaging was also employed to study the morphology of the foams. Over the course of the aging study the foams the decreased in size by a magnitude of 0.001 inches per inch of foam. Micro CT showed the heterogeneous nature of the foam structure likely resulting from flow effects during the molding process. The effect of aging on the compression and tensile strength of the foam was minor and no cause for concern. FT-IR spectroscopy was used to follow the foam chemistry. However, it was difficult to draw definitive conclusions about the changes in chemical nature of the materials due to large variability throughout the samples.

  8. Abdomino-pelvic computed tomography in the management of ovarian carcinoma

    SciTech Connect (OSTI)

    Johnson, R.J.; Blackledge, G.; Eddleston, B.; Crowther, D.

    1983-02-01

    121 CT scans were obtained in 75 women with ovarian cancer, including 108 scans of the abdomen and pelvis and 13 of the pelvis alone. 70 patients had epithelial carcinoma. In 48 cases, pelvic CT was performed within 3 weeks after surgery, confirming the operative findings in all but 6. In the abdomen, CT identifid intraphepatic deposits and minimal ascites not seen at surgery; however, small peritoneal deposits not usually shown by CT were readily found at surgery. CT was superior to clinical examination, detecting unsuspected disease and delineating areas of known disease more accurately. It was also helpful in assessing suitability for repeat laparotomy. In 7 cases, CT demonstrated an operable lesion which had been thought to be inoperable. In 65 cases (59%), CT contributed additional information which was helpful in management, proving it to be an important noninvasive investigation in patients with ovarian carcinoma.

  9. Semi-automatic delineation using weighted CT-MRI registered images...

    Office of Scientific and Technical Information (OSTI)

    delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer Citation Details In-Document Search Title: Semi-automatic delineation using weighted...

  10. An algorithm for constrained one-step inversion of spectral CT data

    E-Print Network [OSTI]

    Barber, Rina Foygel; Schmidt, Taly Gilat; Pan, Xiaochuan

    2015-01-01

    We develop a primal-dual algorithm that allows for one-step inversion of spectral CT transmission photon counts data to a basis map decomposition. The algorithm allows for image constraints to be enforced on the basis maps during the inversion. The derivation of the algorithm makes use of a local upper bounding quadratic approximation to generate descent steps for non-convex spectral CT data discrepancy terms, combined with a new convex-concave optimization algorithm. Convergence of the algorithm is demonstrated on simulated spectral CT data. Simulations with noise and anthropomorphic phantoms show examples of how to employ the constrained one-step algorithm for spectral CT data.

  11. Embedded Library in WebCT: Pushing UCSD Library Resources to Faculty Courses

    E-Print Network [OSTI]

    Ho, SuHui

    2007-01-01

    keeper about pushing the library to department pages & webEmbedded Library in WebCT:Pushing UCSD Library Resources to Faculty Courses Presenter:

  12. A Fossilized Opal A To Opal C-T Transformation On The Northeast...

    Open Energy Info (EERE)

    A Fossilized Opal A To Opal C-T Transformation On The Northeast Atlantic Margin- Support For A Significantly Elevated Palaeogeothermal Gradient During The Neogene? Jump to:...

  13. Automated matching and segmentation of lymphoma on serial CT examinations

    SciTech Connect (OSTI)

    Yan Jiayong; Zhao Binsheng; Curran, Sean; Zelenetz, Andrew; Schwartz, Lawrence H.

    2007-01-15

    In patients with lymphoma, identification and quantification of the tumor extent on serial CT examinations is critical for assessing tumor response to therapy. In this paper, we present a computer method to automatically match and segment lymphomas in follow-up CT images. The method requires that target lymph nodes in baseline CT images be known. A fast, approximate alignment technique along the x, y, and axial directions is developed to provide a good initial condition for the subsequent fast free form deformation (FFD) registration of the baseline and the follow-up images. As a result of the registration, the deformed lymph node contours from the baseline images are used to automatically determine internal and external markers for the marker-controlled watershed segmentation performed in the follow-up images. We applied this automated registration and segmentation method retrospectively to 29 lymph nodes in 9 lymphoma patients treated in a clinical trial at our cancer center. A radiologist independently delineated all lymph nodes on all slices in the follow-up images and his manual contours served as the ''gold standard'' for evaluation of the method. Preliminary results showed that 26/29 (89.7%) lymph nodes were correctly matched; i.e., there was a geometrical overlap between the deformed lymph node from the baseline and its corresponding mass in the follow-up images. Of the matched 26 lymph nodes, 22 (84.6%) were successfully segmented; for these 22 lymph nodes, several metrics were calculated to quantify the method's performance. Among them, the average distance and the Hausdorff distance between the contours generated by the computer and those generated by the radiologist were 0.9 mm (stdev. 0.4 mm) and 3.9 mm (stdev. 2.1 mm), respectively.

  14. DOE - Office of Legacy Management -- American Brass Co - CT 01

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth Dakota Edgemont, South Dakota,You are hereNY 01NJBrass Co - CT 01

  15. CT Scan of Earth Links Mantle Plumes with Volcanic Hotspots

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAudits &BradburyMay 1, 2013, 4:15pmEnergyNovemberComputeCSTEC EnergyCT

  16. BAIC CT T SK Holdings JV | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION JEnvironmental Jump to:EAandAmminex AAustria Geothermal RegionAvraPáginasSolar JumpPowerBAIC CT T

  17. Quantum tomography meets dynamical systems and bifurcations theory

    SciTech Connect (OSTI)

    Goyeneche, D.; Torre, A. C. de la

    2014-06-01

    A powerful tool for studying geometrical problems in Hilbert spaces is developed. We demonstrate the convergence and robustness of our method in every dimension by considering dynamical systems theory. This method provides numerical solutions to hard problems involving many coupled nonlinear equations in low and high dimensions (e.g., quantum tomography problem, existence and classification of Pauli partners, mutually unbiased bases, complex Hadamard matrices, equiangular tight frames, etc.). Additionally, this tool can be used to find analytical solutions and also to implicitly prove the existence of solutions. Here, we develop the theory for the quantum pure state tomography problem in finite dimensions but this approach is straightforwardly extended to the rest of the problems. We prove that solutions are always attractive fixed points of a nonlinear operator explicitly given. As an application, we show that the statistics collected from three random orthonormal bases is enough to reconstruct pure states from experimental (noisy) data in every dimension d ? 32.

  18. Development of neutron tomography and phase contrast imaging technique

    SciTech Connect (OSTI)

    Kashyap, Y. S.; Agrawal, Ashish; Sarkar, P. S.; Shukla, Mayank; Sinha, Amar

    2013-02-05

    This paper presents design and development of a state of art neutron imaging technique at CIRUS reactor with special reference for techniques adopted for tomography and phase contrast imaging applications. Different components of the beamline such as collimator, shielding, sample manipulator, digital imaging system were designed keeping in mind the requirements of data acquisition time and resolution. The collimator was designed in such a way that conventional and phase contrast imaging can be done using same collimator housing. We have done characterization of fuel pins, study of hydride blisters in pressure tubes hydrogen based cells, two phase flow visualization, and online study of locomotive parts etc. using neutron tomography and radiography technique. We have also done some studies using neutron phase contrast imaging technique on this beamline.

  19. Demonstration of Robust Quantum Gate Tomography via Randomized Benchmarking

    E-Print Network [OSTI]

    Blake R. Johnson; Marcus P. da Silva; Colm A. Ryan; Shelby Kimmel; Jerry M. Chow; Thomas A. Ohki

    2015-05-25

    Typical quantum gate tomography protocols struggle with a self-consistency problem: the gate operation cannot be reconstructed without knowledge of the initial state and final measurement, but such knowledge cannot be obtained without well-characterized gates. A recently proposed technique, known as randomized benchmarking tomography (RBT), sidesteps this self-consistency problem by designing experiments to be insensitive to preparation and measurement imperfections. We implement this proposal in a superconducting qubit system, using a number of experimental improvements including implementing each of the elements of the Clifford group in single `atomic' pulses and custom control hardware to enable large overhead protocols. We show a robust reconstruction of several single-qubit quantum gates, including a unitary outside the Clifford group. We demonstrate that RBT yields physical gate reconstructions that are consistent with fidelities obtained by randomized benchmarking.

  20. Discussion - Next Step for Fukushima Daiichi Muon Tomography

    SciTech Connect (OSTI)

    Miyadera, Haruo

    2012-08-13

    Specification of Fukushima Daiichi Muon Tomography (FMT): (1) 18-feet (5.5-m) drift tube, 2-inch (5-cm) diameter; (2) 108 tubes per layer; (3) Unit layer = 2 layer (detection efficiency: 0.96 x 0.96 = 92%); (4) 12 or 16 layer per module; (5) 16 layers allows momentum analysis at 30% level; (6) 2 module per super module (5.5 x 11 m{sup 2}); and (7) FMT = 2 super module. By deploying MMT next to a research reactor, we will be able to measure the impact of low level radiation fields on muon tomography and reconstruction processes. Radiation level during reactor operation is {approx}50 {micro}Sv/h which provides similar radiation environment of inside the FMT radiation shield at Fukushima Daiichi. We will implement coincidence algorithm on the FPGA board.

  1. Using electrical impedance tomography to map subsurface hydraulic conductivity

    DOE Patents [OSTI]

    Berryman, James G. (Danville, CA); Daily, William D. (Livermore, CA); Ramirez, Abelardo L. (Pleasanton, CA); Roberts, Jeffery J. (Livermore, CA)

    2000-01-01

    The use of Electrical Impedance Tomography (EIT) to map subsurface hydraulic conductivity. EIT can be used to map hydraulic conductivity in the subsurface where measurements of both amplitude and phase are made. Hydraulic conductivity depends on at least two parameters: porosity and a length scale parameter. Electrical Resistance Tomography (ERT) measures and maps electrical conductivity (which can be related to porosity) in three dimensions. By introducing phase measurements along with amplitude, the desired additional measurement of a pertinent length scale can be achieved. Hydraulic conductivity controls the ability to flush unwanted fluid contaminants from the surface. Thus inexpensive maps of hydraulic conductivity would improve planning strategies for subsequent remediation efforts. Fluid permeability is also of importance for oil field exploitation and thus detailed knowledge of fluid permeability distribution in three-dimension (3-D) would be a great boon to petroleum reservoir analysts.

  2. Tomography of photon-number resolving continuous-output detectors

    E-Print Network [OSTI]

    Peter C. Humphreys; Benjamin J. Metcalf; Thomas Gerrits; Thomas Hiemstra; Adriana E. Lita; Joshua Nunn; Sae Woo Nam; Animesh Datta; W. Steven Kolthammer; Ian A. Walmsley

    2015-02-26

    We report a comprehensive approach to analysing continuous-output photon detectors. We employ principal component analysis to maximise the information extracted, followed by a novel noise-tolerant parameterised approach to the tomography of PNRDs. We further propose a measure for rigorously quantifying a detector's photon-number-resolving capability. Our approach applies to all detectors with continuous-output signals. We illustrate our methods by applying them to experimental data obtained from a transition-edge sensor (TES) detector.

  3. Cosmological parameters from lensing power spectrum and bispectrum tomography

    E-Print Network [OSTI]

    Masahiro Takada; Bhuvnesh Jain

    2005-07-20

    We examine how lensing tomography with the bispectrum and power spectrum can constrain cosmological parameters and the equation of state of dark energy. Our analysis uses the full information at the two- and three-point level from angular scales of a few degrees to 5 arcminutes (50 < l < 3000), which will be probed by lensing surveys. We use all triangle configurations, cross-power spectra and bispectra constructed from up to three redshift bins with photometric redshifts, and relevant covariances in our analysis. We find that the parameter constraints from bispectrum tomography are comparable to those from power spectrum tomography. Combining the two improves parameter accuracies by a factor of three due to their complementarity. For the dark energy parameterization w(a) = w0 + wa(1-a), the marginalized errors from lensing alone are sigma(w0) = 0.03 fsky^{-1/2} and sigma(wa) = 0.1 fsky^{-1/2}. We show that these constraints can be further improved when combined with measurements of the cosmic microwave background or Type Ia supernovae. The amplitude and shape of the mass power spectrum are also shown to be precisely constrained. We use hyper-extended perturbation theory to compute the nonlinear lensing bispectrum for dark energy models. Accurate model predictions of the bispectrum in the moderately nonlinear regime, calibrated with numerical simulations, will be needed to realize the parameter accuracy we have estimated. Finally, we estimate how well the lensing bispectrum can constrain a model with primordial non-Gaussianity.

  4. Task-Based Optimization of Computed Tomography Imaging Systems

    E-Print Network [OSTI]

    Sanchez, Adrian A

    2015-01-01

    The goal of this thesis is to provide a framework for the use of task-based metrics of image quality to aid in the design, implementation, and evaluation of CT image reconstruction algorithms and CT systems in general. We support the view that task-based metrics of image quality can be useful in guiding the algorithm design and implementation process in order to yield images of objectively superior quality and higher utility for a given task. Further, we believe that metrics such as the Hotelling observer (HO) SNR can be used as summary scalar metrics of image quality for the evaluation of images produced by novel reconstruction algorithms. In this work, we aim to construct a concise and versatile formalism for image reconstruction algorithm design, implementation, and assessment. The bulk of the work focuses on linear analytical algorithms, specifically the ubiquitous filtered back-projection (FBP) algorithm. However, due to the demonstrated importance of optimization-based algorithms in a wide variety of CT...

  5. TU-C-BRE-04: 3D Gel Dosimetry Using ViewRay On-Board MR Scanner: A Feasibility Study

    SciTech Connect (OSTI)

    Zhang, L; Du, D; Green, O; Rodriguez, V; Wooten, H; Xiao, Z; Yang, D; Hu, Y; Li, H

    2014-06-15

    Purpose: MR based 3D gel has been proposed for radiation therapy dosimetry. However, access to MR scanner has been one of the limiting factors for its wide acceptance. Recent commercialization of an on-board MR-IGRT device (ViewRay) may render the availability issue less of a concern. This work reports our attempts to simulate MR based dose measurement accuracy on ViewRay using three different gels. Methods: A spherical BANG gel dosimeter was purchased from MGS Research. Cylindrical MAGIC gel and Fricke gel were fabricated in-house according to published recipes. After irradiation, BANG and MAGIC were imaged using a dual-echo spin echo sequence for T2 measurement on a Philips 1.5T MR scanner, while Fricke gel was imaged using multiple spin echo sequences. Difference between MR measured and TPS calculated dose was defined as noise. The noise power spectrum was calculated and then simulated for the 0.35 T magnetic field associated with ViewRay. The estimated noise was then added to TG-119 test cases to simulate measured dose distributions. Simulated measurements were evaluated against TPS calculated doses using gamma analysis. Results: Given same gel, sequence and coil setup, with a FOV of 1809090 mm3, resolution of 333 mm3, and scanning time of 30 minutes, the simulated measured dose distribution using BANG would have a gamma passing rate greater than 90% (3%/3mm and absolute). With a FOV 1809090 mm3, resolution of 445 mm3, and scanning time of 45 minutes, the simulated measuremened dose distribution would have a gamma passing rate greater than 97%. MAGIC exhibited similar performance while Fricke gel was inferior due to much higher noise. Conclusions: The simulation results demonstrated that it may be feasible to use MAGIC and BANG gels for 3D dose verification using ViewRay low-field on-board MRI scanner.

  6. A Model-Based Iterative Algorithm for Dual-Energy X-Ray CT Reconstruction

    E-Print Network [OSTI]

    A Model-Based Iterative Algorithm for Dual-Energy X-Ray CT Reconstruction Ruoqiao Zhang, Jean, Senior Member, IEEE Abstract--Recent developments in dual-energy X-ray CT have shown a number of benefits the opportunity to reduce noise and artifacts in dual energy reconstructions. However, previous approaches

  7. Location registration and recognition (LRR) for serial analysis of nodules in lung CT scans

    E-Print Network [OSTI]

    Location registration and recognition (LRR) for serial analysis of nodules in lung CT scans Michal t In the clinical workflow for lung cancer management, the comparison of nodules between CT scans from subsequent in investigating the condition of the lung. The algorithm uses a combination of feature extraction, indexing

  8. AUTOMATIC HEART ISOLATION FOR CT CORONARY VISUALIZATION USING G. Funka-Lea1

    E-Print Network [OSTI]

    Boykov, Yuri

    AUTOMATIC HEART ISOLATION FOR CT CORONARY VISUALIZATION USING GRAPH-CUTS G. Funka-Lea1 , Y. Boykov3 isolate the outer surface of the entire heart in Computer Tomogra- phy (CT) cardiac scans. Isolating the entire heart allows the coronary vessels on the surface of the heart to be easily visu- alized despite

  9. University of Connecticut School of Nursing, 231 Glenbrook Road, Storrs, CT 062692026 NEWS RELEASE

    E-Print Network [OSTI]

    Alpay, S. Pamir

    University of Connecticut School of Nursing, 231 Glenbrook Road, Storrs, CT 062692026 NEWS, 2015 Storrs, CT - The University of Connecticut School of Nursing jumped 36 spots from a No. 79 ranking, students, community partners and alumni at the University of Connecticut's School of Nursing," said Dean

  10. Lobe-based Estimating Ventilation and Perfusion from 3D CT scans of the Lungs

    E-Print Network [OSTI]

    Warren, Joe

    Lobe-based Estimating Ventilation and Perfusion from 3D CT scans of the Lungs Travis McPhail Joe Warren Rice University Thomas Guerrero, M.D. M.D. Anderson Cancer Center Introduction Lung cancer for lung cancer includes surgical removal or radiation therapy. 3D imaging technologies such CT, MRI

  11. ROBUST SEGMENTATION OF LUNG TISSUE IN CHEST CT SCANNING Amal Farag, James Graham and Aly Farag

    E-Print Network [OSTI]

    Louisville, University of

    ROBUST SEGMENTATION OF LUNG TISSUE IN CHEST CT SCANNING Amal Farag, James Graham and Aly Farag.edu ABSTRACT This paper deals with segmentation of the lung tissues from low dose CT (LDCT) scans of the chest. Goal is correct segmentation as well as maintaining the details of the lung region in the chest cavity

  12. Proceedings of MICCAI 2010 Workshop: Virtual Colonoscopy & Abdominal Imaging Recent advances in automated lesion detection for CT

    E-Print Network [OSTI]

    van Vliet, Lucas J.

    , techniques for CT colonography evolved rapidly, stimulated by encouraging performance data. Computer aided: computer aided detection, CT colonography, virtual colonoscopy. 1 Introduction Computed tomographic compliance. For digitally removing` the tagged materials, electronic cleansing (EC) methods were developed [1

  13. SU-E-J-103: Setup Errors Analysis by Cone-Beam CT (CBCT)-Based Imaged-Guided Intensity Modulated Radiotherapy for Esophageal Cancer

    SciTech Connect (OSTI)

    Yang, H; Wang, W; Hu, W; Chen, X; Wang, X; Yu, C [Taizhou Hospital, Wenzhou Medical College, Taizhou, Zhejiang (China)

    2014-06-01

    Purpose: To quantify setup errors by pretreatment kilovolt cone-beam computed tomography(KV-CBCT) scans for middle or distal esophageal carcinoma patients. Methods: Fifty-two consecutive middle or distal esophageal carcinoma patients who underwent IMRT were included this study. A planning CT scan using a big-bore CT simulator was performed in the treatment position and was used as the reference scan for image registration with CBCT. CBCT scans(On-Board Imaging v1. 5 system, Varian Medical Systems) were acquired daily during the first treatment week. A total of 260 CBCT scans was assessed with a registration clip box defined around the PTV-thorax in the reference scan based on(nine CBCTs per patient) bony anatomy using Offline Review software v10.0(Varian Medical Systems). The anterior-posterior(AP), left-right(LR), superiorinferior( SI) corrections were recorded. The systematic and random errors were calculated. The CTV-to-PTV margins in each CBCT frequency was based on the Van Herk formula (2.5?+0.7?). Results: The SD of systematic error (?) was 2.0mm, 2.3mm, 3.8mm in the AP, LR and SI directions, respectively. The average random error (?) was 1.6mm, 2.4mm, 4.1mm in the AP, LR and SI directions, respectively. The CTV-to-PTV safety margin was 6.1mm, 7.5mm, 12.3mm in the AP, LR and SI directions based on van Herk formula. Conclusion: Our data recommend the use of 6 mm, 8mm, and 12 mm for esophageal carcinoma patient setup in AP, LR, SI directions, respectively.

  14. Improved fluorescence-enhanced optical imaging and tomography by enhanced excitation light rejection

    E-Print Network [OSTI]

    Hwang, Kil Dong

    2009-05-15

    Fluorescence enhanced optical imaging and tomography studies involve the detection of weak fluorescent signals emanating from nano- to picomolar concentrations of exogenous or endogenously produced fluorophore concurrent ...

  15. A Bayesian Approach to Assess the Importance of Crustal Corrections in Global Anisotropic Surface Wave Tomography

    E-Print Network [OSTI]

    Xing, Z; Beghein, C

    2015-01-01

    from measurements of surface wave phase velocity anomalies,boundary from surface wave dispersion data, J. Geophys.radially anisotropic surface wave tomography, J. Geophys.

  16. Software-defined Radio Based Wireless Tomography: Experimental Demonstration and Verification

    SciTech Connect (OSTI)

    Bonior, Jason D [ORNL; Hu, Zhen [Tennessee Technological University; Guo, Terry N. [Tennessee Technological University; Qiu, Robert C. [Tennessee Technological University; Browning, James P. [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Wicks, Michael C. [University of Dayton Research Institute

    2015-01-01

    This letter presents an experimental demonstration of software-defined-radio-based wireless tomography using computer-hosted radio devices called Universal Software Radio Peripheral (USRP). This experimental brief follows our vision and previous theoretical study of wireless tomography that combines wireless communication and RF tomography to provide a novel approach to remote sensing. Automatic data acquisition is performed inside an RF anechoic chamber. Semidefinite relaxation is used for phase retrieval, and the Born iterative method is utilized for imaging the target. Experimental results are presented, validating our vision of wireless tomography.

  17. Hemangioma of the Interatrial Septum: CT and MRI Features

    SciTech Connect (OSTI)

    Hrabak-Paar, Maja; Huebner, Marisa; Stern-Padovan, Ranka; Lusic, Mario

    2011-02-15

    Hemangioma of the heart is a rare primary benign tumor mainly appearing as enhancing, homogenous, well-circumscribed mass. We report a case of a 61-year-old asymptomatic woman, whose echocardiography showed a cardiac mass, which was described as the atypical myxoma of the right atrium. For further imaging, contrast-enhanced computed tomography and cardiac magnetic resonance imaging were undertaken, which showed a tumor located in the interatrial septum with imaging characteristics of hemangioma. In the literature, cardiac hemangioma is usually described as an intensely enhancing mass. In our opinion, early peripheral puddling of contrast material with filling in on delayed images is a typical pattern of its enhancement. This characteristic, in addition to high signal intensity on T2-weighted images, allows differentiation of a hemangioma from other benign and malignant tumors.

  18. Written Informed Consent for Computed Tomography of the Abdomen/Pelvis is Associated with Decreased CT Utilization in Low-Risk Emergency Department Patients

    E-Print Network [OSTI]

    Merck, Lisa H.; Ward, Laura A.; Applegate, Kimberly E.; Choo, Esther; Lowery-North, Douglas W.; Heilpern, Katherine L.

    2015-01-01

    of cancer from low-dose radiation. Pediatr and neutrons.Eur Urol. Low Doses of Ionizing Radiation: Assessing What WeLand CE. Low-Dose Extrapolation of Radiation Health Risks:

  19. Written Informed Consent for Computed Tomography of the Abdomen/Pelvis is Associated with Decreased CT Utilization in Low-Risk Emergency Department Patients

    E-Print Network [OSTI]

    Merck, Lisa H.; Ward, Laura A.; Applegate, Kimberly E.; Choo, Esther; Lowery-North, Douglas W.; Heilpern, Katherine L.

    2015-01-01

    1):2530. 28. Brenner DJ, Doll R, Goodhead DT, et al. CancerA, Darby SC, Weiss HA, Doll R. 100 years of observation of

  20. Dual energy CT-based characterization of x-ray attenuation properties of breast equivalent material plates

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Dual energy CT-based characterization of x-ray attenuation properties of breast equivalent material of the same nominal breast density equivalence (+ 1.5 HU). In addition, dual energy CT provided mono equivalent material, breast density, attenuation properties, linear attenuation coefficients, dual energy CT

  1. Statistical analysis of Multi-Material Components using Dual Energy CT Christoph Heinzl, Johann Kastner, Torsten Moller, and Eduard Groller

    E-Print Network [OSTI]

    Statistical analysis of Multi-Material Components using Dual Energy CT Christoph Heinzl, Johann plastics-metal components. The presented work makes use of dual energy CT data acquisi- tion for artefact pipeline based on the dual ex- posure technique of dual energy CT. After prefilter- ing and multi

  2. Noise properties of low-dose X-ray CT sinogram data in Radon space , Hongbing Lu2

    E-Print Network [OSTI]

    Noise properties of low-dose X-ray CT sinogram data in Radon space Jing Wang1 , Hongbing Lu2 statistical moments will improve low-dose CT image reconstruction for screening applications. Keywords: Low-dose]. However, clinical use of CT frequently exposes the patients to excessive X-ray radiation [4

  3. T4DT: Processing 4D CT scans of the Lungs Robert Fowler Joe Warren Yin Zhang

    E-Print Network [OSTI]

    Warren, Joe

    T4DT: Processing 4D CT scans of the Lungs Robert Fowler Joe Warren Yin Zhang Rice University technology for processing time-varying CT scans (4D CT) of the lungs. In particular, we propose to develop these tools to quantitatively assess the effectiveness of current treatments for lung cancer. #12;T4DT

  4. A knowledge-based cone-beam x-ray CT algorithm for dynamic volumetric cardiac imaging

    E-Print Network [OSTI]

    Wang, Ge

    A knowledge-based cone-beam x-ray CT algorithm for dynamic volumetric cardiac imaging Ge Wanga, and wider coverage with multislice/cone- beam CT indicate a great potential for dynamic volumetric imaging/ helical multislice/cone-beam CT approach for dynamic volumetric cardiac imaging. This approach assumes

  5. Investigation of statistical iterative reconstruction for dedicated breast CT

    SciTech Connect (OSTI)

    Makeev, Andrey; Glick, Stephen J.

    2013-08-15

    Purpose: Dedicated breast CT has great potential for improving the detection and diagnosis of breast cancer. Statistical iterative reconstruction (SIR) in dedicated breast CT is a promising alternative to traditional filtered backprojection (FBP). One of the difficulties in using SIR is the presence of free parameters in the algorithm that control the appearance of the resulting image. These parameters require tuning in order to achieve high quality reconstructions. In this study, the authors investigated the penalized maximum likelihood (PML) method with two commonly used types of roughness penalty functions: hyperbolic potential and anisotropic total variation (TV) norm. Reconstructed images were compared with images obtained using standard FBP. Optimal parameters for PML with the hyperbolic prior are reported for the task of detecting microcalcifications embedded in breast tissue.Methods: Computer simulations were used to acquire projections in a half-cone beam geometry. The modeled setup describes a realistic breast CT benchtop system, with an x-ray spectra produced by a point source and an a-Si, CsI:Tl flat-panel detector. A voxelized anthropomorphic breast phantom with 280 ?m microcalcification spheres embedded in it was used to model attenuation properties of the uncompressed woman's breast in a pendant position. The reconstruction of 3D images was performed using the separable paraboloidal surrogates algorithm with ordered subsets. Task performance was assessed with the ideal observer detectability index to determine optimal PML parameters.Results: The authors' findings suggest that there is a preferred range of values of the roughness penalty weight and the edge preservation threshold in the penalized objective function with the hyperbolic potential, which resulted in low noise images with high contrast microcalcifications preserved. In terms of numerical observer detectability index, the PML method with optimal parameters yielded substantially improved performance (by a factor of greater than 10) compared to FBP. The hyperbolic prior was also observed to be superior to the TV norm. A few of the best-performing parameter pairs for the PML method also demonstrated superior performance for various radiation doses. In fact, using PML with certain parameter values results in better images, acquired using 2 mGy dose, than FBP-reconstructed images acquired using 6 mGy dose.Conclusions: A range of optimal free parameters for the PML algorithm with hyperbolic and TV norm-based potentials is presented for the microcalcification detection task, in dedicated breast CT. The reported values can be used as starting values of the free parameters, when SIR techniques are used for image reconstruction. Significant improvement in image quality can be achieved by using PML with optimal combination of parameters, as compared to FBP. Importantly, these results suggest improved detection of microcalcifications can be obtained by using PML with lower radiation dose to the patient, than using FBP with higher dose.

  6. SU-E-J-43: Deformed Planning CT as An Electron Density Substitute for Cone-Beam CT

    SciTech Connect (OSTI)

    Mishra, K; Godley, A

    2014-06-01

    Purpose: To confirm that deforming the planning CT to the daily Cone-Beam CTs (CBCT) can provide suitable electron density for adaptive planning. We quantify the dosimetric difference between plans calculated on deformed planning CTs (DPCT) and daily CT-on-rails images (CTOR). CTOR is used as a test of the method as CTOR already contains accurate electron density to compare against. Methods: Five prostate only IMRT patients, each with five CTOR images, were selected and re-planned on Panther (Prowess Inc.) with a uniform 5 mm PTV expansion, prescribed 78 Gy. The planning CT was deformed to match each CTOR using ABAS (Elekta Inc.). Contours were drawn on the CTOR, and copied to the DPCT. The original treatment plan was copied to both the CTOR and DPCT, keeping the center of the prostate as the isocenter. The plans were then calculated using the collapsed cone heterogeneous dose engine of Prowess and typical DVH planning parameters used to compare them. Results: Each DPCT was visually compared to its CTOR with no differences observed. The agreement of the copied CTOR contours with the DPCT anatomy further demonstrated the deformation accuracy. The plans calculated using CTOR and DPCT were compared. Over the 25 plan pairs, the average difference between them for prostate D100, D98 and D95 were 0.5%, 0.2%, and 0.2%; PTV D98, D95 and mean dose: 0.3%, 0.2% and 0.3%; bladder V70, V60 and mean dose: 1.1%, 0.7%, and 0.2%; and rectum mean dose: 0.3%. (D100 is the dose covering 100% of the target; V70 is the volume of the organ receiving 70 Gy). Conclusion: We observe negligible difference between the dose calculated on the DPCT and the CTOR, implying that deformed planning CTs are a suitable substitute for electron density. The method can now be applied to CBCTs. Research version of Panther provided by Prowess Inc. Research version of ABAS provided by Elekta Inc.

  7. Continuous Measurement Quantum State Tomography of Atomic Ensembles

    E-Print Network [OSTI]

    Carlos A. Riofro

    2011-11-23

    Quantum state tomography is a fundamental tool in quantum information processing. It allows us to estimate the state of a quantum system by measuring different observables on many identically prepared copies of the system. This is, in general, a very time-consuming task that requires a large number of measurements. There are, however, systems in which the data acquisition can be done more efficiently. In fact, an ensemble of quantum systems can be prepared and manipulated by external fields while being continuously and collectively probed, producing enough information to estimate its state. This provides a basis for continuous measurement quantum tomography. In this protocol, an ensemble of identically prepared systems is collectively probed and controlled in a time-dependent manner to create an informationally complete continuous measurement record. The measurement history is then inverted to determine the state at the initial time. We use two different estimation methods: maximum likelihood and compressed sensing. The general formalism is applied to the case of reconstruction of the quantum state encoded in the magnetic sub-levels of a large-spin alkali atom, ${}^{133}$Cs. We apply this protocol to the case of reconstruction of states in the full 16-dimensional electronic-ground subspace ($F=3 \\oplus F=4$), controlled by microwaves and radio-frequency magnetic fields. We present an experimental demonstration of continuous measurement quantum tomography in an ensemble of cold cesium atoms with full control of its 16-dimensional Hilbert space. We show the exquisite level of control achieved in the lab and the excellent agreement between the theory discussed in this dissertation and the experimental results. This allows us to achieve fidelities >95% for low complexity quantum states, and >92% for arbitrary random states, which is a formidable accomplishment for a space of this size.

  8. Spectral thresholding quantum tomography for low rank states

    E-Print Network [OSTI]

    Cristina Butucea; Madalin Guta; Theodore Kypraios

    2015-04-30

    The estimation of high dimensional quantum states is an important statistical problem arising in current quantum technology applications. A key example is the tomography of multiple ions states, employed in the validation of state preparation in ion trap experiments \\cite{Haffner2005}. Since full tomography becomes unfeasible even for a small number of ions, there is a need to investigate lower dimensional statistical models which capture prior information about the state, and to devise estimation methods tailored to such models. In this paper we propose several new methods aimed at the efficient estimation of low rank states in multiple ions tomography. All methods consist in first computing the least squares estimator, followed by its truncation to an appropriately chosen smaller rank. The latter is done by setting eigenvalues below a certain "noise level" to zero, while keeping the rest unchanged, or normalising them appropriately. We show that (up to logarithmic factors in the space dimension) the mean square error of the resulting estimators scales as $r\\cdot d/N$ where $r$ is the rank, $d=2^k$ is the dimension of the Hilbert space, and $N$ is the number of quantum samples. Furthermore we establish a lower bound for the asymptotic minimax risk which shows that the above scaling is optimal. The performance of the estimators is analysed in an extensive simulations study, with emphasis on the dependence on the state rank, and the number of measurement repetitions. We find that all estimators perform significantly better that the least squares, with the "physical estimator" (which is a bona fide density matrix) slightly outperforming the other estimators.

  9. Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure

    SciTech Connect (OSTI)

    Maier, Joscha; Sawall, Stefan; Kachelrie, Marc

    2014-05-15

    Purpose: Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. Methods: Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. Results: Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the HDTV algorithm shows the best performance. At 50 mGy, the deviation from the reference obtained at 500 mGy were less than 4%. Also the LDPC algorithm provides reasonable results with deviation less than 10% at 50 mGy while PCF and MKB reconstruction show larger deviations even at higher dose levels. Conclusions: LDPC and HDTV increase CNR and allow for quantitative evaluations even at dose levels as low as 50 mGy. The left ventricular volumes exemplarily illustrate that cardiac parameters can be accurately estimated at lowest dose levels if sophisticated algorithms are used. This allows to reduce dose by a factor of 10 compared to today's gold standard and opens new options for longitudinal studies of the heart.

  10. Digital Pulse Timing in FPGAs for Positron Emission Tomography. M.D. Haselman1

    E-Print Network [OSTI]

    Hauck, Scott

    complex digital signal processing computations with clock rates of above 100MHz. This, combined with their low cost and ease of use, make them an ideal technology for pulse timing, and are a central part of our next generation of electronics for our pre-clinical PET scanner systems. To that end, our

  11. Relation between quantum tomography and optical Fresnel transform

    E-Print Network [OSTI]

    Hong-yi Fan; Li-yun Hu

    2008-01-13

    Corresponding to optical Fresnel transformation characteristic of ray transfer matrix elements (A;B;C;D); AD-BC = 1, there exists Fresnel operator F(A;B;C;D) in quantum optics, we show that under the Fresnel transformation the pure position density |x>_rs,rs__rs,rs_Fresnel quadrature phase is the tomography (Radon transform of Wigner function), and the tomogram of a state |phi> is just the wave function of its Fresnel transformed state F|phi>, i.e. rs_= . Similarly, we find F|p>_rs,rs_

  12. Fiber optic based optical coherence tomography (OCT) for dental applications

    SciTech Connect (OSTI)

    Everett, M. J., LLNL

    1998-06-02

    We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity We have produced, using this scanning device, in viva cross-sectional images of hard and soft dental tissues in human volunteers Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento-enamel junction, were visible in all the images The dento-enamel junction and the alveolar bone were identifiable in approximately two thirds of the images These images represent, to our knowledge, the first in viva OCT images of human dental tissue.

  13. Comparison of Image Registration Based Measures of Regional Lung Ventilation from Dynamic Spiral CT with Xe-CT

    E-Print Network [OSTI]

    Ding, Kai; Fuld, Matthew K; Du, Kaifang; Christensen, Gary E; Hoffman, Eric A; Reinhardt, Joseph M

    2012-01-01

    Purpose: Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this article, we propose a new regional measure of lung mechanics --- the specific air volume change by corrected Jacobian. Methods: 4DCT and Xe-CT data sets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration-based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). Results: After registration, the mean registration err...

  14. A study on planning organ at risk volume for the rectum using cone beam computed tomography in the treatment of prostate cancer

    SciTech Connect (OSTI)

    Prabhakar, Ramachandran; Oates, Richard; Jones, Daryl; Kron, Tomas; Cramb, Jim; Foroudi, Farshad; Geso, Moshi; Gill, Suki

    2014-04-01

    In this study, we analyzed planning organ at risk volume (PRV) for the rectum using a series of cone beam computed tomographies (CBCTs) acquired during the treatment of prostate cancer and evaluated the dosimetric effect of different PRV definitions. Overall, 21 patients with prostate cancer were treated radically with 78 Gy in 39 fractions had in total 418 CBCTs, each acquired at the end of the first 5 fractions and then every alternate fraction. The PRV was generated from the Boolean sum volume of the rectum obtained from first 5 fractions (PRV-CBCT-5) and from all CBCTs (PRV-CBCT-All). The PRV margin was compared at the superior, middle, and inferior slices of the contoured rectum to compare PRV-CBCT-5 and PRV-CBCT-All. We also compared the dose received by the planned rectum (Rectum-computed tomography [CT]), PRV-CBCT-5, PRV-CBCT-All, and average rectum (CBCT-AV-dose-volume histogram [DVH]) at critical dose levels. The average measured rectal volume for all 21 patients for Rectum-CT, PRV-CBCT-5, and PRV-CBCT-All was 44.3 15.0, 92.8 40.40, and 121.5 36.7 cm{sup 3}, respectively. For PRV-CBCT-All, the mean standard deviation displacement in the anterior, posterior, right, and left lateral directions in centimeters was 2.1 1.1, 0.9 0.5, 0.9 0.8, and 1.1 0.7 for the superior rectum; 0.8 0.5, 1.1 0.5, 1.0 0.5, and 1.0 0.5 for the middle rectum; and 0.3 0.3; 0.9 0.5; 0.4 0.2, and 0.5 0.3 for the inferior rectum, respectively. The first 5 CBCTs did not predict the PRV for individual patients. Our study shows that the PRV margin is different for superior, middle, and the inferior parts of the rectum, it is wider superiorly and narrower inferiorly. A uniform PRV margin does not represent the actual rectal variations during treatment for all treatment fractions. The large variation in interpatient rectal size implies a potential role for adaptive radiotherapy for prostate cancer.

  15. Electrical impedance tomography and Calderon's Department of Mathematics, University of Washington, Seattle, WA 98195, USA

    E-Print Network [OSTI]

    Uhlmann, Gunther

    Electrical impedance tomography and Calderon's problem G Uhlmann Department of Mathematics, University of Washington, Seattle, WA 98195, USA E-mail: gunther@math.washington.edu Abstract. We survey mathematical developments in the inverse method of Electrical Impedance Tomography which consists

  16. Analysis of hydraulic tomography using temporal moments of drawdown recovery data

    E-Print Network [OSTI]

    Daniels, Jeffrey J.

    Analysis of hydraulic tomography using temporal moments of drawdown recovery data Junfeng Zhu 2006. [1] Transient hydraulic tomography (THT) is a potentially cost-effective and high- resolution technique for mapping spatial distributions of the hydraulic conductivity and specific storage in aquifers

  17. Seismic tomography constraints on reconstructing the Philippine Sea Plate and its margin

    E-Print Network [OSTI]

    Handayani, Lina

    2005-02-17

    ............................................................. 42 Mariana Subduction Zone.............................................................. 43 Philippine Subduction Zone........................................................... 43 Java Subduction Zone.................................. 38 3.5 P-wave seismic tomography cross sections across Japan (C), Izu-Bonin(D), Mariana (E) and Java (F)......................................... 39 3.6 Tomography cross sections 1 to 5...

  18. Investigating the stratigraphy of an alluvial aquifer using crosswell seismic traveltime tomography

    E-Print Network [OSTI]

    Barrash, Warren

    Investigating the stratigraphy of an alluvial aquifer using crosswell seismic traveltime tomography In this study, we investigate the use of crosswell P-wave seismic tomography to obtain spatially extensive collected cross- well and borehole-to-surface seismic data in wells 17.1 m apart. We carefully considered

  19. Determining both sound speed and internal source in thermo- and photo-acoustic tomography

    E-Print Network [OSTI]

    Hongyu Liu; Gunther Uhlmann

    2015-02-04

    This paper concerns thermoacoustic tomography and photoacoustic tomography, two couple-physics imaging modalities that attempt to combine the high resolution of ultrasound and the high contrast capabilities of electromagnetic waves. We give sufficient conditions to recover both the sound speed of the medium being probed and the source.

  20. INSTABILITY OF THE LINEARIZED PROBLEM IN MULTIWAVE TOMOGRAPHY OF RECOVERY BOTH THE SOURCE AND THE SPEED

    E-Print Network [OSTI]

    Uhlmann, Gunther

    of recovering both the sound speed and the thermal absorption arising in thermoacoustic and photoacoustic tomography, one sends one type of wave to the body of a patient, most often electromag- netic (thermoacoustic] in thermoacoustic tomography. The travel time problem is stable under some geometric assumptions on c (c 2dx2 being

  1. Using computerized tomography to determine ionospheric structures. Part 1, Notivation and basic approaches

    SciTech Connect (OSTI)

    Vittitoe, C.N.

    1993-08-01

    Properties of the ionosphere are reviewed along with its correlations with other geophysical phenomena and with applications of ionospheric studies to communication, navigation, and surveillance systems. Computer tomography is identified as a method to determine the detailed, three-dimensional distribution of electron density within the ionosphere. Several tomography methods are described, with a basic approach illustrated by an example. Limitations are identified.

  2. MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution conductivity imaging

    E-Print Network [OSTI]

    Eybolu, Murat

    MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution are measured by using conventional electrical impedance tomography techniques and high resolution magnetic and the point spread function is not space invariant. On the other hand, magnetic field and electrical current

  3. Photoacoustic tomography of biological tissues with high cross-section resolution: Reconstruction and experiment

    E-Print Network [OSTI]

    Wang, Lihong

    27 November 2002 A modified back-projection approach deduced from an exact reconstruction solution was applied to our photoacoustic tomography of the optical absorption in biological tissues. Pulses from a Ti:sap a spatial resolution around 10 m.8 All of the above photoacoustic tomography systems can be categorized

  4. Hydraulic conductivity imaging from 3-D transient hydraulic tomography at several pumping/observation densities

    E-Print Network [OSTI]

    Barrash, Warren

    Hydraulic conductivity imaging from 3-D transient hydraulic tomography at several pumping August 2013; accepted 7 September 2013; published 13 November 2013. [1] 3-D Hydraulic tomography (3-D HT (primarily hydraulic conductivity, K) is estimated by joint inversion of head change data from multiple

  5. Data-driven classification of ventilated lung tissues using electrical impedance tomography

    E-Print Network [OSTI]

    Adler, Andy

    Data-driven classification of ventilated lung tissues using electrical impedance tomography Camille for identifying ventilated lung regions utilizing electrical impedance tomography (EIT) images rely on dividing of a data-driven classification method to identify ventilated lung ROI based on forming k clusters from

  6. Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle

    E-Print Network [OSTI]

    Allen, Richard M.

    Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle G. R of Iceland, Bustadavegi 9, Reykjavik, Iceland 5 National Energy Authority, Grensasvegi 9, Reykjavik, Iceland of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland

  7. Product measurements and fully symmetric measurements in qubit-pair tomography: A numerical study

    E-Print Network [OSTI]

    Yong Siah Teo; Huangjun Zhu; Berthold-Georg Englert

    2009-07-24

    State tomography on qubit pairs is routinely carried out by measuring the two qubits separately, while one expects a higher efficiency from tomography with highly symmetric joint measurements of both qubits. Our numerical study of simulated experiments does not support such expectations.

  8. Scanning thermoacoustic tomography in biological tissue Geng Ku and Lihong V. Wanga)

    E-Print Network [OSTI]

    Wang, Lihong

    Scanning thermoacoustic tomography in biological tissue Geng Ku and Lihong V. Wanga) Optical-induced thermoacoustic tomography was explored to image biological tissue. Short microwave pulses irradiated tissue to generate acoustic waves by thermoelastic expansion. The microwave-induced thermoacoustic waves were

  9. Pulsed-microwave-induced thermoacoustic tomography: Filtered backprojection in a circular measurement configuration

    E-Print Network [OSTI]

    Wang, Lihong

    Pulsed-microwave-induced thermoacoustic tomography: Filtered backprojection in a circular-microwave-induced thermoacoustic tomography in biological tissues is pre- sented. A filtered backprojection algorithm based on rigorous theory is used to reconstruct the cross-sectional image from a thermoacoustic measurement

  10. WIND TOMOGRAPHY IN BINARY SYSTEMS O.Knill, R.Dgani and M.Vogel

    E-Print Network [OSTI]

    Knill, Oliver

    WIND TOMOGRAPHY IN BINARY SYSTEMS O.Knill, R.Dgani and M.Vogel ETH-Zurich, CH-8092, Switzerland method is particularly suitable for determining the velocity laws of stellar winds. 1. WIND TOMOGRAPHY AND ABEL'S INTEGRAL Binary systems in which a compact, point-like radiation source shines through the wind

  11. THREE-DIMENSIONAL CLOUD STRUCTURE OBSERVED DURING DOE ARM'S 2009 CLOUD TOMOGRAPHY FIELD EXPERIMENT

    E-Print Network [OSTI]

    THREE-DIMENSIONAL CLOUD STRUCTURE OBSERVED DURING DOE ARM'S 2009 CLOUD TOMOGRAPHY FIELD EXPERIMENT on Cloud Physics, Portland, OR June 28-July 2, 2010 Environmental Sciences Department/Atmospheric Sciences Atmospheric Radiation Measurement (ARM)'s cloud tomography Intensive Observation Period (IOP

  12. Cloud tomography: Role of constraints and a new algorithm Dong Huang,1

    E-Print Network [OSTI]

    Cloud tomography: Role of constraints and a new algorithm Dong Huang,1 Yangang Liu,1 and Warren 2008. [1] Retrieving spatial distributions of cloud liquid water content from limited-angle emission data (passive microwave cloud tomography) is ill-posed, and a small inaccuracy in the data and

  13. Determination of cloud liquid water distribution using 3D cloud tomography

    E-Print Network [OSTI]

    Determination of cloud liquid water distribution using 3D cloud tomography Dong Huang,1 Yangang Liu; published 2 July 2008. [1] The cloud microwave tomography method for remotely retrieving 3D distributions of cloud Liquid Water Content (LWC) was originally proposed by Warner et al. in the 1980s but has lain

  14. Introducing Minimum Fisher Regularisation Tomography to Bolometric and Soft X-ray Diagnostic Systems of the COMPASS Tokamak

    E-Print Network [OSTI]

    Introducing Minimum Fisher Regularisation Tomography to Bolometric and Soft X-ray Diagnostic Systems of the COMPASS Tokamak

  15. Determinants of Local Progression After Computed Tomography-Guided Percutaneous Radiofrequency Ablation for Unresectable Lung Tumors: 9-Year Experience in a Single Institution

    SciTech Connect (OSTI)

    Okuma, Tomohisa, E-mail: o-kuma@msic.med.osaka-cu.ac.jp; Matsuoka, Toshiyuki; Yamamoto, Akira; Oyama, Yoshimasa; Hamamoto, Shinichi [Osaka City University Graduate School of Medicine, Department of Radiology (Japan); Toyoshima, Masami [Kobe City Medical Center West Hospital, Department of Radiology (Japan); Nakamura, Kenji; Miki, Yukio [Osaka City University Graduate School of Medicine, Department of Radiology (Japan)

    2010-08-15

    The purpose of this study was to retrospectively determine the local control rate and contributing factors to local progression after computed tomography (CT)-guided radiofrequency ablation (RFA) for unresectable lung tumor. This study included 138 lung tumors in 72 patients (56 men and 16 women; age 70.0 {+-} 11.6 years (range 31-94); mean tumor size 2.1 {+-} 1.2 cm [range 0.2-9]) who underwent lung RFA between June 2000 and May 2009. Mean follow-up periods for patients and tumors were 14 and 12 months, respectively. The local progression-free rate and survival rate were calculated to determine the contributing factors to local progression. During follow-up, 44 of 138 (32%) lung tumors showed local progression. The 1-, 2-, 3-, and 5-year overall local control rates were 61, 57, 57, and 38%, respectively. The risk factors for local progression were age ({>=}70 years), tumor size ({>=}2 cm), sex (male), and no achievement of roll-off during RFA (P < 0.05). Multivariate analysis identified tumor size {>=}2 cm as the only independent factor for local progression (P = 0.003). For tumors <2 cm, 17 of 68 (25%) showed local progression, and the 1-, 2-, and 3-year overall local control rates were 77, 73, and 73%, respectively. Multivariate analysis identified that age {>=}70 years was an independent determinant of local progression for tumors <2 cm in diameter (P = 0.011). The present study showed that 32% of lung tumors developed local progression after CT-guided RFA. The significant risk factor for local progression after RFA for lung tumors was tumor size {>=}2 cm.

  16. Statistical analysis of sampling methods in quantum tomography

    E-Print Network [OSTI]

    Thomas Kiesel

    2012-06-07

    In quantum physics, all measured observables are subject to statistical uncertainties, which arise from the quantum nature as well as the experimental technique. We consider the statistical uncertainty of the so-called sampling method, in which one estimates the expectation value of a given observable by empirical means of suitable pattern functions. We show that if the observable can be written as a function of a single directly measurable operator, the variance of the estimate from the sampling method equals to the quantum mechanical one. In this sense, we say that the estimate is on the quantum mechanical level of uncertainty. In contrast, if the observable depends on non-commuting operators, e.g. different quadratures, the quantum mechanical level of uncertainty is not achieved. The impact of the results on quantum tomography is discussed, and different approaches to quantum tomographic measurements are compared. It is shown explicitly for the estimation of quasiprobabilities of a quantum state, that balanced homodyne tomography does not operate on the quantum mechanical level of uncertainty, while the unbalanced homodyne detection does.

  17. Our Next Two Steps for Fukushima Daiichi Muon Tomography

    SciTech Connect (OSTI)

    Miyadera, Haruo

    2012-04-11

    After the vast disasters caused by the great earthquake and tsunami in eastern Japan, we proposed applying our Muon Tomography (MT) technique to help and improve the emergency situation at Fukushima Daiichi using cosmic-ray muons. A reactor-tomography team was formed at LANL which was supported by the Laboratory as a response to a request by the former Japanese Prime Minister, Naoto Kan. Our goal is to help the Japanese people and support remediation of the reactors. At LANL, we have carried out a proof-of-principle technical demonstration and simulation studies that established the feasibility of MT to image a reactor core. This proposal covers the next two critical steps for Fukushima Daiichi Muon Imaging: (1) undertake case study mock-up experiments of Fukushima Daiichi, and (2) system optimization. We requested funding to the US and Japanese government to assess damage of reactors at Fukushima Daiichi. The two steps will bring our project to the 'ready-to-go' level.

  18. Wavelength-encoded tomography based on optical temporal Fourier transform

    SciTech Connect (OSTI)

    Zhang, Chi; Wong, Kenneth K. Y.

    2014-09-01

    We propose and demonstrate a technique called wavelength-encoded tomography (WET) for non-invasive optical cross-sectional imaging, particularly beneficial in biological system. The WET utilizes time-lens to perform the optical Fourier transform, and the time-to-wavelength conversion generates a wavelength-encoded image of optical scattering from internal microstructures, analogous to the interferometery-based imaging such as optical coherence tomography. Optical Fourier transform, in principle, comes with twice as good axial resolution over the electrical Fourier transform, and will greatly simplify the digital signal processing after the data acquisition. As a proof-of-principle demonstration, a 150?-?m (ideally 36??m) resolution is achieved based on a 7.5-nm bandwidth swept-pump, using a conventional optical spectrum analyzer. This approach can potentially achieve up to 100-MHz or even higher frame rate with some proven ultrafast spectrum analyzer. We believe that this technique is innovative towards the next-generation ultrafast optical tomographic imaging application.

  19. Physically motivated global alignment method for electron tomography

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sanders, Toby; Prange, Micah; Akatay, Cem; Binev, Peter

    2015-04-08

    Electron tomography is widely used for nanoscale determination of 3-D structures in many areas of science. Determining the 3-D structure of a sample from electron tomography involves three major steps: acquisition of sequence of 2-D projection images of the sample with the electron microscope, alignment of the images to a common coordinate system, and 3-D reconstruction and segmentation of the sample from the aligned image data. The resolution of the 3-D reconstruction is directly influenced by the accuracy of the alignment, and therefore, it is crucial to have a robust and dependable alignment method. In this paper, we develop amorenew alignment method which avoids the use of markers and instead traces the computed paths of many identifiable local center-of-mass points as the sample is rotated. Compared with traditional correlation schemes, the alignment method presented here is resistant to cumulative error observed from correlation techniques, has very rigorous mathematical justification, and is very robust since many points and paths are used, all of which inevitably improves the quality of the reconstruction and confidence in the scientific results.less

  20. A SYNERGY OF MICROWAVE CLOUD TOMOGRAPHY AND SCANNING RADAR: MOVING TOWARD A 3D VIEW OF CLOUDS

    E-Print Network [OSTI]

    A SYNERGY OF MICROWAVE CLOUD TOMOGRAPHY AND SCANNING RADAR: MOVING TOWARD A 3D VIEW OF CLOUDS D complementary techniques, i.e., cloud microwave tomography and scanning radar, to retrieve 3D cloud properties the sixth moment of cloud droplets, while cloud tomography, by remotely probing cloud microwave emission

  1. Abstract-A novel imaging method for electrical impedance tomography is implemented. In this method, the magnetic flux

    E-Print Network [OSTI]

    Eybolu, Murat

    - electrical impedance tomography, magnetic resonance imaging. I. INTRODUCTION Electrical impedance tomography conductivity images [11]. Both of these techniques can be named as magnetic resonance-electrical impedanceAbstract- A novel imaging method for electrical impedance tomography is implemented. In this method

  2. Microwave-induced thermoacoustic tomography using multi-sector Minghua Xu, Geng Ku, and Lihong V. Wanga)

    E-Print Network [OSTI]

    Wang, Lihong

    Microwave-induced thermoacoustic tomography using multi-sector scanning Minghua Xu, Geng Ku A study of microwave-induced thermoacoustic tomography of inhomogeneous tissues using multi- sector of Physicists in Medicine. DOI: 10.1118/1.1395037 Key words: microwave, thermoacoustics, tomography, imaging

  3. Iterative image-domain decomposition for dual-energy CT

    SciTech Connect (OSTI)

    Niu, Tianye; Dong, Xue; Petrongolo, Michael; Zhu, Lei

    2014-04-15

    Purpose: Dual energy CT (DECT) imaging plays an important role in advanced imaging applications due to its capability of material decomposition. Direct decomposition via matrix inversion suffers from significant degradation of image signal-to-noise ratios, which reduces clinical values of DECT. Existing denoising algorithms achieve suboptimal performance since they suppress image noise either before or after the decomposition and do not fully explore the noise statistical properties of the decomposition process. In this work, the authors propose an iterative image-domain decomposition method for noise suppression in DECT, using the full variance-covariance matrix of the decomposed images. Methods: The proposed algorithm is formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, the authors include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. The regularization term enforces the image smoothness by calculating the square sum of neighboring pixel value differences. To retain the boundary sharpness of the decomposed images, the authors detect the edges in the CT images before decomposition. These edge pixels have small weights in the calculation of the regularization term. Distinct from the existing denoising algorithms applied on the images before or after decomposition, the method has an iterative process for noise suppression, with decomposition performed in each iteration. The authors implement the proposed algorithm using a standard conjugate gradient algorithm. The method performance is evaluated using an evaluation phantom (Catphan600) and an anthropomorphic head phantom. The results are compared with those generated using direct matrix inversion with no noise suppression, a denoising method applied on the decomposed images, and an existing algorithm with similar formulation as the proposed method but with an edge-preserving regularization term. Results: On the Catphan phantom, the method maintains the same spatial resolution on the decomposed images as that of the CT images before decomposition (8 pairs/cm) while significantly reducing their noise standard deviation. Compared to that obtained by the direct matrix inversion, the noise standard deviation in the images decomposed by the proposed algorithm is reduced by over 98%. Without considering the noise correlation properties in the formulation, the denoising scheme degrades the spatial resolution to 6 pairs/cm for the same level of noise suppression. Compared to the edge-preserving algorithm, the method achieves better low-contrast detectability. A quantitative study is performed on the contrast-rod slice of Catphan phantom. The proposed method achieves lower electron density measurement error as compared to that by the direct matrix inversion, and significantly reduces the error variation by over 97%. On the head phantom, the method reduces the noise standard deviation of decomposed images by over 97% without blurring the sinus structures. Conclusions: The authors propose an iterative image-domain decomposition method for DECT. The method combines noise suppression and material decomposition into an iterative process and achieves both goals simultaneously. By exploring the full variance-covariance properties of the decomposed images and utilizing the edge predetection, the proposed algorithm shows superior performance on noise suppression with high image spatial resolution and low-contrast detectability.

  4. Silben Workshop Mnster, 2011 Christine Mooshammer, Haskins Labs, New Haven, CT

    E-Print Network [OSTI]

    , MA) Elliot Saltzman (Haskins & BU, Boston, MA) Hosung Nam (Haskins) Argyo Katsika (Haskins & Yale, CT und Elliot Saltzman) Grundlegende Einheit in der gesprochenen Sprache sind die Gesten Gesten werden

  5. 10 A.M. CT TODAY: On-the Record Conference Call for Obama Administrati...

    Broader source: Energy.gov (indexed) [DOE]

    White House Rural Economic Council Promotes Production of Next Generation Biofuels, Job Creation and Economic Opportunity WASHINGTON, Aug. 16, 2011 - Today at 10 a.m. CT (11 a.m....

  6. Finite Element Analysis of Ballistic Penetration of Plain Weave Twaron CT709 Fabrics: A Parametric Study

    E-Print Network [OSTI]

    Gogineni, Sireesha

    2011-10-21

    The ballistic impact of Twaron CT709 plain weave fabrics is studied using an explicit finite element method. Many existing approximations pertaining to woven fabrics cannot adequately represent strain rate-dependent behavior exhibited by the Twaron...

  7. Lung nodule detection in low-dose and high-resolution CT scans

    E-Print Network [OSTI]

    Delogu, P; Gori, I; Preite Martnez, A; Retico, A; Tata, A

    2006-01-01

    We are developing a computer-aided detection (CAD) system for the identification of small pulmonary nodules in screening CT scans. The main modules of our system, i.e. a dot-enhancement filter for nodule candidate selection and a neural classifier for false positive finding reduction, are described. The preliminary results obtained on the so-far collected database of lung CT are discussed.

  8. The effects of mapping CT images to Monte Carlo materials on GEANT4 proton simulation accuracy

    SciTech Connect (OSTI)

    Barnes, Samuel; McAuley, Grant; Slater, James; Wroe, Andrew

    2013-04-15

    Purpose: Monte Carlo simulations of radiation therapy require conversion from Hounsfield units (HU) in CT images to an exact tissue composition and density. The number of discrete densities (or density bins) used in this mapping affects the simulation accuracy, execution time, and memory usage in GEANT4 and other Monte Carlo code. The relationship between the number of density bins and CT noise was examined in general for all simulations that use HU conversion to density. Additionally, the effect of this on simulation accuracy was examined for proton radiation. Methods: Relative uncertainty from CT noise was compared with uncertainty from density binning to determine an upper limit on the number of density bins required in the presence of CT noise. Error propagation analysis was also performed on continuously slowing down approximation range calculations to determine the proton range uncertainty caused by density binning. These results were verified with Monte Carlo simulations. Results: In the presence of even modest CT noise (5 HU or 0.5%) 450 density bins were found to only cause a 5% increase in the density uncertainty (i.e., 95% of density uncertainty from CT noise, 5% from binning). Larger numbers of density bins are not required as CT noise will prevent increased density accuracy; this applies across all types of Monte Carlo simulations. Examining uncertainty in proton range, only 127 density bins are required for a proton range error of <0.1 mm in most tissue and <0.5 mm in low density tissue (e.g., lung). Conclusions: By considering CT noise and actual range uncertainty, the number of required density bins can be restricted to a very modest 127 depending on the application. Reducing the number of density bins provides large memory and execution time savings in GEANT4 and other Monte Carlo packages.

  9. A high-field 3He Metastability Exchange Optical Pumping polarizer operating in a 1.5 T medical scanner for lung MRI

    E-Print Network [OSTI]

    Collier, G; Wojna, A; G?owacz, B; Suchanek, M; Olejniczak, Z; Dohnalik, T

    2013-01-01

    After being hyperpolarized using the technique of Metastability Exchange Optical Pumping (MEOP), 3He can be used as a contrast agent for lung magnetic resonance imaging (MRI). MEOP is usually performed at low magnetic field (~ 1 mT) and low pressure (~ 1 mbar), which results in a low magnetization production rate. A delicate polarization-preserving step of compression is also required. It was demonstrated in sealed cells that high nuclear polarization values can be obtained at higher pressures with MEOP, if performed at high magnetic field (non-standard conditions). In this work the feasibility of building a high-field polarizer that operates within a commercial 1.5 T scanner was evaluated. Preliminary measurements of nuclear polarization with sealed cells filled at different 3He gas pressures (1.33 to 267 mbar) were performed. The use of an annular shape for the laser beam increased by 25 % the achievable nuclear polarization equilibrium value (Meq) at 32 and 67 mbar as compared to a Gaussian beam shape. Meq...

  10. Phase Tomography Using X-ray Talbot Interferometer

    SciTech Connect (OSTI)

    Momose, A.; Yashiro, W.; Moritake, M. [Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Takeda, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Uesugi, K.; Suzuki, Y. [SPring-8/JASRI, 1-1-1 Kouto, Mikazuki, Hyogo 679-5198 (Japan); Hattori, T. [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Hyogo 678-1205 (Japan)

    2007-01-19

    A biological tomography result obtained with an X-ray Talbot interferometer is reported. An X-ray Talbot interferometer was constructed using an amplitude grating fabricated by X-ray lithography at the LIGA beamline of NewSUBARU and gold electroplating. The pitch and pattern thickness of the grating were 8 {mu}m and 30 {mu}m, respectively. The effective area was 20 x 20 mm2, which was entirely illuminated with a wide beam available at the medium-length beamline 20B2 of SPring-8, allowing the acquisition of a three-dimensional tomogram of almost the whole body of a fish. The resulting image obtained with 17.7 keV X-rays revealed organs with bones in the same view.

  11. Iterative methods for dose reduction and image enhancement in tomography

    DOE Patents [OSTI]

    Miao, Jianwei; Fahimian, Benjamin Pooya

    2012-09-18

    A system and method for creating a three dimensional cross sectional image of an object by the reconstruction of its projections that have been iteratively refined through modification in object space and Fourier space is disclosed. The invention provides systems and methods for use with any tomographic imaging system that reconstructs an object from its projections. In one embodiment, the invention presents a method to eliminate interpolations present in conventional tomography. The method has been experimentally shown to provide higher resolution and improved image quality parameters over existing approaches. A primary benefit of the method is radiation dose reduction since the invention can produce an image of a desired quality with a fewer number projections than seen with conventional methods.

  12. Application of a nudging technique to thermoacoustic tomography

    E-Print Network [OSTI]

    Bonnefond, Xavier

    2011-01-01

    ThermoAcoustic Tomography (TAT) is a promising, non invasive, medical imaging technique whose inverse problem can be formulated as an initial condition reconstruction. In this paper, we introduce a new algorithm originally designed to correct the state of an evolution model, the \\emph{back and forth nudging} (BFN), for the TAT inverse problem. We show that the flexibility of this algorithm enables to consider a quite general framework for TAT. The backward nudging algorithm is studied and a proof of the geometrical convergence rate of the BFN is given. A method based on Conjugate Gradient (CG) is also introduced. Finally, numerical experiments validate the theoretical results with a better BFN convergence rate for more realistic setups and a comparison is established between BFN, CG and a usual inversion method.

  13. Fourier-based magnetic induction tomography for mapping resistivity

    SciTech Connect (OSTI)

    Puwal, Steffan; Roth, Bradley J. [Department of Physics, Oakland University, Rochester, Michigan 48309 (United States)

    2011-01-01

    Magnetic induction tomography is used as an experimental tool for mapping the passive electromagnetic properties of conductors, with the potential for imaging biological tissues. Our numerical approach to solving the inverse problem is to obtain a Fourier expansion of the resistivity and the stream functions of the magnetic fields and eddy current density. Thus, we are able to solve the inverse problem of determining the resistivity from the applied and measured magnetic fields for a two-dimensional conducting plane. When we add noise to the measured magnetic field, we find the fidelity of the measured to the true resistivity is quite robust for increasing levels of noise and increasing distances of the applied and measured field coils from the conducting plane, when properly filtered. We conclude that Fourier methods provide a reliable alternative for solving the inverse problem.

  14. Characterizing and Quantifying Quantum Chaos with Quantum Tomography

    E-Print Network [OSTI]

    Vaibhav Madhok; Carlos A. Riofro; Ivan H. Deutsch

    2015-06-08

    We explore quantum signatures of classical chaos by studying the rate of information gain in quantum tomography. The tomographic record consists of a time series of expectation values of a Hermitian operator evolving under application of the Floquet operator of a quantum map that possesses (or lacks) time reversal symmetry. We find that the rate of information gain, and hence the fidelity of quantum state reconstruction, depends on the symmetry class of the quantum map involved. Moreover, we find an increase in information gain and hence higher reconstruction fidelities when the Floquet maps employed increase in chaoticity. We make predictions for the information gain and show that these results are well described by random matrix theory in the fully chaotic regime. We derive analytical expressions for bounds on information gain using random matrix theory for different class of maps and show that these bounds are realized by fully chaotic quantum systems.

  15. Hyperspectral image reconstruction for x-ray fluorescence tomography

    SciTech Connect (OSTI)

    Grsoy, Do?a; Bier, Tekin; Lanzirotti, Antonio; Newville, Matthew G.; De Carlo, Francesco

    2015-01-01

    A penalized maximum-likelihood estimation is proposed to perform hyperspectral (spatio-spectral) image reconstruction for X-ray fluorescence tomography. The approach minimizes a Poisson-based negative log-likelihood of the observed photon counts, and uses a penalty term that has the effect of encouraging local continuity of model parameter estimates in both spatial and spectral dimensions simultaneously. The performance of the reconstruction method is demonstrated with experimental data acquired from a seed of arabidopsis thaliana collected at the 13-ID-E microprobe beamline at the Advanced Photon Source. The resulting element distribution estimates with the proposed approach show significantly better reconstruction quality than the conventional analytical inversion approaches, and allows for a high data compression factor which can reduce data acquisition times remarkably. In particular, this technique provides the capability to tomographically reconstruct full energy dispersive spectra without compromising reconstruction artifacts that impact the interpretation of results.

  16. Hyperspectral image reconstruction for x-ray fluorescence tomography

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Grsoy, Do?a; Bier, Tekin; Lanzirotti, Antonio; Newville, Matthew G.; De Carlo, Francesco

    2015-01-01

    A penalized maximum-likelihood estimation is proposed to perform hyperspectral (spatio-spectral) image reconstruction for X-ray fluorescence tomography. The approach minimizes a Poisson-based negative log-likelihood of the observed photon counts, and uses a penalty term that has the effect of encouraging local continuity of model parameter estimates in both spatial and spectral dimensions simultaneously. The performance of the reconstruction method is demonstrated with experimental data acquired from a seed of arabidopsis thaliana collected at the 13-ID-E microprobe beamline at the Advanced Photon Source. The resulting element distribution estimates with the proposed approach show significantly better reconstruction quality than the conventional analytical inversionmoreapproaches, and allows for a high data compression factor which can reduce data acquisition times remarkably. In particular, this technique provides the capability to tomographically reconstruct full energy dispersive spectra without compromising reconstruction artifacts that impact the interpretation of results.less

  17. Atomic Scale Characterization of Compound Semiconductors Using Atom Probe Tomography

    SciTech Connect (OSTI)

    Gorman, B. P.; Norman, A. G.; Lawrence, D.; Prosa, T.; Guthrey, H.; Al-Jassim, M.

    2011-01-01

    Internal interfaces are critical in determining the performance of III-V multijunction solar cells. Studying these interfaces with atomic resolution using a combination of transmission electron microscopy (TEM), atom probe tomography (APT), and density functional calculations enables a more fundamental understanding of carrier dynamics in photovoltaic (PV) device structures. To achieve full atomic scale spatial and chemical resolution, data acquisition parameters in laser pulsed APT must be carefully studied to eliminate surface diffusion. Atom probe data with minimized group V ion clustering and expected stoichiometry can be achieved by adjusting laser pulse power, pulse repetition rate, and specimen preparation parameters such that heat flow away from the evaporating surface is maximized. Applying these improved analysis conditions to III-V based PV gives an atomic scale understanding of compositional and dopant profiles across interfaces and tunnel junctions and the initial stages of alloy clustering and dopant accumulation. Details on APT experimental methods and future in-situ instrumentation developments are illustrated.

  18. Statistical analysis of motion contrast in optical coherence tomography angiography

    E-Print Network [OSTI]

    Cheng, Yuxuan; Pan, Cong; Lu, Tongtong; Hong, Tianyu; Ding, Zhihua; Li, Peng

    2015-01-01

    Optical coherence tomography angiography (Angio-OCT), mainly based on the temporal dynamics of OCT scattering signals, has found a range of potential applications in clinical and scientific researches. In this work, based on the model of random phasor sums, temporal statistics of the complex-valued OCT signals are mathematically described. Statistical distributions of the amplitude differential (AD) and complex differential (CD) Angio-OCT signals are derived. The theories are validated through the flow phantom and live animal experiments. Using the model developed in this work, the origin of the motion contrast in Angio-OCT is mathematically explained, and the implications in the improvement of motion contrast are further discussed, including threshold determination and its residual classification error, averaging method, and scanning protocol. The proposed mathematical model of Angio-OCT signals can aid in the optimal design of the system and associated algorithms.

  19. Thermal stability of curved ray tomography for corrosion monitoring

    SciTech Connect (OSTI)

    Willey, C. L.; Simonetti, F.; Nagy, P. B.; Instanes, G.

    2014-02-18

    Guided wave tomography is being developed as an effective tool for continuous monitoring of corrosion and erosion depth in pipelines. A pair of transmit- and receive-ring arrays of ultrasonic transducers encircles the pipe and delimits the section to be monitored. In curved ray tomography (CRT), the depth profile is estimated from the time delay matrix, ??, whose ij-th entry is the phase traveltime difference between the current and baseline signals measured between transducers i and j of the transmit and receive-ring arrays, respectively. Under perfectly stable experimental conditions, the non-zero entries of ?? are only due to the occurrence of damage and provide a reliable input to CRT. However, during field operation, ?? can develop non-zero entries due to a number of environmental changes ranging from temperature variations to degradation of transducer-pipe coupling and transducer intrinsic performance. Here, we demonstrate that these sources of instability can be eliminated by exploiting the spatial diversity of array measurements in conjunction with EMAT transducer technology which is intrinsically stable owing to its non-contact nature. The study is based on a full-scale experiment performed on a schedule 40, 8 diameter, 3 m length steel pipe, monitored with two EMAT ring arrays. It is shown that for an irregularly shaped defect the proposed method yields maximum depth estimations that are as accurate as single point ultrasonic thickness gaging measurements and over a wide temperature range up to 175C. The results indicate that advanced inversion schemes in combination with EMAT transduction offer great potential for continuously monitoring the progression of corrosion or erosion damage in the oil and gas industry.

  20. MO-E-17A-03: Monte Carlo CT Dose Calculation: A Comparison Between Experiment and Simulation Using ARCHER-CT

    SciTech Connect (OSTI)

    Liu, T; Du, X; Su, L; Gao, Y; Ji, W; Xu, X; Zhang, D; Shi, J; Liu, B; Kalra, M

    2014-06-15

    Purpose: To compare the CT doses derived from the experiments and GPU-based Monte Carlo (MC) simulations, using a human cadaver and ATOM phantom. Methods: The cadaver of an 88-year old male and the ATOM phantom were scanned by a GE LightSpeed Pro 16 MDCT. For the cadaver study, the Thimble chambers (Model 105?0.6CT and 106?0.6CT) were used to measure the absorbed dose in different deep and superficial organs. Whole-body scans were first performed to construct a complete image database for MC simulations. Abdomen/pelvis helical scans were then conducted using 120/100 kVps, 300 mAs and a pitch factor of 1.375:1. For the ATOM phantom study, the OSL dosimeters were used and helical scans were performed using 120 kVp and x, y, z tube current modulation (TCM). For the MC simulations, sufficient particles were run in both cases such that the statistical errors of the results by ARCHER-CT were limited to 1%. Results: For the human cadaver scan, the doses to the stomach, liver, colon, left kidney, pancreas and urinary bladder were compared. The difference between experiments and simulations was within 19% for the 120 kVp and 25% for the 100 kVp. For the ATOM phantom scan, the doses to the lung, thyroid, esophagus, heart, stomach, liver, spleen, kidneys and thymus were compared. The difference was 39.2% for the esophagus, and within 16% for all other organs. Conclusion: In this study the experimental and simulated CT doses were compared. Their difference is primarily attributed to the systematic errors of the MC simulations, including the accuracy of the bowtie filter modeling, and the algorithm to generate voxelized phantom from DICOM images. The experimental error is considered small and may arise from the dosimeters. R01 grant (R01EB015478) from National Institute of Biomedical Imaging and Bioengineering.

  1. Predicting target vessel location on robot-assisted coronary artery bypass graft using CT to ultrasound registration

    SciTech Connect (OSTI)

    Cho, Daniel S.; Linte, Cristian; Chen, Elvis C. S.; Bainbridge, Daniel; Wedlake, Chris; Moore, John; Barron, John; Patel, Rajni; Peters, Terry

    2012-03-15

    Purpose: Although robot-assisted coronary artery bypass grafting (RA-CABG) has gained more acceptance worldwide, its success still depends on the surgeon's experience and expertise, and the conversion rate to full sternotomy is in the order of 15%-25%. One of the reasons for conversion is poor pre-operative planning, which is based solely on pre-operative computed tomography (CT) images. In this paper, the authors propose a technique to estimate the global peri-operative displacement of the heart and to predict the intra-operative target vessel location, validated via both an in vitro and a clinical study. Methods: As the peri-operative heart migration during RA-CABG has never been reported in the literatures, a simple in vitro validation study was conducted using a heart phantom. To mimic the clinical workflow, a pre-operative CT as well as peri-operative ultrasound images at three different stages in the procedure (Stage{sub 0}--following intubation; Stage{sub 1}--following lung deflation; and Stage{sub 2}--following thoracic insufflation) were acquired during the experiment. Following image acquisition, a rigid-body registration using iterative closest point algorithm with the robust estimator was employed to map the pre-operative stage to each of the peri-operative ones, to estimate the heart migration and predict the peri-operative target vessel location. Moreover, a clinical validation of this technique was conducted using offline patient data, where a Monte Carlo simulation was used to overcome the limitations arising due to the invisibility of the target vessel in the peri-operative ultrasound images. Results: For the in vitro study, the computed target registration error (TRE) at Stage{sub 0}, Stage{sub 1}, and Stage{sub 2} was 2.1, 3.3, and 2.6 mm, respectively. According to the offline clinical validation study, the maximum TRE at the left anterior descending (LAD) coronary artery was 4.1 mm at Stage{sub 0}, 5.1 mm at Stage{sub 1}, and 3.4 mm at Stage{sub 2}. Conclusions: The authors proposed a method to measure and validate peri-operative shifts of the heart during RA-CABG. In vitro and clinical validation studies were conducted and yielded a TRE in the order of 5 mm for all cases. As the desired clinical accuracy imposed by this procedure is on the order of one intercostal space (10-15 mm), our technique suits the clinical requirements. The authors therefore believe this technique has the potential to improve the pre-operative planning by updating peri-operative migration patterns of the heart and, consequently, will lead to reduced conversion to conventional open thoracic procedures.

  2. Liver segmentation in contrast enhanced CT data using graph cuts and interactive 3D segmentation refinement methods

    SciTech Connect (OSTI)

    Beichel, Reinhard; Bornik, Alexander; Bauer, Christian; Sorantin, Erich [Departments of Electrical and Computer Engineering and Internal Medicine, Iowa Institute for Biomedical Imaging, University of Iowa, Iowa City, Iowa 52242 (United States); Institute for Computer Graphics and Vision, Graz University of Technology, Inffeldgasse 16, A-8010 Graz (Austria); Department of Electrical and Computer Engineering, Iowa Institute for Biomedical Imaging, University of Iowa, Iowa City, Iowa 52242 (United States); Department of Radiology, Medical University Graz, Auenbruggerplatz 34, A-8010 Graz (Austria)

    2012-03-15

    Purpose: Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. Methods: A graph cuts segmentation method was combined with a three-dimensional virtual reality based segmentation refinement approach. The developed interactive segmentation system allowed the user to manipulate volume chunks and/or surfaces instead of 2D contours in cross-sectional images (i.e, slice-by-slice). The method was evaluated on twenty routinely acquired portal-phase contrast enhanced multislice computed tomography (CT) data sets. An independent reference was generated by utilizing a currently clinically utilized slice-by-slice segmentation method. After 1 h of introduction to the developed segmentation system, three experts were asked to segment all twenty data sets with the proposed method. Results: Compared to the independent standard, the relative volumetric segmentation overlap error averaged over all three experts and all twenty data sets was 3.74%. Liver segmentation required on average 16 min of user interaction per case. The calculated relative volumetric overlap errors were not found to be significantly different [analysis of variance (ANOVA) test, p = 0.82] between experts who utilized the proposed 3D system. In contrast, the time required by each expert for segmentation was found to be significantly different (ANOVA test, p = 0.0009). Major differences between generated segmentations and independent references were observed in areas were vessels enter or leave the liver and no accepted criteria for defining liver boundaries exist. In comparison, slice-by-slice based generation of the independent standard utilizing a live wire tool took 70.1 min on average. A standard 2D segmentation refinement approach applied to all twenty data sets required on average 38.2 min of user interaction and resulted in statistically not significantly different segmentation error indices (ANOVA test, significance level of 0.05). Conclusions: All three experts were able to produce liver segmentations with low error rates. User interaction time savings of up to 71% compared to a 2D refinement approach demonstrate the utility and potential of our approach. The system offers a range of different tools to manipulate segmentation results, and some users might benefit from a longer learning phase to develop efficient segmentation refinement strategies. The presented approach represents a generally applicable segmentation approach that can be applied to many medical image segmentation problems.

  3. Spectral/ Fourier domain Doppler Optical Coherence Tomography in the rodent retina

    E-Print Network [OSTI]

    Liu, Jonathan Jaoshin

    2008-01-01

    Optical Coherence Tomography (OCT) is an emerging imaging technique based on low-coherence interferometry for noninvasive, high- resolution, cross-sectional imaging in a variety of biomedical fields. In ophthalmology, OCT ...

  4. Feasibility study on bonding quality inspection of microfluidic devices by optical coherence tomography

    E-Print Network [OSTI]

    Li, Shiguang

    This paper reports the feasibility of optical coherence tomography (OCT) technology for inspection of bonding quality of microfluidic devices in manufacturing environments. A compact optical-fiberbased OCT is developed ...

  5. Advances in Optical Coherence Tomography and Microscopy for endoscopic applications and functional neuroimaging

    E-Print Network [OSTI]

    Aguirre, Aaron Dominic, 1977-

    2008-01-01

    Optical Coherence Tomography (OCT) is a developing medical imaging technology that generates micron resolution cross-sectional images of subsurface internal tissue structure in situ and in real time, without the need to ...

  6. High-speed Fourier domain Optical Coherence Tomography for structural and functional imaging of the retina

    E-Print Network [OSTI]

    Srinivasan, Vivek Jay

    2008-01-01

    Optical Coherence Tomography (OCT) is an emerging optical biomedical imaging technology that enables cross-sectional imaging of scattering tissue with high sensitivity and micron-scale resolution. In conventional OCT, the ...

  7. High-resolution three-dimensional optical coherence tomography imaging of kidney microanatomy ex vivo

    E-Print Network [OSTI]

    Chen, Yu

    Optical coherence tomography (OCT) is an emerging medical imaging technology that enables high-resolution, noninvasive, cross-sectional imaging of microstructure in biological tissues in situ and in real time. When combined ...

  8. HFSS code for Thermoacoustic Tomography Testbed Liping Yan, co-investigator (sherryyan05@gmail.com)

    E-Print Network [OSTI]

    Patch, Sarah

    HFSS code for Thermoacoustic Tomography Testbed Liping Yan, co-investigator (sherryyan05@gmail to design the UW-Milwaukee Thermoacoustic Testbed. "Testbed.hfss" can be run material, testbed length, etc. The UWM thermoacoustic testbed is essentially

  9. Endoscopic optical coherence tomography for clinical studies in the gastrointestinal tract

    E-Print Network [OSTI]

    Tsai, Tsung-Han, Ph. D. Massachusetts Institute of Technology

    2013-01-01

    Optical coherence tomography (OCT) performs micrometer-scale, cross-sectional and three dimensional imaging by measuring the echo time delay of backscattered light. OCT imaging is performed using low-coherence interferometry. ...

  10. Experimental Fluorescence Optical Tomography using Adaptive Finite Elements and Planar Illumination with

    E-Print Network [OSTI]

    Bangerth, Wolfgang

    Experimental Fluorescence Optical Tomography using Adaptive Finite Elements and Planar Illumination with Modulated Excitation Light Amit Joshia , Wolfgang Bangerthb , Alan B. Thompsona , and Eva M. Sevick adaptive discretization strategies. To date, the efficacy of adaptive mesh refinement techniques has yet

  11. P- and S- wave tomography of the crust and uppermost mantle in China and surrounding areas

    E-Print Network [OSTI]

    Sun, Youshun, 1970-

    2005-01-01

    This thesis involves inverting the seismic structure of the crust and uppermost mantle in China from the P- and S-wave travel-time tomography. The main contributions of this research are: 1) introducing the adaptive moving ...

  12. Optical coherence tomography based on intensity correlations of quasi-thermal light

    E-Print Network [OSTI]

    Zerom, Petros

    We show theoretically that the longitudinal resolution of conventional optical coherence tomography can be improved by a factor of radic2 when a two-photon (as opposed to a single-photon) sensitive detector is used, and ...

  13. Imaging the Soultz Enhanced Geothermal Reservoir using double-difference tomography and microseismic data

    E-Print Network [OSTI]

    Pieros Concha, Diego Alvaro

    2010-01-01

    We applied the double-difference tomography method to image the P and S-wave velocity structure of the European Hot Dry Rock geothermal reservoir (also known as the Soultz Enhanced Geothermal System) at Soultz-sous-Forets, ...

  14. Digital signal processing techniques for optical coherence tomography : OCT and OCT image enhancement

    E-Print Network [OSTI]

    Adler, Desmond Christopher, 1978-

    2004-01-01

    Digital signal processing (DSP) techniques were developed to improve the flexibility, functionality, and image quality of ultrahigh resolution optical coherence tomography (OCT) systems. To reduce the dependence of OCT ...

  15. Review paper Seismic interferometry and ambient noise tomography in the British Isles

    E-Print Network [OSTI]

    Review paper Seismic interferometry and ambient noise tomography in the British Isles Heather. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 2. Theory and method of seismic interferometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 4.2. Seismic interferometry across the Scottish Highlands

  16. Barium Titanate Nanoparticles as Exogenous Contrast Agents in Second Harmonic Optical Coherence Tomography

    E-Print Network [OSTI]

    Pearson, Jeremy T

    2013-05-06

    I propose and demonstrate a method by which barium titanate nanoparticle clusters can be used as exogenous contrast agents in Second Harmonic Optical Coherence Tomography imaging systems to localize and highlight desired ...

  17. Estimated cumulative radiation dose from PET/CT in children with malignancies: a 5-year retrospective review

    E-Print Network [OSTI]

    2010-01-01

    both PET and CT studies. The ALARA principle must be appliedprotocols that follow the ALARA principle (as low asis necessary to apply the ALARA principle in the radiation

  18. A microwave tomography system using a tunable mirror for beam steering

    SciTech Connect (OSTI)

    Tayebi, A. [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824 (United States); Non-Destructive Evaluation Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physic (United States); Tang, J. [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824 (United States); Paladhi, P. Roy; Udpa, L.; Udpa, S. [Department of Electrical and Computer Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824 (United States); Non-Destructive Evaluation Laboratory, Michigan State University, East Lansing, MI 48824 (United States)

    2014-02-18

    Microwave tomography is a fast-growing technique in the fields of NDE and medical industry. This paper presents a new microwave tomography system which reduces the complexities of conventional microwave imaging systems by utilizing a reconfigurable mirror, a tunable reflectarray antenna. In order to build a tunable reflectarray with beam steering capabilities, the unit cell characteristics should dynamically alter. Modelling and experimental results of a single unit cell are presented in this work.

  19. Digital Radiography and Computed Tomography (DRCT) Product Improvement Plan (PIP)

    SciTech Connect (OSTI)

    Tim Roney; Bob Pink; Karen Wendt; Robert Seifert; Mike Smith

    2010-12-01

    The Idaho National Laboratory (INL) has been developing and deploying x-ray inspection systems for chemical weapons containers for the past 12 years under the direction of the Project Manager for Non-Stockpile Chemical Materiel (PMNSCM). In FY-10 funding was provided to advance the capabilities of these systems through the DRCT (Digital Radiography and Computed Tomography) Product Improvement Plan (PIP), funded by the PMNSCM. The DRCT PIP identified three research tasks; end user study, detector evaluation and DRCT/PINS integration. Work commenced in February, 2010. Due to the late start and the schedule for field inspection of munitions at various sites, it was not possible to spend sufficient field time with operators to develop a complete end user study. We were able to interact with several operators, principally Mr. Mike Rowan who provided substantial useful input through several discussions and development of a set of field notes from the Pueblo, CO field mission. We will be pursuing ongoing interactions with field personnel as opportunities arise in FY-11.

  20. Measurement strategy for rectangular electrical capacitance tomography sensor

    SciTech Connect (OSTI)

    Ye, Jiamin; Ge, Ruihuan; Qiu, Guizhi; Wang, Haigang [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, 100190 (China)

    2014-04-11

    To investigate the influence of the measurement strategy for the rectangular electrical capacitance tomography (ECT) sensor, a Finite Element Method (FEM) is utilized to create the model for simulation. The simulation was carried out using COMSOL Multiphysics(trade mark, serif) and Matlab(trade mark, serif). The length-width ratio of the rectangular sensing area is 5. Twelve electrodes are evenly arranged surrounding the pipe. The covering ratio of the electrodes is 90%. The capacitances between different electrode pairs are calculated for a bar distribution. The air of the relative permittivity 1.0 and the material of the permittivity 3.0 are used for the calibration. The relative permittivity of the second phase is 3.0. The noise free and noise data are used for the image reconstruction using the Linear Back Projection (LBP). The measurement strategies with 1-, 2- and 4- electrode excitation are compared using the correlation coefficient. Preliminary results show that the measurement strategy with 2-electrode excitation outperforms other measurement strategies with 1- or 4-electrode excitation.