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1

AUTOCORRECTING RECONSTRUCTION FOR FLEXIBLE CT SCANNERS Jeff Orchard  

E-Print Network [OSTI]

revolutionize the world of computed tomography (CT). Tiny x-ray emitters and detectors could be embedded scanners. Index Terms: computed tomography, image reconstruction, entropy, nanotechnology, autofocus 1. An automatic (data-driven) motion-correction method for SPECT (single photon emission computed tomog- raphy

Orchard, Jeffery J.

2

Compact conscious animal positron emission tomography scanner  

DOE Patents [OSTI]

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.

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)

2006-10-24T23:59:59.000Z

3

SU-E-I-18: CT Scanner QA Using Normalized CTDI Ratio  

SciTech Connect (OSTI)

Purpose: To create a ratio of weighted computed tomography dose index (CTDIw) data normalized to in-air measurements (CTDIair) as a function of beam quality to create a look-up table for frequent, rapid quality assurance (QA) checks of CTDI. Methods: The CTDIw values were measured according to TG-63 protocol using a pencil ionization chamber (Unfors Xi CT detector) and head and body Polymethyl methacrylate (PMMA) phantoms (16 and 32 cm diameter, respectively). Single scan dose profiles were measured at each clinically available energy (80,100,120,140 kVp) on three different CT scanners (two Siemens SOMATOM Definition Flash and one GE Optima), using a tube current of 400 mA, a one second rotation time, and the widest available beam width (32 × 0.6 mm and 16 × 1.25 mm, respectively). These values were normalized to CTDIair measurements using the same conditions as CTDIw. The ratios (expressed in cGy/R) were assessed for each scanner as a function of each energy's half value layer (HVL) paired with the phantom's appropriate bow tie filter measured in mmAl. Results: Normalized CTDI values vary linearly with HVL for both the head and body phantoms. The ratios for the two Siemens machines are very similar at each energy. Compared to the GE scanner, these values vary between 10–20% for each kVp setting. Differences in CTDIair contribute most to the deviation of the ratios across machines. Ratios are independent of both mAs and collimation. Conclusion: Look-up tables constructed of normalized CTDI values as a function of HVL can be used to derive CTDIw data from only three in-air measurements (one for CTDIair and two with added filtration for HVL) to allow for simple, frequent QA checks without CT phantom setup. Future investigations will involve comparing results with Monte Carlo simulations for validation.

Randazzo, M; Tambasco, M; Russell, B [San Diego State University, San Diego, CA (United States)

2014-06-01T23:59:59.000Z

4

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

E-Print Network [OSTI]

· . · , , , , . · , " , , . · , . , . : · . ·2-4 . ·2-3 -. ·) D,DMAIC, SPC, FMEA, Control Plan, Lean) 8(-. · -. ·. ·. NPI ·. · , , .' , ·" . " * . : ·) B.A ,(-. ·4-6. ·) QFD, CtQ breakdown, DfSS, SPC, AQP, FMEA, Control Plan.( ·Six Sigma GB

Pinsky, Ross

5

Quantitative comparison of noise texture across CT scanners from different manufacturers  

SciTech Connect (OSTI)

Purpose: To quantitatively compare noise texture across computed tomography (CT) scanners from different manufacturers using the noise power spectrum (NPS). Methods: The American College of Radiology CT accreditation phantom (Gammex 464, Gammex, Inc., Middleton, WI) was imaged on two scanners: Discovery CT 750HD (GE Healthcare, Waukesha, WI), and SOMATOM Definition Flash (Siemens Healthcare, Germany), using a consistent acquisition protocol (120 kVp, 0.625/0.6 mm slice thickness, 250 mAs, and 22 cm field of view). Images were reconstructed using filtered backprojection and a wide selection of reconstruction kernels. For each image set, the 2D NPS were estimated from the uniform section of the phantom. The 2D spectra were normalized by their integral value, radially averaged, and filtered by the human visual response function. A systematic kernel-by-kernel comparison across manufacturers was performed by computing the root mean square difference (RMSD) and the peak frequency difference (PFD) between the NPS from different kernels. GE and Siemens kernels were compared and kernel pairs that minimized the RMSD and |PFD| were identified. Results: The RMSD (|PFD|) values between the NPS of GE and Siemens kernels varied from 0.01 mm{sup 2} (0.002 mm{sup -1}) to 0.29 mm{sup 2} (0.74 mm{sup -1}). The GE kernels 'Soft,''Standard,''Chest,' and 'Lung' closely matched the Siemens kernels 'B35f,''B43f,''B41f,' and 'B80f' (RMSD < 0.05 mm{sup 2}, |PFD| < 0.02 mm{sup -1}, respectively). The GE 'Bone,''Bone+,' and 'Edge' kernels all matched most closely with Siemens 'B75f' kernel but with sizeable RMSD and |PFD| values up to 0.18 mm{sup 2} and 0.41 mm{sup -1}, respectively. These sizeable RMSD and |PFD| values corresponded to visually perceivable differences in the noise texture of the images. Conclusions: It is possible to use the NPS to quantitatively compare noise texture across CT systems. The degree to which similar texture across scanners could be achieved varies and is limited by the kernels available on each scanner.

Solomon, Justin B.; Christianson, Olav; Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories and Clinical Imaging Physics Group, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories and Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories and Clinical Imaging Physics Group, Medical Physics Graduate Program, Departments of Radiology, Physics, Biomedical Engineering, and Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States)

2012-10-15T23:59:59.000Z

6

Construction and Test of Low Cost X-Ray Tomography Scanner for Physical-Chemical Analysis and Nondestructive Inspections  

SciTech Connect (OSTI)

X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe the development of a low cost micro-CT X-ray scanner that is being developed for nondestructive testing. This tomograph operates using a microfocus X-ray source and contains a silicon photodiode as detectors. The performance of the system, by its spatial resolution, has been estimated through its Modulation Transfer Function-MTF and the obtained value at 10% of MTF is 661 {mu}m. It was built as a general purpose nondestructive testing device.

Oliveira, Jose Martins Jr. de [Universidade de Sorocaba-UNISO, Campus Seminario, Caixa Postal 578, Av. Dr. Eugenio Salermo, 100, Centro, 18035-430, Sorocaba, SP (Brazil); Martins, Antonio Cesar Germano [Universidade Estadual Paulista Julio de Mesquita Filho-UNESP, GASI, Av. 3 de Marco, 511, Alto da Boa Vista, 18087-180, Sorocaba, SP (Brazil)

2009-06-03T23:59:59.000Z

7

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]

ModPET: 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 for Gamma-Ray Imaging, we are developing a novel small-animal PET scanner that utilizes common modular

Arizona, University of

8

E-Print Network 3.0 - angiographic cone-beam ct Sample Search...  

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

Summary: medical multi-slicecone-beam CT scanners typically use equiangular projection data, our new formula may... : Computed tomography (CT), cone-beam geometry, Feldkamp-type...

9

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

SciTech Connect (OSTI)

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.

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)

2013-06-15T23:59:59.000Z

10

Effects of the difference in tube voltage of the CT scanner on dose calculation  

E-Print Network [OSTI]

Computed Tomography (CT) measures the attenuation coefficient of an object and converts the value assigned to each voxel into a CT number. In radiation therapy, CT number, which is directly proportional to the linear attenuation coefficient, is required to be converted to electron density for radiation dose calculation for cancer treatment. However, if various tube voltages were applied to take the patient CT image without applying the specific CT number to electron density conversion curve, the accuracy of dose calculation would be unassured. In this study, changes in CT numbers for different materials due to change in tube voltage were demonstrated and the dose calculation errors in percentage depth dose (PDD) and a clinical case were analyzed. The maximum dose difference in PDD from TPS dose calculation and Monte Carlo simulation were 1.3 % and 1.1 % respectively when applying the same CT number to electron density conversion curve to the 80 kVp and 140 kVp images. In the clinical case, the different CT nu...

Rhee, Dong Joo; Moon, Young Min; Kim, Jung Ki; Jeong, Dong Hyeok

2015-01-01T23:59:59.000Z

11

E-Print Network 3.0 - abdominal multislice ct Sample Search Results  

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

Ge Wanga) and Michael W. Vannier Department... in multislice spiralhelical computed tomography CT and provide guidelines for scanner design and protocol... optimization....

12

Positron Emission Tomography-Scanner at Children`s Hospital of Michigan at Detroit, Michigan  

SciTech Connect (OSTI)

The Department of Energy has prepared an environmental assessment (EA), DOE/EA-0795, to support the DOE decision to provide a grant of $7,953,600 to be used in support of a proposed Positron Emission Tomography Scanner at Children`s Hospital of Michigan at Detroit, Michigan. Based upon the analysis in the EA, DOE has determined that the proposed action is not a major Federal action significantly affected the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an Environmental Impact Statement is not required and DOE is issuing this Finding of No Significant Impact (FONSI).

Not Available

1992-12-31T23:59:59.000Z

13

Silicon photomultiplier choice for the scintillating fibre tracker in second generation proton computed tomography scanner  

SciTech Connect (OSTI)

Scintillating fibers are capable of charged particle tracking with high position resolution, as demonstrated by the central fiber tracker of the D0 experiment. The charged particles will deposit less energy in the polystyrene scintillating fibers as opposed to a typical silicon tracker of the same thickness, while SiPM's are highly efficient at detecting photons created by the passage of the charged particle through the fibers. The current prototype of the Proton Computed Tomography (pCT) tracker uses groups of three 0.5 mm green polystyrene based scintillating fibers connected to a single SiPM, while first generation prototype tracker used Silicon strip detectors. The results of R&D for the Scintillating Fiber Tracker (SFT) as part of the pCT detector are outlined, and the premise for the selection of SiPM is discussed.

Gearhart, A.; Johnson, E.; Medvedev, V.; /Northern Illinois U.; Ronzhin, A.; /Fermilab; Rykalin, V.; /Northern Illinois U.; Rubinov, P.; /Fermilab; Sleptcov, V.; /Unlisted, RU

2012-03-01T23:59:59.000Z

14

Coronary artery wall imaging in mice using osmium tetroxide and micro-computed tomography (micro-CT)  

SciTech Connect (OSTI)

The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO{sub 4}) solution. As a tissue-staining contrast agent, OsO{sub 4} is retained in the vessel wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO{sub 4} preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE{sup -/-}) mice at 10 {mu}m resolution. The results show that walls of coronary arteries as small as 45 {mu}m in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO{sub 4} and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts.

Pai, Vinay M.; Kozlowski, Megan; Donahue, Danielle; Miller, Elishiah; Xiao, Xianghui; Chen, Marcus Y.; Yu, Zu-Xi; Connelly, Patricia; Jeffries, Kenneth; Wen, Han (NIH)

2012-05-10T23:59:59.000Z

15

Patient radiation dose in prospectively gated axial CT coronary angiography and retrospectively gated helical technique with a 320-detector row CT scanner  

SciTech Connect (OSTI)

Purpose: The aim of this study was to evaluate radiation dose to patients undergoing computed tomography coronary angiography (CTCA) for prospectively gated axial (PGA) technique and retrospectively gated helical (RGH) technique. Methods: Radiation doses were measured for a 320-detector row CT scanner (Toshiba Aquilion ONE) using small sized silicon-photodiode dosimeters, which were implanted at various tissue and organ positions within an anthropomorphic phantom for a standard Japanese adult male. Output signals from photodiode dosimeters were read out on a personal computer, from which organ and effective doses were computed according to guidelines published in the International Commission on Radiological Protection Publication 103. Results: Organs that received high doses were breast, followed by lung, esophagus, and liver. Breast doses obtained with PGA technique and a phase window width of 16% at a simulated heart rate of 60 beats per minute were 13 mGy compared to 53 mGy with RGH technique using electrocardiographically dependent dose modulation at the same phase window width as that in PGA technique. Effective doses obtained in this case were 4.7 and 20 mSv for the PGA and RGH techniques, respectively. Conversion factors of dose length product to the effective dose in PGA and RGH were 0.022 and 0.025 mSv mGy{sup -1} cm{sup -1} with a scan length of 140 mm. Conclusions: CTCA performed with PGA technique provided a substantial effective dose reduction, i.e., 70%-76%, compared to RGH technique using the dose modulation at the same phase windows as those in PGA technique. Though radiation doses in CTCA with RGH technique were the same level as, or some higher than, those in conventional coronary angiography (CCA), the use of PGA technique reduced organ and effective doses to levels less than CCA except for breast dose.

Seguchi, Shigenobu; Aoyama, Takahiko; Koyama, Shuji; Fujii, Keisuke; Yamauchi-Kawaura, Chiyo [Graduate School of Medicine, Nagoya University, Daikominami, Higashi-ku, Nagoya 461-8673 (Japan) and Department of Medical Technology, Nagoya Daini Red Cross Hospital, Myouken-chou, Showa-ku, Nagoya 466-8650 (Japan); Graduate School of Medicine, Nagoya University, Daikominami, Higashi-ku, Nagoya 461-8673 (Japan); Section of Radiological Protection, National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Medicine, Nagoya University, Daikominami, Higashi-ku, Nagoya 461-8673 (Japan)

2010-11-15T23:59:59.000Z

16

Simultaneous CT and SPECT tomography using CZT detectors  

DOE Patents [OSTI]

A method for simultaneous transmission x-ray computed tomography (CT) and single photon emission tomography (SPECT) comprises the steps of: injecting a subject with a tracer compound tagged with a .gamma.-ray emitting nuclide; directing an x-ray source toward the subject; rotating the x-ray source around the subject; emitting x-rays during the rotating step; rotating a cadmium zinc telluride (CZT) two-sided detector on an opposite side of the subject from the source; simultaneously detecting the position and energy of each pulsed x-ray and each emitted .gamma.-ray captured by the CZT detector; recording data for each position and each energy of each the captured x-ray and .gamma.-ray; and, creating CT and SPECT images from the recorded data. The transmitted energy levels of the x-rays lower are biased lower than energy levels of the .gamma.-rays. The x-ray source is operated in a continuous mode. The method can be implemented at ambient temperatures.

Paulus, Michael J. (Knoxville, TN); Sari-Sarraf, Hamed (Lubbock, TX); Simpson, Michael L. (Knoxville, TN); Britton, Jr., Charles L. (Alcoa, TN)

2002-01-01T23:59:59.000Z

17

PIXSCAN: Pixel Detector CT-Scanner for Small Animal Imaging P. Delpierrea  

E-Print Network [OSTI]

very large dynamic range of photons counting at very low detector noise. They also provide high-scanner, especially for soft tissues, and to reduce both the scan duration and the absorbed dose. A proof of principle initially built for detection of X-ray synchrotron radiations. Despite the relatively large pixel size

Boyer, Edmond

18

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

SciTech Connect (OSTI)

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 system—MultiPlan (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.

Kim, Haksoo; Welford, Scott [Department of Radiation Oncology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)] [Department of Radiation Oncology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States); Fabien, Jeffrey; Zheng, Yiran; Yuan, Jake; Brindle, James; Yao, Min; Lo, Simon; Wessels, Barry; Machtay, Mitchell; Sohn, Jason W., E-mail: jason.sohn@case.edu [Department of Radiation Oncology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 and University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, Ohio 44106 (United States); Sloan, Andrew [Department of Neurosurgery, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)] [Department of Neurosurgery, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)

2014-02-15T23:59:59.000Z

19

Design and evaluation of a variable aperture collimator for conformal radiotherapy of small animals using a microCT scanner  

SciTech Connect (OSTI)

Treatment of small animals with radiation has in general been limited to planar fields shaped with lead blocks, complicating spatial localization of dose and treatment of deep-seated targets. In order to advance laboratory radiotherapy toward what is accomplished in the clinic, we have constructed a variable aperture collimator for use in shaping the beam of microCT scanner. This unit can image small animal subjects at high resolution, and is capable of delivering therapeutic doses in reasonable exposure times. The proposed collimator consists of two stages, each containing six trapezoidal brass blocks that move along a frame in a manner similar to a camera iris producing a hexagonal aperture of variable size. The two stages are offset by 30 deg. and adjusted for the divergence of the x-ray beam so as to produce a dodecagonal profile at isocenter. Slotted rotating driving plates are used to apply force to pins in the collimator blocks and effect collimator motion. This device has been investigated through both simulation and measurement. The collimator aperture size varied from 0 to 8.5 cm as the driving plate angle increased from 0 to 41 deg. . The torque required to adjust the collimator varied from 0.5 to 5 N{center_dot}m, increasing with increasing driving plate angle. The transmission profiles produced by the scanner at isocenter exhibited a penumbra of approximately 10% of the collimator aperture width. Misalignment between the collimator assembly and the x-ray source could be identified on the transmission images and corrected by adjustment of the collimator location. This variable aperture collimator technology is therefore a feasible and flexible solution for adjustable shaping of radiation beams for use in small animal radiotherapy as well as other applications in which beam shaping is desired.

Graves, Edward E.; Zhou Hu; Chatterjee, Raja; Keall, Paul J.; Gambhir, Sanjiv Sam; Contag, Christopher H.; Boyer, Arthur L. [Department of Radiology Oncology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California 94305 (United States); Department of Mechanical Engineering, Molecular Imaging Program at Stanford, Stanford University, Stanford, California 94305 (United States); Department of Radiology Oncology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Scott and White Hospital, Temple, Texas 76508 (United States)

2007-11-15T23:59:59.000Z

20

NETL CT Imaging Facility  

SciTech Connect (OSTI)

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.

None

2013-09-04T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

NETL CT Imaging Facility  

ScienceCinema (OSTI)

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.

None

2014-05-21T23:59:59.000Z

22

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

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

with Additional Information Additional information about the non-medical uses of nuclear imaging, computed tomography, and non-destructive testing is available in DOE...

23

Automated size-specific CT dose monitoring program: Assessing variability in CT dose  

SciTech Connect (OSTI)

Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED{sub adj}). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED{sub adj} between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED{sub adj} that differed by up to 44% from effective dose estimates that were not adjusted by patient size. Additionally, considerable differences were noted in ED{sub adj} distributions between scanners, with scanners employing iterative reconstruction exhibiting significantly lower ED{sub adj} (range: 9%-64%). Finally, a significant difference (up to 59%) in ED{sub adj} distributions was observed between institutions, indicating the potential for dose reduction. Conclusions: The authors developed a robust automated size-specific radiation dose monitoring program for CT. Using this program, significant differences in ED{sub adj} were observed between scanner models and across institutions. This new dose monitoring program offers a unique tool for improving quality assurance and standardization both within and across institutions.

Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan [Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States) and Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States)

2012-11-15T23:59:59.000Z

24

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

SciTech Connect (OSTI)

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 (? ? 200–400 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.

Hulme, K. W.; Kappadath, S. C., E-mail: skappadath@mdanderson.org [Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences, Houston, Texas 77030 (United States)

2014-04-15T23:59:59.000Z

25

Basic Idea on Interior Tomography Development and Applications of Interior Tomography  

E-Print Network [OSTI]

transforms. International Journal of Biomedical Imaging, Article ID 63634, 8 pages, 2007 Yu H, Wang G. 14-15, March 2010 Siemens dual-source scanner was introduced in 2005 but it is still not suffi Demonstration with Animal CT/Micro-CT Data Siemens Clinical CT Scanner http://www.siemens.com A sheep

Wang, Ge

26

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

SciTech Connect (OSTI)

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 abdomen–pelvis 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.

Trattner, Sigal [Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York 10032 (United States)] [Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York 10032 (United States); Cheng, Bin [Department of Biostatistics, Columbia University Mailman School of Public Health, New York, New York 10032 (United States)] [Department of Biostatistics, Columbia University Mailman School of Public Health, New York, New York 10032 (United States); Pieniazek, Radoslaw L. [Center for Radiological Research, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York 10032 (United States)] [Center for Radiological Research, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York 10032 (United States); Hoffmann, Udo [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)] [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); Douglas, Pamela S. [Department of Medicine, Division of Cardiology, Duke University, Durham, North Carolina 27715 (United States)] [Department of Medicine, Division of Cardiology, Duke University, Durham, North Carolina 27715 (United States); Einstein, Andrew J., E-mail: andrew.einstein@columbia.edu [Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York and Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York (United States)

2014-04-15T23:59:59.000Z

27

CT Scans of Cores Metadata, Barrow, Alaska 2015  

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

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.

Katie McKnight; Tim Kneafsey; Craig Ulrich

28

Cone-beam Computed Tomography-guided Stereotactic Liver Punctures: A Phantom Study  

SciTech Connect (OSTI)

Purpose: Images from computed tomography (CT), combined with navigation systems, improve the outcomes of local thermal therapies that are dependent on accurate probe placement. Although the usage of CT is desired, its availability for time-consuming radiological interventions is limited. Alternatively, three-dimensional images from C-arm cone-beam CT (CBCT) can be used. The goal of this study was to evaluate the accuracy of navigated CBCT-guided needle punctures, controlled with CT scans. Methods: Five series of five navigated punctures were performed on a nonrigid phantom using a liver specific navigation system and CBCT volumetric dataset for planning and navigation. To mimic targets, five titanium screws were fixed to the phantom. Target positioning accuracy (TPE{sub CBCT}) was computed from control CT scans and divided into lateral and longitudinal components. Additionally, CBCT-CT guidance accuracy was deducted by performing CBCT-to-CT image coregistration and measuring TPE{sub CBCT-CT} from fused datasets. Image coregistration was evaluated using fiducial registration error (FRE{sub CBCT-CT}) and target registration error (TRE{sub CBCT-CT}). Results: Positioning accuracies in lateral directions pertaining to CBCT (TPE{sub CBCT} = 2.1 {+-} 1.0 mm) were found to be better to those achieved from previous study using CT (TPE{sub CT} = 2.3 {+-} 1.3 mm). Image coregistration error was 0.3 {+-} 0.1 mm, resulting in an average TRE of 2.1 {+-} 0.7 mm (N = 5 targets) and average Euclidean TPE{sub CBCT-CT} of 3.1 {+-} 1.3 mm. Conclusions: Stereotactic needle punctures might be planned and performed on volumetric CBCT images and controlled with multidetector CT with positioning accuracy higher or similar to those performed using CT scanners.

Toporek, Grzegorz, E-mail: grzegorz.toporek@artorg.unibe.ch; Wallach, Daphne, E-mail: daphne.wallach@artorg.unibe.ch; Weber, Stefan [ARTORG Center for Biomedical Engineering Research, University of Bern (Switzerland)] [ARTORG Center for Biomedical Engineering Research, University of Bern (Switzerland); Bale, Reto; Widmann, Gerlig [Innsbruck Medical University, Section of Microinvasive Therapy, Department of Radiology (Austria)] [Innsbruck Medical University, Section of Microinvasive Therapy, Department of Radiology (Austria)

2013-12-15T23:59:59.000Z

29

Biochip scanner device  

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

30

Artifact reduction in industrial computed tomography via data fusion  

SciTech Connect (OSTI)

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.

Schrapp, Michael; Goldammer, Matthias; Stephan, Jürgen [Siemens AG, Corporate Technology, Otto-Hahn-Ring 6, 81739 Munich (Germany)

2014-02-18T23:59:59.000Z

31

Optical fuel pin scanner  

DOE Patents [OSTI]

An optical scanner for indicia arranged in a focal plane at a cylindrical outside surface by use of an optical system including a rotatable dove prism. The dove prism transmits a rotating image of an encircled cylindrical surface area to a stationary photodiode array.

Kirchner, Tommy L. (Richland, WA); Powers, Hurshal G. (Richland, WA)

1983-01-01T23:59:59.000Z

32

Positron Emission Tomography Physics, Instrumentation, Data Analysis  

E-Print Network [OSTI]

1 Positron Emission Tomography Physics, Instrumentation, Data Analysis Carl K. Hoh, MD Department fast computer Filtered Back Projection Iterative Reconstruction PET Image Reconstruction #12 PET Scanner Design · Smaller individual crystal size = better spatial resolution · Physical limit

Liu, Thomas T.

33

High throughput optical scanner  

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

34

Molecular imaging in oncology: the acceptance of PET/CT and the emergence of MR/PET imaging  

E-Print Network [OSTI]

CT—Computed tomography . PET—Positron Emission Tomography .body imaging with MRI or PET/CT: the future for single-Sollitto RA et al (2009) 18F-FDG PET/CT of transitional cell

Schiepers, Christiaan; Dahlbom, Magnus

2011-01-01T23:59:59.000Z

35

Improved proton computed tomography by dual modality image reconstruction  

SciTech Connect (OSTI)

Purpose: Proton computed tomography (CT) is a promising image modality for improving the stopping power estimates and dose calculations for particle therapy. However, the finite range of about 33 cm of water of most commercial proton therapy systems limits the sites that can be scanned from a full 360° rotation. In this paper the authors propose a method to overcome the problem using a dual modality reconstruction (DMR) combining the proton data with a cone-beam x-ray prior. Methods: A Catphan 600 phantom was scanned using a cone beam x-ray CT scanner. A digital replica of the phantom was created in the Monte Carlo code Geant4 and a 360° proton CT scan was simulated, storing the entrance and exit position and momentum vector of every proton. Proton CT images were reconstructed using a varying number of angles from the scan. The proton CT images were reconstructed using a constrained nonlinear conjugate gradient algorithm, minimizing total variation and the x-ray CT prior while remaining consistent with the proton projection data. The proton histories were reconstructed along curved cubic-spline paths. Results: The spatial resolution of the cone beam CT prior was retained for the fully sampled case and the 90° interval case, with the MTF = 0.5 (modulation transfer function) ranging from 5.22 to 5.65?linepairs/cm. In the 45° interval case, the MTF = 0.5 dropped to 3.91?linepairs/cm For the fully sampled DMR, the maximal root mean square (RMS) error was 0.006 in units of relative stopping power. For the limited angle cases the maximal RMS error was 0.18, an almost five-fold improvement over the cone beam CT estimate. Conclusions: Dual modality reconstruction yields the high spatial resolution of cone beam x-ray CT while maintaining the improved stopping power estimation of proton CT. In the case of limited angles, the use of prior image proton CT greatly improves the resolution and stopping power estimate, but does not fully achieve the quality of a 360° proton CT scan.

Hansen, David C., E-mail: dch@ki.au.dk; Bassler, Niels [Experimental Clinical Oncology, Aarhus University, 8000 Aarhus C (Denmark)] [Experimental Clinical Oncology, Aarhus University, 8000 Aarhus C (Denmark); Petersen, Jørgen Breede Baltzer [Medical Physics, Aarhus University Hospital, 8000 Aarhus C (Denmark)] [Medical Physics, Aarhus University Hospital, 8000 Aarhus C (Denmark); Sørensen, Thomas Sangild [Computer Science, Aarhus University, 8000 Aarhus C, Denmark and Clinical Medicine, Aarhus University, 8200 Aarhus N (Denmark)] [Computer Science, Aarhus University, 8000 Aarhus C, Denmark and Clinical Medicine, Aarhus University, 8200 Aarhus N (Denmark)

2014-03-15T23:59:59.000Z

36

Analysis framework for the J-PET scanner  

E-Print Network [OSTI]

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.

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

2015-01-01T23:59:59.000Z

37

Laser Scanner Demonstration  

SciTech Connect (OSTI)

In the Summer of 2004 a request for proposals went out to potential vendors to offer a three-dimensional laser scanner for a number of unique metrology tasks at the Stanford Linear Accelerator Center (SLAC). Specifications were established including range, accuracy, scan density, resolution and field of view in consideration of anticipated department requirements. Four vendors visited the site to present their system and they were asked to perform three unique tests with their system on a two day visit to SLAC. Two of the three tests were created to emulate real-world applications at SLAC while the third was an accuracy and resolution series of experiments. The scope of these tests is presented and some of the vendor's results are included.

Fuss, B.

2005-09-06T23:59:59.000Z

38

E-Print Network 3.0 - angiography computed tomography Sample...  

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

Solutions Computed Tomography (CTCAT) 3D volume is reconstructed... ) Computer Tomography (CT): Radon-Transformation reconstructs images from projection data-profiles ...

39

In-patient to isocenter KERMA ratios in CT  

SciTech Connect (OSTI)

Purpose: To estimate in-patient KERMA for specific organs in computed tomography (CT) scanning using ratios to isocenter free-in-air KERMA obtained using a Rando phantom.Method: A CT scan of an anthropomorphic phantom results in an air KERMA K at a selected phantom location and air kerma K{sub CT} at the CT scanner isocenter when the scan is repeated in the absence of the phantom. The authors define the KERMA ratio (R{sub K}) as K/ K{sub CT}, which were experimentally determined in a Male Rando Phantom using lithium fluoride chips (TLD-100). R{sub K} values were obtained for a total of 400 individual point locations, as well as for 25 individual organs of interest in CT dosimetry. CT examinations of Rando were performed on a GE LightSpeed Ultra scanner operated at 80 kV, 120 kV, and 140 kV, as well as a Siemens Sensation 16 operated at 120 kV. Results: At 120 kV, median R{sub K} values for the GE and Siemens scanners were 0.60 and 0.64, respectively. The 10th percentile R{sub K} values ranged from 0.34 at 80 kV to 0.54 at 140 kV, and the 90th percentile R{sub K} values ranged from 0.64 at 80 kV to 0.78 at 140 kV. The average R{sub K} for the 25 Rando organs at 120 kV was 0.61 {+-} 0.08. Average R{sub K} values in the head, chest, and abdomen showed little variation. Relative to R{sub K} values in the head, chest, and abdomen obtained at 120 kV, R{sub K} values were about 12% lower in the pelvis and about 58% higher in the cervical spine region. Average R{sub K} values were about 6% higher on the Siemens Sensation 16 scanner than the GE LightSpeed Ultra. Reducing the x-ray tube voltage from 120 kV to 80 kV resulted in an average reduction in R{sub K} value of 34%, whereas increasing the x-ray tube voltage to 140 kV increased the average R{sub K} value by 9%. Conclusions: In-patient to isocenter relative KERMA values in Rando phantom can be used to estimate organ doses in similar sized adults undergoing CT examinations from easily measured air KERMA values at the isocenter (free in air). Conversion from in-patient air KERMA values to tissue dose would require the use of energy-appropriate conversion factors.

Huda, Walter; Ogden, Kent M.; Lavallee, Robert L.; Roskopf, Marsha L.; Scalzetti, Ernest M. [Department of Radiology and Radiological Science, Medical University of South Carolina (MUSC), 96 Jonathan Lucas Street (MSC 323), Charleston, South Carolina 29425-3230 (United States); Department of Radiology, SUNY Upstate Medical University, 750 E Adams Street, Syracuse, New York 13210 (United States)

2011-10-15T23:59:59.000Z

40

VACT: Visualization-Aware CT Reconstruction Ziyi Zheng and Klaus Mueller, Senior Member, IEEE  

E-Print Network [OSTI]

Abstract-- Computed tomography (CT) reconstruction methods are often unaware of the requirements Medical routine frequently utilizes 3D visualization tools for diagnosis. Computed tomography (CT between the raw projection data and their visualization via vol- ume rendering. Our framework can

Mueller, Klaus

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

LimitedAngle Computed Tomography for Sandwich Structures using Data Fusion  

E-Print Network [OSTI]

1 Limited­Angle Computed Tomography for Sandwich Structures using Data Fusion Jeffrey E. Boyd and limited­angle computed­tomography (CT) are ill­posed problems, but where conventional CT has a small null. #12; 2 1. INTRODUCTION This paper presents a novel method for limited­angle computed tomography (CT

Boyd, Jeffrey E.

42

Computed Tomography software and standards  

SciTech Connect (OSTI)

This document establishes the software design, nomenclature, and conventions for industrial Computed Tomography (CT) used in the Nondestructive Evaluation Section at Lawrence Livermore National Laboratory. It is mainly a users guide to the technical use of the CT computer codes, but also presents a proposed standard for describing CT experiments and reconstructions. Each part of this document specifies different aspects of the CT software organization. A set of tables at the end describes the CT parameters of interest in our project. 4 refs., 6 figs., 1 tab.

Azevedo, S.G.; Martz, H.E.; Skeate, M.F.; Schneberk, D.J.; Roberson, G.P.

1990-02-20T23:59:59.000Z

43

Computed tomography:the details.  

SciTech Connect (OSTI)

Computed Tomography (CT) is a well established technique, particularly in medical imaging, but also applied in Synthetic Aperture Radar (SAR) imaging. Basic CT imaging via back-projection is treated in many texts, but often with insufficient detail to appreciate subtleties such as the role of non-uniform sampling densities. Herein are given some details often neglected in many texts.

Doerry, Armin Walter

2007-07-01T23:59:59.000Z

44

abdominal ct findings: Topics by E-print Network  

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

planning. It includes an abdominal computer tomography (CT) image Leow, Wee Kheng 11 CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1 Physics...

45

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)

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.

Brunner, Claudia C.; Stern, Stanley H.; Chakrabarti, Kish [U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States)] [U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States); Minniti, Ronaldo [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States)] [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Parry, Marie I. [Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, Maryland 20889 (United States)] [Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, Maryland 20889 (United States); Skopec, Marlene [National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892 (United States)] [National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892 (United States)

2013-08-15T23:59:59.000Z

46

Improvements to Existing Jefferson Lab Wire Scanners  

SciTech Connect (OSTI)

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.

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

2013-06-01T23:59:59.000Z

47

angiographic computed tomography: Topics by E-print Network  

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

the development and application of a 4-Dimensional Computed Tomography (4D CT) simulation program. The simulation is used to understand and quantify the sources of image...

48

CT Measurements of Two-Phase Flow in Fractured Porous Media  

SciTech Connect (OSTI)

This report describes the design, construction, and preliminary results of an experiment that studies imbibition displacement in two fracture blocks. Multiphase (oil/water) displacements will be conducted at the same rate on three core configurations. The configurations are a compact core, a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. The blocks are sealed in epoxy so that saturation measurements can be made throughout the displacement experiments using a Computed Tomography (CT) scanner. Preliminary results are presented from a water/air experiment. These results suggest that it is incorrect to assume negligible capillary continuity between matrix blocks as is often done.

Brigham, William E.; Castanier Louis M.; Hughes, Richard G.

1999-08-09T23:59:59.000Z

49

Improving Soft-Tissue Contrast in Four-Dimensional Computed Tomography Images of Liver Cancer Patients Using a Deformable Image Registration Method  

SciTech Connect (OSTI)

Purpose: To investigate a deformable image registration method to improve soft-tissue contrast in four-dimensional (4D) computed tomography (CT) images of the liver. Methods and Materials: Ten patients with hepatocellular carcinoma underwent 4D CT scan for radiotherapy treatment planning on a positron emission tomography/CT scanner. Four-dimensional CT images were binned into 10 equispaced phases. The exhale phase served as the reference phase, and images from the other nine phases were coregistered to the reference phase image using an intensity-based, automatic deformable image registration method. Then the coregistered images were combined to create a single, high-quality reconstructed CT image at exhale phase as the new reference for target delineation. The extent of image quality enhancement was quantified relative to the original CT by calculating the signal-to-noise ratio and the contrast-to-noise ratio. Results: The soft tissue image contrast was noticeably better after deformable image registration than in the original scans. Signal-to-noise ratios inside the liver region of interest increased for all patients by a factor of 3.0 (range, 2.3-3.7). The improvement in image quality was not linearly proportionate to the number of images averaged. Using only 6 phases can achieve at least 85% of the contrast enhancement that can be achieved using all 10 phases. We also found that contrast enhancement was inversely proportional to the original image quality (p = 0.006), and the contrast enhancement is attained with little loss of spatial resolution. Conclusions: This deformable image registration method is feasible to improve soft-tissue image quality in 4D CT images.

Wang He [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Krishnan, Sunil [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Wang Xiaochun; Beddar, A. Sam; Briere, Tina M. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Crane, Christopher H. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Dong Lei [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)], E-mail: ldong@mdanderson.org

2008-09-01T23:59:59.000Z

50

Thoracic CT-PET Registration Using a 3D Breathing Model  

E-Print Network [OSTI]

Thoracic CT-PET Registration Using a 3D Breathing Model Antonio Moreno1 , Sylvie Chambon1 , Anand P Orlando, USA Abstract. In the context of thoracic CT-PET volume registration, we present a novel method applications. We consider Computed Tomography (CT) and Positron Emission Tomography (PET) in thoracic regions

Paris-Sud XI, Université de

51

X-Ray CT Image Reconstruction via Wavelet Frame Based Regularization and Radon Domain  

E-Print Network [OSTI]

to reconstruct high quality CT images from limited and noisy projection data. One of the common CT systems Bin Dong Jia Li Zuowei Shen December 22, 2011 Abstract X-ray computed tomography (CT) has been,8]. Numerical simulations and comparisons will be presented at the end. Keywords: Computed tomography, wavelet

Zakharov, Vladimir

52

Limited View Angle Iterative CT Reconstruction  

E-Print Network [OSTI]

;Some Prior Literature in Limited View Tomography CT with limited-angle data and few views IRR algorithm Iterative Reconstruction-Reprojection (IRR) : An Algorithm for Limited Data Cardiac- Computed-views and limited-angle data in divergent-beam CT by E. Y. Sidky, CM Kao, and X. Pan (2006) Few-View Projection

53

Efficacy of Lower-Body Shielding in Computed Tomography Fluoroscopy-Guided Interventions  

SciTech Connect (OSTI)

Purpose: Computed tomography (CT) fluoroscopy-guided interventions pose relevant radiation exposure to the interventionalist. The goal of this study was to analyze the efficacy of lower-body shielding as a simple structural method for decreasing radiation dose to the interventionalist without limiting access to the patient. Material and Methods: All examinations were performed with a 128-slice dual source CT scanner (12 Multiplication-Sign 1.2-mm collimation; 120 kV; and 20, 40, 60, and 80 mAs) and an Alderson-Rando phantom. Scatter radiation was measured with an ionization chamber and a digital dosimeter at standardized positions and heights with and without a lower-body lead shield (0.5-mm lead equivalent; Kenex, Harlow, UK). Dose decreases were computed for the different points of measurement. Results: On average, lower-body shielding decreased scatter radiation by 38.2% within a 150-cm radius around the shielding. This decrease is most significant close to the gantry opening and at low heights of 50 and 100 cm above the floor with a maximum decrease of scatter radiation of 95.9% close to the scanner's isocentre. With increasing distance to the gantry opening, the effect decreased. There is almost no dose decrease effect at {>=}150 above the floor. Scatter radiation and its decrease were linearly correlated with the tube current-time product (r{sup 2} = 0.99), whereas percent scatter radiation decrease was independent of the tube current-time product. Conclusion: Lower-body shielding is an effective way to decrease radiation exposure to the interventionalist and should routinely be used in CT fluoroscopy-guided interventions.

Mahnken, Andreas H., E-mail: mahnken@rad.rwth-aachen.de [RWTH Aachen, Department of Diagnostic and Interventional Radiology (Germany); Sedlmair, Martin [Siemens, Healthcare Sector (Germany); Ritter, Christine [University of Copenhagen, Niels Bohr Institute (Denmark); Banckwitz, Rosemarie; Flohr, Thomas [Siemens, Healthcare Sector (Germany)

2012-12-15T23:59:59.000Z

54

Reduction of Metal Artifacts in Computed Tomographies for the Planning and Simulation of Radiation Therapy  

E-Print Network [OSTI]

tomographies (CT). Compared to simulated CT projection data, real measurements allowed less improvementsReduction of Metal Artifacts in Computed Tomographies for the Planning and Simulation of Radiation and numerical stability. 1. INTRODUCTION In radiation therapy, computed tomographies are used for patient

Zerfowski, Detlef

55

Cone Beam Tomography using MPI on Heterogeneous Workstation Clusters  

E-Print Network [OSTI]

tomography is a computed tomography method which efficiently acquires projectional data through a single. Introduction Tomographic reconstruction from projections using computed tomography (CT) provides a noninvasive, the projectional data is projected back onto an image buffer with each de- tected ray backprojected in it

Chaudhary, Vipin

56

Combined PET/MRI scanner  

DOE Patents [OSTI]

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.

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)

2007-10-23T23:59:59.000Z

57

E-Print Network 3.0 - aneurysm ct evaluation Sample Search Results  

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

OF SURGERY VOL 30 NO 4 OCTOBER 2007 2007 Elsevier. All rights reserved. Summary: tomography (CT). Follow-up CT scan at 22 months showed the presence of a markedly enlarged...

58

E-Print Network 3.0 - aided ct image Sample Search Results  

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

10 ARTICLE IN PRESS Computer-Aided Design ( ) Summary: a limited number of computed tomography (CT) images. The three-dimensional template geometry of a healthy... contour shown...

59

Performance dependence of hybrid x-ray computed tomography/fluorescence molecular  

E-Print Network [OSTI]

Performance dependence of hybrid x-ray computed tomography/fluorescence molecular tomography imaging systems combining x-ray computed tomography (CT) and fluorescence tomography can im- prove Ntziachristos2 1 Department of Electrical and Computer Engineering, Northeastern University, 360 Huntington Ave

Miller, Eric

60

Positron emission tomography wrist detector  

DOE Patents [OSTI]

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.

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)

2006-08-15T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Explosive Detection in Aviation Applications Using CT  

SciTech Connect (OSTI)

CT scanners are deployed world-wide to detect explosives in checked and carry-on baggage. Though very similar to single- and dual-energy multi-slice CT scanners used today in medical imaging, some recently developed explosives detection scanners employ multiple sources and detector arrays to eliminate mechanical rotation of a gantry, photon counting detectors for spectral imaging, and limited number of views to reduce cost. For each bag scanned, the resulting reconstructed images are first processed by automated threat recognition algorithms to screen for explosives and other threats. Human operators review the images only when these automated algorithms report the presence of possible threats. The US Department of Homeland Security (DHS) has requirements for future scanners that include dealing with a larger number of threats, higher probability of detection, lower false alarm rates and lower operating costs. One tactic that DHS is pursuing to achieve these requirements is to augment the capabilities of the established security vendors with third-party algorithm developers. A third-party in this context refers to academics and companies other than the established vendors. DHS is particularly interested in exploring the model that has been used very successfully by the medical imaging industry, in which university researchers develop algorithms that are eventually deployed in commercial medical imaging equipment. The purpose of this paper is to discuss opportunities for third-parties to develop advanced reconstruction and threat detection algorithms.

Martz, H E; Crawford, C R

2011-02-15T23:59:59.000Z

62

Hand-held optical fuel pin scanner  

DOE Patents [OSTI]

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.

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

1980-12-07T23:59:59.000Z

63

Hand-held optical fuel pin scanner  

DOE Patents [OSTI]

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.

Kirchner, Tommy L. (Richland, WA); Powers, Hurshal G. (Richland, WA)

1987-01-01T23:59:59.000Z

64

Locating the Eyes in CT Brain Scan Data Kostis Kaggelides, Peter J. Elliott  

E-Print Network [OSTI]

, a technique for locating the eyes in Computed Tomography brain scan data, is described. The objective and implemented an algorithm which automaticallyidenti es and locates the eyes in a Computed Tomography(CT) brainLocating the Eyes in CT Brain Scan Data Kostis Kaggelides, Peter J. Elliott IBM UK Scienti c Centre

Fisher, Bob

65

LANSCE Wire Scanner System Prototype: Switchyard Test  

SciTech Connect (OSTI)

On November 19, 2011, the beam diagnostics team of Los Alamos National Laboratory's LANSCE accelerator facility conducted a test of a prototype wire scanner system for future deployment within the accelerator's switchyard area. The primary focus of this test was to demonstrate the wire scanner control system's ability to extend its functionality beyond acquiring lower energy linac beam profile measurements to acquiring data in the switchyard. This study summarizes the features and performance characteristics of the electronic and mechanical implementation of this system with details focusing on the test results.

Sedillo, James D [Los Alamos National Laboratory

2012-04-11T23:59:59.000Z

66

Nuclear Instruments and Methods in Physics Research A 571 (2007) 102105 Preliminary studies of a simultaneous PET/MRI scanner based on the  

E-Print Network [OSTI]

of a simultaneous PET/MRI scanner based on the RatCAP small animal tomograph C. Woodya,Ã?, D. Schlyera , P. Vaskaa data using positron emission tomography (PET). The approach is based on the technology used for the RatCAP conscious small animal PET tomograph which utilizes block detectors consisting of pixelated arrays of LSO

67

Application of X-ray CT for investigating fluid flow and conformance control during CO2 injection in highly heterogeneous media  

E-Print Network [OSTI]

were performed using homogeneous and heterogeneous cores and a 4th generation X-Ray CT scanner was used to visualize heterogeneity and fluid flow in the core. Porosity and saturation measurements were made during the course of the experiment...

Chakravarthy, Deepak

2005-08-29T23:59:59.000Z

68

The Mathematics of the Imaging Techniques of MEG, CT, PET and SPECT  

E-Print Network [OSTI]

The Mathematics of the Imaging Techniques of MEG, CT, PET and SPECT A.S. Fokas, V. Marinakis), of positron emission tomography (PET) and of single photon emission computed to­ mography (SPECT) are reviewed techniques of positron emission tomography (PET) and of single photon emission computed tomography (SPECT

Fokas, A. S.

69

Bioengineering 280ABioengineering 280A Principles ofPrinciples of  

E-Print Network [OSTI]

for tomography, now called the Radon transform. 1972 Godfrey Hounsfield develops first CT system. Unaware://www.sprawls.org/resources/CTIMG/classroom.htm Thomas Liu, BE280A Fall 04, UCSD 9/23/04 Computed TomographyComputed Tomography Image from Siemens Siretom CT scanner, circa 1975. 128x128 matrix. Modern CT image acquired with a Siemens scanner. 512x512

Liu, Thomas T.

70

Miniature 'Wearable' PET Scanner Ready for Use  

ScienceCinema (OSTI)

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.

Paul Vaska

2013-07-22T23:59:59.000Z

71

Current segmented gamma-ray scanner technology  

SciTech Connect (OSTI)

A new generation of segmented gamma-ray scanners has been developed at Los Alamos for scrap and waste measurements at the Savannah River Plant and the Los Alamos Plutonium Facility. The new designs are highly automated and exhibit special features such as good segmentation and thorough shielding to improve performance.

Bjork, C.W.

1987-01-01T23:59:59.000Z

72

Conventional wire scanners for TESLA K. Wittenburg  

E-Print Network [OSTI]

in the undulator section. The heat load of the wires is calculated in the following for the TESLA parameters to the high heat load. At some locations in TESLA both beam diameters are larger than a few microns. The heat load defines the wire scanner parameters, mainly the scanning speed, and other limitations

73

MagViz Bottled Liquid Scanner at Albuquerque International Sunport  

ScienceCinema (OSTI)

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

Surko, Stephen; Dennis, Steve; Espy, Michelle

2014-08-12T23:59:59.000Z

74

Raw Data Compression in Computed Tomography: Noise Shaping  

E-Print Network [OSTI]

Raw Data Compression in Computed Tomography: Noise Shaping Yao Xie (team member: Adam Wang) Project.1 Background X-ray computed tomography (CT) builds on the physical principles of radiography. It uses multiple ring that has a limited data transfer rate. Compression can be used to reduce the data rate through

Xie, Yao

75

Bayesian Image Reconstruction for Transmission Tomography Using Deterministic Annealing  

E-Print Network [OSTI]

and non-medical applications, however, the measured projection data are photon limited and the imaging;1 INTRODUCTION Transmission tomography is perhaps most familiar in its medical guise as CT (computed tomogra- phy procedure. Because of the relatively high dose in conventional CT, the measured projection data contain

Rangarajan, Anand

76

The effects of gantry tilt on breast dose and image noise in cardiac CT  

SciTech Connect (OSTI)

Purpose: This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.Methods: Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a clinical CT scanner (CT750HD, GE Healthcare) using an anthropomorphic phantom with MOSFET dosimeters in the breast regions. In both simulations and experiments, scans were performed at gantry tilt angles of 0°–30°, in 5° increments. The percent change in breast dose was calculated relative to the nontilted scan for all tilt angles. The percent change in noise standard deviation due to gantry tilt was calculated in all reconstructed simulated and experimental images.Results: Tilting the gantry reduced the breast dose in all simulated and experimental phantoms, with generally greater dose reduction at increased gantry tilts. For example, at 30° gantry tilt, the dosimeters located in the superior, middle, and inferior breast regions measured dose reductions of 74%, 61%, and 9%, respectively. The simulations estimated 0%–30% total breast dose reduction across the eight phantoms and range of tilt angles. However, tilted-gantry acquisition also increased the noise standard deviation in the simulated phantoms by 2%–50% due to increased pathlength through the iodine-filled heart. The experimental phantom, which did not contain iodine in the blood, demonstrated decreased breast dose and decreased noise at all gantry tilt angles.Conclusions: Tilting the gantry reduced the dose to the breast, while also increasing noise standard deviation. Overall, the noise increase outweighed the dose reduction for the eight voxelized phantoms, suggesting that tilted gantry acquisition may not be beneficial for reducing breast dose while maintaining image quality.

Hoppe, Michael E.; Gandhi, Diksha; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States)] [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Stevens, Grant M. [GE Healthcare, Waukesha, Wisconsin 53188 (United States)] [GE Healthcare, Waukesha, Wisconsin 53188 (United States); Foley, W. Dennis [Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, Milwaukee, Wisconsin 53226 (United States)] [Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, Milwaukee, Wisconsin 53226 (United States)

2013-12-15T23:59:59.000Z

77

Neutron Tomography and Space  

E-Print Network [OSTI]

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

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

2007-01-01T23:59:59.000Z

78

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]

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 ...

Eastwick, Gary (Gary A.)

2010-01-01T23:59:59.000Z

79

Pseudolocal tomography  

DOE Patents [OSTI]

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.

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

1996-07-23T23:59:59.000Z

80

Pseudolocal tomography  

DOE Patents [OSTI]

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.

Katsevich, Alexander J. (Los Alamos, NM); Ramm, Alexander G. (Manhattan, KS)

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Doppler Tomography  

E-Print Network [OSTI]

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.

T. R. Marsh

2000-11-01T23:59:59.000Z

82

Bioengineering 280A Principles of  

E-Print Network [OSTI]

the mathematical framework for tomography, now called the Radon transform. 1972 Godfrey Hounsfield develops first Tomography Image from Siemens Siretom CT scanner, circa 1975. 128x128 matrix. Modern CT image acquired with a Siemens scanner. 512x512 matrix. #12;7 Computed Tomography #12;8 #12;9 History of Ultrasound 1942 Dr

Liu, Thomas T.

83

Bioengineering 280A Principles of  

E-Print Network [OSTI]

establishes the mathematical framework for tomography, now called the Radon transform. 1972 Godfrey://www.sprawls.org/resources/CTIMG/classroom.htm Computed Tomography Image from Siemens Siretom CT scanner, circa 1975. 128x128 matrix. Modern CT image acquired with a Siemens scanner. 512x512 matrix. #12;4 Computed Tomography #12;5 History of Ultrasound

Liu, Thomas T.

84

Transient foam flow in porous media with CAT Scanner  

SciTech Connect (OSTI)

Transient behavior is likely to dominate over most of the duration of a foam injection field project. Due to the lack of date, little is presently known about transient foam flow behavior. Foam flow does not follow established models such as the Buckley-Leverett theory, and no general predictive model has been derived. Therefore, both experimental data and a foam flow theory are needed. In this work, foam was injected at a constant mass rate into one-dimensional sandpacks of 1-in diameter and 24-in or 48-in length that had initially been saturate with distilled water. The system was placed in a cat Scanner. Data, obtained at room temperature and low pressure at various times, include both the pressure and saturation distributions. Pressure profiles showed that the pressure gradient is much greater behind the foam front than ahead of it. Moreover, the pressure gradients keep changing as the foam advances in the sandpack. This behavior differs from Buckley-Leverett theory. The CT scan results demonstrated gas channeling near the front, but eventually the foam block all these channels and sweeps the entire cross section after many pore volumes of injection. Three series of experiments were run: (1) surfactant adsorption measurements; (2) gas displacements of surfactant-laden solutions and (3) foam displacements. The first two series of experiments were made to provide the necessary parameters required to match the foam displacements. To this end, it was necessary to smooth the saturation history data, using a Langmuir-type formula. A theory was proposed based on the principles of the fractional flow curve construction method. This foam theory treats the foam as composed of infinitesimal slugs of gas of varying viscosities. The foam front has the lowest viscosity and foam at the injection end has the highest.

Liu, Dianbin; Brigham, W.E.

1992-03-01T23:59:59.000Z

85

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).

86

E-Print Network 3.0 - abnormal brain ct Sample Search Results  

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

P R I N G 2 0 0 7 N Y U P H Y S I C I A N S P R I N G 2 0 0 7 1 1 Summary: to put their head in a CT scanner," says Dr. de Leon. At the time, brain scans were used in dementia...

87

Examination of viscous fingering using the Cat-Scanner  

E-Print Network [OSTI]

fingering is believed to be partly initiated by rock heterogeneities. To study viscous fingering, a Cat-Scanner was used to visualize the in-situ fluid displacement mechanism in Berea sandstone cores. The Cat-Scanner cross-sectional images of -the core...

D'Souza, Michael Anthony

2012-06-07T23:59:59.000Z

88

X-ray MicroCT Training Presentation  

E-Print Network [OSTI]

X-ray MicroCT Training Presentation T. Fettah Kosar, PhD Center for Nanoscale Systems Harvard) Model: HMXST225 (max. 225 kV) #12;Overview 3 Introduction to X-ray imaging and Computed Tomography (CT) · What are X-rays and how do we generate and image them? · How do we magnify X-ray images and keep them

89

Monte Carlo simulations of adult and pediatric computed tomography exams: Validation studies of organ doses with physical phantoms  

SciTech Connect (OSTI)

Purpose: To validate the accuracy of a Monte Carlo source model of the Siemens SOMATOM Sensation 16 CT scanner using organ doses measured in physical anthropomorphic phantoms. Methods: The x-ray output of the Siemens SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code, MCNPX version 2.6. The resulting source model was able to perform various simulated axial and helical computed tomographic (CT) scans of varying scan parameters, including beam energy, filtration, pitch, and beam collimation. Two custom-built anthropomorphic phantoms were used to take dose measurements on the CT scanner: an adult male and a 9-month-old. The adult male is a physical replica of University of Florida reference adult male hybrid computational phantom, while the 9-month-old is a replica of University of Florida Series B 9-month-old voxel computational phantom. Each phantom underwent a series of axial and helical CT scans, during which organ doses were measured using fiber-optic coupled plastic scintillator dosimeters developed at University of Florida. The physical setup was reproduced and simulated in MCNPX using the CT source model and the computational phantoms upon which the anthropomorphic phantoms were constructed. Average organ doses were then calculated based upon these MCNPX results. Results: For all CT scans, good agreement was seen between measured and simulated organ doses. For the adult male, the percent differences were within 16% for axial scans, and within 18% for helical scans. For the 9-month-old, the percent differences were all within 15% for both the axial and helical scans. These results are comparable to previously published validation studies using GE scanners and commercially available anthropomorphic phantoms. Conclusions: Overall results of this study show that the Monte Carlo source model can be used to accurately and reliably calculate organ doses for patients undergoing a variety of axial or helical CT examinations on the Siemens SOMATOM Sensation 16 scanner.

Long, Daniel J.; Lee, Choonsik; Tien, Christopher; Fisher, Ryan; Hoerner, Matthew R.; Hintenlang, David; Bolch, Wesley E. [J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States); National Cancer Institute, National Institute of Health, Bethesda, Maryland 20892-1502 (United States); J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States); Department of Radiology, University of Florida, Gainesville, Florida 32610-0374 (United States); J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131 (United States)

2013-01-15T23:59:59.000Z

90

Evaluation of Turbine Blades Using Computed Tomography  

E-Print Network [OSTI]

Turbine blades are high value castings having complex internal geometry. Computed Tomography has been employed on Turbine blades for finding out defects and internal details. The wall thickness, rib thickness and radius of curvature are measured from the CT slices. The discontinuities including blockages of cooling passages in the cast material can be detected. 3D visualization of the turbine blade provides in extracting its internal features including inaccessible areas nondestructively, which is not possible through conventional NDE methods. The salient features for evaluation of turbine blades using Tomography are brought out.

C. Muralidhar; S. N. Lukose; M. P. Subramanian

2006-01-01T23:59:59.000Z

91

CT imaging of enhanced oil recovery experiments  

SciTech Connect (OSTI)

X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a good'' surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

Gall, B.L.

1992-12-01T23:59:59.000Z

92

CT imaging of enhanced oil recovery experiments  

SciTech Connect (OSTI)

X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a ``good`` surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

Gall, B.L.

1992-12-01T23:59:59.000Z

93

Hemorrhage Slices Detection in Brain CT Images Ruizhe Liu, Chew Lim Tan, Tze Yun Leong  

E-Print Network [OSTI]

Hemorrhage Slices Detection in Brain CT Images Ruizhe Liu, Chew Lim Tan, Tze Yun Leong Department) scans are widely used in today's diagnosis of head traumas. It is effective to disclose the bleeding Tomography (CT) scans are widely used in today's diagnosis of head traumas. It is effective to disclose

Tan, Chew Lim

94

GPU IMPLEMENTATION OF A 3D BAYESIAN CT ALGORITHM AND ITS APPLICATION ON REAL FOAM RECONSTRUCTION  

E-Print Network [OSTI]

Tomography (CT) [1, 3]. The limits of these meth- ods appear when the number of projections is small, and as well as any iterative algebraic meth- ods is the computation time and especially for projection solve is to reconstruct the object f from the projection data g collected by a cone beam 3D CT. The link

Paris-Sud XI, Université de

95

Searching Effective Parameters for Low-Dose CT Reconstruction by Ant Colony Optimization  

E-Print Network [OSTI]

, Eric Papenhausen and Klaus Mueller Abstract-- Low-dose Computed Tomography (CT) has been gaining. To cope with the limited data collected at 30% of standard radiation, low-dose CT reconstruction algorithms generally require several iterations of forward projection, back-projection and regularization

Mueller, Klaus

96

Estimation of the weighted CTDI{sub {infinity}} for multislice CT examinations  

SciTech Connect (OSTI)

Purpose: The aim of this study was to examine the variations of CT dose index (CTDI) efficiencies, {epsilon}(CTDI{sub 100})=CTDI{sub 100}/CTDI{sub {infinity}}, with bowtie filters and CT scanner types. Methods: This was an extension of our previous study [Li, Zhang, and Liu, Phys. Med. Biol. 56, 5789-5803 (2011)]. A validated Monte Carlo program was used to calculate {epsilon}(CTDI{sub 100}) on a Siemens Somatom Definition scanner. The {epsilon}(CTDI{sub 100}) dependencies on tube voltages and beam widths were tested in previous studies. The influences of different bowtie filters and CT scanner types were examined in this work. The authors tested the variations of {epsilon}(CTDI{sub 100}) with bowtie filters on the Siemens Definition scanner. The authors also analyzed the published CTDI measurements of four independent studies on five scanners of four models from three manufacturers. Results: On the Siemens Definition scanner, the difference in {epsilon}(CTDI{sub W}) between using the head and body bowtie filters was 2.5% (maximum) in the CT scans of the 32-cm phantom, and 1.7% (maximum) in the CT scans of the 16-cm phantom. Compared with CTDI{sub W}, the weighted CTDI{sub {infinity}} increased by 30.5% (on average) in the 32-cm phantom, and by 20.0% (on average) in the 16-cm phantom. These results were approximately the same for 80-140 kV and 1-40 mm beam widths (4.2% maximum deviation). The differences in {epsilon}(CTDI{sub 100}) between the simulations and the direct measurements of four previous studies were 1.3%-5.0% at the center/periphery of the 16-cm/32-cm phantom (on average). Conclusions: Compared with CTDI{sub vol}, the equilibrium dose for large scan lengths is 30.5% higher in the 32-cm phantom, and is 20.0% higher in the 16-cm phantom. The relative increases are practically independent of tube voltages (80-140 kV), beam widths (up to 4 cm), and the CT scanners covered in this study.

Li Xinhua; Zhang Da; Liu, Bob [Division of Diagnostic Imaging Physics, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)

2012-02-15T23:59:59.000Z

97

Fast and High Accuracy Wire Scanner  

E-Print Network [OSTI]

Scanning of a high intensity particle beam imposes challenging requirements on a Wire Scanner system. It is expected to reach a scanning speed of 20 m.s-1 with a position accuracy of the order of 1 ?m. In addition a timing accuracy better than 1 millisecond is needed. The adopted solution consists of a fork holding a wire rotating by a maximum of 200°. Fork, rotor and angular position sensor are mounted on the same axis and located in a chamber connected to the beam vacuum. The requirements imply the design of a system with extremely low vibration, vacuum compatibility, radiation and temperature tolerance. The adopted solution consists of a rotary brushless synchronous motor with the permanent magnet rotor installed inside of the vacuum chamber and the stator installed outside. The accurate position sensor will be mounted on the rotary shaft inside of the vacuum chamber, has to resist a bake-out temperature of 200°C and ionizing radiation up to a dozen of kGy/year. A digital feedback controller allows maxi...

Koujili, M; Koopman, J; Ramos, D; Sapinski, M; De Freitas, J; Ait Amira, Y; Djerdir, A

2009-01-01T23:59:59.000Z

98

1996 InternationalConference on Parallel Processing PARALLEL IMPLEMENTATION OF CONE BEAM TOMOGRAPHY  

E-Print Network [OSTI]

projections us- ing computed tomography (CT) is the noninvasive measure of structure from external as follows: A. Weight projection data B. Convolve weighted projection data Pe*(u,v) = P&L, U) * h(u) C1996 InternationalConference on Parallel Processing PARALLEL IMPLEMENTATION OF CONE BEAM TOMOGRAPHY

Chaudhary, Vipin

99

Nuclear Medicine CT Angiography  

E-Print Network [OSTI]

Nuclear Medicine CT Angiography Stress Testing Rotation The Nuclear Medicine/CT angiography. Understand the indications for exercise treadmill testing and specific nuclear cardiology tests, safe use Level 2 proficiency in performing and interpreting cardiac nuclear imaging tests. Progression

Ford, James

100

Automatic Channel Fault Detection and Diagnosis System for a Small Animal APD-Based Digital PET Scanner  

E-Print Network [OSTI]

Fault detection and diagnosis is critical to many applications in order to ensure proper operation and performance over time. Positron emission tomography (PET) systems that require regular calibrations by qualified scanner operators are good candidates for such continuous improvements. Furthermore, for scanners employing one-to-one coupling of crystals to photodetectors to achieve enhanced spatial resolution and contrast, the calibration task is even more daunting because of the large number of independent channels involved. To cope with the additional complexity of the calibration and quality control procedures of these scanners, an intelligent system (IS) was designed to perform fault detection and diagnosis (FDD) of malfunctioning channels. The IS can be broken down into four hierarchical modules: parameter extraction, channel fault detection, fault prioritization and diagnosis. Of these modules, the first two have previously been reported and this paper focuses on fault prioritization and diagnosis. The purpose of the fault prioritization module is to help the operator to zero in on the faults that need immediate attention. The fault diagnosis module will then identify the causes of the malfunction and propose an explanation of the reasons that lead to the diagnosis. The FDD system was implemented on a LabPET avalanche photodiode (APD)-based digital PET scanner. Experiments demonstrated a FDD Sensitivity of 99.3 % (with a 95% confidence interval (CI) of: [98.7, 99.9]) for major faults. Globally, the Balanced Accuracy of the diagnosis for varying fault severities is 92 %. This suggests the IS can greatly benefit the operators in their maintenance task.

Jonathan Charest; Jean-François Beaudoin; Jules Cadorette; Roger Lecomte; Charles-Antoine Brunet; Réjean Fontaine

2014-06-16T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

CT measurements of two-phase flow in fractured porous media  

SciTech Connect (OSTI)

The simulation of flow in naturally fractured reservoirs commonly divides the reservoir into two continua - the matrix system and the fracture system. Flow equations are written presuming that the primary flow between grid blocks occurs through the fracture system and that the primary fluid storage is in the matrix system. The dual porosity formulation of the equations assumes that there is no flow between matrix blocks while the dual permeability formulation allows fluid movement between matrix blocks. Since most of the fluid storage is contained in the matrix, recovery is dominated by the transfer of fluid from the matrix to the high conductivity fractures. The physical mechanisms influencing this transfer have been evaluated primarily through numerical studies. Relatively few experimental studies have investigated the transfer mechanisms. Early studies focused on the prediction of reservoir recoveries from the results of scaled experiments on single reservoir blocks. Recent experiments have investigated some of the mechanisms that are dominant in gravity drainage situations and in small block imbibition displacements. The mechanisms active in multiphase flow in fractured media need to be further illuminated, since some of the experimental results appear to be contradictory. This report describes the design, construction, and preliminary results of an experiment that studies imbibition displacement in two fracture blocks. Multiphase (oil/water) displacements will be conducted at the same rate on three core configurations. The configurations are a compact core, a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. The blocks are sealed in epoxy so that saturation measurements can be made throughout the displacement experiments using a Computed Tomography (CT) scanner.

Hughes, R.G.; Brigham, W.E.; Castanier, L.M.

1997-06-01T23:59:59.000Z

102

A quality assurance framework for the fully automated and objective evaluation of image quality in cone-beam computed tomography  

SciTech Connect (OSTI)

Purpose: Thousands of cone-beam computed tomography (CBCT) scanners for vascular, maxillofacial, neurological, and body imaging are in clinical use today, but there is no consensus on uniform acceptance and constancy testing for image quality (IQ) and dose yet. The authors developed a quality assurance (QA) framework for fully automated and time-efficient performance evaluation of these systems. In addition, the dependence of objective Fourier-based IQ metrics on direction and position in 3D volumes was investigated for CBCT. Methods: The authors designed a dedicated QA phantom 10 cm in length consisting of five compartments, each with a diameter of 10 cm, and an optional extension ring 16 cm in diameter. A homogeneous section of water-equivalent material allows measuring CT value accuracy, image noise and uniformity, and multidimensional global and local noise power spectra (NPS). For the quantitative determination of 3D high-contrast spatial resolution, the modulation transfer function (MTF) of centrally and peripherally positioned aluminum spheres was computed from edge profiles. Additional in-plane and axial resolution patterns were used to assess resolution qualitatively. The characterization of low-contrast detectability as well as CT value linearity and artifact behavior was tested by utilizing sections with soft-tissue-equivalent and metallic inserts. For an automated QA procedure, a phantom detection algorithm was implemented. All tests used in the dedicated QA program were initially verified in simulation studies and experimentally confirmed on a clinical dental CBCT system. Results: The automated IQ evaluation of volume data sets of the dental CBCT system was achieved with the proposed phantom requiring only one scan for the determination of all desired parameters. Typically, less than 5 min were needed for phantom set-up, scanning, and data analysis. Quantitative evaluation of system performance over time by comparison to previous examinations was also verified. The maximum percentage interscan variation of repeated measurements was less than 4% and 1.7% on average for all investigated quality criteria. The NPS-based image noise differed by less than 5% from the conventional standard deviation approach and spatially selective 10% MTF values were well comparable to subjective results obtained with 3D resolution pattern. Determining only transverse spatial resolution and global noise behavior in the central field of measurement turned out to be insufficient. Conclusions: The proposed framework transfers QA routines employed in conventional CT in an advanced version to CBCT for fully automated and time-efficient evaluation of technical equipment. With the modular phantom design, a routine as well as an expert version for assessing IQ is provided. The QA program can be used for arbitrary CT units to evaluate 3D imaging characteristics automatically.

Steiding, Christian; Kolditz, Daniel; Kalender, Willi A., E-mail: willi.kalender@imp.uni-erlangen.de [Institute of Medical Physics, University of Erlangen-Nürnberg, Henkestraße 91, 91052 Erlangen, Germany and CT Imaging GmbH, 91052 Erlangen (Germany)

2014-03-15T23:59:59.000Z

103

Enlarged longitudinal dose profiles in cone-beam CT and the need for modified dosimetry  

SciTech Connect (OSTI)

In order to examine phantom length necessary to assess radiation dose delivered to patients in cone-beam CT with an enlarged beamwidth, we measured dose profiles in cylindrical phantoms of sufficient length using a prototype 256-slice CT-scanner developed at our institute. Dose profiles parallel to the rotation axis were measured at the central and peripheral positions in PMMA (polymethylmethacrylate) phantoms of 160 or 320 mm diameter and 900 mm length. For practical application, we joined unit cylinders (150 mm long) together to provide phantoms of 900 mm length. Dose profiles were measured with a pin photodiode sensor having a sensitive region of approximately 2.8x2.8 mm{sup 2} and 2.7 mm thickness. Beamwidths of the scanner were varied from 20 to 138 mm. Dose profile integrals (DPI) were calculated using the measured dose profiles for various beamwidths and integration ranges. For the body phantom (320-mm-diam phantom), 76% of the DPI was represented for a 20 mm beamwidth and 60% was represented for a 138 mm beamwidth if dose profiles were integrated over a 100 mm range, while more than 90% of the DPI was represented for beamwidths between 20 and 138 mm if integration was carried out over a 300 mm range. The phantom length and integration range for dosimetry of cone-beam CT needed to be more than 300 mm to represent more than 90% of the DPI for the body phantom with the beamwidth of more than 20 mm. Although we reached this conclusion using the prototype 256-slice CT-scanner, it may be applied to other multislice CT-scanners as well.

Mori, Shinichiro; Endo, Masahiro; Nishizawa, Kanae; Tsunoo, Takanori; Aoyama, Takahiko; Fujiwara, Hideaki; Murase, Kenya [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); School of Health Sciences, Nagoya University, Nagoya 461-8673 (Japan); School of Allied Health Sciences, Faculty of Medicine, Osaka University, Osaka 565-0871 (Japan)

2005-04-01T23:59:59.000Z

104

Nonrigid registration-based coronary artery motion correction for cardiac computed tomography  

SciTech Connect (OSTI)

Purpose: X-ray computed tomography angiography (CTA) is the modality of choice to noninvasively monitor and diagnose heart disease with coronary artery health and stenosis detection being of particular interest. Reliable, clinically relevant coronary artery imaging mandates high spatiotemporal resolution. However, advances in intrinsic scanner spatial resolution (CT scanners are available which combine nearly 900 detector columns with focal spot oversampling) can be tempered by motion blurring, particularly in patients with unstable heartbeats. As a result, recently numerous methods have been devised to improve coronary CTA imaging. Solutions involving hardware, multisector algorithms, or {beta}-blockers are limited by cost, oversimplifying assumptions about cardiac motion, and populations showing contraindications to drugs, respectively. This work introduces an inexpensive algorithmic solution that retrospectively improves the temporal resolution of coronary CTA without significantly affecting spatial resolution. Methods: Given the goal of ruling out coronary stenosis, the method focuses on 'deblurring' the coronary arteries. The approach makes no assumptions about cardiac motion, can be used on exams acquired at high heart rates (even over 75 beats/min), and draws on a fast and accurate three-dimensional (3D) nonrigid bidirectional labeled point matching approach to estimate the trajectories of the coronary arteries during image acquisition. Motion compensation is achieved by employing a 3D warping of a series of partial reconstructions based on the estimated motion fields. Each of these partial reconstructions is created from data acquired over a short time interval. For brevity, the algorithm 'Subphasic Warp and Add' (SWA) reconstruction. Results: The performance of the new motion estimation-compensation approach was evaluated by a systematic observer study conducted using nine human cardiac CTA exams acquired over a range of average heart rates between 68 and 86 beats/min. Algorithm performance was based-lined against exams reconstructed using standard filtered-backprojection (FBP). The study was performed by three experienced reviewers using the American Heart Association's 15-segment model. All vessel segments were evaluated to quantify their viability to allow a clinical diagnosis before and after motion estimation-compensation using SWA. To the best of the authors' knowledge this is the first such observer study to show that an image processing-based software approach can improve the clinical diagnostic value of CTA for coronary artery evaluation. Conclusions: Results from the observer study show that the SWA method described here can dramatically reduce coronary artery motion and preserve real pathology, without affecting spatial resolution. In particular, the method successfully mitigated motion artifacts in 75% of all initially nondiagnostic coronary artery segments, and in over 45% of the cases this improvement was enough to make a previously nondiagnostic vessel segment clinically diagnostic.

Bhagalia, Roshni; Pack, Jed D.; Miller, James V.; Iatrou, Maria [GE Global Research, Niskayuna, New York 12309 (United States); GE Healthcare, Hoboken, New Jersey 07030 (United States)

2012-07-15T23:59:59.000Z

105

An RF dosimeter for independent SAR measurement in MRI scanners  

SciTech Connect (OSTI)

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.

Qian, Di; Bottomley, Paul A. [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)] [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); El-Sharkawy, AbdEl-Monem M.; Edelstein, William A., E-mail: w.edelstein@gmail.com [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 (United States)

2013-12-15T23:59:59.000Z

106

Modulated Luminescent Tomography  

E-Print Network [OSTI]

modalities behave differently than Photoacoustic and Thermoacoustic Tomography, where the ex- citation is highly diffusive but the emitted ultrasound signal ...

2015-01-28T23:59:59.000Z

107

AFIP-7 Tomography – 2013 Status Report  

SciTech Connect (OSTI)

This project seeks to assess the geometric stability of the U-Mo monolithic fuel system by evaluating the radiation-induced changes in the AFIP-7 experiment device. Neutron radiography and computed tomography (CT) provide valuable information about the post-irradiation condition of the fuel specimen. Tomographic reconstructions of the AFIP-7 fuel element will be analyzed to assess the geometric condition of the element after irradiation and provide information regarding the condition of the fuel, including gross geometric defects, bowing, twist, plate buckling, cracks, and other defects. The INL, in collaboration with Oregon State University (OSU), Missouri University of Science and Technology (Missouri S&T), and Real Time Tomography, is developing advanced neutron detector systems and tomographic reconstruction techniques to evaluate the AFIP-7 fuel element. Neutron computed tomography using the current neutron radiography technique available at the Neutron Radiography reactor (NRAD) is impractical due to the long time and high cost to produce a set of images for tomographic reconstruction. Advanced neutron radiography systems such as the micro-channel plate (MCP) detector and neutron computed radiography (CR) may reduce the time and cost of acquiring images for neutron CT.

A.E. Craft; W.J. Williams; M.I.K. Abir; D.M. Wachs

2013-10-01T23:59:59.000Z

108

Bioengineering 280A Principles of  

E-Print Network [OSTI]

the mathematical framework for tomography, now called the Radon transform. 1972 Godfrey Hounsfield develops first from Siemens Siretom CT scanner, circa 1975. 128x128 matrix. Modern CT image acquired with a Siemens

Liu, Thomas T.

109

Cone-beam mammo-computed tomography from data along two tilting arcs Hengyong Yu,b  

E-Print Network [OSTI]

Cone-beam mammo-computed tomography from data along two tilting arcs Kai Zeng,a Hengyong Yu . To address this problem, x-ray tomosynthesis and cone-beam computed tomography CT are two compelling from a limited num- ber of projections.4 Since its introduction in 1972, the area of tomosynthesis has

Virginia Tech

110

Bioengineering 280A Principles of  

E-Print Network [OSTI]

, now called the Radon transform. 1972 Godfrey Hounsfield develops first CT system. Unaware http://www.sprawls.org/resources/CTIMG/classroom.htm Computed Tomography Image from Siemens Siretom CT scanner, circa 1975. 128x128 matrix. Modern CT image acquired with a Siemens scanner. 512x512

Liu, Thomas T.

111

Bioengineering 280A Principles of  

E-Print Network [OSTI]

, now called the Radon transform. 1972 Godfrey Hounsfield develops first CT system. Unaware of either http://www.sprawls.org/resources/CTIMG/classroom.htm Computed Tomography Image from Siemens Siretom CT scanner, circa 1975. 128x128 matrix. Modern CT image acquired with a Siemens scanner. 512x512

Liu, Thomas T.

112

animal pet scanner: Topics by E-print Network  

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

animal pet scanner First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Atlas-based attenuation correction...

113

animal pet scanners: Topics by E-print Network  

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

animal pet scanners First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Atlas-based attenuation correction...

114

CHARACTERIZATION OF VIBRATIONINDUCED IMAGE DEFECTS IN INPUT SCANNERS  

E-Print Network [OSTI]

) by dynamic errors of gears, timing bets, and motors, and indirectly by structural vibrations induced by gearsCHARACTERIZATION OF VIBRATION­INDUCED IMAGE DEFECTS IN INPUT SCANNERS Robert P. Loce George Wolberg. Keywords: image defects, digital documents, scanned documents, vibrations, motion quality 1. INTRODUCTION

Wolberg, George

115

Diffraction and coherence in breast ultrasound tomography: a study with a toroidal array  

SciTech Connect (OSTI)

Ultrasound is commonly used as an adjunct to mammography for diagnostic evaluation of suspicions arising from breast cancer screening. As an alternative to conventional sonography that uses hand-held transducers, toroidal array probes that encircle the breast immersed in a water bath have been investigated for ultrasound tomography. In this paper, two sets of experiments performed with a prototype ultrasound scanner on a phantom and a human breast in vivo are used to investigate the effects of diffraction and coherence in ultrasound tomography. Reconstructions obtained with transmission diffraction tomography (TDT) are compared with conventional reflection imaging and computerized ultrasound tomography showing a substantial improvement. The in vivo tests demonstrate that TDT can image the complex boundary of a cancer mass and suggest that it can reveal the anatomy of milk ducts and Cooper's ligaments.

Huang, Lianjie [Los Alamos National Laboratory; Simonetti, Francesco [IMPERIAL COLL.; Duric, Neb [KCI; Littrup, Peter [KCI

2008-01-01T23:59:59.000Z

116

A Cost Effective Multi-Spectral Scanner for Natural Gas Detection  

SciTech Connect (OSTI)

The objective of this project is to design, fabricate and demonstrate a cost effective, multi-spectral scanner for natural gas leak detection in transmission and distribution pipelines. During the first year of the project, a laboratory version of the multi-spectral scanner was designed, fabricated, and tested at EnUrga Inc. The multi-spectral scanner was also evaluated using a blind Department of Energy study at the Rocky Mountain Oilfield Testing Center. The performance of the scanner was inconsistent during the blind study. However, most of the leaks were outside the view of the multi-spectral scanner that was developed during the first year of the project. Therefore, a definite evaluation of the capability of the scanner was not obtained. Despite the results, sufficient number of plumes was detected fully confirming the feasibility of the multi-spectral scanner. During the second year, the optical design of the scanner was changed to improve the sensitivity of the system. Laboratory tests show that the system can reliably detect small leaks (20 SCFH) at 30 to 50 feet. A prototype scanner was built and evaluated during the second year of the project. Only laboratory evaluations were completed during the second year. The laboratory evaluations show the feasibility of using the scanner to determine natural gas pipeline leaks. Further field evaluations and optimization of the scanner are required before commercialization of the scanner can be initiated.

Yudaya Sivathanu; Jongmook Lim; Vinoo Narayanan; Seonghyeon Park

2005-12-07T23:59:59.000Z

117

Turbocharging Quantum Tomography.  

SciTech Connect (OSTI)

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.

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

2015-01-01T23:59:59.000Z

118

A Detector for Proton Computed Tomography  

SciTech Connect (OSTI)

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.

Blazey, G.; et al.,

2013-12-06T23:59:59.000Z

119

Complications in CT-guided Procedures: Do We Really Need Postinterventional CT Control Scans?  

SciTech Connect (OSTI)

PurposeThe aim of this study is twofold: to determine the complication rate in computed tomography (CT)-guided biopsies and drainages, and to evaluate the value of postinterventional CT control scans.MethodsRetrospective analysis of 1,067 CT-guided diagnostic biopsies (n = 476) and therapeutic drainages (n = 591) in thoracic (n = 37), abdominal (n = 866), and musculoskeletal (ms) (n = 164) locations. Severity of any complication was categorized as minor or major. To assess the need for postinterventional CT control scans, it was determined whether complications were detected clinically, on peri-procedural scans or on postinterventional scans only.ResultsThe complication rate was 2.5 % in all procedures (n = 27), 4.4 % in diagnostic punctures, and 1.0 % in drainages; 13.5 % in thoracic, 2.0 % in abdominal, and 3.0 % in musculoskeletal procedures. There was only 1 major complication (0.1 %). Pneumothorax (n = 14) was most frequent, followed by bleeding (n = 9), paresthesia (n = 2), material damage (n = 1), and bone fissure (n = 1). Postinterventional control acquisitions were performed in 65.7 % (701 of 1,067). Six complications were solely detectable in postinterventional control acquisitions (3 retroperitoneal bleeds, 3 pneumothoraces); all other complications were clinically detectable (n = 4) and/or visible in peri-interventional controls (n = 21).ConclusionComplications in CT-guided interventions are rare. Of these, thoracic interventions had the highest rate, while pneumothoraces and bleeding were most frequent. Most complications can be detected clinically or peri-interventionally. To reduce the radiation dose, postinterventional CT controls should not be performed routinely and should be restricted to complicated or retroperitoneal interventions only.

Nattenmüller, Johanna, E-mail: johanna.nattenmueller@med.uni-heidelberg.de; Filsinger, Matthias, E-mail: Matthias_filsinger@web.de; Bryant, Mark, E-mail: mark.bryant@med.uni-heidelberg.de; Stiller, Wolfram, E-mail: Wolfram.Stiller@med.uni-heidelberg.de; Radeleff, Boris, E-mail: boris.radeleff@med.uni-heidelberg.de; Grenacher, Lars, E-mail: lars.grenacher@med.uni-heidelberg.de; Kauczor, Hans-Ullrich, E-mail: hu.kauczor@med.uni-heidelberg.de; Hosch, Waldemar, E-mail: waldemar.hosch@urz.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

2013-06-19T23:59:59.000Z

120

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

E-Print Network [OSTI]

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.

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

2014-08-29T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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121

Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development  

SciTech Connect (OSTI)

The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H{sup -} beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

Gilpatrick, John D. [Los Alamos National Laboratory; Batygin, Yuri K. [Los Alamos National Laboratory; Gonzales, Fermin [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Pillai, Chandra [Los Alamos National Laboratory; Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory

2012-05-15T23:59:59.000Z

122

CT Solar Loan  

Broader source: Energy.gov [DOE]

The Clean Energy Finance and Investment Authority is offering a pilot loan program, CT Solar Loan, to provide homeowners with 15-year loans for solar PV equipment. The loans are administered...

123

Dual seven pinhole tomography  

SciTech Connect (OSTI)

Emission tomography using two orthogonal sets of projections through seven pinhole collimators is considered. This paper describes the acquisition system, the reconstruction algorithm, presents results obtained in phantom studies, and discusses the advantages and disadvantages of this method over conventional Seven Pinhole Tomography.

Bizais, Y.; Zubal, I.G.; Rowe, R.W.; Bennett, G.W.; Brill, A.B.

1982-01-01T23:59:59.000Z

124

TLD assessment of mouse dosimetry during microCT imaging  

SciTech Connect (OSTI)

Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high resolution anatomic images of small animals. Because microCT utilizes ionizing radiation for image formation, radiation exposure during imaging is a concern. The objective of this study was to quantify the radiation dose delivered during a standard microCT scan. Radiation dose was measured using thermoluminescent dosimeters (TLDs), which were irradiated employing an 80 kVp x-ray source, with 0.5 mm Al filtration and a total of 54 mA s for a full 360 deg rotation of the unit. The TLD data were validated using a 3.2 cm{sup 3} CT ion chamber probe. TLD results showed a single microCT scan air kerma of 78.0{+-}5.0 mGy when using a poly(methylmethacrylate) (PMMA) anesthesia support module and an air kerma of 92.0{+-}6.0 mGy without the use of the anesthesia module. The validation CT ion chamber study provided a measured radiation air kerma of 81.0{+-}4.0 mGy and 97.0{+-}5.0 mGy with and without the PMMA anesthesia module, respectively. Internal TLD analysis demonstrated an average mouse organ radiation absorbed dose of 76.0{+-}5.0 mGy. The author's results have defined x-ray exposure for a routine microCT study which must be taken into consideration when performing serial molecular imaging studies involving the microCT imaging modality.

Figueroa, Said Daibes; Winkelmann, Christopher T.; Miller, William H.; Volkert, Wynn A.; Hoffman, Timothy J. [Harry S. Truman Memorial VA Hospital, Columbia, Missouri 65201 (United States) and Department of Radiology, University of Missouri, Columbia, Missouri 65201 (United States); Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65201 (United States); Nuclear Science and Engineering Institute, University of Missouri, Columbia, Missouri 65201 (United States); Department of Radiology, University of Missouri, Columbia, Missouri 65201 (United States); Harry S. Truman Memorial VA Hospital, Columbia, Missouri 65201 (United States) and Departments of Internal Medicine, Chemistry, and the Nuclear Science and Engineering Institute, University of Missouri, Columbia, Missouri 65201 (United States)

2008-09-15T23:59:59.000Z

125

Computerized method for evaluating diagnostic image quality of calcified plaque images in cardiac CT: Validation on a physical dynamic cardiac phantom  

SciTech Connect (OSTI)

Purpose: In cardiac computed tomography (CT), important clinical indices, such as the coronary calcium score and the percentage of coronary artery stenosis, are often adversely affected by motion artifacts. As a result, the expert observer must decide whether or not to use these indices during image interpretation. Computerized methods potentially can be used to assist in these decisions. In a previous study, an artificial neural network (ANN) regression model provided assessability (image quality) indices of calcified plaque images from the software NCAT phantom that were highly agreeable with those provided by expert observers. The method predicted assessability indices based on computer-extracted features of the plaque. In the current study, the ANN-predicted assessability indices were used to identify calcified plaque images with diagnostic calcium scores (based on mass) from a physical dynamic cardiac phantom. The basic assumption was that better quality images were associated with more accurate calcium scores. Methods: A 64-channel CT scanner was used to obtain 500 calcified plaque images from a physical dynamic cardiac phantom at different heart rates, cardiac phases, and plaque locations. Two expert observers independently provided separate sets of assessability indices for each of these images. Separate sets of ANN-predicted assessability indices tailored to each observer were then generated within the framework of a bootstrap resampling scheme. For each resampling iteration, the absolute calcium score error between the calcium scores of the motion-contaminated plaque image and its corresponding stationary image served as the ground truth in terms of indicating images with diagnostic calcium scores. The performances of the ANN-predicted and observer-assigned indices in identifying images with diagnostic calcium scores were then evaluated using ROC analysis. Results: Assessability indices provided by the first observer and the corresponding ANN performed similarly (AUC{sub OBS1}=0.80 [0.73,0.86] vs AUC{sub ANN1}=0.88 [0.82,0.92]) as that of the second observer and the corresponding ANN (AUC{sub OBS2}=0.87 [0.83,0.91] vs AUC{sub ANN2}=0.90 [0.85,0.94]). Moreover, the ANN-predicted indices were generated in a fraction of the time required to obtain the observer-assigned indices. Conclusions: ANN-predicted assessability indices performed similar to observer-assigned assessability indices in identifying images with diagnostic calcium scores from the physical dynamic cardiac phantom. The results of this study demonstrate the potential of using computerized methods for identifying images with diagnostic clinical indices in cardiac CT images.

King, Martin; Rodgers, Zachary; Giger, Maryellen L.; Bardo, Dianna M. E.; Patel, Amit R. [Department of Radiology, Committee on Medical Physics, University of Chicago, 5841 South Maryland Avenue, MC 2026, Chicago, Illinois 60637 (United States); Department of Diagnostic Radiology, Oregon Health and Science University, 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97239 (United States); Department of Medicine, University of Chicago, 5841 South Maryland Avenue, MC 5084, Chicago, Illinois 60637 (United States)

2010-11-15T23:59:59.000Z

126

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

E-Print Network [OSTI]

materials (e.g., carbon-fibre-reinforced plas- tics) induce manufacturers to design new functionSurface 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

127

Data fusion in neutron and X-ray computed tomography  

SciTech Connect (OSTI)

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.

Schrapp, Michael J. [Siemens AG, Corporate Technology, Otto-Hahn-Ring 6, 81739 Munich (Germany); Physik Department E21, Technische Universität München, James-Franck-Strasse 1, 85747 Garching (Germany); Goldammer, Matthias [Siemens AG, Corporate Technology, Otto-Hahn-Ring 6, 81739 Munich (Germany); Schulz, Michael [Physik Department E21, Technische Universität München, James-Franck-Strasse 1, 85747 Garching (Germany); Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstrasse 1, 85747 Garching (Germany); Issani, Siraj; Bhamidipati, Suryanarayana [Siemens AG, Corporate Technology, Bangalore (India); Böni, Peter [Physik Department E21, Technische Universität München, James-Franck-Strasse 1, 85747 Garching (Germany)

2014-10-28T23:59:59.000Z

128

Calculations of two new dose metrics proposed by AAPM Task Group 111 using the measurements with standard CT dosimetry phantoms  

SciTech Connect (OSTI)

Purpose: AAPM Task Group 111 proposed to measure the equilibrium dose-pitch product D-caret{sub eq} for scan modes involving table translation and the midpoint dose D{sub L}(0) for stationary-table modes on the central and peripheral axes of sufficiently long (e.g., at least 40 cm) phantoms. This paper presents an alternative approach to calculate both metrics using the measurements of scanning the standard computed tomographic (CT) dosimetry phantoms on CT scanners.Methods: D-caret{sub eq} was calculated from CTDI{sub 100} and ?(CTDI{sub 100}) (CTDI{sub 100} efficiency), and D{sub L}(0) was calculated from D-caret{sub eq} and the approach to equilibrium function H(L) =D{sub L}(0)/D{sub eq}, where D{sub eq} was the equilibrium dose. CTDI{sub 100} may be directly obtained from several sources (such as medical physicist's CT scanner performance evaluation or the IMPACT CT patient dosimetry calculator), or be derived from CTDI{sub Vol} using the central to peripheral CTDI{sub 100} ratio (R{sub 100}). The authors have provided the required ?(CTDI{sub 100}) and H(L) data in two previous papers [X. Li, D. Zhang, and B. Liu, Med. Phys. 39, 901–905 (2012); and ibid. 40, 031903 (10pp.) (2013)]. R{sub 100} was assessed for a series of GE, Siemens, Philips, and Toshiba CT scanners with multiple settings of scan field of view, tube voltage, and bowtie filter.Results: The calculated D{sub L}(0) and D{sub L}(0)/D{sub eq} in PMMA and water cylinders were consistent with the measurements on two GE CT scanners (LightSpeed 16 and VCT) by Dixon and Ballard [Med. Phys. 34, 3399–3413 (2007)], the measurements on a Siemens CT scanner (SOMATOM Spirit Power) by Descamps et al. [J. Appl. Clin. Med. Phys. 13, 293–302 (2012)], and the Monte Carlo simulations by Boone [Med. Phys. 36, 4547–4554 (2009)].Conclusions: D-caret{sub eq} and D{sub L}(0) can be calculated using the alternative approach. The authors have provided the required ?(CTDI{sub 100}) and H(L) data in two previous papers. R{sub 100} is presented for a majority of multidetector CT scanners currently on the market, and can be easily assessed for other CT scanners or operating conditions not covered in this study. The central to peripheral D{sub eq} ratio is about 1.50 and 1.12 times of R{sub 100} for the 32- and 16-cm diameter PMMA phantom, respectively.

Li, Xinhua; Zhang, Da; Liu, Bob [Division of Diagnostic Imaging Physics and Webster Center for Advanced Research and Education in Radiation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)] [Division of Diagnostic Imaging Physics and Webster Center for Advanced Research and Education in Radiation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)

2013-08-15T23:59:59.000Z

129

Scanner position sensor for an integrated laser/film rangefiner  

SciTech Connect (OSTI)

In an integrated laser/FLIR rangefinder a scanner position sensor comprising an LED of the array of LEDs of a forward looking infrared (FLIR) system, a reticle grating located at the image plane of LED optical path and a silicon detector positioned to receive the light passing through the reticle grating for producing a plurality of signals in response to light passing through each grating slot. One of the signals is selected for the synchronization logic for controlling the charging and firing of the laser. If there is no range return a second signal is selected for adjusting the position of the timing pulse.

Berdanier, B. N.

1985-09-24T23:59:59.000Z

130

High contrast, CdTe portal scanner for radiation therapy  

SciTech Connect (OSTI)

This paper reports on one of the most promising new technologies for improving the qualify of radiation therapy, the use of real-time systems to produce portal images. In the authors' approach, they are constructing a linear array of 256 CdTe photovoltaic detectors attached to a very compact linear scanner, all of which will be mounted in a cassette shaped package to be located under the patient table. The high stopping power of the CdTe allows a high contrast image to be made using only a single Linac pulse per line, resulting in a high contrast image in under 5 seconds.

Entine, G.; Squillante, M.R.; Hahn, R.; Cirignano, L.J.; McGann, W. (Radiation Monitoring Devices, Inc., Watertown, MA (United States)); Biggs, P.J. (Massachusetts General Hospital, Boston, MA (United States))

1992-10-01T23:59:59.000Z

131

E-Print Network 3.0 - active neutron scanner Sample Search Results  

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

Search Sample search results for: active neutron scanner Page: << < 1 2 3 4 5 > >> 1 The Neutron Scattering Society www.neutronscattering.org Summary: techniques; and service and...

132

E-Print Network 3.0 - aircraft scanner mapping Sample Search...  

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

Technical University of Denmark WindScanner... .eu Envisioned new RI European Centre for Wind Energy Research in Atmospheric Turbulent Flow "The ... Source: Ris National...

133

E-Print Network 3.0 - airborne laser scanner Sample Search Results  

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

Powered by Explorit Topic List Advanced Search Sample search results for: airborne laser scanner Page: << < 1 2 3 4 5 > >> 1 International Conference on Machine Control &...

134

Line-source based X-ray Tomography Deepak Bharkhada1,2  

E-Print Network [OSTI]

resolution is limited by the time necessary to acquire sufficient projection data over an angular range. #12 Science, Wake Forest University, Winston-Salem, NC 27109 Abstract: Current computed tomography (CT reconstruction technique (SART) algorithm for image reconstruction from projection data generated by an x

Plemmons, Robert J.

135

CT volumetry of the skeletal tissues  

SciTech Connect (OSTI)

Computed tomography (CT) is an important and widely used modality in the diagnosis and treatment of various cancers. In the field of molecular radiotherapy, the use of spongiosa volume (combined tissues of the bone marrow and bone trabeculae) has been suggested as a means to improve the patient-specificity of bone marrow dose estimates. The noninvasive estimation of an organ volume comes with some degree of error or variation from the true organ volume. The present study explores the ability to obtain estimates of spongiosa volume or its surrogate via manual image segmentation. The variation among different segmentation raters was explored and found not to be statistically significant (p value >0.05). Accuracy was assessed by having several raters manually segment a polyvinyl chloride (PVC) pipe with known volumes. Segmentation of the outer region of the PVC pipe resulted in mean percent errors as great as 15% while segmentation of the pipe's inner region resulted in mean percent errors within {approx}5%. Differences between volumes estimated with the high-resolution CT data set (typical of ex vivo skeletal scans) and the low-resolution CT data set (typical of in vivo skeletal scans) were also explored using both patient CT images and a PVC pipe phantom. While a statistically significant difference (p value <0.002) between the high-resolution and low-resolution data sets was observed with excised femoral heads obtained following total hip arthroplasty, the mean difference between high-resolution and low-resolution data sets was found to be only 1.24 and 2.18 cm{sup 3} for spongiosa and cortical bone, respectively. With respect to differences observed with the PVC pipe, the variation between the high-resolution and low-resolution mean percent errors was a high as {approx}20% for the outer region volume estimates and only as high as {approx}6% for the inner region volume estimates. The findings from this study suggest that manual segmentation is a reasonably accurate and reliable means for the in vivo estimation of spongiosa volume. This work also provides a foundation for future studies where spongiosa volumes are estimated by various raters in more comprehensive CT data sets.

Brindle, James M.; Alexandre Trindade, A.; Pichardo, Jose C.; Myers, Scott L.; Shah, Amish P.; Bolch, Wesley E. [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States); Department of Statistics, University of Florida, Gainesville, Florida 32611 (United States); Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States); Department of Orthopaedics and Rehabilitation, University of Florida, Gainesville, Florida 32611 (United States); MD Anderson Cancer Center Orlando, Orlando, Florida 32806 (United States); Department of Nuclear and Radiological and Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States)

2006-10-15T23:59:59.000Z

136

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

SciTech Connect (OSTI)

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.

Walker, Gary V. [Department of Radiation Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Niikura, Naoki [Department of Breast and Endocrine Surgery, Tokai University School of Medicine, Kanagawa (Japan)] [Department of Breast and Endocrine Surgery, Tokai University School of Medicine, Kanagawa (Japan); Yang Wei [Department of Diagnostic Radiology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Diagnostic Radiology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rohren, Eric [Department of Nuclear Medicine, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Nuclear Medicine, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Valero, Vicente [Department of Breast Medical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Breast Medical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Woodward, Wendy A. [Department of Radiation Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Alvarez, Ricardo H. [Department of Breast Medical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Breast Medical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lucci, Anthony [Department of Surgical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Surgical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ueno, Naoto T. [Department of Breast Medical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Breast Medical Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Buchholz, Thomas A., E-mail: tbuchhol@mdanderson.org [Department of Radiation Oncology, Morgan Welch Inflammatory Breast Cancer Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

2012-08-01T23:59:59.000Z

137

REGOLAMENTO ed ISTRUZIONI per l'utilizzo delle fotocopiatrici/stampanti/scanner  

E-Print Network [OSTI]

(XEROX 7232) possono essere utilizzate oltre che come fotocopiatrici e scanner, anche come stampanti 7232, che si trova presso la portineria di ingresso al Palazzo San Niccolò può stampare a colori e;FOTOCOPIATRICE STAMPANTE SCANNER XEROX WORKCENTRE 7232 (portineria ingresso) Login: Inserire il proprio numero o

Garulli, Andrea

138

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

E-Print Network [OSTI]

A Laser Range Scanner Designed for Minimum Calibration Complexity James Davis, Xing Chen Computer are a popular method for acquiring three-dimensional geometry due to their accuracy and robustness. Maximizing a two camera range scanner design, specifically chosen to minimize calibration complexity and cost

Stanford University

139

Hysteresis Modeling and Inverse Feedforward Control of an AFM Piezoelectric Scanner Based on Nano Images  

E-Print Network [OSTI]

Hysteresis Modeling and Inverse Feedforward Control of an AFM Piezoelectric Scanner Based on Nano of micro/nano technology. As a critical part of AFM system, the piezoelectric scanner exists many defects in this paper possess a good performance for AFM nano imaging. Index Terms-- Hysteresis modeling, feedforward

Li, Yangmin

140

Portable Digital Radiography and Computed Tomography Manual  

SciTech Connect (OSTI)

This user manual describes the function and use of the portable digital radiography and computed tomography (DRCT) scanner. The manual gives a general overview of x-ray imaging systems along with a description of the DRCT system. An inventory of the all the system components, organized by shipping container, is also included. In addition, detailed, step-by-step procedures are provided for all of the exercises necessary for a novice user to successfully collect digital radiographs and tomographic images of an object, including instructions on system assembly and detector calibration and system alignment. There is also a short section covering the limited system care and maintenance needs. Descriptions of the included software packages, the DRCT Digital Imager used for system operation, and the DRCT Image Processing Interface used for image viewing and tomographic data reconstruction are given in the appendixes. The appendixes also include a cheat sheet for more experienced users, a listing of known system problems and how to mitigate them, and an inventory check-off sheet suitable for copying and including with the machine for shipment purposes.

Not Available

2007-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Comparison of Fusion Imaging Using a Combined SPECT/CT System and Intra-arterial CT: Assessment of Drug Distribution by an Implantable Port System in Patients Undergoing Hepatic Arterial Infusion Chemotherapy  

SciTech Connect (OSTI)

Hepatic arterial infusion (HAI) chemotherapy is effective for treating primary and metastatic carcinoma of the liver. We compared the perfusion patterns of HAI chemotherapy on intra-arterial port-catheter computed tomography (iapc-CT) and fused images obtained with a combined single-photon emission computed tomography/computed tomography (SPECT/CT) system. We studied 28 patients with primary or metastatic carcinoma of the liver who bore an implantable HAI port system. All underwent abdominal SPECT using Tc-99m-MAA (185 Mbq); the injection rate was 1 mL/min, identical to the chemotherapy infusion rate, and 0.5 mL/sec for iapc-CT. Delivery was through an implantable port. We compared the intrahepatic perfusion (IHP) and extrahepatic perfusion (EHP) patterns of HAI chemotherapy on iapc-CT images and fused images obtained with a combined SPECT/CT system. In 23 of 28 patients (82%), IHP patterns on iapc-CT images and fused images were identical. In 5 of the 28 patients (18%), IHP on fusion images was different from IHP on iapc-CT images. EHP was seen on fused images in 12 of the 28 patients (43%) and on iapc-CT images in 8 patients (29%). In 17 patients (61%), upper gastrointestinal endoscopy revealed gastroduodenal mucosal lesions. EHP was revealed on fused images in 10 of these patients; 9 of them manifested gastroduodenal toxicity at the time of subsequent HAI chemotherapy. Fusion imaging using the combined SPECT/CT system reflects the actual distribution of the infused anticancer agent. This information is valuable not only for monitoring adequate drug distribution but also for avoiding potential extrahepatic complications.

Ikeda, Osamu, E-mail: osamu-3643ik@do9.enjoy.ne.jp; Kusunoki, Shinichiroh; Nakaura, Takeshi; Shiraishi, Shinya; Kawanaka, Kouichi; Tomiguchi, Seiji; Yamashita, Yasuyuki [Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Department of Diagnostic Radiology (Japan); Takamori, Hiroshi; Chikamoto, Akira; Kanemitsu, Keiichiro [Kumamoto University Graduate School of Medical and Pharmaceutical Sciences, Gastroenterological Surgery (Japan)

2006-06-15T23:59:59.000Z

142

Geometric Tomography: A Limited-View Approach for Computed Tomography  

E-Print Network [OSTI]

Geometric Tomography: A Limited-View Approach for Computed Tomography Peter B. Noël, Jinhui Xu Keywords Computed Tomography; Geometric Compressed Sensing; Topo- logical Peeling. ABSTRACT Computed to generate 3D data, denoted f, directly from projec- tions, denoted g. Thus, the projection relationship can

Corso, Jason J.

143

X-ray Computed Tomography of coal: Final report  

SciTech Connect (OSTI)

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.

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

1986-12-01T23:59:59.000Z

144

Computed tomography of the thorax: a status report  

SciTech Connect (OSTI)

Computed tomography (CT) of the thorax shows early promise of important diagnostic advances. We believe that CT often provides information superior to that provided by standard roentgenographic techniques, is capable of significantly influencing patient management, and in selected instances, offers unique information not available by other methods. Computed tomography permits the imaging of mediastinal structures not possible with conventional roentgenographic methods and can diagnose with certainty benign mediastinal conditions such as pericardial cysts and focal or diffuse accumulations of fat. It is ideal for detecting pleural abnormalities and for displaying underlying parenchymal disease in patients with complex pleuroparenchymal shadows on conventional films. Pulmonary metastases unseen on the plain chest film can be detected with greater sensitivity than by any other method. Future applications of CT include the staging of mediastinal lymph nodes in bronchogenic carcinoma, the differentiation of benign from malignant solitary pulmonary nodules, and the detection of diffuse diseases involving the lung parenchyma before they are visible on conventional roentgenograms. Additional clinical experience and careful studies will determine CTs final role as a diagnostic aid for disorders of the thorax.

Pugatch, R.D.; Faling, L.J.

1981-11-01T23:59:59.000Z

145

ContaCt  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to User Group andCompositionalInitial Validation andPWRContaCt The nuclear

146

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou areDowntown Site -MiamiYVE r.x-L* d! CT NC0 - i , ,.

147

Multi-GPU parallelization of a 3D Bayesian CT algorithm and its application on real foam reconstruction with incomplete  

E-Print Network [OSTI]

Tomography (CT) [1,2]. The limits of these methods appear when the number of projections is small, and for example, the data set are not complete due to the limited acquistion time. In this specific context is the computation time and especially for projection and backprojection steps. In this study, first we show how we

Paris-Sud XI, Université de

148

Mechanical optimisation of a high-precision fast wire scanner at CERN  

E-Print Network [OSTI]

Wire scanners are instruments used to measure the transverse beam prole in particle accelerators by passing a thin wire through the particle beam. To avoid the issues of vacuum leakage through the bellows and wire failure related to current designs of wire scanners, a new concept for a wire scanner has been developed at CERN. This design has all moving parts inside the beam vacuum and has a nominal wire scanning speed of 20 m/s. The demands on the design associated with this together with the high precision requirements create a need for\

Samuelsson, Sebastian; Veness, Raymond

149

Wire Scanner Beam Profile Measurements for the LANSCE Facility  

SciTech Connect (OSTI)

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.

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

2012-05-15T23:59:59.000Z

150

Neutron computed tomography  

E-Print Network [OSTI]

to make the Donner Algorithms run. TABLE OF CONTEliiTS CHAPTF. . R I NEI. TRON RADIOGRAPHY . I. 1 Background . I. 2 Theory . l. 3 Neutron Beam Characterization I. 4 Image Detectors . COMPI'TED TOMOGRAPHY . Il I Background . II. 2 Notation II. 3... data which is generated by rays traveling (and being attenuated) in straight lines. However in neutron radiography, what is measured is, to most extents, the levels of neutrons which are not attenuated. Neutrons are particles. They scatter...

Russell, Clifford Marlow

2012-06-07T23:59:59.000Z

151

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

E-Print Network [OSTI]

IEEE Transactions on Automation Science and Engineering Compensation of Scanner Creep uncertainties associated with creep and hysteresis, and supports automated, computer-controlled manipulation) and by automation, which bypasses the time- consuming

Southern California, University of

152

E-Print Network 3.0 - assisted laser scanner Sample Search Results  

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

Powered by Explorit Topic List Advanced Search Sample search results for: assisted laser scanner Page: << < 1 2 3 4 5 > >> 1 Accuracy of 3D Scanning Technologies in a Face...

153

Enhanced local tomography  

DOE Patents [OSTI]

Local tomography is enhanced 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. In a first method for evaluating the value of the discontinuity, the relative attenuation data is inputted to a local tomography function .function..sub..LAMBDA. to define the location S of the density discontinuity. The asymptotic behavior of .function..sub..LAMBDA. is determined in a neighborhood of S, and the value for the discontinuity is estimated from the asymptotic behavior of .function..sub..LAMBDA.. In a second method for evaluating the value of the discontinuity, a gradient value for a mollified local tomography function .gradient..function..sub..LAMBDA..epsilon. (x.sub.ij) is determined along the discontinuity; and the value of the jump of the density across the discontinuity curve (or surface) S is estimated from the gradient values.

Katsevich, Alexander J. (Los Alamos, NM); Ramm, Alexander G. (Manhattan, KS)

1996-01-01T23:59:59.000Z

154

Generalized local emission tomography  

DOE Patents [OSTI]

Emission tomography enables locations and values of internal isotope density distributions to be determined from radiation emitted from the whole object. In the method for locating the values of discontinuities, the intensities of radiation emitted from either the whole object or a region of the object containing the discontinuities are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the isotope density discontinuity. The asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) is determined in a neighborhood of S, and the value for the discontinuity is estimated from the asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) knowing pointwise values of the attenuation coefficient within the object. In the method for determining the location of the discontinuity, the intensities of radiation emitted from an object are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the density discontinuity and the location .GAMMA. of the attenuation coefficient discontinuity. Pointwise values of the attenuation coefficient within the object need not be known in this case.

Katsevich, Alexander J. (Los Alamos, NM)

1998-01-01T23:59:59.000Z

155

Link between Tomography and Copula1 Doriano-Boris Pougaza, Ali Mohammad-Djafari, Jean-Francois Bercher2  

E-Print Network [OSTI]

in Computed To- mography (CT) is to reconstruct an image from its projections. In the bivariate case of Environmental Data [2, 3]. Recently, in17 Computational Biology, copulas were used for the reconstructionLink between Tomography and Copula1 Doriano-Boris Pougaza, Ali Mohammad-Djafari, Jean

Bercher, Jean-François

156

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

SciTech Connect (OSTI)

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.

Hullar, Ted; Anastasio, Cort, E-mail: canastasio@ucdavis.edu [Department of Land, Air, and Water Resources, University of California, Davis, California 95616 (United States)] [Department of Land, Air, and Water Resources, University of California, Davis, California 95616 (United States); Paige, David F. [Paige Instruments, Woodland, California 95776 (United States)] [Paige Instruments, Woodland, California 95776 (United States); Rowland, Douglas J. [Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California, Davis, California 95616 (United States)] [Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California, Davis, California 95616 (United States)

2014-04-15T23:59:59.000Z

157

An indirect transmission measurement-based spectrum estimation method for computed tomography  

E-Print Network [OSTI]

The characteristics of an x-ray spectrum can greatly influence imaging and related tasks. In practice, due to the pile-up effect of the detector, it's difficult to directly measure the spectrum of a CT scanner using an energy resolved detector. An alternative solution is to estimate the spectrum using transmission measurements with a step phantom or other CT phantom. In this work, we present a new spectrum estimation method based on indirect transmission measurement and model spectra mixture approach. The estimated x-ray spectrum was expressed as weighted summation of a set of model spectra, which can significantly reduce the degrees of freedom (DOF) of the spectrum estimation problem. Next, an estimated projection can be calculated with the assumed spectrum. By iteratively updating the unknown weights, we minimized the difference between the estimated projection data and the raw projection data. The final spectrum was calculated with these calibrated weights and the model spectra. Both simulation and experim...

Zhao, Wei; Schafer, Sebastian; Royalty, Kevin

2015-01-01T23:59:59.000Z

158

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

SciTech Connect (OSTI)

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.

Schrapp, Michael J. [Siemens AG, CT Munich, Germany and Physics Department E21, Technical University of Munich, Munich (Germany)] [Siemens AG, CT Munich, Germany and Physics Department E21, Technical University of Munich, Munich (Germany); Herman, Gabor T. [Department of Computer Science, The Graduate Center, City University of New York, New York, New York 10016 (United States)] [Department of Computer Science, The Graduate Center, City University of New York, New York, New York 10016 (United States)

2014-05-15T23:59:59.000Z

159

Optical Tomography in two dimensions  

E-Print Network [OSTI]

so-called diffused tomography [SGKZ]. Other areas of applications are atmospheric remote sensing [Bi], nuclear physics (see [MC] for a review), etc. We describe ...

160

Radial reflection diffraction tomography  

DOE Patents [OSTI]

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.

Lehman, Sean K.

2012-12-18T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Positron Emission Tomography (PET)  

DOE R&D Accomplishments [OSTI]

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.

Welch, M. J.

1990-01-00T23:59:59.000Z

162

Atom Probe Tomography | EMSL  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone byDear Friend,Arthur J. NozikAtom Probe Tomography Atom Probe

163

Thermoacoustic tomography with variable sound speed  

E-Print Network [OSTI]

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

2009-10-26T23:59:59.000Z

164

Electrical Impedance Tomography Liliana Borcea  

E-Print Network [OSTI]

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

Borcea, Liliana

165

Brachial Plexus Injury from CT-Guided RF Ablation Under General Anesthesia  

SciTech Connect (OSTI)

Brachial plexus injury in a patient under general anesthesia (GA) is not uncommon, despite careful positioning and, particularly, awareness of the possibility. The mechanism of injury is stretching and compression of the brachial plexus over a prolonged period. Positioning the patient within the computed tomography (CT) gantry for abdominal or chest procedures can simulate a surgical procedure, particularly when GA is used. The potential for brachial plexus injury is increased if the case is prolonged and the patient's arms are raised above the head to avoid CT image degradation from streak artifacts. We report a case of profound brachial plexus palsy following a CT-guided radiofrequency ablation procedure under GA. Fortunately, the patient recovered completely. We emphasize the mechanism of injury and detail measures to combat this problem, such that radiologists are aware of this potentially serious complication.

Shankar, Sridhar, E-mail: shankars@ummhc.org; Sonnenberg, Eric van; Silverman, Stuart G.; Tuncali, Kemal [Brigham and Women's Hospital, Department of Radiology (United States); Flanagan, Hugh L. [Brigham and Women's Hospital, Department of Anesthesia (United States); Whang, Edward E. [Brigham and Women's Hospital, Department of Surgery (United States)

2005-06-15T23:59:59.000Z

166

Prior-based artifact correction (PBAC) in computed tomography  

SciTech Connect (OSTI)

Purpose: Image quality in computed tomography (CT) often suffers from artifacts which may reduce the diagnostic value of the image. In many cases, these artifacts result from missing or corrupt regions in the projection data, e.g., in the case of metal, truncation, and limited angle artifacts. The authors propose a generalized correction method for different kinds of artifacts resulting from missing or corrupt data by making use of available prior knowledge to perform data completion. Methods: The proposed prior-based artifact correction (PBAC) method requires prior knowledge in form of a planning CT of the same patient or in form of a CT scan of a different patient showing the same body region. In both cases, the prior image is registered to the patient image using a deformable transformation. The registered prior is forward projected and data completion of the patient projections is performed using smooth sinogram inpainting. The obtained projection data are used to reconstruct the corrected image. Results: The authors investigate metal and truncation artifacts in patient data sets acquired with a clinical CT and limited angle artifacts in an anthropomorphic head phantom data set acquired with a gantry-based flat detector CT device. In all cases, the corrected images obtained by PBAC are nearly artifact-free. Compared to conventional correction methods, PBAC achieves better artifact suppression while preserving the patient-specific anatomy at the same time. Further, the authors show that prominent anatomical details in the prior image seem to have only minor impact on the correction result. Conclusions: The results show that PBAC has the potential to effectively correct for metal, truncation, and limited angle artifacts if adequate prior data are available. Since the proposed method makes use of a generalized algorithm, PBAC may also be applicable to other artifacts resulting from missing or corrupt data.

Heußer, Thorsten, E-mail: thorsten.heusser@dkfz-heidelberg.de; Brehm, Marcus [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Ritschl, Ludwig [Ziehm Imaging GmbH, Donaustraße 31, 90451 Nürnberg (Germany)] [Ziehm Imaging GmbH, Donaustraße 31, 90451 Nürnberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, Friedrich–Alexander–University (FAU) of Erlangen–Nürnberg, Henkestraße 91, 91052 Erlangen (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, Friedrich–Alexander–University (FAU) of Erlangen–Nürnberg, Henkestraße 91, 91052 Erlangen (Germany)

2014-02-15T23:59:59.000Z

167

Comparison of MRI-based and CT/MRI fusion-based postimplant dosimetric analysis of prostate brachytherapy  

SciTech Connect (OSTI)

Purpose: The aim of this study was to compare the outcomes between magnetic resonance imaging (MRI)-based and computed tomography (CT)/MRI fusion-based postimplant dosimetry methods in permanent prostate brachytherapy. Methods and Materials: Between October 2004 and March 2006, a total of 52 consecutive patients with prostate cancer were treated by brachytherapy, and postimplant dosimetry was performed using CT/MRI fusion. The accuracy and reproducibility were prospectively compared between MRI-based dosimetry and CT/MRI fusion-based dosimetry based on the dose-volume histogram (DVH) related parameters as recommended by the American Brachytherapy Society. Results: The prostate volume was 15.97 {+-} 6.17 cc (mean {+-} SD) in MRI-based dosimetry, and 15.97 {+-} 6.02 cc in CT/MRI fusion-based dosimetry without statistical difference. The prostate V100 was 94.5% and 93.0% in MRI-based and CT/MRI fusion-based dosimetry, respectively, and the difference was statistically significant (p = 0.002). The prostate D90 was 119.4% and 114.4% in MRI-based and CT/MRI fusion-based dosimetry, respectively, and the difference was statistically significant (p = 0.004). Conclusion: Our current results suggested that, as with fusion images, MR images allowed accurate contouring of the organs, but they tended to overestimate the analysis of postimplant dosimetry in comparison to CT/MRI fusion images. Although this MRI-based dosimetric discrepancy was negligible, MRI-based dosimetry was acceptable and reproducible in comparison to CT-based dosimetry, because the difference between MRI-based and CT/MRI fusion-based results was smaller than that between CT-based and CT/MRI fusion-based results as previously reported.

Tanaka, Osamu [Department of Radiology, Gifu University School of Medicine, Gifu City (Japan)]. E-mail: osa-mu@umin.ac.jp; Hayashi, Shinya [Department of Radiology, Gifu University School of Medicine, Gifu City (Japan); Matsuo, Masayuki [Department of Radiology, Gifu University School of Medicine, Gifu City (Japan); Sakurai, Kota [Department of Radiology, Gifu University School of Medicine, Gifu City (Japan); Department of Urology, Gifu University School of Medicine, Gifu City (Japan); Nakano, Masahiro [Department of Urology, Gifu University School of Medicine, Gifu City (Japan); Maeda, Sunaho [Department of Radiology, Gifu University School of Medicine, Gifu City (Japan); Kajita, Kimihiro R.T. [Department of Radiology, Gifu University School of Medicine, Gifu City (Japan); Deguchi, Takashi [Department of Urology, Gifu University School of Medicine, Gifu City (Japan); Hoshi, Hiroaki [Department of Radiology, Gifu University School of Medicine, Gifu City (Japan)

2006-10-01T23:59:59.000Z

168

Preventive maintenance system for the photomultiplier detector blocks of PET scanners  

DOE Patents [OSTI]

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.

Levy, A.V.; Warner, D.

1995-01-24T23:59:59.000Z

169

Preventive maintenance system for the photomultiplier detector blocks of pet scanners  

DOE Patents [OSTI]

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.

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

1995-01-24T23:59:59.000Z

170

Upright cone beam CT imaging using the onboard imager  

SciTech Connect (OSTI)

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.

Fave, Xenia, E-mail: xjfave@mdanderson.org; Martin, Rachael [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States)] [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); Yang, Jinzhong; Balter, Peter; Court, Laurence [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)] [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Carvalho, Luis [Varian Medical Systems, Zug 6303 (Switzerland)] [Varian Medical Systems, Zug 6303 (Switzerland); Pan, Tinsu [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)] [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

2014-06-15T23:59:59.000Z

171

SU-E-J-113: The Influence of Optimizing Pediatric CT Simulator Protocols On the Treatment Dose Calculation in Radiotherapy  

SciTech Connect (OSTI)

Purpose: To investigate the possibility of applying optimized scanning protocols for pediatric CT simulation by quantifying the dosimetric inaccuracy introduced by using a fixed HU to density conversion. Methods: The images of a CIRS electron density reference phantom (Model 062) were acquired by a Siemens CT simulator (Sensation Open) using the following settings of tube voltage and beam current: 120 kV/190mA (the reference protocol used to calibrate CT for our treatment planning system (TPS)); Fixed 190mA combined with all available kV: 80, 100, and 140; fixed 120 kV and various current from 37 to 444 mA (scanner extremes) with interval of 30 mA. To avoid the HU uncertainty of point sampling in the various inserts of known electron densities, the mean CT numbers of the central cylindrical volume were calculated using DICOMan software. The doses per 100 MU to the reference point (SAD=100cm, Depth=10cm, Field=10X10cm, 6MV photon beam) in a virtual cubic phantom (30X30X30cm) were calculated using Eclipse TPS (calculation model: AcurosXB-11031) by assigning the CT numbers to HU of typical materials acquired by various protocols. Results: For the inserts of densities less than muscle, CT number fluctuations of all protocols were within the tolerance of 10 HU as accepted by AAPM-TG66. For more condensed materials, fixed kV yielded stable HU with any mA combination where largest disparities were found in 1750mg/cc insert: HU{sub reference}=1801(106.6cGy), HU{sub minimum}=1799 (106.6cGy, error{sub dose}=0.00%), HU{sub maximum}=1815 (106.8cGy, error{sub dose}=0.19%). Yet greater disagreements were observed with increasing density when kV was modified: HU{sub minimum}=1646 (104.5cGy, error{sub dose}=- 1.97%), HU{sub maximum}=2487 (116.4cGy, error{sub dose}=9.19%) in 1750mg/cc insert. Conclusion: Without affecting treatment dose calculation, personalized mA optimization of CT simulator can be conducted by fixing kV for a better cost-effectiveness of imaging dose and quality especially for children. Unless recalibrated, kV should be constant for all anatomical sites if diagnostic CT scanner is used as a simulator. This work was partially supported by Capital Medical Development Scientific Research Fund of China.

Zhang, Y; Zhang, J; Hu, Q; Tie, J; Wu, H [Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiotherapy, Peking University Cancer Hospital ' Institute, Beijing (China); Deng, J [Department of Therapeutic Radiology, Yale University, New Haven, CT (United States)

2014-06-01T23:59:59.000Z

172

Relationship of brain imaging with radionuclides and with x-ray computed tomography  

SciTech Connect (OSTI)

Because of high sensitivity and specificity for altered local cerebral structure, x-ray computed tomography (CT) is the preferred initial diagnostic imaging study under most circumstances when cerebral disease is suspected. CT has no competitor for detecting fresh intracerebral hemorrhage. Radionuclide imaging (RN) scan is preferred when relative perfusion is to be assessed, in patients allergic to contrast media, and when an adequate CT study is not technically possible. (RN) plays an important complementary role to CT, especially for patients suspected of subacute or chronic subdura hematoma, cerebral infarction, arteriovenous malformations, meningitis, encephalitis, normal pressure hydrocephalus, or when CT findings are inconclusive. When CT is not available, RN serves as a good screening study for suspected cerebral tumor, infection, recent infarction, arteriovenous malformation, and chronic subdural hematoma. Future improvement in radionuclide imaging by means of emission composition potential. The compound plating approacl threshold for all the investigated transistors and fast neutron spectra lies within the raal. The value of the potential slightly changes with the coordinate change in this region, i.e. the charge on a collecting electrode is not practically guided up to a certain moment of time during the movement of nonequilibrium carriers.

Kuhl, D.E.

1981-03-03T23:59:59.000Z

173

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

SciTech Connect (OSTI)

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.

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

2012-04-15T23:59:59.000Z

174

Computed tomography of coals. Quarterly technical progress report No. 1, August 16, 1982-November 28, 1982  

SciTech Connect (OSTI)

The purpose of this contract is to examine the utility and advantages of x-ray computed tomography (CT) for investigating the structure within coal and the changes that occur in these structures during such processes as combustion and gasification. The CT technique is noninvasive and nondestructive. It can produce interior views of the coal and, with a data acquisition time of ca 9 seconds, can be used for following many coal processes in real time. This is the first in-depth study of the application of the x-ray tomography technique to the problems in coal utilization, and consequently, considerable time will be spent in the early stages of this contract in examining CT pictures of coal and relating them to more conventional petrographic and mineral analyses. This phase of the work is being undertaken in Task 1 of the contract and is reported for this period. Building on this foundation, the succeeding tasks will follow changes in the coal structure during reaction. The first series of CT experiments is scheduled to take place on December 11-13, 1982, at the General Electric Company, Medical Systems Operation, Milwaukee, Wisconsin. 4 figures, 1 table.

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

1982-01-01T23:59:59.000Z

175

3D objects visualization for remote interactive medical applications Johan Montagnat, Eduardo Davila, Isabelle E. Magnin  

E-Print Network [OSTI]

], such as Computed Tomography scanners (CT), Magnetic Resonance Imagers (MRI), Positon Emission To- mography scannersGrid project (EDG)1 although it is not limited to this architecture and it intends to provide a generic produced in health centers represent tremendous amounts of data spread over different places. Automatic

Paris-Sud XI, Université de

176

A multispectral scanner survey of the Salmon Site and surrounding area, Lamar County, Mississippi  

SciTech Connect (OSTI)

An airborne multispectral scanner survey was conducted over the Salmon Site and the surrounding area in Lamar County, Mississippi, on May 8, 1992. Twelve-channel daytime multispectral data were collected from altitudes of 2,000 feet, 4,000 feet, and 6,000 feet above ground level. Large-scale color photography was acquired simultaneously with the scanner data. Three different composite images have been prepared to demonstrate the digital image enhancement techniques that can be applied to the data. The data that were acquired offer opportunity for further standard and customized analysis based on any specific environmental characterization issues associated with this site.

Blohm, J.D.; Brewster, S.B. Jr.; Shines, J.E.

1994-06-01T23:59:59.000Z

177

High resolution cortical thickness measurement from clinical CT data G.M. Treece, A.H. Gee, P.M. Mayhew and K.E.S. Poole  

E-Print Network [OSTI]

) methods of assessing hip structure, most notably with multi-detector computed tomography, MDCT (Bouxsein and technically limited by thresholding errors caused by relatively low resolution data sets. Ideally, we wouldHigh resolution cortical thickness measurement from clinical CT data G.M. Treece, A.H. Gee, P

Drummond, Tom

178

Using Synchrotron X-Ray Nano-CT to Characterize SOFC Electrode Microstructures in Three-Dimensions at Operating Temperature  

SciTech Connect (OSTI)

In recent years, developments in tomography tools have provided unprecedented insight into the microstructure of electrodes for solid oxide fuel cells, enabling researchers to establish direct links between electrode microstructure and electrochemical performance. Here we present results of high resolution, synchrotron X-ray nano computed tomography experiments, which have enabled microstructural characterisation of a mixed ionic electronic conducting lanthanum strontium cobalt iron oxide (LSCF) cathode with sub-50nm resolution at operating temperature. Using the uniquely non-destructive nano-CT platform, it is possible to characterise microstructural evolution processes associated with heating and operation in-situ.

Shearing, P.R.; Bradley, R.S.; Gelb, J.; Lee, S.N.; Atkinson, A.; Withers, P.J.; Brandon, N.P. (Manchester); (Xradia); (ICL)

2012-01-20T23:59:59.000Z

179

Teleseismic transmission and reflection tomography  

E-Print Network [OSTI]

The aim of seismic tomography is to determine a model of Earth properties that best explain observed seismic data. In practice, the limitations placed on our observations and computational capabilities force us to make a ...

Burdick, Scott A. (Scott Anthony)

2014-01-01T23:59:59.000Z

180

Positron Emission Tomography/Computed Tomography Imaging of Residual Skull Base Chordoma Before Radiotherapy Using Fluoromisonidazole and Fluorodeoxyglucose: Potential Consequences for Dose Painting  

SciTech Connect (OSTI)

Purpose: To detect the presence of hypoxic tissue, which is known to increase the radioresistant phenotype, by its uptake of fluoromisonidazole (18F) (FMISO) using hybrid positron emission tomography/computed tomography (PET/CT) imaging, and to compare it with the glucose-avid tumor tissue imaged with fluorodeoxyglucose (18F) (FDG), in residual postsurgical skull base chordoma scheduled for radiotherapy. Patients and Methods: Seven patients with incompletely resected skull base chordomas were planned for high-dose radiotherapy (dose {>=}70 Gy). All 7 patients underwent FDG and FMISO PET/CT. Images were analyzed qualitatively by visual examination and semiquantitatively by computing the ratio of the maximal standardized uptake value (SUVmax) of the tumor and cerebellum (T/C R), with delineation of lesions on conventional imaging. Results: Of the eight lesion sites imaged with FDG PET/CT, only one was visible, whereas seven of nine lesions were visible on FMISO PET/CT. The median SUVmax in the tumor area was 2.8 g/mL (minimum 2.1; maximum 3.5) for FDG and 0.83 g/mL (minimum 0.3; maximum 1.2) for FMISO. The T/C R values ranged between 0.30 and 0.63 for FDG (median, 0.41) and between 0.75 and 2.20 for FMISO (median,1.59). FMISO T/C R >1 in six lesions suggested the presence of hypoxic tissue. There was no correlation between FMISO and FDG uptake in individual chordomas (r = 0.18, p = 0.7). Conclusion: FMISO PET/CT enables imaging of the hypoxic component in residual chordomas. In the future, it could help to better define boosted volumes for irradiation and to overcome the radioresistance of these lesions. No relationship was founded between hypoxia and glucose metabolism in these tumors after initial surgery.

Mammar, Hamid, E-mail: hamid.mammar@unice.fr [Radiation Oncology Department, Antoine Lacassagne Center, Nice (France) [Radiation Oncology Department, Antoine Lacassagne Center, Nice (France); CNRS-UMR 6543, Institute of Developmental Biology and Cancer, University of Nice Sophia Antipolis, Nice (France); Kerrou, Khaldoun; Nataf, Valerie [Department of Nuclear Medicine and Radiopharmacy, Tenon Hospital, and University Pierre et Marie Curie, Paris (France)] [Department of Nuclear Medicine and Radiopharmacy, Tenon Hospital, and University Pierre et Marie Curie, Paris (France); Pontvert, Dominique [Proton Therapy Center of Orsay, Curie Institute, Paris (France)] [Proton Therapy Center of Orsay, Curie Institute, Paris (France); Clemenceau, Stephane [Department of Neurosurgery, Pitie-Salpetriere Hospital, Paris (France)] [Department of Neurosurgery, Pitie-Salpetriere Hospital, Paris (France); Lot, Guillaume [Department of Neurosurgery, Adolph De Rothschild Foundation, Paris (France)] [Department of Neurosurgery, Adolph De Rothschild Foundation, Paris (France); George, Bernard [Department of Neurosurgery, Lariboisiere Hospital, Paris (France)] [Department of Neurosurgery, Lariboisiere Hospital, Paris (France); Polivka, Marc [Department of Pathology, Lariboisiere Hospital, Paris (France)] [Department of Pathology, Lariboisiere Hospital, Paris (France); Mokhtari, Karima [Department of Pathology, Pitie-Salpetriere Hospital, Paris (France)] [Department of Pathology, Pitie-Salpetriere Hospital, Paris (France); Ferrand, Regis; Feuvret, Loiec; Habrand, Jean-louis [Proton Therapy Center of Orsay, Curie Institute, Paris (France)] [Proton Therapy Center of Orsay, Curie Institute, Paris (France); Pouyssegur, Jacques; Mazure, Nathalie [CNRS-UMR 6543, Institute of Developmental Biology and Cancer, University of Nice Sophia Antipolis, Nice (France)] [CNRS-UMR 6543, Institute of Developmental Biology and Cancer, University of Nice Sophia Antipolis, Nice (France); Talbot, Jean-Noeel [Department of Nuclear Medicine and Radiopharmacy, Tenon Hospital, and University Pierre et Marie Curie, Paris (France)] [Department of Nuclear Medicine and Radiopharmacy, Tenon Hospital, and University Pierre et Marie Curie, Paris (France)

2012-11-01T23:59:59.000Z

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181

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

182

Adaptive mean filtering for noise reduction in CT polymer gel dosimetry  

SciTech Connect (OSTI)

X-ray computed tomography (CT) as a method of extracting 3D dose information from irradiated polymer gel dosimeters is showing potential as a practical means to implement gel dosimetry in a radiation therapy clinic. However, the response of CT contrast to dose is weak and noise reduction is critical in order to achieve adequate dose resolutions with this method. Phantom design and CT imaging technique have both been shown to decrease image noise. In addition, image postprocessing using noise reduction filtering techniques have been proposed. This work evaluates in detail the use of the adaptive mean filter for reducing noise in CT gel dosimetry. Filter performance is systematically tested using both synthetic patterns mimicking a range of clinical dose distribution features as well as actual clinical dose distributions. Both low and high signal-to-noise ratio (SNR) situations are examined. For all cases, the effects of filter kernel size and the number of iterations are investigated. Results indicate that adaptive mean filtering is a highly effective tool for noise reduction CT gel dosimetry. The optimum filtering strategy depends on characteristics of the dose distributions and image noise level. For low noise images (SNR {approx}20), the filtered results are excellent and use of adaptive mean filtering is recommended as a standard processing tool. For high noise images (SNR {approx}5) adaptive mean filtering can also produce excellent results, but filtering must be approached with more caution as spatial and dose distortions of the original dose distribution can occur.

Hilts, Michelle; Jirasek, Andrew [Medical Physics, BC Cancer Agency-Vancouver Island Centre, Victoria, British Columbia, V8R6V5 (Canada); Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8W2Y2 (Canada)

2008-01-15T23:59:59.000Z

183

High-speed digitization readout of silicon photomultipliers for time of flight positron emission tomography  

SciTech Connect (OSTI)

We report on work to develop a system with about 100 picoseconds (ps) time resolution for time of flight positron emission tomography [TOF-PET]. The chosen photo detectors for the study were Silicon Photomultipliers (SiPM's). This study was based on extensive experience in studying timing properties of SiPM's. The readout of these devices used the commercial high speed digitizer DRS4. We applied different algorithms to get the best time resolution of 155 ps Guassian (sigma) for a LYSO crystal coupled to a SiPM. We consider the work as a first step in building a prototype TOF-PET module. The field of positron-emission-tomography (PET) has been rapidly developing. But there are significant limitations in how well current PET scanners can reconstruct images, related to how fast data can be acquired, how much volume they can image, and the spatial and temporal resolution of the generated photons. Typical modern scanners now include multiple rings of detectors, which can image a large volume of the patient. In this type of scanner, one can treat each ring as a separate detector and require coincidences only within the ring, or treat the entire region viewed by the scanner as a single 3 dimensional volume. This 3d technique has significantly better sensitivity since more photon pair trajectories are accepted. However, the scattering of photons within the volume of the patient, and the effect of random coincidences limits the technique. The advent of sub-nanosecond timing resolution detectors means that there is potentially much better rejection of scattered photon events and random coincidence events in the 3D technique. In addition, if the timing is good enough, then the origin of photons pairs can be determined better, resulting in improved spatial resolution - so called 'Time-of-Flight' PET, or TOF-PET. Currently a lot of activity has occurred in applications of SiPMs for TOF-PET. This is due to the devices very good time resolution, low profile, lack of high voltage needed, and their non-sensitivity to magnetic fields. While investigations into this technique have begun elsewhere, we feel that the extensive SiPM characterization and data acquisition expertise of Fermilab, and the historical in-depth research of PET imaging at University of Chicago will combine to make significant strides in this field. We also benefit by a working relationship with the SiPM producer STMicroelectronics (STM).

Ronzhin, A.; Los, S.; Martens, M.; Ramberg, E.; /Fermilab; Kim, H.; Chen, C.; Kao, C.; /Chicago U.; Niessen, K.; /SUNY, Buffalo; Zatserklyaniy, A.; /Puerto Rico U., Mayaguez; Mazzillo, M.; Carbone, B.; /SGS Thomson, Catania

2011-02-01T23:59:59.000Z

184

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

SciTech Connect (OSTI)

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.

Maloney, D.; Doggett, K.

1997-08-01T23:59:59.000Z

185

A glacier inventory for South Tyrol, Italy, based on airborne laser-scanner data  

E-Print Network [OSTI]

A glacier inventory for South Tyrol, Italy, based on airborne laser-scanner data Christoph KNOLL-mail: christoph.knoll@uibk.ac.at ABSTRACT. A new approach to glacier inventory, based on airborne laser supervision. Earlier inventories, from 1983 and 1997, are used to compare changes in area, volume

Kerschner, Hanns

186

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

187

TE Connectivity Finds Answers in Tomography  

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

TE Connectivity Finds Answers in Tomography TE Connectivity Finds Answers in Tomography Print Thursday, 22 August 2013 10:50 TE Connectivity is a world leader in connectivity-the...

188

SU-E-I-93: Improved Imaging Quality for Multislice Helical CT Via Sparsity Regularized Iterative Image Reconstruction Method Based On Tensor Framelet  

SciTech Connect (OSTI)

Purpose: Inspired by compressive sensing, sparsity regularized iterative reconstruction method has been extensively studied. However, its utility pertinent to multislice helical 4D CT for radiotherapy with respect to imaging quality, dose, and time has not been thoroughly addressed. As the beginning of such an investigation, this work carries out the initial comparison of reconstructed imaging quality between sparsity regularized iterative method and analytic method through static phantom studies using a state-of-art 128-channel multi-slice Siemens helical CT scanner. Methods: In our iterative method, tensor framelet (TF) is chosen as the regularization method for its superior performance from total variation regularization in terms of reduced piecewise-constant artifacts and improved imaging quality that has been demonstrated in our prior work. On the other hand, X-ray transforms and its adjoints are computed on-the-fly through GPU implementation using our previous developed fast parallel algorithms with O(1) complexity per computing thread. For comparison, both FDK (approximate analytic method) and Katsevich algorithm (exact analytic method) are used for multislice helical CT image reconstruction. Results: The phantom experimental data with different imaging doses were acquired using a state-of-art 128-channel multi-slice Siemens helical CT scanner. The reconstructed image quality was compared between TF-based iterative method, FDK and Katsevich algorithm with the quantitative analysis for characterizing signal-to-noise ratio, image contrast, and spatial resolution of high-contrast and low-contrast objects. Conclusion: The experimental results suggest that our tensor framelet regularized iterative reconstruction algorithm improves the helical CT imaging quality from FDK and Katsevich algorithm for static experimental phantom studies that have been performed.

Nam, H [Ewha Womans University, Seoul, Seoul (Korea, Republic of); Guo, M [Shanghai JiaoTong University, Shanghai, Shanghai (China); Lee, K [Stanford University, Stanford, CA (United States); Li, R [Stanford University, Palo Alto, CA (United States); Xing, L [Stanford UniversitySchool of Medicine, Stanford, CA (United States); Gao, H [Shanghai Jiao Tong University, Shanghai, Shanghai (China)

2014-06-01T23:59:59.000Z

189

Thermoacoustic and Photoacoustic Tomography ... - Purdue University  

E-Print Network [OSTI]

Thermoacoustic and Photoacoustic Tomography with a variable continuous or discontinuous sound speed. Plamen Stefanov. Purdue University. Based on a ...

Plamen Stefanov

2010-11-09T23:59:59.000Z

190

Electron tomography of dislocation structures  

SciTech Connect (OSTI)

Recent developments in the application of electron tomography for characterizing microstructures in crystalline solids are described. The underlying principles for electron tomography are presented in the context of typical challenges in adapting the technique to crystalline systems and in using diffraction contrast imaging conditions. Methods for overcoming the limitations associated with the angular range, the number of acquired images, and uniformity of image contrast are introduced. In addition, a method for incorporating the real space coordinate system into the tomogram is presented. As the approach emphasizes development of experimental solutions to the challenges, the solutions developed and implemented are presented in the form of examples.

Liu, G.S.; House, S.D.; Kacher, J. [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, IL 61801 (United States); Tanaka, M.; Higashida, K. [Department of Materials Science and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Robertson, I.M., E-mail: irobertson@wisc.edu [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, IL 61801 (United States); Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2014-01-15T23:59:59.000Z

191

Discrete Tomography: A Neural Network Approach  

E-Print Network [OSTI]

Abstract Tomography tries to reconstruct an object from a number of projections in multiple directions quality reconstructions from a limited set of projections, while avoiding image artifacts that are often present in traditional approaches. 1 Introduction Tomography, or more especially computed tomography

Kosters, Walter

192

Drift-insensitive distributed calibration of probe microscope scanner in nanometer range: Real mode  

E-Print Network [OSTI]

A method is described intended for distributed calibration of a probe microscope scanner consisting in a search for a net of local calibration coefficients (LCCs) in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be defined by a unique set of scale factors. Feature-oriented scanning (FOS) methodology is used to implement the distributed calibration, which permits to exclude in situ the negative influence of thermal drift, creep and hysteresis on the obtained results. The sensitivity of LCCs to errors in determination of position coordinates of surface features forming the local calibration structure (LCS) is eliminated by performing multiple repeated measurements followed by building regression surfaces. There are no principle restrictions on the number of repeated LCS measurements. Possessing the calibration database enables correcting in one procedure all the spatial distortions caused by nonlinearity, nonorthogonality and spurious cro...

Lapshin, Rostislav V

2015-01-01T23:59:59.000Z

193

Drift-insensitive distributed calibration of probe microscope scanner in nanometer range: Approach description  

E-Print Network [OSTI]

A method is described intended for distributed calibration of a probe microscope scanner consisting in a search for a net of local calibration coefficients (LCCs) in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be defined by a unique set of scale factors. Feature-oriented scanning (FOS) methodology is used to implement the distributed calibration, which permits to exclude in situ the negative influence of thermal drift, creep and hysteresis on the obtained results. The sensitivity of LCCs to errors in determination of position coordinates of surface features forming the local calibration structure (LCS) is eliminated by performing multiple repeated measurements followed by building regression surfaces. There are no principle restrictions on the number of repeated LCS measurements. Possessing the calibration database enables correcting in one procedure all the spatial distortions caused by nonlinearity, nonorthogonality and spurious cro...

Lapshin, Rostislav V

2015-01-01T23:59:59.000Z

194

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

SciTech Connect (OSTI)

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.

Tewari, Sanjit O., E-mail: tewaris@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Petre, Elena N., E-mail: petree@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States); Osborne, Joseph, E-mail: osbornej@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States)] [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Sofocleous, Constantinos T., E-mail: sofoclec@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States)

2013-12-15T23:59:59.000Z

195

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

SciTech Connect (OSTI)

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.

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)

2013-05-15T23:59:59.000Z

196

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

E-Print Network [OSTI]

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.

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

2013-01-01T23:59:59.000Z

197

Julie A. Arruda R.T.(R) Woods Hole Oceanographic Institution Massachusetts Eye & Ear Infirmary  

E-Print Network [OSTI]

and necropsies of specimens. Equipment and Training: · Siemens Volume Zoom CT scanner · Siemens Emotion CT hours. Equipment and Training: · 3.0 T Philips Achieva MRI scanner · 1.5T Siemens Magnatom Vision MRI scanner · Siemens Sensation CT scanner · Siemens Volume Zoom CT scanner · Siemens Plus-4 CT scanner 1986

198

A Fast local Reconstruction algorithm by selective backprojection for Low-Dose in Dental Computed Tomography  

E-Print Network [OSTI]

High radiation dose in computed tomography (CT) scans increases the lifetime risk of cancer, which become a major clinical concern. The backprojection-filtration (BPF) algorithm could reduce radiation dose by reconstructing images from truncated data in a short scan. In dental CT, it could reduce radiation dose for the teeth by using the projection acquired in a short scan, and could avoid irradiation to other part by using truncated projection. However, the limit of integration for backprojection varies per PI-line, resulting in low calculation efficiency and poor parallel performance. Recently, a tent BPF (T-BPF) has been proposed to improve calculation efficiency by rearranging projection. However, the memory-consuming data rebinning process is included. Accordingly, the chose-BPF (C-BPF) algorithm is proposed in this paper. In this algorithm, the derivative of projection is backprojected to the points whose x coordinate is less than that of the source focal spot to obtain the differentiated backprojection...

Bin, Yan; Yu, Han; Feng, Zhang; Chao, Wang Xian; Lei, Li

2013-01-01T23:59:59.000Z

199

Earthquake Forecast via Neutrino Tomography  

E-Print Network [OSTI]

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 \

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

2011-03-29T23:59:59.000Z

200

Impact of Computed Tomography Image Quality on Image-Guided Radiation Therapy Based on Soft Tissue Registration  

SciTech Connect (OSTI)

Purpose: In image-guided radiation therapy (IGRT), different computed tomography (CT) modalities with varying image quality are being used to correct for interfractional variations in patient set-up and anatomy changes, thereby reducing clinical target volume to the planning target volume (CTV-to-PTV) margins. We explore how CT image quality affects patient repositioning and CTV-to-PTV margins in soft tissue registration-based IGRT for prostate cancer patients. Methods and Materials: Four CT-based IGRT modalities used for prostate RT were considered in this study: MV fan beam CT (MVFBCT) (Tomotherapy), MV cone beam CT (MVCBCT) (MVision; Siemens), kV fan beam CT (kVFBCT) (CTVision, Siemens), and kV cone beam CT (kVCBCT) (Synergy; Elekta). Daily shifts were determined by manual registration to achieve the best soft tissue agreement. Effect of image quality on patient repositioning was determined by statistical analysis of daily shifts for 136 patients (34 per modality). Inter- and intraobserver variability of soft tissue registration was evaluated based on the registration of a representative scan for each CT modality with its corresponding planning scan. Results: Superior image quality with the kVFBCT resulted in reduced uncertainty in soft tissue registration during IGRT compared with other image modalities for IGRT. The largest interobserver variations of soft tissue registration were 1.1 mm, 2.5 mm, 2.6 mm, and 3.2 mm for kVFBCT, kVCBCT, MVFBCT, and MVCBCT, respectively. Conclusions: Image quality adversely affects the reproducibility of soft tissue-based registration for IGRT and necessitates a careful consideration of residual uncertainties in determining different CTV-to-PTV margins for IGRT using different image modalities.

Morrow, Natalya V.; Lawton, Colleen A. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Qi, X. Sharon [Department of Radiation Oncology, University of Colorado Denver, Denver, Colorado (United States); Li, X. Allen, E-mail: ali@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States)

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Self-guided quantum tomography  

E-Print Network [OSTI]

We introduce a self-learning tomographic technique in which the experiment guides itself to an estimate of its own state. Self-guided quantum tomography (SGQT) uses measurements to directly test hypotheses in an iterative algorithm which converges to the true state. We demonstrate through simulation on many qubits that SGQT is a more efficient and robust alternative to the usual paradigm of taking a large amount of informationally complete data and solving the inverse problem of post-processed state estimation.

Christopher Ferrie

2014-11-10T23:59:59.000Z

202

A comparison of CT- and ultrasound-based imaging to localize the prostate for external beam radiotherapy  

SciTech Connect (OSTI)

Purpose: This study assesses the accuracy of NOMOS B-mode acquisition and targeting system (BAT) compared with computed tomography (CT) in localizing the prostate. Methods and Materials: Twenty-six patients were CT scanned, and the prostate was localized by 3 observers using the BAT system. The BAT couch shift measurements were compared with the CT localization. Six of the patients had gold markers present in the prostate, and the prostate movement determined by BAT was compared with the movement determined by the gold markers. Results: Using the BAT system, the 3 observers determined the prostate position to be a mean of 1-5 mm over all directions with respect to the CT. The proportion of readings with a difference >3 mm between the observers was in the range of 25% to 44%. The prostate movement based on gold markers was an average of 3-5 mm different from that measured by BAT. The literature assessing the accuracy and reproducibility on BAT is summarized and compared with our findings. Conclusions: We have found that there are systematic differences between the BAT-defined prostate position compared with that estimated on CT using gold grain marker seeds.

McNair, Helen A. [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom)]. E-mail: Helen.McNair@rmh.nhs.uk; Mangar, Stephen A. [Department of Academic Urology Unit, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Coffey, Jerome [Department of Academic Urology Unit, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Shoulders, Beverley [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Hansen, Vibeke N. [Department of Physics, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Norman, Andrew [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Department of Physics, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Department of Radiology, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Department of Academic Urology Unit, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Staffurth, John [Department of Academic Urology Unit, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Sohaib, S. Aslam [Department of Radiology, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Warrington, Alan P. [Department of Physics, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Dearnaley, David P. [Department of Academic Urology Unit, Royal Marsden NHS Foundation Trust, Sutton (United Kingdom)

2006-07-01T23:59:59.000Z

203

Siemens AG, CT, September 2001 CORPORATETECHNOLOGY  

E-Print Network [OSTI]

s © Siemens AG, CT, September 2001 CORPORATETECHNOLOGY Research and Technology at Siemens Transportation Power Information & Communications Health Automation & Control #12;2© Siemens AGResearch and Technology at Siemens CORPORATETECHNOLOGY CT / E 020 a - 02.01 Key Figures for 2000 Amounts in billions

204

Lack of Correlation Between External Fiducial Positions and Internal Tumor Positions During Breath-Hold CT  

SciTech Connect (OSTI)

Purpose: For thoracic tumors, if four-dimensional computed tomography (4DCT) is unavailable, the internal margin can be estimated by use of breath-hold (BH) CT scans acquired at end inspiration (EI) and end expiration (EE). By use of external surrogates for tumor position, BH accuracy is estimated by minimizing the difference between respiratory extrema BH and mean equivalent-phase free breathing (FB) positions. We tested the assumption that an external surrogate for BH accuracy correlates with internal tumor positional accuracy during BH CT. Methods and Materials: In 16 lung cancer patients, 4DCT images, as well as BH CT images at EI and EE, were acquired. Absolute differences between BH and mean equivalent-phase (FB) positions were calculated for both external fiducials and gross tumor volume (GTV) centroids as metrics of external and internal BH accuracy, respectively, and the results were correlated. Results: At EI, the absolute difference between mean FB and BH fiducial displacement correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R{sup 2} = 0.11). Similarly, at EE, the absolute difference between mean FB and BH fiducial displacements correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R{sup 2} = 0.18). Conclusions: External surrogates for tumor position are not an accurate metric of BH accuracy for lung cancer patients. This implies that care should be taken when using such an approach because an incorrect internal margin could be generated.

Hunjan, Sandeep, E-mail: shunjan@mdanderson.or [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Starkschall, George; Prado, Karl; Dong Lei; Balter, Peter [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

2010-04-15T23:59:59.000Z

205

Software Development for a CompactRIO-Based Wire Scanner Control and Data Acquisition SYstem  

SciTech Connect (OSTI)

The Beam Diagnostics and Instrumentation Team at the Los Alamos Neutron Science Center is developing a wire scanner data acquisition and control system with a National Instrument's compactRIO at its core. For this application, the compactRIO controller not only requires programming the FPGA and RT computer internal to the compactRIO, but also requires programming a client computer and a touch panel display. This article will summarize the hardware interfaces and describe the software design approach utilized for programming and interfacing the four systems together in order to fulfill the design requirements and promote reliable interoperability.

Sedillo, James Daniel [Los Alamos National Laboratory

2012-05-16T23:59:59.000Z

206

Correlation between internal fiducial tumor motion and external marker motion for liver tumors imaged with 4D-CT  

SciTech Connect (OSTI)

Purpose: We investigated the correlation between the motions of an external marker and internal fiducials implanted in the liver for 8 patients undergoing respiratory-based computed tomography (four-dimensional CT [4D-CT]) procedures. Methods and Materials: The internal fiducials were gold seeds, 3 mm in length and 1.2 mm in diameter. Four patients each had one implanted fiducial, and the other four had three implanted fiducials. The external marker was a plastic box, which is part of the Real-Time Position Management System (RPM) used to track the patient's respiration. Each patient received a standard helical CT scan followed by a time-correlated CT-image acquisition (4D-CT). The 4D-CT images were reconstructed in 10 separate phases covering the entire respiratory cycle. Results: The internal fiducial motion is predominant in the superior-inferior direction, with a range of 7.5-17.5 mm. The correlation between external respiration and internal fiducial motion is best during expiration. For 2 patients with their three fiducials separated by a maximum of 3.2 cm, the motions of the fiducials were well correlated, whereas for 2 patients with more widely spaced fiducials, there was less correlation. Conclusions: In general, there is a good correlation between internal fiducial motion imaged by 4D-CT and external marker motion. We have demonstrated that gating may be best performed at the end of the respiratory cycle. Special attention should be paid to gating for patients whose fiducials do not move in synchrony, because targeting on the correct respiratory amplitude alone would not guarantee that the entire tumor volume is within the treatment field.

Beddar, A. Sam [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)]. E-mail: abeddar@mdanderson.org; Kainz, Kristofer [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Briere, Tina Marie [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Tsunashima, Yoshikazu [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Pan Tinsu [Department of Diagnostic Imaging, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Prado, Karl [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Gillin, Michael [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Krishnan, Sunil [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

2007-02-01T23:59:59.000Z

207

Clinical Evaluation of Spatial Accuracy of a Fusion Imaging Technique Combining Previously Acquired Computed Tomography and Real-Time Ultrasound for Imaging of Liver Metastases  

SciTech Connect (OSTI)

Purpose: This study was designed to evaluate the spatial accuracy of matching volumetric computed tomography (CT) data of hepatic metastases with real-time ultrasound (US) using a fusion imaging system (VNav) according to different clinical settings. Methods: Twenty-four patients with one hepatic tumor identified on enhanced CT and US were prospectively enrolled. A set of three landmarks markers was chosen on CT and US for image registration. US and CT images were then superimposed using the fusion imaging display mode. The difference in spatial location between the tumor visible on the CT and the US on the overlay images (reviewer no. 1, comment no. 2) was measured in the lateral, anterior-posterior, and vertical axis. The maximum difference (Dmax) was evaluated for different predictive factors.CT performed 1-30 days before registration versus immediately before. Use of general anesthesia for CT and US versus no anesthesia.Anatomic landmarks versus landmarks that include at least one nonanatomic structure, such as a cyst or a calcificationResultsOverall, Dmax was 11.53 {+-} 8.38 mm. Dmax was 6.55 {+-} 7.31 mm with CT performed immediately before VNav versus 17.4 {+-} 5.18 with CT performed 1-30 days before (p < 0.0001). Dmax was 7.05 {+-} 6.95 under general anesthesia and 16.81 {+-} 6.77 without anesthesia (p < 0.0015). Landmarks including at least one nonanatomic structure increase Dmax of 5.2 mm (p < 0.0001). The lowest Dmax (1.9 {+-} 1.4 mm) was obtained when CT and VNav were performed under general anesthesia, one immediately after the other. Conclusions: VNav is accurate when adequate clinical setup is carefully selected. Only under these conditions (reviewer no. 2), liver tumors not identified on US can be accurately targeted for biopsy or radiofrequency ablation using fusion imaging.

Hakime, Antoine, E-mail: thakime@yahoo.com; Deschamps, Frederic; Garcia Marques de Carvalho, Enio; Teriitehau, Christophe; Auperin, Anne; De Baere, Thierry [Gustave Roussy Institute (France)

2011-04-15T23:59:59.000Z

208

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

SciTech Connect (OSTI)

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.

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)

2014-02-24T23:59:59.000Z

209

THERMOACOUSTIC TOMOGRAPHY ARISING IN BRAIN IMAGING ...  

E-Print Network [OSTI]

In this paper, we study the mathematical model of thermoacoustic and photoacoustic tomography for a sound speed that jumps across a smooth closed surface.

2011-02-21T23:59:59.000Z

210

Imaging and sensing based on muon tomography  

DOE Patents [OSTI]

Techniques, apparatus and systems for detecting particles such as muons for imaging applications. Subtraction techniques are described to enhance the processing of the muon tomography data.

Morris, Christopher L; Saunders, Alexander; Sossong, Michael James; Schultz, Larry Joe; Green, J. Andrew; Borozdin, Konstantin N; Hengartner, Nicolas W; Smith, Richard A; Colthart, James M; Klugh, David C; Scoggins, Gary E; Vineyard, David C

2012-10-16T23:59:59.000Z

211

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas Conchas recoveryLaboratory | NationalJohnSecurity Complex Non-destructive Assay

212

Comparison of Computed Tomography and Cineangiography in the Demonstration of Central Pulmonary Arteries in Cyanotic Congenital Heart Disease  

SciTech Connect (OSTI)

Purpose: To assess the diagnostic accuracy of contrast-enhanced computed tomography (CT) for central pulmonary artery pathology in patients with cyanotic congenital heart disease (CCHD) and right ventricular outflow obstruction. Methods: We compared contrast-enhanced CT and cine pulmonary arteriography in 24 patients with CCHD to assess central pulmonary arteries including the confluence. Both investigations were interpreted by a cardiac radiologist in a double-blinded manner at an interval of 3 weeks. Angiography was used as the gold standard for comparison. Results: The sensitivity for visualization of main pulmonary artery (MPA), right pulmonary artery (RPA), left pulmonary artery (LPA), and confluence on CT was 94%, 100%, 92.8%, and 92.8%, respectively. Diagnostic specificity for the same entities was 28.5%, 100%, 80%, and 50%, respectively. The positive predictive value for each was 76.2%, 100%, 94.1%, and 72.2%, respectively. The low specificity of CT in the evaluation of the MPA and the confluence is perhaps due to distorted right ventricular outflow anatomy in CCHD. Large aortopulmonary collaterals in this region were mistaken for the MPA in some patients with pulmonary atresia. Conclusion: CT is a useful, relatively noninvasive, imaging technique for the central pulmonary arteries in selected patients. It can supplement diagnostic information from angiography but cannot replace it. LPA demonstration on axial images alone is inadequate.

Taneja, Karuna; Sharma, Sanjiv [Department of Cardiovascular Radiology, C.T. Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029 (India); Kumar, Krishan [Department of Cardiology, C.T. Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029 (India); Rajani, Mira [Department of Cardiovascular Radiology, C.T. Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029 (India)

1996-03-15T23:59:59.000Z

213

Understanding Atom Probe Tomography of Oxide-Supported Metal...  

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

Atom Probe Tomography of Oxide-Supported Metal Nanoparticles by Correlation with Atomic Resolution Electron Understanding Atom Probe Tomography of Oxide-Supported Metal...

214

Using X-Ray Computed Tomography in Pore Structure Characterization...  

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

Using X-Ray Computed Tomography in Pore Structure Characterization for a Berea Sandstone: Resolution Effect. Using X-Ray Computed Tomography in Pore Structure Characterization for...

215

Surface Impedance Tomography for Antarctic Sea Ice  

E-Print Network [OSTI]

Surface Impedance Tomography for Antarctic Sea Ice C. Sampsona , K. M. Goldena , A. Gullya , A. P, Australia Abstract During the 2007 SIPEX expedition in pack ice off the coast of East Antarctica, we measured the electrical conductivity of sea ice via surface impedance tomography. Resistance data from

Golden, Kenneth M.

216

ALGEBRAIC ASPECTS OF EMISSION TOMOGRAPHY WITH ABSORPTION  

E-Print Network [OSTI]

ALGEBRAIC ASPECTS OF EMISSION TOMOGRAPHY WITH ABSORPTION L. Hajdu and R. Tijdeman Abstract of emission tomography with absorption, con- sider a ray (such as light or X-ray) transmitting through #1; e #22;x ; where #22; #21; 0 denotes the absorption coeÃ?cient of the material, and x is the length

Tijdeman, Robert

217

Fast Globally Convergent Reconstruction in Emission Tomography  

E-Print Network [OSTI]

considerable speedup by using only a subset of the projection data per sub- iteration. However, OSEM1 Fast Globally Convergent Reconstruction in Emission Tomography Using COSEM, an Incremental EM globally convergent incremental EM algorithms for reconstruction in emission tomography, COSEM- ML

Rangarajan, Anand

218

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

SciTech Connect (OSTI)

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.

Noid, G; Chen, G; Tai, A; Li, X [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)

2014-06-01T23:59:59.000Z

219

Student ConduCt Student Affairs  

E-Print Network [OSTI]

Code of Student ConduCt 2013-14 Student Affairs #12;Contents Letter from the Dean of Students .........................................................................................ii University Code of Student Conduct Preamble............................................. 1 Section I: Rules of Student Conduct.............................................................. 1 Section

Suzuki, Masatsugu

220

Cone-Beam CT with Flat-Panel-Detector Digital Angiography System: Early Experience in Abdominal Interventional Procedures  

SciTech Connect (OSTI)

We developed a cone-beam computed tomography (CBCT) system equipped with a large flat-panel detector. Data obtained by 200{sup o} rotation imaging are reconstructed by means of CBCT to generate three-dimensional images. We report the use of CBCT angiography using CBCT in 10 patients with 8 liver malignancies and 2 hypersplenisms during abdominal interventional procedures. CBCT was very useful for interventional radiologists to confirm a perfusion area of the artery catheter wedged on CT by injection of contrast media through the catheter tip, although the image quality was slightly degraded, scoring as 2.60 on average by streak artifacts. CBCT is space-saving because it does not require a CT system with a gantry, and it is also time-saving because it does not require the transfer of patients.

Hirota, Shozo, E-mail: hirota-s@hyo-med.ac.jp; Nakao, Norio; Yamamoto, Satoshi; Kobayashi, Kaoru; Maeda, Hiroaki; Ishikura, Reiichi; Miura, Koui; Sakamoto, Kiyoshi [Hyogo College of Medicine, Department of Radiology (Japan); Ueda, Ken [Hitachi Medical Corporation, Research and Development Center (Japan); Baba, Rika [Hitachi Limited, Central Research Laboratory (Japan)

2006-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Methane hydrate distribution from prolonged and repeated formation in natural and compacted sand samples: X-ray CT observations  

SciTech Connect (OSTI)

To study physical properties of methane gas hydrate-bearing sediments, it is necessary to synthesize laboratory samples due to the limited availability of cores from natural deposits. X-ray computed tomography (CT) and other observations have shown gas hydrate to occur in a number of morphologies over a variety of sediment types. To aid in understanding formation and growth patterns of hydrate in sediments, methane hydrate was repeatedly formed in laboratory-packed sand samples and in a natural sediment core from the Mount Elbert Stratigraphic Test Well. CT scanning was performed during hydrate formation and decomposition steps, and periodically while the hydrate samples remained under stable conditions for up to 60 days. The investigation revealed the impact of water saturation on location and morphology of hydrate in both laboratory and natural sediments during repeated hydrate formations. Significant redistribution of hydrate and water in the samples was observed over both the short and long term.

Rees, E.V.L.; Kneafsey, T.J.; Seol, Y.

2010-07-01T23:59:59.000Z

222

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

E-Print Network [OSTI]

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.

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

2014-08-07T23:59:59.000Z

223

Collimator-free photon tomography  

DOE Patents [OSTI]

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.

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

1998-10-06T23:59:59.000Z

224

Collimator-free photon tomography  

DOE Patents [OSTI]

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.

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

1998-10-06T23:59:59.000Z

225

TERRESTRIAL 3D-LASER SCANNER ZLS07 DEVELOPED AT ETH ZURICH: AN OVERVIEW OF ITS CONFIGURATION,  

E-Print Network [OSTI]

Utility Cavern ABSTRACT This paper introduces the terrestrial 3D-laser scanner ZLS07 which has been and the application of underground utility cavern acquisition for water and sewage engineering are presented. For utility cavern acquisitions, the ZLS07 is guided headfirst through a manhole into the utility cavern

226

Atlas-based attenuation correction for small animal PET/MRI scanners Abhijit J. Chaudhari, ajchaudhari@ucdavis.edu,  

E-Print Network [OSTI]

Atlas-based attenuation correction for small animal PET/MRI scanners 1 Abhijit J. Chaudhari densities and not on electron densities. We propose a deformable mouse atlas-based registration method for AC in small animal PET/MRI. In this method, we first match the posture of the atlas to the posture

Leahy, Richard M.

227

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

E-Print Network [OSTI]

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

Walker, Thad G.

228

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

SciTech Connect (OSTI)

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.

Jensen, Michael D. [Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada)] [Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Hrinivich, W. Thomas; Jung, Jongho A. [Department of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada)] [Department of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Holdsworth, David W. [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8 (Canada) [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8 (Canada); Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Surgery, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Drangova, Maria [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8, Canada and Department of Medical Biophysics, The University of Western Ontario 1151 Richmond Street, London, Ontario N6A 3K7 (Canada)] [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8, Canada and Department of Medical Biophysics, The University of Western Ontario 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Chen, Jeff [Department of Physics and Engineering, London Regional Cancer Program, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario N6A 5W9 (Canada) [Department of Physics and Engineering, London Regional Cancer Program, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario N6A 5W9 (Canada); Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Oncology, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Wong, Eugene [Department of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada) [Department of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Oncology, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Physics and Engineering, London Regional Cancer Program, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario N6A 5W9 (Canada)

2013-08-15T23:59:59.000Z

229

Geometric classification of open-cell metal foams using X-ray micro-computed tomography  

SciTech Connect (OSTI)

The geometry of foams has long been an area of interest, and a number of idealized geometric descriptions have been proposed. In order to acquire detailed, quantitative, geometric data for aluminum open-cell metal foams, X-ray {mu}CT is employed. The X-ray {mu}CT images are analyzed using specialized software, FoamView Registered-Sign , from which geometric information including strut length and pore shapes are extracted. The X-ray {mu}CT analysis allows comparison of the ideal geometric models to the actual geometric characteristics of the metal foam samples. The results reveal a high variability in ligament length, as well as features supporting the ideal geometry known as the Weaire-Phelan unit cell. The geometric findings provide information useful for improving current models of open-cell metal foam. Applications can range from predicting heat transfer or load failure to predicting liquid retention. Highlights: Black-Right-Pointing-Pointer Aluminum open-cell metal foams are geometrically classified Black-Right-Pointing-Pointer X-ray micro-computed tomography and specialized software are used to gather geometric data Black-Right-Pointing-Pointer The foams are shown to have a high variability in strut length Black-Right-Pointing-Pointer The Weaire-Phelan unit cell is shown to be a better representative of these foams.

Bock, Jessica, E-mail: bock6@illinois.edu; Jacobi, Anthony M., E-mail: a-jacobi@illinois.edu

2013-01-15T23:59:59.000Z

230

PET/CT image registration: Preliminary tests for its application to clinical dosimetry in radiotherapy  

SciTech Connect (OSTI)

The quality of dosimetry in radiotherapy treatment requires the accurate delimitation of the gross tumor volume. This can be achieved by complementing the anatomical detail provided by CT images through fusion with other imaging modalities that provide additional metabolic and physiological information. Therefore, use of multiple imaging modalities for radiotherapy treatment planning requires an accurate image registration method. This work describes tests carried out on a Discovery LS positron emission/computed tomography (PET/CT) system by General Electric Medical Systems (GEMS), for its later use to obtain images to delimit the target in radiotherapy treatment. Several phantoms have been used to verify image correlation, in combination with fiducial markers, which were used as a system of external landmarks. We analyzed the geometrical accuracy of two different fusion methods with the images obtained with these phantoms. We first studied the fusion method used by the PET/CT system by GEMS (hardware fusion) on the basis that there is satisfactory coincidence between the reconstruction centers in CT and PET systems; and secondly the fiducial fusion, a registration method, by means of least-squares fitting algorithm of a landmark points system. The study concluded with the verification of the centroid position of some phantom components in both imaging modalities. Centroids were estimated through a calculation similar to center-of-mass, weighted by the value of the CT number and the uptake intensity in PET. The mean deviations found for the hardware fusion method were: vertical bar {delta}x vertical bar {+-}{sigma}=3.3 mm{+-}1.0 mm and vertical bar {delta}y vertical bar {+-}{sigma}=3.6 mm{+-}1.0 mm. These values were substantially improved upon applying fiducial fusion based on external landmark points: vertical bar {delta}x vertical bar {+-}{sigma}=0.7 mm{+-}0.8 mm and vertical bar {delta}y vertical bar {+-}{sigma}=0.3 mm{+-}1.7 mm. We also noted that differences found for each of the fusion methods were similar for both the axial and helical CT image acquisition protocols.

Banos-Capilla, M. C.; Garcia, M. A.; Bea, J.; Pla, C.; Larrea, L.; Lopez, E. [Department of Medical Physics, Radiation Oncology, Hospital Virgen del Consuelo, Callosa de Ensarria 12-Valencia, Valencia 46007 (Spain); Department of Radiation Oncology, H. NISA 'Virgen del Consuelo', Valencia (Spain)

2007-06-15T23:59:59.000Z

231

Friction Reduction for Microhole CT Drilling  

SciTech Connect (OSTI)

The objective of this 24 month project focused on improving microhole coiled tubing drilling bottom hole assembly (BHA) reliability and performance, while reducing the drilling cost and complexity associated with inclined/horizontal well sections. This was to be accomplished by eliminating the need for a downhole drilling tractor or other downhole coiled tubing (CT) friction mitigation techniques when drilling long (>2,000 ft.) of inclined/horizontal wellbore. The technical solution to be developed and evaluated in this project was based on vibrating the coiled tubing at surface to reduce the friction along the length of the downhole CT drillstring. The Phase 1 objective of this project centered on determining the optimum surface-applied vibration system design for downhole CT friction mitigation. Design of the system would be based on numerical modeling and laboratory testing of the CT friction mitigation achieved with various types of surface-applied vibration. A numerical model was developed to predict how far downhole the surface-applied vibration would travel. A vibration test fixture, simulating microhole CT drilling in a horizontal wellbore, was constructed and used to refine and validate the numerical model. Numerous tests, with varying surface-applied vibration parameters were evaluated in the vibration test fixture. The data indicated that as long as the axial force on the CT was less than the helical buckling load, axial vibration of the CT was effective at mitigating friction. However, surface-applied vibration only provided a small amount of friction mitigation as the helical buckling load on the CT was reached or exceeded. Since it would be impractical to assume that routine field operations be conducted at less than the helical buckling load of the CT, it was determined that this technical approach did not warrant the additional cost and maintenance issues that would be associated with the surface vibration equipment. As such, the project was concluded following completion of Phase 1, and Phase 2 (design, fabrication, and testing of a prototype surface vibration system) was not pursued.

Ken Newman; Patrick Kelleher; Edward Smalley

2007-03-31T23:59:59.000Z

232

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

SciTech Connect (OSTI)

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.

Drescher, A.C.

1995-06-01T23:59:59.000Z

233

A new correction method serving to eliminate the parabola effect of flatbed scanners used in radiochromic film dosimetry  

SciTech Connect (OSTI)

Purpose: The purpose of this study is the correction of the lateral scanner artifact, i.e., the effect that, on a large homogeneously exposed EBT3 film, a flatbed scanner measures different optical densities at different positions along thex axis, the axis parallel to the elongated light source. At constant dose, the measured optical densitiy profiles along this axis have a parabolic shape with significant dose dependent curvature. Therefore, the effect is shortly called the parabola effect. The objective of the algorithm developed in this study is to correct for the parabola effect. Any optical density measured at given position x is transformed into the equivalent optical density c at the apex of the parabola and then converted into the corresponding dose via the calibration of c versus dose. Methods: For the present study EBT3 films and an Epson 10000XL scanner including transparency unit were used for the analysis of the parabola effect. The films were irradiated with 6 MV photons from an Elekta Synergy accelerator in a RW3 slab phantom. In order to quantify the effect, ten film pieces with doses graded from 0 to 20.9 Gy were sequentially scanned at eight positions along thex axis and at six positions along the z axis (the movement direction of the light source) both for the portrait and landscape film orientations. In order to test the effectiveness of the new correction algorithm, the dose profiles of an open square field and an IMRT plan were measured by EBT3 films and compared with ionization chamber and ionization chamber array measurement. Results: The parabola effect has been numerically studied over the whole measuring field of the Epson 10000XL scanner for doses up to 20.9 Gy and for both film orientations. The presented algorithm transforms any optical density at positionx into the equivalent optical density that would be measured at the same dose at the apex of the parabola. This correction method has been validated up to doses of 5.2 Gy all over the scanner bed with 2D dose distributions of an open square photon field and an IMRT distribution. Conclusions: The algorithm presented in this study quantifies and corrects the parabola effect of EBT3 films scanned in commonly used commercial flatbed scanners at doses up to 5.2 Gy. It is easy to implement, and no additional work steps are necessary in daily routine film dosimetry.

Poppinga, D., E-mail: daniela.poppinga@uni-oldenburg.de; Schoenfeld, A. A.; Poppe, B. [Medical Radiation Physics, Carl v. Ossietzky University, Oldenburg 26127, Germany and Department for Radiation Oncology, Pius Hospital, Oldenburg 26121 (Germany)] [Medical Radiation Physics, Carl v. Ossietzky University, Oldenburg 26127, Germany and Department for Radiation Oncology, Pius Hospital, Oldenburg 26121 (Germany); Doerner, K. J. [Radiotherapy Department, General Hospital, Celle 29223 (Germany)] [Radiotherapy Department, General Hospital, Celle 29223 (Germany); Blanck, O. [CyberKnife Center Northern Germany, Güstrow 18273, Germany and Department for Radiation Oncology, University Clinic Schleswig-Holstein, Lübeck 23562 (Germany)] [CyberKnife Center Northern Germany, Güstrow 18273, Germany and Department for Radiation Oncology, University Clinic Schleswig-Holstein, Lübeck 23562 (Germany); Harder, D. [Medical Physics and Biophysics, Georg-August-University, Göttingen 37073 (Germany)] [Medical Physics and Biophysics, Georg-August-University, Göttingen 37073 (Germany)

2014-02-15T23:59:59.000Z

234

Comparison of CT and MR-CT Fusion for Prostate Post-Implant Dosimetry  

SciTech Connect (OSTI)

Purpose: The use of T2 MR for postimplant dosimetry (PID) after prostate brachytherapy allows more anatomically accurate and precise contouring but does not readily permit seed identification. We developed a reproducible technique for performing MR-CT fusion and compared the resulting dosimetry to standard CT-based PID. Methods and Materials: CT and T1-weighted MR images for 45 patients were fused and aligned based on seed distribution. The T2-weighted MR image was then fused to the aligned T1. Reproducibility of the fusion technique was tested by inter- and intraobserver variability for 13 patients. Dosimetry was computed for the prostate as a whole and for the prostate divided into anterior and posterior sectors of the base, mid-prostate, and apex. Results: Inter- and intraobserver variability for the fusion technique showed less than 1% variation in D90. MR-CT fusion D90 and CT D90 were nearly equivalent for the whole prostate, but differed depending on the identification of superior extent of the base (p = 0.007) and on MR/CT prostate volume ratio (p = 0.03). Sector analysis showed a decrease in MR-CT fusion D90 in the anterior base (ratio 0.93 {+-}0.25, p < 0.05) and an increase in MR-CT fusion D90 in the apex (p < 0.05). The volume of extraprostatic tissue encompassed by the V100 is greater on MR than CT. Factors associated with this difference are the MR/CT volume ratio (p < 0.001) and the difference in identification of the inferior extent of the apex (p = 0.03). Conclusions: We developed a reproducible MR-CT fusion technique that allows MR-based dosimetry. Comparing the resulting postimplant dosimetry with standard CT dosimetry shows several differences, including adequacy of coverage of the base and conformity of the dosimetry around the apex. Given the advantage of MR-based tissue definition, further study of MR-based dosimetry is warranted.

Maletz, Kristina L. [Department of Radiation Oncology, St. Luke's-Roosevelt Hospital Center, Beth Israel Medical Center, Continuum Health Partners, New York, NY (Israel); Columbia University College of Physicians and Surgeons, New York, NY (United States); Ennis, Ronald D., E-mail: REnnis@chpnet.org [Department of Radiation Oncology, St. Luke's-Roosevelt Hospital Center, Beth Israel Medical Center, Continuum Health Partners, New York, NY (Israel); Ostenson, Jason; Pevsner, Alexander [Department of Radiation Oncology, St. Luke's-Roosevelt Hospital Center, Beth Israel Medical Center, Continuum Health Partners, New York, NY (Israel); Kagen, Alexander [Department of Radiology, Beth Israel Medical Center, St. Luke's-Roosevelt Hospital, Continuum Health Partners, New York, NY (Israel); Wernick, Iddo [Department of Radiation Oncology, St. Luke's-Roosevelt Hospital Center, Beth Israel Medical Center, Continuum Health Partners, New York, NY (Israel)

2012-04-01T23:59:59.000Z

235

Economical standard quantum process tomography  

E-Print Network [OSTI]

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.

Xiaohua Wu; Ke Xu

2010-11-30T23:59:59.000Z

236

abdominal ct images: Topics by E-print Network  

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

methods establish microCT imaging as a useful tool for comparative Metscher, Brian 31 CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1 Physics...

237

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

SciTech Connect (OSTI)

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.

Khalvati, Farzad, E-mail: farzad.khalvati@uwaterloo.ca; Tizhoosh, Hamid R. [Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)] [Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Salmanpour, Aryan; Rahnamayan, Shahryar [Department of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4 (Canada)] [Department of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4 (Canada); Rodrigues, George [Department of Radiation Oncology, London Regional Cancer Program, London, Ontario N6C 2R6, Canada and Department of Epidemiology/Biostatistics, University of Western Ontario, London, Ontario N6A 3K7 (Canada)] [Department of Radiation Oncology, London Regional Cancer Program, London, Ontario N6C 2R6, Canada and Department of Epidemiology/Biostatistics, University of Western Ontario, London, Ontario N6A 3K7 (Canada)

2013-12-15T23:59:59.000Z

238

Anatomic measurement accuracy: CT parameters and 3D rendering effects  

E-Print Network [OSTI]

Anatomic measurement accuracy: CT parameters and 3D rendering effects Brian J Whyms a, E Michael of Neuroscience #12;INTRODUCTION · Measurements from 3D-CT rendering are used in research and clinical management-CT rendering techniques on measurements #12;METHODS Scanned: · 3 human mandibles · a phantom object Phantom

Vorperian, Houri K.

239

Mechanical Design and Evaluation of the MP-11-Like Wire Scanner Prototype  

SciTech Connect (OSTI)

A wire scanner (WS) is a linearly actuated diagnostic device that uses fiber wires (such as Tungsten or Silicon Carbide) to obtain the position and intensity profile of the proton beam at the Los Alamos Neutron Science Center (LANSCE) particle accelerator. LANSCE will be installing approximately 86 new WS in the near future as part of the LANSCE Risk Mitigation project. These 86 new WS include the replacement of many current WS and some newly added to the current linear accelerator and other beam lines. The reason for the replacement and addition of WS is that many of the existing actuators have parts that are no longer readily available and are difficult to find, thus making maintenance very difficult. One of the main goals is to construct the new WS with as many commercially-available-off-the-shelf components as possible. In addition, faster beam scans (both mechanically and in term of data acquisition) are desired for better operation of the accelerator. This document outlines the mechanical design of the new MP-11-like WS prototype and compares it to a previously built and tested SNS-like WS prototype.

Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Maestas, Alfred J. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory; Raybun, Joseph L. [Los Alamos National Laboratory; Martinez, Jason P. [Los Alamos National Laboratory; Sattler, F. D. [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory

2012-05-16T23:59:59.000Z

240

Recent results with a CdTe imaging portal scanner for radiation therapy  

SciTech Connect (OSTI)

One of the most promising means for improving the quality of radiation therapy is the use of real-time imaging systems for routine portal position verification. The authors have constructed a prototype portal imager using a linear array of 256 CdTe photovoltaic detectors, each 2X2X2 mm. The array is attached to a compact linear scanner which is to be mounted in a cassette shaped package located below the patient table. The array of detectors is moved under the patient during image acquisition. The high stopping power of the CdTe allows a high contrast image to be made using a single linac pulse for each array position. In tests conducted with a 4 MV linac, this system produced 50 cm x 35 cm images with an open field signal-to-noise ratio of 143 and 2 mm spatial resolution in less than 3 seconds. This corresponds to a signal-to-noise ratio of 1 for 1% contrast objects. Ultimately, a signal-to-noise ratio greater than 5 at 1% contrast should be achievable with no loss of spatial resolution or increase in acquisition time.

Entine, G.; Redus, R.H.; Feyder, A. (Radiation Monitoring Devices, Inc., Watertown, MA (United States)); Biggs, P.J. (Massachusetts General Hospital, Boston, MA (United States))

1993-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
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241

Introduction of heat map to fidelity assessment of compressed CT images  

SciTech Connect (OSTI)

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.

Lee, Hyunna; Kim, Bohyoung; Seo, Jinwook; Park, Seongjin; Shin, Yeong-Gil [School of Computer Science and Engineering, Seoul National University, 599 Kwanak-ro, Kwanak-gu, Seoul 151-742 (Korea, Republic of); Kim, Kil Joong [Department of Radiation Applied Life Science, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744 (Korea, Republic of); Lee, Kyoung Ho [Department of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Institute of Radiation Medicine and Seoul National University Medical Research Center, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707 (Korea, Republic of)

2011-08-15T23:59:59.000Z

242

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

SciTech Connect (OSTI)

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.

Amoretti, Nicolas, E-mail: amorettinicolas@yahoo.fr; Huwart, Laurent, E-mail: huwart.laurent@wanadoo.fr [Centre Hospitalo-Universitaire de Nice, Department of Radiology (France)

2012-12-15T23:59:59.000Z

243

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

SciTech Connect (OSTI)

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-Beer’s 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.

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

2014-02-18T23:59:59.000Z

244

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)

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.

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)

2013-08-01T23:59:59.000Z

245

Comparison of CT, PET, and PET/CT for Staging of Patients with Indolent Non-Hodgkin’s Lymphoma  

E-Print Network [OSTI]

B. J. Fueger et al. : PET/CT for indolent lymphoma Table 2.Performance for detection of nodal disease Sensitivity PETCT PET/CT pG0.001 vs PET, CT Specificity pG0.001 vs PET

Fueger, Barbara J.; Yeom, Kristen; Czernin, Johannes; Sayre, James W.; Phelps, Michael E.; Allen-Auerbach, Martin S.

2009-01-01T23:59:59.000Z

246

Thoracic target volume delineation using various maximum-intensity projection computed tomography image sets for radiotherapy treatment planning  

SciTech Connect (OSTI)

Purpose: Four-dimensional computed tomography (4D-CT) is commonly used to account for respiratory motion of target volumes in radiotherapy to the thorax. From the 4D-CT acquisition, a maximum-intensity projection (MIP) image set can be created and used to help define the tumor motion envelope or the internal gross tumor volume (iGTV). The purpose of this study was to quantify the differences in automatically contoured target volumes for usage in the delivery of stereotactic body radiation therapy using MIP data sets generated from one of the four methods: (1) 4D-CT phase-binned (PB) based on retrospective phase calculations, (2) 4D-CT phase-corrected phase-binned (PC-PB) based on motion extrema, (3) 4D-CT amplitude-binned (AB), and (4) cine CT built from all available images. Methods: MIP image data sets using each of the four methods were generated for a cohort of 28 patients who had prior thoracic 4D-CT scans that exhibited lung tumor motion of at least 1 cm. Each MIP image set was automatically contoured on commercial radiation treatment planning system. Margins were added to the iGTV to observe differences in the final simulated planning target volumes (PTVs). Results: For all patients, the iGTV measured on the MIP generated from the entire cine CT data set (iGTV{sub cine}) was the largest. Expressed as a percentage of iGTV{sub cine}, 4D-CT iGTV (all sorting methods) ranged from 83.8% to 99.1%, representing differences in the absolute volume ranging from 0.02 to 4.20 cm{sup 3}; the largest average and range of 4D-CT iGTV measurements was from the PC-PB data set. Expressed as a percentage of PTV{sub cine} (expansions applied to iGTV{sub cine}), the 4D-CT PTV ranged from 87.6% to 99.6%, representing differences in the absolute volume ranging from 0.08 to 7.42 cm{sup 3}. Regions of the measured respiratory waveform corresponding to a rapid change of phase or amplitude showed an increased susceptibility to the selection of identical images for adjacent bins. Duplicate image selection was most common in the AB implementation, followed by the PC-PB method. The authors also found that the image associated with the minimum amplitude measurement did not always correlate with the image that showed maximum tumor motion extent. Conclusions: The authors identified cases in which the MIP generated from a 4D-CT sorting process under-represented the iGTV by more than 10% or up to 4.2 cm{sup 3} when compared to the iGTV{sub cine}. They suggest utilization of a MIP generated from the full cine CT data set to ensure maximum inclusive tumor extent.

Zamora, David A.; Riegel, Adam C.; Sun Xiaojun; Balter, Peter; Starkschall, George; Mawlawi, Osama; Pan Tinsu [Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

2010-11-15T23:59:59.000Z

247

The effect of spatial micro-CT image resolution and surface complexity on the morphological 3D analysis of open porous structures  

SciTech Connect (OSTI)

In material science microfocus X-ray computed tomography (micro-CT) is one of the most popular non-destructive techniques to visualise and quantify the internal structure of materials in 3D. Despite constant system improvements, state-of-the-art micro-CT images can still hold several artefacts typical for X-ray CT imaging that hinder further image-based processing, structural and quantitative analysis. For example spatial resolution is crucial for an appropriate characterisation as the voxel size essentially influences the partial volume effect. However, defining the adequate image resolution is not a trivial aspect and understanding the correlation between scan parameters like voxel size and the structural properties is crucial for comprehensive material characterisation using micro-CT. Therefore, the objective of this study was to evaluate the influence of the spatial image resolution on the micro-CT based morphological analysis of three-dimensional (3D) open porous structures with a high surface complexity. In particular the correlation between the local surface properties and the accuracy of the micro-CT-based macro-morphology of 3D open porous Ti6Al4V structures produced by selective laser melting (SLM) was targeted and revealed for rough surfaces a strong dependence of the resulting structure characteristics on the scan resolution. Reducing the surface complexity by chemical etching decreased the sensitivity of the overall morphological analysis to the spatial image resolution and increased the detection limit. This study showed that scan settings and image processing parameters need to be customized to the material properties, morphological parameters under investigation and the desired final characteristics (in relation to the intended functional use). Customization of the scan resolution can increase the reliability of the micro-CT based analysis and at the same time reduce its operating costs. - Highlights: • We examine influence of the image resolution on ?CT-based morphological analysis. • Surface properties influence accuracy of ?CT-based morphology of porous structures. • Total porosity was the least sensitive to surface complexity and scan voxel size. • The beam thickness analysis was overestimated by the surface roughness. • Voxel size customization can significantly reduce a cost of the ?CT-based analysis.

Pyka, Grzegorz, E-mail: gregory.pyka@mtm.kuleuven.be [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 – PB2450, B-3001 Leuven (Belgium); Kerckhofs, Greet [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 – PB2450, B-3001 Leuven (Belgium); Biomechanics Research Unit, Université de Liege, Chemin des Chevreuils 1 - BAT 52/3, B-4000 Liège (Belgium); Schrooten, Jan; Wevers, Martine [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 – PB2450, B-3001 Leuven (Belgium)

2014-01-15T23:59:59.000Z

248

Multilevel bioluminescence tomography based on radiative transfer equation  

E-Print Network [OSTI]

, "A fast forward solver of radiative transfer equation," Transport Theory and Statistical Physics 38Multilevel bioluminescence tomography based on radiative transfer equation Part 1: l1 approach for bioluminescence tomography based on radiative transfer equation with the emphasis on improving

Soatto, Stefano

249

Tomography and High-Resolution Electron Microscopy Study of Surfaces...  

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

Tomography and High-Resolution Electron Microscopy Study of Surfaces and Porosity in a Plate-Like ?-Al2O3. Tomography and High-Resolution Electron Microscopy Study of...

250

Analysis of in-situ rock joint strength using digital borehole scanner images  

SciTech Connect (OSTI)

The availability of high resolution digital images of borehole walls using the Borehole Scanner System has made it possible to develop new methods of in-situ rock characterization. This thesis addresses particularly new approaches to the characterization of in-situ joint strength arising from surface roughness. An image processing technique is used to extract the roughness profile from joints in the unrolled image of the borehole wall. A method for estimating in-situ Rengers envelopes using this data is presented along with results from using the method on joints in a borehole in porphyritic granite. Next, an analysis of the joint dilation angle anisotropy is described and applied to the porphyritic granite joints. The results indicate that the dilation angle of the joints studied are anisotropic at small scales and tend to reflect joint waviness as scale increases. A procedure to unroll the opposing roughness profiles to obtain a two dimensional sample is presented. The measurement of apertures during this process is shown to produce an error which increases with the dip of the joint. The two dimensional sample of opposing profiles is used in a new kinematic analysis of the joint shear stress-shear deformation behavior. Examples of applying these methods on the porphyritic granite joints are presented. The unrolled opposing profiles were used in a numerical simulation of a direct shear test using Discontinuous Deformation Analysis. Results were compared to laboratory test results using core samples containing the same joints. The simulated dilatancy and shear stress-shear deformation curves were close to the laboratory curves in the case of a joint in porphyritic granite.

Thapa, B.B.

1994-09-01T23:59:59.000Z

251

PET/CT shielding design comparisons  

E-Print Network [OSTI]

moving through the gantry (with permission from Bushong 2001). 7 Positron Emission Tomography (PET) is a noninvasive diagnostic imaging tool that takes advantage of certain radiopharmaceuticals and allows abnormal metabolic... activity in and around organs to be examined by injection of a radionuclide into a patient (Radiology 2006). These radiopharmaceuticals, biological compounds linked to radiation-emitting radionuclides, can in some cases be tailored for concentration...

Coker, Audra Lee

2007-09-17T23:59:59.000Z

252

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

E-Print Network [OSTI]

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

Boschi, Lapo

253

Positron Emission Tomography/Computed Tomography in the Staging and Treatment of Anal Cancer  

SciTech Connect (OSTI)

Purpose: This study was intended to determine the role of PET/CT in the staging of anal cancer as a supplement to three-dimensional transanal ultrasound (TAUS) and inguinal ultrasound (US). The impact of the PET/CT on the initial stage and treatment plan proposed by TAUS/US was assessed. Methods and Materials: Ninety-five (95) patients referred to our clinic between July 1, 2005, and December 31, 2009, were retrospectively reviewed. All patients had biopsy-proven primary squamous cell cancer of the anal canal. There were 65 females (68%) and 30 males (32%), and the median age was 58 years (range, 35-88 years). Six (6%) of the patients were HIV positive. All patients were staged with TAUS/US and PET/CT. Results: Twenty-eight (28) patients were diagnosed with suspicious perirectal node metastases. TAUS visualized 24 of these, whereas PET/CT detected 15. Suspicious inguinal nodes were visualized on either US or PET/CT in 41 patients. Seventeen (17) of these had confirmed malignant disease on biopsy, and 15 had confirmed benign disease. All 17 patients (100%) with malignant inguinal nodes were diagnosed by PET/CT, whereas US identified 16 (94%). Ten patients were diagnosed with suspicious inguinal nodes on PET/CT that had not been seen on US. One of these was malignant, three were benign, and six were not biopsied. PET/CT diagnosed eight metastatic sites, whereas TAUS/US diagnosed three. PET/CT discovered three of the five synchronous cancers seen in this study. PET/CT upstaged the disease in 14% of the cases and changed the treatment plan proposed by TAUS/US in 17%. Conclusion: PET/CT has great potential influence on the staging and treatment of anal cancer. TAUS is important in the staging of the primary tumor and N1-stage, whereas PET/CT seems necessary for the N2/3-stage, the M-stage and synchronous cancers.

Sveistrup, Joen, E-mail: joensveistrup@hotmail.com [Department of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark); Loft, Annika [PET and Cyclotron Unit, Department of Clinical Physiology and Nuclear Medicine, Centre of Diagnostic Investigations, Rigshospitalet, Copenhagen (Denmark); Berthelsen, Anne Kiil [Department of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark); PET and Cyclotron Unit, Department of Clinical Physiology and Nuclear Medicine, Centre of Diagnostic Investigations, Rigshospitalet, Copenhagen (Denmark); Henriksen, Birthe Merete; Nielsen, Michael Bachmann [Department of Radiology, Section of Ultrasound X4123, Rigshospitalet, Copenhagen (Denmark); Engelholm, Svend Aage [Department of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark)

2012-05-01T23:59:59.000Z

254

Improving Electrical Resistivity Tomography for Characterization of  

E-Print Network [OSTI]

Improving Electrical Resistivity Tomography for Characterization of Non-point Source Contaminants on the environment. Urban and agricultural runoff are often associated with an increase in water electrical conductivity. Although electrical conductivity (EC) cannot be used to identify individual chemical species

Fay, Noah

255

Binary Tomography with Deblurring Stefan Weber1  

E-Print Network [OSTI]

two scenarios of limited-angle binary tomography with data distorted with an unknown convolution: Either the projec- tion data are taken from a blurred object, or the projection data them- selves the projection data before reconstruction (let us call them preprocessing) and then the reconstruction

Schnörr, Christoph

256

Single-Shot Quantum Process Tomography  

E-Print Network [OSTI]

The standard procedure for quantum process tomography (QPT) involves applying the quantum process on a system initialized in each of a complete set of orthonormal states. The corresponding outputs are then characterized by quantum state tomography (QST), which itself requires the measurement of non-commuting observables realized by independent experiments on identically prepared system states. Thus QPT procedure demands a number of independent measurements, and moreover, this number increases rapidly with the size of the system. However, the total number of independent measurements can be greatly reduced with the availability of ancilla qubits. Ancilla assisted process tomography (AAPT) has earlier been shown to require a single QST of system-ancilla space. Ancilla assisted quantum state tomography (AAQST) has also been shown to perform QST in a single measurement. Here we combine AAPT with AAQST to realize a `single-shot QPT' (SSPT), a procedure to characterize a general quantum process in a single collective measurement of a set of commuting observables. We demonstrate experimental SSPT by characterizing several single-qubit processes using a three-qubit NMR quantum register. Furthermore, using the SSPT procedure we experimentally characterize the twirling process and compare the results with theory.

Abhishek Shukla; T. S. Mahesh

2014-05-27T23:59:59.000Z

257

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

E-Print Network [OSTI]

of the central slice of Siemens SOMATOM sensation 64 CT3.6. The three inserts from Siemens’ image quality phantom,3.6. The three inserts from Siemens’ image quality EMMA

Zhao, Yunzhe

2012-01-01T23:59:59.000Z

258

Experimental Investigation of Material Flows Within FSWs Using 3D Tomography  

SciTech Connect (OSTI)

There exists significant prior work using tracers or pre-placed hardened markers within friction stir welding (FSWing) to experimentally explore material flow within the FSW process. Our experiments replaced markers with a thin sheet of copper foil placed between the 6061 aluminum lap and butt joints that were then welded. The absorption characteristics of x-rays for copper and aluminum are significantly different allowing for non-destructive evaluation (NDE) methods such as x-ray computed tomography (CT) to be used to demonstrate the material movement within the weldment on a much larger scale than previously shown. 3D CT reconstruction of the copper components of the weldment allows for a unique view into the final turbulent state of the welding process as process parameters are varied. The x-ray CT data of a section of the weld region was collected using a cone-beam x-ray imaging system developed at the INL. Six-hundred projections were collected over 360-degrees using a 160-kVp Bremsstrahlung x-ray generator (25-micrometer focal spot) and amorphoussilicon x-ray detector. The region of the object that was imaged was about 3cm tall and 1.5cm x 1cm in cross section, and was imaged at a magnification of about 3.6x. The data were reconstructed on a 0.5x0.5x0.5 mm3 voxel grid. After reconstruction, the aluminum and copper could be easily discriminated using a gray level threshold allowing visualization of the copper components. Fractal analysis of the tomographic reconstructed material topology is investigated as a means to quantify macro level material flow based on process parameters. The results of multi-pass FSWs show increased refinement of the copper trace material. Implications of these techniques for quantifying process flow are discussed.

Charles R. Tolle; Timothy A. White; Karen S. Miller; Denis E. Clark; Herschel B. Smartt

2008-06-01T23:59:59.000Z

259

Three-dimensional multiphase segmentation of X-ray CT data of porous materials using a Bayesian Markov random field framework  

SciTech Connect (OSTI)

Advancements in noninvasive imaging methods such as X-ray computed tomography (CT) have led to a recent surge of applications in porous media research with objectives ranging from theoretical aspects of pore-scale fluid and interfacial dynamics to practical applications such as enhanced oil recovery and advanced contaminant remediation. While substantial efforts and resources have been devoted to advance CT technology, microscale analysis, and fluid dynamics simulations, the development of efficient and stable three-dimensional multiphase image segmentation methods applicable to large data sets is lacking. To eliminate the need for wet-dry or dual-energy scans, image alignment, and subtraction analysis, commonly applied in X-ray micro-CT, a segmentation method based on a Bayesian Markov random field (MRF) framework amenable to true three-dimensional multiphase processing was developed and evaluated. Furthermore, several heuristic and deterministic combinatorial optimization schemes required to solve the labeling problem of the MRF image model were implemented and tested for computational efficiency and their impact on segmentation results. Test results for three grayscale data sets consisting of dry glass beads, partially saturated glass beads, and partially saturated crushed tuff obtained with synchrotron X-ray micro-CT demonstrate great potential of the MRF image model for three-dimensional multiphase segmentation. While our results are promising and the developed algorithm is stable and computationally more efficient than other commonly applied porous media segmentation models, further potential improvements exist for fully automated operation.

Kulkarni, Ramaprasad; Tuller, Markus; Fink, Wolfgang; Wildschild, Dorthe (Oregon State U.); (Ariz)

2012-07-27T23:59:59.000Z

260

Spatial variation of void ratio and shear band thickness in sand using X-ray computed tomography  

SciTech Connect (OSTI)

A detailed study of spatial variation of void ratio and shear band thickness measurements is presented in this paper. A prismatic sand specimen that initially measured 57{center_dot}4 mm wide x 120{center_dot}5 mm long x 182{center_dot}1 mm high was sheared under plane-strain (biaxial) loading conditions. The specimen was prepared at a relative density of 79% using F-75 Ottawa sand. X-ray computed tomography was used to scan the specimen before shearing and after the onset of the shear band. The specimen failed through a single shear band with an inclination angle of 65{center_dot}6{sup o} measured from the direction of the minor principal stress. Computer algorithms were developed to calibrate CT images and quantify void ratio (e) variation within the specimen. CT data analysis revealed cross-sectional spatial variation in void ratio where density is higher in regions close to the edges of the specimen due to membrane effects and confining pressure with no significant variation in void ratio in the axial direction (top to bottom) before shearing. The shear band was easily identified from the CT images, and analysis of void ratio showed a noticeable jump in void ratio profile across the shear band. A detailed statistical summary of the thickness of the shear band and variation of void ratio across the shear band is presented and discussed.

Alshibli, K.A.; Hasan, A. (LSU)

2008-05-01T23:59:59.000Z

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261

Fluorodeoxyglucose Positron Emission Tomography Response and Normal Tissue Regeneration After Stereotactic Body Radiotherapy to Liver Metastases  

SciTech Connect (OSTI)

Purpose: To characterize changes in standardized uptake value (SUV) in positron emission tomography (PET) scans and determine the pace of normal tissue regeneration after stereotactic body radiation therapy (SBRT) for solid tumor liver metastases. Methods and Materials: We reviewed records of patients with liver metastases treated with SBRT to {>=}40 Gy in 3-5 fractions. Evaluable patients had pretreatment PET and {>=}1 post-treatment PET. Each PET/CT scan was fused to the planning computed tomography (CT) scan. The maximum SUV (SUV{sub max}) for each lesion and the total liver volume were measured on each PET/CT scan. Maximum SUV levels before and after SBRT were recorded. Results: Twenty-seven patients with 35 treated liver lesions were studied. The median follow-up was 15.7 months (range, 1.5-38.4 mo), with 5 PET scans per patient (range, 2-14). Exponential decay curve fitting (r=0.97) showed that SUV{sub max} declined to a plateau of 3.1 for controlled lesions at 5 months after SBRT. The estimated SUV{sub max} decay half-time was 2.0 months. The SUV{sub max} in controlled lesions fluctuated up to 4.2 during follow-up and later declined; this level is close to 2 standard deviations above the mean normal liver SUV{sub max} (4.01). A failure cutoff of SUV{sub max} {>=}6 is twice the calculated plateau SUV{sub max} of controlled lesions. Parenchymal liver volume decreased by 20% at 3-6 months and regenerated to a new baseline level approximately 10% below the pretreatment level at 12 months. Conclusions: Maximum SUV decreases over the first months after SBRT to plateau at 3.1, similar to the median SUV{sub max} of normal livers. Transient moderate increases in SUV{sub max} may be observed after SBRT. We propose a cutoff SUV{sub max} {>=}6, twice the baseline normal liver SUV{sub max}, to score local failure by PET criteria. Post-SBRT values between 4 and 6 would be suspicious for local tumor persistence or recurrence. The volume of normal liver reached nadir 3-6 months after SBRT and regenerated within the next 6 months.

Stinauer, Michelle A., E-mail: Michelle.Stinauer@ucdenver.edu [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States); Diot, Quentin; Westerly, David C.; Schefter, Tracey E.; Kavanagh, Brian D. [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States)] [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States)

2012-08-01T23:59:59.000Z

262

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou areDowntown Site -MiamiYVE r.x-L* d! CT NC0 - i ,

263

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 CenterFranconia, Virginia:FAQ < RAPID Jump to:Seadov Pty Ltd Jump to: navigation,Pvt LtdShrub Oak, New York: EnergySibleySidney,EnergyCT

264

The Effect of a Contrast Agent on Proton Beam Range in Radiotherapy Planning Using Computed Tomography for Patients With Locoregionally Advanced Lung Cancer  

SciTech Connect (OSTI)

Purpose: We evaluated the effect of a contrast agent (CA) on proton beam range in a treatment planning system (TPS) for patients with locoregionally advanced lung cancer. Methods and Materials: Two sets of computed tomography (CT) images (with and without CA) were obtained from 20 patients with lung cancer. Because the increase in Hounsfield unit ( Increment HU) value of the heart and great vessels due to the effect of CA is most prominent among thoracic structures, to evaluate the effect of CA on proton beam range in the TPS, we compared the calculated distal ranges in the plan with CA-enhanced CT with those with corrected CT, in which the HU values of the heart and great vessels in the CA-enhanced CT were replaced by average HU values obtained from the unenhanced CT. Results: The mean Increment HU value and the longest length of the heart and great vessels within the proton beam path in the field that passed through these structures were 189 {+-} 29 HU (range, 110-250 HU) and 7.1 {+-} 1.1 cm (range, 2.6-11.2 cm), respectively. The mean distal range error in the TPS because of the presence of CA was 1.0 {+-} 0.7 cm (range, 0.2-2.6 cm). Conclusion: If CA-enhanced CT images are used for radiotherapy planning using a proton beam for the treatment of lung cancer, our results suggest that the HU values of the heart and great vessels should be replaced by the average HU values of soft tissue to avoid discrepancies between planned and delivered doses.

Hwang, Ui-Jung; Shin, Dong Ho [Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi (Korea, Republic of); Kim, Tae Hyun, E-mail: k2onco@naver.com [Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi (Korea, Republic of); Moon, Sung Ho; Lim, Young Kyung; Jeong, Hojin; Rah, Jeong-Eun; Kim, Sang Soo; Kim, Joo-Young; Kim, Dae Yong; Park, Sung Yong; Cho, Kwan Ho [Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi (Korea, Republic of)

2011-11-15T23:59:59.000Z

265

Mathematics Master acadmique  

E-Print Network [OSTI]

, cosmos) to Geology (oil reserves), from Medical Technology (computerized axial tomography scanners

Thalmaier, Anton

266

CT Poison Control Center 2014 Video Contest Rules  

E-Print Network [OSTI]

entry form (found on posioncontrol.uchc.edu) b. Include a link to your video from your You Tube account and community partners. Judges will consider: length of video, appropriate format, accuracy of information poison center means to you, value of the CT Poison Control Center · Programming your phone with the CT

Kim, Duck O.

267

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

SciTech Connect (OSTI)

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.

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

2014-11-01T23:59:59.000Z

268

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

SciTech Connect (OSTI)

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].

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

2011-09-22T23:59:59.000Z

269

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

SciTech Connect (OSTI)

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].

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

2011-09-22T23:59:59.000Z

270

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...

271

White-Etching Crack Failure Overview, Tomography Analysis, and...  

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

White-Etching Crack Failure Overview, Tomography Analysis, and Test Development Presented by Aaron Greco of Argonne National Laboratory at the Wind Turbine Tribology Seminar 2014....

272

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

Open Energy Info (EERE)

changes in Earth structure are commonly determined using local earthquake tomography computer programs that invert multiple seismic-wave arrival time data sets separately and...

273

Instability of the linearized problem in multiwave tomography of ...  

E-Print Network [OSTI]

the sound speed and the thermal absorption arising in thermoacoustic and ... body of a patient, most often electromagnetic (thermoacoustic tomography) or op-

2013-10-03T23:59:59.000Z

274

Constrained optimization in seismic reflection tomography: an SQP ...  

E-Print Network [OSTI]

Seismic reflection tomography is a method for determining a subsurface velocity model from the traveltimes of seismic waves reflecting on geological interfaces.

2004-07-06T23:59:59.000Z

275

In-line x-ray phase-contrast tomography and diffraction-contrast tomography study of the ferrite-cementite microstructure in steel  

E-Print Network [OSTI]

In-line x-ray phase-contrast tomography and diffraction-contrast tomography study of the ferrite;In-line X-ray phase-contrast tomography and diffraction-contrast tomography study of the ferrite embedded in a ferrite matrix of medium-carbon steel. The measurements were carried out at the material

van Vliet, Lucas J.

276

28,183HUSEN ET AL.: TOMOGRAPHY OF SHALLOW SUBDUCTION IN CHILE Local earthquake tomography of shallow subduction in north Chile: A  

E-Print Network [OSTI]

[Graeber and Asch, 1999; C. Haberland and A. Rietbrock, Attenuation tomography in the western central Andes

Boschi, Lapo

277

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

SciTech Connect (OSTI)

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.

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)

2014-10-15T23:59:59.000Z

278

A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability  

SciTech Connect (OSTI)

We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d{sub 31} coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.

Wang, Qi; Wang, Junting; Lu, Qingyou, E-mail: qxl@ustc.edu.cn [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China) [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China); Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hou, Yubin [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China)] [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China)

2013-11-15T23:59:59.000Z

279

Characterizing aquifer heterogeneity using hydraulic tomography  

E-Print Network [OSTI]

such as sands and gravels because these materials drain the water so quickly. The K value is highly localized and only represents the portion of the aquifer in which the core was taken. When working with unconsolidated sediments, care must be taken to pack...?????. .?????.1 17 vi LIST OF FIGURES Figure 1: Map of field site and layout of wells used in study (figure modified from Engard, 2006). Figure 2: MOG setup for tomography study. Figure 3: Packed versus unpacked response in an observation well...

Wachter, Brian James

2008-07-29T23:59:59.000Z

280

Adaptive schemes for incomplete quantum process tomography  

SciTech Connect (OSTI)

We propose an iterative algorithm for incomplete quantum process tomography with the help of quantum state estimation. The algorithm, which is based on the combined principles of maximum likelihood and maximum entropy, yields a unique estimator for an unknown quantum process when one has less than a complete set of linearly independent measurement data to specify the quantum process uniquely. We apply this iterative algorithm adaptively in various situations and so optimize the amount of resources required to estimate a quantum process with incomplete data.

Teo, Yong Siah [Centre for Quantum Technologies, National University of Singapore, Singapore 117543 (Singapore); NUS Graduate School for Integrative Sciences and Engineering, Singapore 117597 (Singapore); Englert, Berthold-Georg [Centre for Quantum Technologies, National University of Singapore, Singapore 117543 (Singapore); Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Rehacek, Jaroslav; Hradil, Zdenek [Department of Optics, Palacky University, 17. listopadu 12, CZ-77146 Olomouc (Czech Republic)

2011-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 5, NO. 1, JANUARY/FEBRUARY 1999 75 Diffraction Grating Scanners Using  

E-Print Network [OSTI]

THERE is an increasing need in today's marketplace to develop low-cost high-precision optical scanners for a variety with single and pyramidal diffraction grating elements fabricated on the polished surface of large-area rotors, the technology has advanced toward optical applications [2]. A 20- m-tall reflective nickel polygon, plated

Merat, Francis L.

282

XEDS STEM Tomography For 3D Chemical CharacterizationOf Nanoscale...  

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

XEDS STEM Tomography For 3D Chemical CharacterizationOf Nanoscale Particles. XEDS STEM Tomography For 3D Chemical CharacterizationOf Nanoscale Particles. Abstract: We present a...

283

E-Print Network 3.0 - artery computed tomography Sample Search...  

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

computed tomography Search Powered by Explorit Topic List Advanced Search Sample search results for: artery computed tomography Page: << < 1 2 3 4 5 > >> 1 Abstract Computed...

284

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

SciTech Connect (OSTI)

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 dose–volume 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.

Li, Xiaoqiang; Quan, Enzhuo M.; Li, Yupeng [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Pan, Xiaoning [Department of Radiation Oncology, University of Texas Health Science Center at Tyler, Tyler, Texas (United States); Zhou, Yin [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang, Xiaochun [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Du, Weiliang [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kudchadker, Rajat J.; Johnson, Jennifer L. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kuban, Deborah A.; Lee, Andrew K. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhang, Xiaodong, E-mail: xizhang@mdanderson.org [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

2013-08-01T23:59:59.000Z

285

Screening of mixed surfactant systems: Phase behavior studies and CT imaging of surfactant-enhanced oil recovery experiments  

SciTech Connect (OSTI)

A systematic chemical screening study was conducted on selected anionic-nonionic and nonionic-nonionic systems. The objective of the study was to evaluate and determine combinations of these surfactants that would exhibit favorable phase behavior and solubilization capacity. The effects of different parameters including (a) salinity, (b) temperature, (c) alkane carbon number, (c) hydrophilic/lipophilic balance (HLB) of nonionic component, and (d) type of surfactant on the behavior of the overall chemical system were evaluated. The current work was conducted using a series of ethoxylated nonionic surfactants in combinations of several anionic systems with various hydrocarbons. Efforts to correlate the behavior of these mixed systems led to the development of several models for the chemical systems tested. The models were used to compare the different systems and provided some guidelines for formulating them to account for variations in salinity, oil hydrocarbon number, and temperature. The models were also evaluated to determine conformance with the results from experimental measurements. The models provided good agreement with experimental results. X-ray computed tomography (CT) was used to study fluid distributions during chemical enhanced oil recovery experiments. CT-monitored corefloods were conducted to examine the effect of changing surfactant slug size injection on oil bank formation and propagation. Reducing surfactant slug size resulted in lower total oil production. Oil recovery results, however, did not correlate with slug size for the low-concentration, alkaline, mixed surfactant system used in these tests. The CT measurements showed that polymer mobility control and core features also affected the overall oil recovery results.

Llave, F.M.; Gall, B.L.; Lorenz, P.B.; Cook, I.M.; Scott, L.J.

1993-11-01T23:59:59.000Z

286

Tumor Tracking Method Based on a Deformable 4D CT Breathing Motion Model Driven by an External Surface Surrogate  

SciTech Connect (OSTI)

Purpose: To develop a tumor tracking method based on a surrogate-driven motion model, which provides noninvasive dynamic localization of extracranial targets for the compensation of respiration-induced intrafraction motion in high-precision radiation therapy. Methods and Materials: The proposed approach is based on a patient-specific breathing motion model, derived a priori from 4-dimensional planning computed tomography (CT) images. Model parameters (respiratory baseline, amplitude, and phase) are retrieved and updated at each treatment fraction according to in-room radiography acquisition and optical surface imaging. The baseline parameter is adapted to the interfraction variations obtained from the daily cone beam (CB) CT scan. The respiratory amplitude and phase are extracted from an external breathing surrogate, estimated from the displacement of the patient thoracoabdominal surface, acquired with a noninvasive surface imaging device. The developed method was tested on a database of 7 lung cancer patients, including the synchronized information on internal and external respiratory motion during a CBCT scan. Results: About 30 seconds of simultaneous acquisition of CBCT and optical surface images were analyzed for each patient. The tumor trajectories identified in CBCT projections were used as reference and compared with the target trajectories estimated from surface displacement with the a priori motion model. The resulting absolute differences between the reference and estimated tumor motion along the 2 image dimensions ranged between 0.7 and 2.4 mm; the measured phase shifts did not exceed 7% of the breathing cycle length. Conclusions: We investigated a tumor tracking method that integrates breathing motion information provided by the 4-dimensional planning CT with surface imaging at the time of treatment, representing an alternative approach to point-based external–internal correlation models. Although an in-room radiograph-based assessment of the reliability of the motion model is envisaged, the developed technique does not involve the estimation and continuous update of correlation parameters, thus requiring a less intense use of invasive imaging.

Fassi, Aurora, E-mail: aurora.fassi@mail.polimi.it [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Schaerer, Joël; Fernandes, Mathieu [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy); Sarrut, David [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Baroni, Guido [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy)

2014-01-01T23:59:59.000Z

287

Multilevel bioluminescence tomography based on radiative transfer equation  

E-Print Network [OSTI]

Multilevel bioluminescence tomography based on radiative transfer equation Part 2: total variation with both l1 and total- variation norm for bioluminescence tomography based on radiative transfer equation, Radiative Transfer (Dover Publications, 1960). 14. K. M. Case and P. F. PF Zweifel, Linear Transport Theory

Soatto, Stefano

288

Neutron Stimulated Emission Computed Tomography of Stable Isotopes  

E-Print Network [OSTI]

Neutron Stimulated Emission Computed Tomography of Stable Isotopes Carey E. Floyd Jr.*ab , Calvin North Carolina Keywords: imaging, neutrons, tomography, spectroscopy ABSTRACT Here we report on the development of a new molecular imaging technique using inelastic scattering of fast neutrons. Earlier studies

289

Scattered Neutron Tomography Based on A Neutron Transport Inverse Problem  

SciTech Connect (OSTI)

Neutron radiography and computed tomography are commonly used techniques to non-destructively examine materials. Tomography refers to the cross-sectional imaging of an object from either transmission or reflection data collected by illuminating the object from many different directions.

William Charlton

2007-07-01T23:59:59.000Z

290

Total variation based Fourier reconstruction and regularization for computer tomography  

E-Print Network [OSTI]

of the reconstruted image. Insufficiency of data may be caused by the undersampling of projections, by the limitedTotal variation based Fourier reconstruction and regularization for computer tomography Xiao. Index Terms-- Computer tomography, reconstruction, regular- ization, iterative method, Fourier method

Zhang, Xiaoqun

291

Full-wavelet approach for fluorescence diffuse optical tomography  

E-Print Network [OSTI]

Full-wavelet approach for fluorescence diffuse optical tomography with structured illumination Leonardo da Vinci 32, I-20133 Milan, Italy 3 Centre for Medical Image Computing, University College London); published October 28, 2010 We present a fast reconstruction method for fluorescence optical tomography

Boyer, Edmond

292

Propagation Beam Consideration for 3D THz Computed Tomography  

E-Print Network [OSTI]

Propagation Beam Consideration for 3D THz Computed Tomography B. Recur, 1, J.P. Guillet, 2 I. Manek, "Refraction losses in terahertz computed tomography," Opt. Commun. 283, 2050­2055 (2010). 8. S. Nadar, H, "Accelerated image reconstruction using ordered subsets of projection data," IEEE Trans. Med. Imaging 13, 601

Boyer, Edmond

293

Registration of Planar Film Radiographs with Computed Tomography  

E-Print Network [OSTI]

Registration of Planar Film Radiographs with Computed Tomography Lisa M. Gottesfeld Brown lisabHigh University Bethlehem, PA 18015 Abstract In this paper we describe a method to register Computed Tomography, high resolution, three dimensional, structural med- ical images, such as data from X-ray computed

Boult, Terrance E.

294

Double-Difference Tomography for Sequestration MVA  

SciTech Connect (OSTI)

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.

Westman, Erik

2008-12-31T23:59:59.000Z

295

Low-Dose Dual-Energy CT for PET Attenuation Correction with Statistical Sinogram Restoration  

E-Print Network [OSTI]

1 Low-Dose Dual-Energy CT for PET Attenuation Correction with Statistical Sinogram Restoration. of Michigan & Univ. of Washington Outline Introduction - PET/CT background - CT-based attenuation correction for PET Conventional sinogram decomposition in DE-CT Statistically motivated sinogram restoration in DE

Fessler, Jeffrey A.

296

Multi-atlas segmentation in head and neck CT scans  

E-Print Network [OSTI]

We investigate automating the task of segmenting structures in head and neck CT scans, to minimize time spent on manual contouring of structures of interest. We focus on the brainstem and left and right parotids. To generate ...

Arbisser, Amelia M

2012-01-01T23:59:59.000Z

297

Obscure pulmonary masses: bronchial impaction revealed by CT  

SciTech Connect (OSTI)

Dilated bronchi impacted with mucus or tumor are recognized on standard chest radiographs because they are surrounded by aerated pulmonary parenchyma. When imaged in different projections, these lesions produce a variety of appearances that are generally familiar. This report characterizes less familiar computed tomographic (CT) findings in eight patients with pathologic bronchial distension of congenital, neoplastic, or infectious etiologies and correlates them with chest films. In seven patients, CT readily revealed dilated bronchi and/or regional lung hypodensity. In four of these cases, CT led to the initial suspicion of dilated bronchi. CT should be used early in the evaluation of atypical pulmonary mass lesions or to confirm suspected bronchial impaction because of the high probability it will reveal diagnostic features.

Pugatch, R.D.; Gale, M.E.

1983-11-01T23:59:59.000Z

298

Out-of-Plane Computed-Tomography-Guided Biopsy Using a Magnetic-Field-Based Navigation System  

SciTech Connect (OSTI)

The purpose of this article is to report our clinical experience with out-of-plane computed-tomography (CT)-guided biopsies using a magnetic-field-based navigation system. Between February 2002 and March 2003, 20 patients underwent CT-guided biopsy in which an adjunct magnetic-field-based navigation system was used to aid an out-of-plane biopsy approach. Eighteen patients had an underlying primary malignancy. All biopsies involved the use of a coaxial needle system in which an outer 18G guide needle was inserted to the lesion using the navigation system and an inner 22G needle was then used to obtain fine-needle aspirates. Complications and technical success were recorded. Target lesions were located in the adrenal gland (n = 7), liver (n = 6), pancreas (n = 3), lung (n = 2), retroperitoneal lymph node (n = 1), and pelvis (n = 1). The mean lesion size (maximum transverse diameter) was 26.5 mm (range: 8-70 mm) and the mean and median cranial-caudal distance, between the transaxial planes of the final needle tip location and the needle insertion site, was 40 mm (range: 18-90 mm). Needle tip positioning was successfully placed within the lesion in all 20 biopsies. A diagnosis of malignancy was obtained in 14 biopsies. Benign diagnoses were encountered in the remaining six biopsies and included a benign adrenal gland (n = 2), fibroelastic tissue (n = 1), hepocytes with steatosis (n = 2) and reactive hepatocytes (n = 1). No complications were encountered. A magnetic-field-based navigation system is an effective adjunct tool for accurate and safe biopsy of lesions that require an out-of-plane CT approach.

Wallace, Michael J., E-mail: mwallace@di.mdacc.tmc.edu; Gupta, Sanjay; Hicks, Marshall E. [University of Texas M. D. Anderson Cancer Center, Departments of Diagnostic Radiology, Section of Vascular and Interventional Radiology (United States)

2006-02-15T23:59:59.000Z

299

Ultra-high resolution computed tomography imaging  

DOE Patents [OSTI]

A method for ultra-high resolution computed tomography imaging, comprising the steps of: focusing a high energy particle beam, for example x-rays or gamma-rays, onto a target object; acquiring a 2-dimensional projection data set representative of the target object; generating a corrected projection data set by applying a deconvolution algorithm, having an experimentally determined a transfer function, to the 2-dimensional data set; storing the corrected projection data set; incrementally rotating the target object through an angle of approximately 180.degree., and after each the incremental rotation, repeating the radiating, acquiring, generating and storing steps; and, after the rotating step, applying a cone-beam algorithm, for example a modified tomographic reconstruction algorithm, to the corrected projection data sets to generate a 3-dimensional image. The size of the spot focus of the beam is reduced to not greater than approximately 1 micron, and even to not greater than approximately 0.5 microns.

Paulus, Michael J. (Knoxville, TN); Sari-Sarraf, Hamed (Knoxville, TN); Tobin, Jr., Kenneth William (Harriman, TN); Gleason, Shaun S. (Knoxville, TN); Thomas, Jr., Clarence E. (Knoxville, TN)

2002-01-01T23:59:59.000Z

300

Measuring momentum for charged particle tomography  

DOE Patents [OSTI]

Methods, apparatus and systems for detecting charged particles and obtaining tomography of a volume by measuring charged particles including measuring the momentum of a charged particle passing through a charged particle detector. Sets of position sensitive detectors measure scattering of the charged particle. The position sensitive detectors having sufficient mass to cause the charged particle passing through the position sensitive detectors to scatter in the position sensitive detectors. A controller can be adapted and arranged to receive scattering measurements of the charged particle from the charged particle detector, determine at least one trajectory of the charged particle from the measured scattering; and determine at least one momentum measurement of the charged particle from the at least one trajectory. The charged particle can be a cosmic ray-produced charged particle, such as a cosmic ray-produced muon. The position sensitive detectors can be drift cells, such as gas-filled drift tubes.

Morris, Christopher (Los Alamos, NM); Fraser, Andrew Mcleod (Los Alamos, NM); Schultz, Larry Joe (Los Alamos, NM); Borozdin, Konstantin N. (Los Alamos, NM); Klimenko, Alexei Vasilievich (Maynard, MA); Sossong, Michael James (Los Alamos, NM); Blanpied, Gary (Lexington, SC)

2010-11-23T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Magnified Weak Lensing Cross Correlation Tomography  

SciTech Connect (OSTI)

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

Ulmer, Melville P., Clowe, Douglas I.

2010-11-30T23:59:59.000Z

302

Compact adaptive optic-optical coherence tomography system  

DOE Patents [OSTI]

Badal Optometer and rotating cylinders are inserted in the AO-OCT to correct large spectacle aberrations such as myopia, hyperopic and astigmatism for ease of clinical use and reduction. Spherical mirrors in the sets of the telescope are rotated orthogonally to reduce aberrations and beam displacement caused by the scanners. This produces greatly reduced AO registration errors and improved AO performance to enable high order aberration correction in a patient eyes.

Olivier, Scot S. (Livermore, CA); Chen, Diana C. (Fremont, CA); Jones, Steven M. (Danville, CA); McNary, Sean M. (Stockton, CA)

2012-02-28T23:59:59.000Z

303

Compact adaptive optic-optical coherence tomography system  

DOE Patents [OSTI]

Badal Optometer and rotating cylinders are inserted in the AO-OCT to correct large spectacle aberrations such as myopia, hyperopic and astigmatism for ease of clinical use and reduction. Spherical mirrors in the sets of the telescope are rotated orthogonally to reduce aberrations and beam displacement caused by the scanners. This produces greatly reduced AO registration errors and improved AO performance to enable high order aberration correction in a patient eyes.

Olivier, Scot S. (Livermore, CA); Chen, Diana C. (Fremont, CA); Jones, Steven M. (Danville, CA); McNary, Sean M. (Stockton, CA)

2011-05-17T23:59:59.000Z

304

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

SciTech Connect (OSTI)

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.

Rotstein, S.; Lax, I.; Svane, G. (Karolinska Hospital, Stockholm (Sweden))

1990-01-01T23:59:59.000Z

305

Applying Nonlinear Signal Analysis Technologies to Flame Scanner Signals to Improve Staging of Cyclone Boilers for NOx control  

SciTech Connect (OSTI)

Cyclone{trademark} boiler owners continue to drive down NO{sub x} emissions by increasingly sophisticated staging and air distribution schemes. For example, Alliant Energy has employed RMT's SmartBurn{reg_sign} technology, and Ameren UE has pioneered neural nets to reduce emissions. Over the last 11 years under sponsorship of EPRI, the team of ORNL and B&W has developed pulverized coal burner diagnostic technology by applying nonlinear signal analysis techniques to flame scanner signals. The team has extended the technology to cyclones to facilitate deeper staging of the cyclones to reduce NO{sub x} emissions. Development projects were conducted at the Alliant Energy Edgewater Units 3 and 4, and Ameren UE Sioux Unit 1. Nonlinear analysis statistics were correlated to upsets in cyclone operation resulting from poor air distribution in the burner and barrel. The team demonstrated that the lighter and main flame scanners can be used to independently guide adjustments to the burner and barrel.

Flynn, T. J. [Babcock and Wilcox Company, The; Bailey, R. T. [Babcock and Wilcox Company, The; Fuller, T. A. [Babcock and Wilcox Company, The; FINNEY, Charles E A [ORNL; Daw, C Stuart [ORNL; Stallings, J. [Electric Power Research Institute (EPRI); Himes, R. [Electric Power Research Institute (EPRI); Bermke, R. [Alliant Energy

2006-08-01T23:59:59.000Z

306

Laser hazard analysis for LASIRIS Model MAG-501L-670M-1000-45[degree]-K diode laser associated with high resolution pulsed scanner.  

SciTech Connect (OSTI)

A laser hazard analysis and safety assessment was performed for the LASIRISTM Model MAG-501L-670M-1000-45o-K diode laser associated with the High Resolution Pulse Scanner based on the ANSI Standard Z136.1-2000, American National Standard for the Safe Use of Lasers and the ANSI Standard Z136.6-2000, American National Standard for the Safe Use of Lasers Outdoors. The laser was evaluated for both indoor and outdoor use.

Augustoni, Arnold L.

2004-11-01T23:59:59.000Z

307

Embrittlement of RPV steels; An atom probe tomography perspective  

SciTech Connect (OSTI)

Atom probe tomography has played a key role in the understanding of the embrittlement of neutron irradiated reactor pressure vessel steels through the atomic level characterization of the microstructure. Atom probe tomography has been used to demonstrate the importance of the post weld stress relief treatment in reducing the matrix copper content in high copper alloys, the formation of {approx}-nm-diameter copper-, nickel-, manganese- and silicon-enriched precipitates during neutron irradiation in copper containing RPV steels, and the coarsening of these precipitates during post irradiation heat treatments. Atom probe tomography has been used to detect {approx}2-nm-diameter nickel-, silicon- and manganese-enriched clusters in neutron irradiated low copper and copper free alloys. Atom probe tomography has also been used to quantify solute segregation to, and precipitation on, dislocations and grain boundaries.

Miller, Michael K [ORNL; Russell, Kaye F [ORNL

2007-01-01T23:59:59.000Z

308

Functional lung imaging in humans using Positron Emission Tomography  

E-Print Network [OSTI]

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 ...

Layfield, Dominick, 1971-

2003-01-01T23:59:59.000Z

309

Scattered neutron tomography based on a neutron transport problem  

E-Print Network [OSTI]

scattering objects because it does not adequately account for the scattering component of the neutron beam intensity exiting the sample. We proposed a new method of computed tomography which employs an inverse problem analysis of both the transmitted...

Scipolo, Vittorio

2005-11-01T23:59:59.000Z

310

Breast ultrasound tomography with total-variation regularization  

SciTech Connect (OSTI)

Breast ultrasound tomography is a rapidly developing imaging modality that has the potential to impact breast cancer screening and diagnosis. A new ultrasound breast imaging device (CURE) with a ring array of transducers has been designed and built at Karmanos Cancer Institute, which acquires both reflection and transmission ultrasound signals. To extract the sound-speed information from the breast data acquired by CURE, we have developed an iterative sound-speed image reconstruction algorithm for breast ultrasound transmission tomography based on total-variation (TV) minimization. We investigate applicability of the TV tomography algorithm using in vivo ultrasound breast data from 61 patients, and compare the results with those obtained using the Tikhonov regularization method. We demonstrate that, compared to the Tikhonov regularization scheme, the TV regularization method significantly improves image quality, resulting in sound-speed tomography images with sharp (preserved) edges of abnormalities and few artifacts.

Huang, Lianjie [Los Alamos National Laboratory; Li, Cuiping [KARMANOS CANCER INSTIT.; Duric, Neb [KARMANOS CANCER INSTIT

2009-01-01T23:59:59.000Z

311

Computational Inversion of Electron Tomography Images -Gradient Flows  

E-Print Network [OSTI]

Computational Inversion of Electron Tomography Images Using L2 -Gradient Flows Guoliang Xu 1) Ming Computing Institute of Computational Mathematics, Academy of Mathematics and System Sciences, Chinese Academy of Sciences, Beijing 100190, China 2) Department of Computer Sciences and Institute

Texas at Austin, University of

312

SU-E-I-02: A Framework to Perform Batch Simulations of Computational Voxel Phantoms to Study Organ Doses in Computed Tomography Using a Commercial Monte Carlo Software Package  

SciTech Connect (OSTI)

Purpose: ImpactMC (CT Imaging, Erlangen, Germany) is a Monte Carlo (MC) software package that offers a GPU enabled, user definable and validated method for 3D dose distribution calculations for radiography and Computed Tomography (CT). ImpactMC, in and of itself, offers limited capabilities to perform batch simulations. The aim of this work was to develop a framework for the batch simulation of absorbed organ dose distributions from CT scans of computational voxel phantoms. Methods: The ICRP 110 adult Reference Male and Reference Female computational voxel phantoms were formatted into compatible input volumes for MC simulations. A Matlab (The MathWorks Inc., Natick, MA) script was written to loop through a user defined set of simulation parameters and 1) generate input files required for the simulation, 2) start the MC simulation, 3) segment the absorbed dose for organs in the simulated dose volume and 4) transfer the organ doses to a database. A demonstration of the framework is made where the glandular breast dose to the adult Reference Female phantom, for a typical Chest CT examination, is investigated. Results: A batch of 48 contiguous simulations was performed with variations in the total collimation and spiral pitch. The demonstration of the framework showed that the glandular dose to the right and left breast will vary depending on the start angle of rotation, total collimation and spiral pitch. Conclusion: The developed framework provides a robust and efficient approach to performing a large number of user defined MC simulations with computational voxel phantoms in CT (minimal user interaction). The resulting organ doses from each simulation can be accessed through a database which greatly increases the ease of analyzing the resulting organ doses. The framework developed in this work provides a valuable resource when investigating different dose optimization strategies in CT.

Bujila, R; Nowik, P; Poludniowski, G [Karolinska University Hospital, Stockholm, Stockholm (Sweden)

2014-06-01T23:59:59.000Z

313

E-Print Network 3.0 - anemia computed tomographic Sample Search...  

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

tomographic scanner inventors A. Cormack and G. Hounsfield built the first computed tomography scanners... geometric transforms A classification of tomographic procedures...

314

The Relationship between Organ Dose and Patients Size in Multidetector Computed Tomography (MDCT) Scans Utilizing Tube Current Modulation (TCM)  

E-Print Network [OSTI]

However, the generated conversion factors were based on fixeis provided by conversion factors based on organ doseswhich established conversion factors applied to the scanner-

Khatonabadi, Maryam

2013-01-01T23:59:59.000Z

315

Nonlinear regularization techniques for seismic tomography  

SciTech Connect (OSTI)

The effects of several nonlinear regularization techniques are discussed in the framework of 3D seismic tomography. Traditional, linear, l{sub 2} penalties are compared to so-called sparsity promoting l{sub 1} and l{sub 0} penalties, and a total variation penalty. Which of these algorithms is judged optimal depends on the specific requirements of the scientific experiment. If the correct reproduction of model amplitudes is important, classical damping towards a smooth model using an l{sub 2} norm works almost as well as minimizing the total variation but is much more efficient. If gradients (edges of anomalies) should be resolved with a minimum of distortion, we prefer l{sub 1} damping of Daubechies-4 wavelet coefficients. It has the additional advantage of yielding a noiseless reconstruction, contrary to simple l{sub 2} minimization ('Tikhonov regularization') which should be avoided. In some of our examples, the l{sub 0} method produced notable artifacts. In addition we show how nonlinear l{sub 1} methods for finding sparse models can be competitive in speed with the widely used l{sub 2} methods, certainly under noisy conditions, so that there is no need to shun l{sub 1} penalizations.

Loris, I. [Mathematics Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels (Belgium)], E-mail: igloris@vub.ac.be; Douma, H. [Department of Geosciences, Princeton University, Guyot Hall, Washington Road, Princeton, NJ 08544 (United States); Nolet, G. [Geosciences Azur, Universite de Nice-Sophia Antipolis, CNRS/IRD, 250 Rue Albert Einstein, Sophia Antipolis 06560 (France); Daubechies, I. [Program in Applied and Computational Mathematics, Princeton University, Fine Hall, Washington Road, Princeton, NJ 08544 (United States); Regone, C. [BP America Inc., 501 Westlake Park Blvd., Houston, TX 77079 (United States)

2010-02-01T23:59:59.000Z

316

On Recent Claims Concerning the R_h=ct Universe  

E-Print Network [OSTI]

The R_h=ct Universe is a Friedmann-Robertson-Walker (FRW) cosmology which, like LCDM, assumes the presence of dark energy in addition to (baryonic and non-luminous) matter and radiation. Unlike LCDM, however, it is also constrained by the equation of state (EOS) p=-rho/3, in terms of the total pressure p and energy density rho. One-on-one comparative tests between R_h=ct and LCDM have been carried out using over 14 different cosmological measurements and observations. In every case, the data have favoured R_h=ct over the standard model, with model selection tools yielding a likelihood ~90-95% that the former is correct, versus only ~5-10% for the latter. In other words, the standard model without the EOS p=-rho/3 does not appear to be the optimal description of nature. Yet in spite of these successes---or perhaps because of them---several concerns have been published recently regarding the fundamental basis of the theory itself. The latest paper on this subject even claims---quite remarkably---that R_h=ct is a vacuum solution, though quite evidently rho is not 0. Here, we address these concerns and demonstrate that all criticisms leveled thus far against R_h=ct, including the supposed vacuum condition, are unwarranted. They all appear to be based on incorrect assumptions or basic theoretical errors. Nevertheless, continued scrutiny such as this will be critical to establishing R_h=ct as the correct description of nature.

Fulvio Melia

2014-10-17T23:59:59.000Z

317

PET/CT-guided Interventions: Personnel Radiation Dose  

SciTech Connect (OSTI)

PurposeTo quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.MethodsIn this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).ResultsThe median effective dose was 0.02 (range 0-0.13) mSv for the primary operator, 0.01 (range 0-0.05) mSv for the nurse anesthetist, and 0.02 (range 0-0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0-0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).ConclusionThe operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient.

Ryan, E. Ronan, E-mail: ronan@ronanryan.com; Thornton, Raymond; Sofocleous, Constantinos T.; Erinjeri, Joseph P. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Hsu, Meier [Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics (United States); Quinn, Brian; Dauer, Lawrence T. [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics (United States); Solomon, Stephen B. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States)

2013-08-01T23:59:59.000Z

318

Unusual association of alveolar rhabdomyosarcoma with pancreatic metastasis: emerging role of PET-CT in tumor staging  

E-Print Network [OSTI]

Christie R, Daw NC et al ( 2005) PET/CT in the evaluation ofComparative study of FDG PET/CT and conventional imaging inet al (2009) Diagnostic value of PET/CT for the staging and

2010-01-01T23:59:59.000Z

319

Brain Imaging with Positron Emission Tomography: Quantification and Biomedical Applications in Alzheimer's Disease and Brain Tumors  

E-Print Network [OSTI]

HC, Ysaguirre T, inventors; Siemens Medical Solutions USA,HC, Ysaguirre T, inventors; Siemens Medical Solutions USA,ECAT EXACT HR+ PET scanner (Siemens/CTI, Inc. ) consists of

Wardak, Mirwais

2013-01-01T23:59:59.000Z

320

Reduction of radiation dose to radiosensitive organs and its tradeoff with image quality in Computed Tomography  

E-Print Network [OSTI]

major manufacturers, including the Siemens Sensation 64, GEthis study 87 Scanner/Mode Siemens Sensation 64 GE VCT axiallisted in the Table. For Siemens Sensation 64 and GE VCT

Zhang, Di

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

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)

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.

Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis; Papadakis, Antonios E.; Damilakis, John [Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete (Greece); Medical Diagnostic Center 'Ayios Therissos,' P.O. Box 28405, Nicosia 2033, Cyprus and Department of Medical Physics, Medical School, Democritus University of Thrace, Panepistimioupolis, Dragana 68100, Alexandroupolis (Greece); Department of Medical Physics, University Hospital of Heraklion, P.O. Box 1352, Heraklion 71110, Crete (Greece); Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete (Greece)

2013-01-15T23:59:59.000Z

322

Quantum tomography with wavelet transform in Banach space on Homogeneous space  

E-Print Network [OSTI]

The intimate connection between the Banach space wavelet reconstruction method on homogeneous spaces with both singular and nonsingular vacuum vectors, and some of well known quantum tomographies, such as: Moyal-representation for a spin, discrete phase space tomography, tomography of a free particle, Homodyne tomography, phase space tomography and SU(1,1) tomography is explained. Also both the atomic decomposition and banach frame nature of these quantum tomographic examples is explained in details. Finally the connection between the wavelet formalism on Banach space and Q-function is discussed.

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

2008-01-25T23:59:59.000Z

323

Detektion von Phäochromozytomen und rekurrenten medullären Schilddrüsenkarzinomen mit F18 DOPA PET/CT.  

E-Print Network [OSTI]

??Evaluating [18F]dihydroxyphenylalanine (DOPA) in patients with clinical suspicion for a primary or recurrent pheochromocytoma (pheo) by means of whole body PET/CT. In pheos PET/CT detects… (more)

Zeich, Katrin

2009-01-01T23:59:59.000Z

324

ACCELERATING REGULARIZED ITERATIVE CT RECONSTRUCTION ON COMMODITY GRAPHICS HARDWARE (GPU)  

E-Print Network [OSTI]

overhead to very moderate levels. Index Terms-- Iterative Reconstruction, Computed Tomography, Ordered Klaus Mueller Center for Visual Computing, Computer Science Department, Stony Brook University ABSTRACT) is the overall theme in many efforts to lower these exposures. Effective methods here include limiting either

Mueller, Klaus

325

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

SciTech Connect (OSTI)

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.

Jason M. Harp; Paul A. Demkowicz

2014-10-01T23:59:59.000Z

326

Quantitative CT of lung nodules: Dependence of calibration on patient body size, anatomic region, and calibration nodule size for single- and dual-energy techniques  

SciTech Connect (OSTI)

Calcium concentration may be a useful feature for distinguishing benign from malignant lung nodules in computer-aided diagnosis. The calcium concentration can be estimated from the measured CT number of the nodule and a CT number vs calcium concentration calibration line that is derived from CT scans of two or more calcium reference standards. To account for CT number nonuniformity in the reconstruction field, such calibration lines may be obtained at multiple locations within lung regions in an anthropomorphic phantom. The authors performed a study to investigate the effects of patient body size, anatomic region, and calibration nodule size on the derived calibration lines at ten lung region positions using both single energy (SE) and dual energy (DE) CT techniques. Simulated spherical lung nodules of two concentrations (50 and 100 mg/cc CaCO{sub 3}) were employed. Nodules of three different diameters (4.8, 9.5, and 16 mm) were scanned in a simulated thorax section representing the middle of the chest with large lung regions. The 4.8 and 9.5 mm nodules were also scanned in a section representing the upper chest with smaller lung regions. Fat rings were added to the peripheries of the phantoms to simulate larger patients. Scans were acquired on a GE-VCT scanner at 80, 120, and 140 kVp and were repeated three times for each condition. The average absolute CT number separations between the calibration lines were computed. In addition, under- or overestimates were determined when the calibration lines for one condition (e.g., small patient) were used to estimate the CaCO{sub 3} concentrations of nodules for a different condition (e.g., large patient). The authors demonstrated that, in general, DE is a more accurate method for estimating the calcium contents of lung nodules. The DE calibration lines within the lung field were less affected by patient body size, calibration nodule size, and nodule position than the SE calibration lines. Under- or overestimates in CaCO{sub 3} concentrations of nodules were also in general smaller in quantity with DE than with SE. However, because the slopes of the calibration lines for DE were about one-half the slopes for SE, the relative improvement in the concentration estimates for DE as compared to SE was about one-half the relative improvement in the separation between the calibration lines. Results in the middle of the chest thorax section with large lungs were nearly completely consistent with the above generalization. On the other hand, results in the upper-chest thorax section with smaller lungs and greater amounts of muscle and bone were mixed. A repeat of the entire study in the upper thorax section yielded similar mixed results. Most of the inconsistencies occurred for the 4.8 mm nodules and may be attributed to errors caused by beam hardening, volume averaging, and insufficient sampling. Targeted, higher resolution reconstructions of the smaller nodules, application of high atomic number filters to the high energy x-ray beam for improved spectral separation, and other future developments in DECT may alleviate these problems and further substantiate the superior accuracy of DECT in quantifying the calcium concentrations of lung nodules.

Goodsitt, Mitchell M.; Chan, Heang-Ping; Way, Ted W.; Schipper, Mathew J.; Larson, Sandra C.; Christodoulou, Emmanuel G. [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-5842 (United States)

2009-07-15T23:59:59.000Z

327

A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation  

SciTech Connect (OSTI)

Purpose: The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. Methods: The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360 Degree-Sign through anthropomorphic voxelized female chest and head (0 Degree-Sign and 30 Degree-Sign tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tables of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDI{sub vol} and multiplying by a physical CTDI{sub vol} measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30 Degree-Sign relative to a nontilted scan. Results: Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate total organ doses calculated using our database are within 1% of those calculated using Monte Carlo simulations with the same geometry and scan parameters for all organs except red bone marrow (within 6%), and within 23% of published estimates for different voxelized phantoms. Results from the example of using the database to estimate organ dose for coronary angiography CT acquisitions show 2.1%, 1.1%, and -32% change in breast dose and 2.1%, -0.74%, and 4.7% change in lung dose for reduced kVp, tube current modulated, and partial angle protocols, respectively, relative to the reference protocol. Results show -19.2% difference in dose to eye lens for a tilted scan relative to a nontilted scan. The reported relative changes in organ doses are presented without quantification of image quality and are for the sole purpose of demonstrating the use of the proposed database. Conclusions: The proposed database and calculation method enable the estimation of organ dose for coronary angiography and brain perfusion CT scans utilizing any spectral shape and angular tube current modulation scheme by taking advantage of the precalculated Monte Carlo simulation results. The database can be used in conjunction with image quality studies to develop optimized acquisition techniques and may be particularly beneficial for optimizing dual kVp acquisitions for which numerous kV, mA, and filtration combinations may be investigated.

Rupcich, Franco; Badal, Andreu; Kyprianou, Iacovos; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Division of Imaging and Applied Mathematics (OSEL/CDRH), US Food and Drug Administration, Silver Spring, Maryland 20905 (United States); Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States)

2012-09-15T23:59:59.000Z

328

State Waste Discharge Permit Application: Electric resistance tomography testing  

SciTech Connect (OSTI)

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.

Not Available

1994-04-01T23:59:59.000Z

329

On Recent Claims Concerning the R_h=ct Universe  

E-Print Network [OSTI]

The R_h=ct Universe is a Friedmann-Robertson-Walker (FRW) cosmology which, like LCDM, assumes the presence of dark energy in addition to (baryonic and non-luminous) matter and radiation. Unlike LCDM, however, it is also constrained by the equation of state (EOS) p=-rho/3, in terms of the total pressure p and energy density rho. One-on-one comparative tests between R_h=ct and LCDM have been carried out using over 14 different cosmological measurements and observations. In every case, the data have favoured R_h=ct over the standard model, with model selection tools yielding a likelihood ~90-95% that the former is correct, versus only ~5-10% for the latter. In other words, the standard model without the EOS p=-rho/3 does not appear to be the optimal description of nature. Yet in spite of these successes---or perhaps because of them---several concerns have been published recently regarding the fundamental basis of the theory itself. The latest paper on this subject even claims---quite remarkably---that R_h=ct is ...

Melia, Fulvio

2014-01-01T23:59:59.000Z

330

Status and Promise CT's and Magnetized Target Fusion  

E-Print Network [OSTI]

. Hill (LLNL) #12;CT's: Spheromaks & Field Reversed Configurations At LLNL, the SSPX experiment is investigating spheromak formation, sustainment, and confinement issues. (Hill, Mclean, Wood, Ryutov). At UC-Davis, formation and acceleration of spheromaks. (Hwang) At the U of Washington, field reversed configuration

331

Saturday Workshop 2/7/2009 RS: Molly Burke CT's: Roy Center & Lee Kelly  

E-Print Network [OSTI]

Saturday Workshop 2/7/2009 RS: Molly Burke CT's: Roy Center & Lee Kelly Drosophila Handbook page 1 2/7/2009 RS: Molly Burke CT's: Roy Center & Lee Kelly Drosophila Handbook page 2 Table of Contents Standards 22 #12;Saturday Workshop 2/7/2009 RS: Molly Burke CT's: Roy Center & Lee Kelly Drosophila Handbook

Rose, Michael R.

332

Measurements from 3D-CT renderings are used in research and clinical management  

E-Print Network [OSTI]

Measurements from 3D-CT renderings are used in research and clinical management: · Characterization for the prism]) RENDERING TECHNIQUES USED in ANALYZE 10.0: - Volume Render - (2) Volumes of Interest 1) VOI-Auto & 2) VOI-Manual TOTAL 3D-CT MODELS: 3 mandibles X 18 CT series X 3 rendering techniques = 162 mandible

Vorperian, Houri K.

333

Characterization of adaptive statistical iterative reconstruction algorithm for dose reduction in CT: A pediatric oncology perspective  

SciTech Connect (OSTI)

Purpose: This study demonstrates a means of implementing an adaptive statistical iterative reconstruction (ASiR Trade-Mark-Sign ) technique for dose reduction in computed tomography (CT) while maintaining similar noise levels in the reconstructed image. The effects of image quality and noise texture were assessed at all implementation levels of ASiR Trade-Mark-Sign . Empirically derived dose reduction limits were established for ASiR Trade-Mark-Sign for imaging of the trunk for a pediatric oncology population ranging from 1 yr old through adolescence/adulthood. Methods: Image quality was assessed using metrics established by the American College of Radiology (ACR) CT accreditation program. Each image quality metric was tested using the ACR CT phantom with 0%-100% ASiR Trade-Mark-Sign blended with filtered back projection (FBP) reconstructed images. Additionally, the noise power spectrum (NPS) was calculated for three common reconstruction filters of the trunk. The empirically derived limitations on ASiR Trade-Mark-Sign implementation for dose reduction were assessed using (1, 5, 10) yr old and adolescent/adult anthropomorphic phantoms. To assess dose reduction limits, the phantoms were scanned in increments of increased noise index (decrementing mA using automatic tube current modulation) balanced with ASiR Trade-Mark-Sign reconstruction to maintain noise equivalence of the 0% ASiR Trade-Mark-Sign image. Results: The ASiR Trade-Mark-Sign algorithm did not produce any unfavorable effects on image quality as assessed by ACR criteria. Conversely, low-contrast resolution was found to improve due to the reduction of noise in the reconstructed images. NPS calculations demonstrated that images with lower frequency noise had lower noise variance and coarser graininess at progressively higher percentages of ASiR Trade-Mark-Sign reconstruction; and in spite of the similar magnitudes of noise, the image reconstructed with 50% or more ASiR Trade-Mark-Sign presented a more smoothed appearance than the pre-ASiR Trade-Mark-Sign 100% FBP image. Finally, relative to non-ASiR Trade-Mark-Sign images with 100% of standard dose across the pediatric phantom age spectrum, similar noise levels were obtained in the images at a dose reduction of 48% with 40% ASIR Trade-Mark-Sign and a dose reduction of 82% with 100% ASIR Trade-Mark-Sign . Conclusions: The authors' work was conducted to identify the dose reduction limits of ASiR Trade-Mark-Sign for a pediatric oncology population using automatic tube current modulation. Improvements in noise levels from ASiR Trade-Mark-Sign reconstruction were adapted to provide lower radiation exposure (i.e., lower mA) instead of improved image quality. We have demonstrated for the image quality standards required at our institution, a maximum dose reduction of 82% can be achieved using 100% ASiR Trade-Mark-Sign ; however, to negate changes in the appearance of reconstructed images using ASiR Trade-Mark-Sign with a medium to low frequency noise preserving reconstruction filter (i.e., standard), 40% ASiR Trade-Mark-Sign was implemented in our clinic for 42%-48% dose reduction at all pediatric ages without a visually perceptible change in image quality or image noise.

Brady, S. L.; Yee, B. S.; Kaufman, R. A. [Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 (United States)

2012-09-15T23:59:59.000Z

334

Dictionary-Learning-Based Reconstruction Method for Electron Tomography  

E-Print Network [OSTI]

Electron tomography usually suffers from so called missing wedge artifacts caused by limited tilt angle range. An equally sloped tomography (EST) acquisition scheme (which should be called the linogram sampling scheme) was recently applied to achieve 2.4-angstrom resolution. On the other hand, a compressive sensing-inspired reconstruction algorithm, known as adaptive dictionary based statistical iterative reconstruction (ADSIR), has been reported for x-ray computed tomography. In this paper, we evaluate the EST, ADSIR and an ordered-subset simultaneous algebraic reconstruction technique (OS-SART), and compare the ES and equally angled (EA) data acquisition modes. Our results show that OS-SART is comparable to EST, and the ADSIR outperforms EST and OS-SART. Furthermore, the equally sloped projection data acquisition mode has no advantage over the conventional equally angled mode in the context.

Liu, Baodong; Verbridge, Scott S; Sun, Lizhi; Wang, Ge

2013-01-01T23:59:59.000Z

335

E-Print Network 3.0 - agent-enhanced computed tomography Sample...  

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

computed tomography Page: << < 1 2 3 4 5 > >> 1 CAT scan and RadonX-ray transform Relations with the Fourier transform. Dual Radon Summary: problems X-ray tomography...

336

E-Print Network 3.0 - advanced computed tomography Sample Search...  

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

advanced computed tomography Page: << < 1 2 3 4 5 > >> 1 CAT scan and RadonX-ray transform Relations with the Fourier transform. Dual Radon Summary: problems X-ray tomography...

337

Quantum Process Tomography by 2D Fluorescence Spectroscopy  

E-Print Network [OSTI]

Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement and signal-to-noise ratio ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter $\\Gamma$ of the doubly-excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

Leonardo A. Pachon; Andrew H. Marcus; Alan Aspuru-Guzik

2015-02-09T23:59:59.000Z

338

Quantum Process Tomography by 2D Fluorescence Spectroscopy  

E-Print Network [OSTI]

Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement and signal-to-noise ratio ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter $\\Gamma$ of the doubly-excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

Pachon, Leonardo A; Aspuru-Guzik, Alan

2015-01-01T23:59:59.000Z

339

Multiplexed absorption tomography with calibration-free wavelength modulation spectroscopy  

SciTech Connect (OSTI)

We propose a multiplexed absorption tomography technique, which uses calibration-free wavelength modulation spectroscopy with tunable semiconductor lasers for the simultaneous imaging of temperature and species concentration in harsh combustion environments. Compared with the commonly used direct absorption spectroscopy (DAS) counterpart, the present variant enjoys better signal-to-noise ratios and requires no baseline fitting, a particularly desirable feature for high-pressure applications, where adjacent absorption features overlap and interfere severely. We present proof-of-concept numerical demonstrations of the technique using realistic phantom models of harsh combustion environments and prove that the proposed techniques outperform currently available tomography techniques based on DAS.

Cai, Weiwei; Kaminski, Clemens F., E-mail: cfk23@cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA (United Kingdom)

2014-04-14T23:59:59.000Z

340

Quantum Process Tomography via L1-norm Minimization  

E-Print Network [OSTI]

For an initially well designed but imperfect quantum information system, the process matrix is almost sparse in an appropriate basis. Existing theory and associated computational methods (L1-norm minimization) for reconstructing sparse signals establish conditions under which the sparse signal can be perfectly reconstructed from a very limited number of measurements (resources). Although a direct extension to quantum process tomography of the L1-norm minimization theory has not yet emerged, the numerical examples presented here, which apply L1-norm minimization to quantum process tomography, show a significant reduction in resources to achieve a desired estimation accuracy over existing methods.

Robert L. Kosut

2009-03-05T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
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341

The Potential Role of Optical Coherence Tomography in the Evaluation of Vulnerable Carotid Atheromatous Plaques: A Pilot Study  

SciTech Connect (OSTI)

Purpose. The decision to intervene surgically in patients with carotid artery disease is based on the presence of symptoms, along with the severity of carotid artery stenosis as assessed by ultrasound or X-ray computed tomography (CT). Optical coherence tomography (OCT) is a relatively new imaging technique that offers potential in the identification of, as well as the distinction between, stable and unstable atherosclerotic plaques. The purpose of our study was to evaluate whether OCT can be used as a noninvasive diagnostic tool to reveal the morphology of carotid stenosis from the adventitial surface of the carotid artery. To achieve this aim, excised atheromatous plaques were scanned by OCT from the external surface. Methods. Plaques removed at carotid endarterectomy were scanned by OCT from the external surface within 72 hr of surgery and then examined histologically. The images of the histologic slides and the scans were then compared. Results. We examined 10 carotid endarterectomy specimens and were able to identify calcification, cholesterol crystal clefts, and lipid deposits in the OCT images with histologic correlation. The strong light scattering from the calcified tissue and cholesterol crystal clefts limited the depth of light penetration, making observation of the intimal surface and the detail of the fibrous cap difficult. However, we were able to confidently identify the absence of an atherosclerotic plaque by OCT scans even from the external surface. Conclusion. The results of this pilot study demonstrate that OCT can reveal the main features of carotid stenosis but that plaque vulnerability cannot be reliably and precisely assessed if scanned from the external surface with OCT in its present form.

Prabhudesai, Vikramaditya [St. Joseph's Hospital, Diagnostic Imaging (Canada); Phelan, Cordelia [University Hospital of North Staffordshire, NHS Trust, Department of Pathology (United Kingdom); Yang, Ying [Institute of Science and Technology in Medicine, Keele University (United Kingdom)], E-mail: bea00@keele.ac.uk; Wang, Ruikang K. [Oregon Health and Science University, Department of Biomedical Engineering (United States); Cowling, Mark G. [University Hospital of North Staffordshire, NHS Trust, Department of Radiology (United Kingdom)

2006-12-15T23:59:59.000Z

342

Quantitative electron holographic tomography for the 3D characterisation of semiconductor device structures  

E-Print Network [OSTI]

Quantitative electron holographic tomography for the 3D characterisation of semiconductor device tomography Silicon devices Device characterisation a b s t r a c t Electron tomography and electron rights reserved. 1. Introduction Dopant profiling of semiconductor devices using off-axis electron

Dunin-Borkowski, Rafal E.

343

Design of Mega-Voltage X-ray Digital Radiography and Computed Tomography Performance Phantoms  

SciTech Connect (OSTI)

A number of fundamental scientific questions have arisen concerning the operation of high-energy DR and CT systems. Some of these questions include: (1) How deeply can such systems penetrate thickly shielded objects? (2) How well can such systems distinguish between dense and relatively high Z materials such as lead, tungsten and depleted uranium and lower Z materials such as steel, copper and tin? (3) How well will such systems operate for a uranium material which is an intermediate case between low density yellowcake and high density depleted uranium metal? These questions have led us to develop a set of phantoms to help answer these questions, but do not have any direct bearing on any smuggling concern. These new phantoms are designed to allow a systemic exploration of these questions by gradually varying their compositions and thicknesses. These phantoms are also good probes of the blurring behavior of radiography and tomography systems. These phantoms are composed of steel ({rho} assumed to be 7.8 g/cc), lead ({rho} assumed to be 11.4 g/cc), tungsten ({rho} assumed to be 19.25 g/cc), uranium oxide (UO{sub 3}) ({rho} assumed to be 4.6 g/cc), and depleted uranium (DU) ({rho} assumed to be 18.9 g/cc). There are five designed phantoms described in this report: (1) Cylindrical shells of Tungsten and Steel; (2) Depleted Uranium Inside Tungsten Hemi-cube Shells; (3) Nested Spherical Shells; (4) UO{sub 3} Cylinder; and (5) Shielded DU Sphere.

Aufderheide, M B; Martz, H E; Curtin, M

2009-06-22T23:59:59.000Z

344

The Relationship between Organ Dose and Patients Size in Multidetector Computed Tomography (MDCT) Scans Utilizing Tube Current Modulation (TCM)  

E-Print Network [OSTI]

dose at CT in pediatric patients. Radiology, 1997. 203(2):Cancer Risk for Pediatric Chest CT. Radiology, 2011. 259(3):

Khatonabadi, Maryam

2013-01-01T23:59:59.000Z

345

X-ray micro-tomography investigation of the foaming process in the system of waste glass–silica mud–MnO{sub 2}  

SciTech Connect (OSTI)

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)

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, Ašker?eva 12, 1000 Ljubljana (Slovenia)

2013-12-15T23:59:59.000Z

346

Assessment of Interfraction Patient Setup for Head-and-Neck Cancer Intensity Modulated Radiation Therapy Using Multiple Computed Tomography-Based Image Guidance  

SciTech Connect (OSTI)

Purpose: Various image guidance systems are commonly used in conjunction with intensity modulated radiation therapy (IMRT) in head-and-neck cancer irradiation. The purpose of this study was to assess interfraction patient setup variations for 3 computed tomography (CT)-based on-board image guided radiation therapy (IGRT) modalities. Methods and Materials: A total of 3302 CT scans for 117 patients, including 53 patients receiving megavoltage cone-beam CT (MVCBCT), 29 receiving kilovoltage cone-beam CT (KVCBCT), and 35 receiving megavoltage fan-beam CT (MVFBCT), were retrospectively analyzed. The daily variations in the mediolateral (ML), craniocaudal (CC), and anteroposterior (AP) dimensions were measured. The clinical target volume-to-planned target volume (CTV-to-PTV) margins were calculated using 2.5? + 0.7 ?, where ? and ? were systematic and random positioning errors, respectively. Various patient characteristics for the MVCBCT group, including weight, weight loss, tumor location, and initial body mass index, were analyzed to determine their possible correlation with daily patient setup. Results: The average interfraction displacements (± standard deviation) in the ML, CC, and AP directions were 0.5 ± 1.5, ?0.3 ± 2.0, and 0.3 ± 1.7 mm (KVCBCT); 0.2 ± 1.9, ?0.2 ± 2.4, and 0.0 ± 1.7 mm (MVFBCT); and 0.0 ± 1.8, 0.5 ± 1.7, and 0.8 ± 3.0 mm (MVCBCT). The day-to-day random errors for KVCBCT, MVFBCT, and MVCBCT were 1.4-1.6, 1.7, and 2.0-2.1 mm. The interobserver variations were 0.8, 1.1, and 0.7 mm (MVCBCT); 0.5, 0.4, and 0.8 mm (MVFBCT); and 0.5, 0.4, and 0.6 mm (KVCBCT) in the ML, CC, and AP directions, respectively. The maximal calculated uniform CTV-to-PTV margins were 5.6, 6.9, and 8.9 mm for KVCBCT, MVFBCT, and MVCBCT, respectively. For the evaluated patient characteristics, the calculated margins for different patient parameters appeared to differ; analysis of variance (ANOVA) and/or t test analysis found no statistically significant setup difference in any direction. Conclusions: Daily random setup errors and CTV-to-PTV margins for treatment of head-and-neck cancer were affected by imaging quality. Our data indicated that larger margins were associated with MVFBCT and MVCBCT, compared with smaller margins for KVCBCT. IGRT modalities with better image quality are encouraged in clinical practice.

Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu [Department of Radiation Oncology, David of Geffen School of Medicine at UCLA, Los Angeles, California (United States); Hu, Angie Y. [Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado (United States)] [Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado (United States); Lee, Steve P.; Lee, Percy; DeMarco, John [Department of Radiation Oncology, David of Geffen School of Medicine at UCLA, Los Angeles, California (United States)] [Department of Radiation Oncology, David of Geffen School of Medicine at UCLA, Los Angeles, California (United States); Li, X. Allen [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States)] [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Steinberg, Michael L.; Kupelian, Patrick; Low, Daniel [Department of Radiation Oncology, David of Geffen School of Medicine at UCLA, Los Angeles, California (United States)] [Department of Radiation Oncology, David of Geffen School of Medicine at UCLA, Los Angeles, California (United States)

2013-07-01T23:59:59.000Z

347

USING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF  

E-Print Network [OSTI]

: (1) a homogeneous glassy phase; (2) a liquid­liquid phase separated state; and (3) a crystallizedUSING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF CHINESE GLAZES M of their glazes. The images revealed unique phase assemblage modes in different samples. The results suggest

Barton, Jennifer K.

348

Adaptive optics enhanced simultaneous en-face optical coherence tomography  

E-Print Network [OSTI]

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

Dainty, Chris

349

Cone-based electrical resistivity tomography Adam Pidlisecky1  

E-Print Network [OSTI]

Cone-based electrical resistivity tomography Adam Pidlisecky1 , Rosemary Knight1 , and Eldad Haber2 that can provide information about the 3D distribu- tion of electrical conductivity. The technique, cone-bert method. C-bert data are inverted using an inexact Gauss-Newton algorithm to produce a 3D electrical

Knight, Rosemary

350

Microwave-induced thermoacoustic tomography: reconstruction by synthetic aperture  

E-Print Network [OSTI]

-induced thermoacoustic tomography (LMTT) based on focused transducers. Two microwave sources, which had frequencies of 9 GHz and 3 GHz, respectively, were used in the experiments for comparison. The 3-GHz system had a much larger imaging depth but a lower signal...

Feng, Dazi

2001-01-01T23:59:59.000Z

351

3D Tomography from Few Projections in Experimental Fluid Dynamics  

E-Print Network [OSTI]

3D Tomography from Few Projections in Experimental Fluid Dynamics Stefania Petra, Andreas Schr projections due to both limited optical access to wind and water tunnels and cost S. Petra, C. Schn projection data. The latter are the pixel entries in the recorded 2D images that represent the integration

Schnörr, Christoph

352

Volumetric Reconstruction in the MicroCAT Tomography System  

E-Print Network [OSTI]

of projection data . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.2 Illustration of Feldkamp filteredVolumetric Reconstruction in the MicroCAT Tomography System A Thesis Presented for the Master essential data and an intimate knowledge of the MicroCAT system. Dr. Sam Jordan of the University

Cates, Josh

353

Insights into the structure of the upper mantle beneath the Murray Basin from 3D teleseismic tomography  

E-Print Network [OSTI]

tomography studies have been carried out in western Victoria (Graeber et al. 2002) and northern Tasmania

Rawlinson, Nick

354

E-Print Network 3.0 - analysis dual-source-ct in-vitro-charakterisieru...  

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

and Medicine 2 Experimental measurement of human head motion for high-resolution computed tomography Summary: other methods are also available to reduce motion artifacts, such as...

355

The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI): A Completed Reference Database of Lung Nodules on CT Scans  

SciTech Connect (OSTI)

Purpose: The development of computer-aided diagnostic (CAD) methods for lung nodule detection, classification, and quantitative assessment can be facilitated through a well-characterized repository of computed tomography (CT) scans. The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI) completed such a database, establishing a publicly available reference for the medical imaging research community. Initiated by the National Cancer Institute (NCI), further advanced by the Foundation for the National Institutes of Health (FNIH), and accompanied by the Food and Drug Administration (FDA) through active participation, this public-private partnership demonstrates the success of a consortium founded on a consensus-based process. Methods: Seven academic centers and eight medical imaging companies collaborated to identify, address, and resolve challenging organizational, technical, and clinical issues to provide a solid foundation for a robust database. The LIDC/IDRI Database contains 1018 cases, each of which includes images from a clinical thoracic CT scan and an associated XML file that records the results of a two-phase image annotation process performed by four experienced thoracic radiologists. In the initial blinded-read phase, each radiologist independently reviewed each CT scan and marked lesions belonging to one of three categories (''nodule{>=}3 mm,''''nodule<3 mm,'' and ''non-nodule{>=}3 mm''). In the subsequent unblinded-read phase, each radiologist independently reviewed their own marks along with the anonymized marks of the three other radiologists to render a final opinion. The goal of this process was to identify as completely as possible all lung nodules in each CT scan without requiring forced consensus. Results: The Database contains 7371 lesions marked ''nodule'' by at least one radiologist. 2669 of these lesions were marked ''nodule{>=}3 mm'' by at least one radiologist, of which 928 (34.7%) received such marks from all four radiologists. These 2669 lesions include nodule outlines and subjective nodule characteristic ratings. Conclusions: The LIDC/IDRI Database is expected to provide an essential medical imaging research resource to spur CAD development, validation, and dissemination in clinical practice.

NONE

2011-02-15T23:59:59.000Z

356

Rotational micro-CT using a clinical C-arm angiography gantry  

SciTech Connect (OSTI)

Rotational angiography (RA) gantries are used routinely to acquire sequences of projection images of patients from which 3D renderings of vascular structures are generated using Feldkamp cone-beam reconstruction algorithms. However, these systems have limited resolution (<4 lp/mm). Micro-computed tomography (micro-CT) systems have better resolution (>10 lp/mm) but to date have relied either on rotating object imaging or small bore geometry for small animal imaging, and thus are not used for clinical imaging. The authors report here the development and use of a 3D rotational micro-angiography (RMA) system created by mounting a micro-angiographic fluoroscope (MAF) [35 {mu}m pixel, resolution >10 lp/mm, field of view (FOV)=3.6 cm] on a standard clinical FPD-based RA gantry (Infinix, Model RTP12303J-G9E, Toshiba Medical Systems Corp., Tustin, CA). RA image sequences are obtained using the MAF and reconstructed. To eliminate artifacts due to image truncation, lower-dose (compared to MAF acquisition) full-FOV (FFOV) FPD RA sequences (194 {mu}m pixel, FOV=20 cm) were also obtained to complete the missing data. The RA gantry was calibrated using a helical bead phantom. To ensure high-quality high-resolution reconstruction, the high-resolution images from the MAF were aligned spatially with the lower-dose FPD images, and the pixel values in the FPD image data were scaled to match those of the MAF. Images of a rabbit with a coronary stent placed in an artery in the Circle of Willis were obtained and reconstructed. The MAF images appear well aligned with the FPD images (average correlation coefficient before and after alignment: 0.65 and 0.97, respectively) Greater details without any visible truncation artifacts are seen in 3D RMA (MAF-FPD) images than in those of the FPD alone. The FWHM of line profiles of stent struts (100 {mu}m diameter) are approximately 192{+-}21 and 313{+-}38 {mu}m for the 3D RMA and FPD data, respectively. In addition, for the dual-acquisition 3D RMA, FFOV FPD data need not be of the highest quality, and thus may be acquired at lower dose compared to a standard FPD acquisition. These results indicate that this system could provide the basis for high resolution images of regions of interest in patients with a reduction in the integral dose compared to the standard FPD approach.

Patel, V.; Hoffmann, K. R.; Ionita, C. N.; Keleshis, C.; Bednarek, D. R.; Rudin, S. [Toshiba Stroke Research Center, Department of Physics, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Neurosurgery, Department of Physics, Department of Physiology and Biophysics, Department of Mechanical and Aerospace Engineering, and Department of Computer Science, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Neurosurgery, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Radiology, Department of Neurosurgery, Department of Physics, and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Radiology, Department of Neurosurgery, Department of Physiology and Biophysics, Department of Mechanical and Aerospace Engineering, and Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, New York 14214 (United States)

2008-10-15T23:59:59.000Z

357

E-Print Network 3.0 - air ct cisternography Sample Search Results  

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

James E. Mason* and Cristina L. Archer1 Summary: supply with electricity from compressed air energy storage combustion turbine (CAES CT) power plants... compressed air energy...

358

E-Print Network 3.0 - axial ct scan Sample Search Results  

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

Biology and Medicine 12 Projection-based features for reducing false positives in computer-aided detection of colonic polyps in CT colonography Summary: indicates one IPC....

359

E-Print Network 3.0 - abdominal ct replace Sample Search Results  

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

Leeds Collection: Computer Technologies and Information Sciences 23 ARTICLE IN PRESS Computer-Aided Design ( ) Summary: a limited number of CT images. The three- dimensional...

360

Quantum tomography meets dynamical systems and bifurcations theory  

SciTech Connect (OSTI)

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.

Goyeneche, D., E-mail: dardo.goyeneche@cefop.udec.cl [Departamento de Fisíca, Universidad de Concepción, Casilla 160-C, Concepción, Chile and Center for Optics and Photonics, Universidad de Concepción, Casilla 4012, Concepción (Chile); Torre, A. C. de la [Departamento de Física, Universidad Nacional de Mar del Plata, IFIMAR-CONICET, Dean Funes 3350, 7600 Mar del Plata (Argentina)

2014-06-15T23:59:59.000Z

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
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361

Discussion - Next Step for Fukushima Daiichi Muon Tomography  

SciTech Connect (OSTI)

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.

Miyadera, Haruo [Los Alamos National Laboratory

2012-08-13T23:59:59.000Z

362

Using electrical impedance tomography to map subsurface hydraulic conductivity  

DOE Patents [OSTI]

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.

Berryman, James G. (Danville, CA); Daily, William D. (Livermore, CA); Ramirez, Abelardo L. (Pleasanton, CA); Roberts, Jeffery J. (Livermore, CA)

2000-01-01T23:59:59.000Z

363

Systematic errors in current quantum state tomography tools  

E-Print Network [OSTI]

Common tools for obtaining physical density matrices in experimental quantum state tomography are shown here to cause systematic errors. For example, using maximum likelihood or least squares optimization for state reconstruction, we observe a systematic underestimation of the fidelity and an overestimation of entanglement. A solution for this problem can be achieved by a linear evaluation of the data yielding reliable and computational simple bounds including error bars.

Christian Schwemmer; Lukas Knips; Daniel Richart; Tobias Moroder; Matthias Kleinmann; Otfried Gühne; Harald Weinfurter

2014-07-22T23:59:59.000Z

364

Photoacoustic computed tomography in biological tissues: algorithms and breast imaging  

E-Print Network [OSTI]

are investigated in Chapter III and IV, respectively. Finally, a prototype of an RF-induced PA imaging system is introduced and experiments using phantom samples as well as a preliminary study of breast imaging for cancer detection are reported in Chapter V... PHOTOACOUSTIC COMPUTED TOMOGRAPHY IN BIOLOGICAL TISSUES: ALGORITHMS AND BREAST IMAGING A Dissertation by MINGHUA XU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements...

Xu, Minghua

2004-11-15T23:59:59.000Z

365

?A cylindrical specimen holder for electron cryo-tomography  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . . . . 57 3.6 Characterisation of carbon nanopipettes . . . . . . . . . . . . . . . . 59 3.7 Discussion of the manufacturing process . . . . . . . . . . . . . . . . 63 4 Cryo-tomography 67 4.1 Specimen preparation I... . . . . . . . . . . . . . . . . . 60 3.7 Elemental maps and longitudinal EDX linescan of a carbon nanopipette 61 3.8 Transverse EDX linescan of a carbon nanopipette . . . . . . . . . . . 62 4.1 Transmission electron micrograph of a blocked carbon nanopipette tip 68 4.2 A carbon...

Palmer, Colin Michael

2013-03-12T23:59:59.000Z

366

Coral Extension Rate Analysis Using Computed Axial Tomography  

E-Print Network [OSTI]

CORAL EXTENSION RATE ANALYSIS USING COMPUTED AXIAL TOMOGRAPHY A Thesis by ELEANOR ANN YUDELMAN Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE Chair of Committee, Niall Slowey Committee Members, Deborah Thomas Benjamin Giese George P. Schmahl Head of Department, Deborah Thomas May 2014 Major Subject: Oceanography Copyright 2014 Eleanor Ann Yudelman ii ABSTRACT...

Yudelman, Eleanor Ann

2014-01-10T23:59:59.000Z

367

DOE - Office of Legacy Management -- Dorr Corp - CT 14  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou are here Home »HillNY 28Dorr Corp - CT 14

368

DOE - Office of Legacy Management -- Fenn Machinery Co - CT 11  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou are here Home »HillNYEra ToolFenn Machinery Co - CT

369

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTR.l\CT  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011Astudies smartHistory:CONTR.l\CT 2.

370

Recent developments in guided wave travel time tomography  

SciTech Connect (OSTI)

The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation is an interesting addition to the current method of periodic inspections. Guided wave tomography had been developed to create a map of the wall thickness using the travel times of guided waves. It can be used for both monitoring and for inspection of pipe-segments that are difficult to access, for instance at the location of pipe-supports. An important outcome of the tomography is the minimum remaining wall thickness, as this is critical in the scheduling of a replacement of the pipe-segment. In order to improve the sizing accuracy we have improved the tomography scheme. A number of major improvements have been realized allowing to extend the application envelope to pipes with a larger wall thickness and to larger distances between the transducer rings. Simulation results indicate that the sizing accuracy has improved and that is now possible to have a spacing of 8 meter between the source-ring and the receiver-ring. Additionally a reduction of the number of sensors required might be possible as well.

Zon, Tim van; Volker, Arno [TNO, Stieltjesweg 1, P.O. box 155 2600 AD Delft (Netherlands)

2014-02-18T23:59:59.000Z

371

Comparison of x ray computed tomography number to proton relative linear stopping power conversion functions using a standard phantom  

SciTech Connect (OSTI)

Purpose: Adequate evaluation of the results from multi-institutional trials involving light ion beam treatments requires consideration of the planning margins applied to both targets and organs at risk. A major uncertainty that affects the size of these margins is the conversion of x ray computed tomography numbers (XCTNs) to relative linear stopping powers (RLSPs). Various facilities engaged in multi-institutional clinical trials involving proton beams have been applying significantly different margins in their patient planning. This study was performed to determine the variance in the conversion functions used at proton facilities in the U.S.A. wishing to participate in National Cancer Institute sponsored clinical trials. Methods: A simplified method of determining the conversion function was developed using a standard phantom containing only water and aluminum. The new method was based on the premise that all scanners have their XCTNs for air and water calibrated daily to constant values but that the XCTNs for high density/high atomic number materials are variable with different scanning conditions. The standard phantom was taken to 10 different proton facilities and scanned with the local protocols resulting in 14 derived conversion functions which were compared to the conversion functions used at the local facilities. Results: For tissues within ±300 XCTN of water, all facility functions produced converted RLSP values within ±6% of the values produced by the standard function and within 8% of the values from any other facility's function. For XCTNs corresponding to lung tissue, converted RLSP values differed by as great as ±8% from the standard and up to 16% from the values of other facilities. For XCTNs corresponding to low-density immobilization foam, the maximum to minimum values differed by as much as 40%. Conclusions: The new method greatly simplifies determination of the conversion function, reduces ambiguity, and in the future could promote standardization between facilities. Although it was not possible from these experiments to determine which conversion function is most appropriate, the variation between facilities suggests that the margins used in some facilities to account for the uncertainty in converting XCTNs to RLSPs may be too small.

Moyers, M. F., E-mail: MFMoyers@roadrunner.com [Shanghai Proton and Heavy Ion Center, Shanghai, China 201321 (China)

2014-06-15T23:59:59.000Z

372

E-Print Network 3.0 - aids computed tomography Sample Search...  

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

of Mathematics, Tufts University Collection: Mathematics 2 CAT scan and RadonX-ray transform Relations with the Fourier transform. Dual Radon Summary: problems X-ray tomography...

373

E-Print Network 3.0 - attenuated vector tomography Sample Search...  

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

Kansas State University Collection: Mathematics 2 CAT scan and RadonX-ray transform Relations with the Fourier transform. Dual Radon Summary: Optical Tomography Novel...

374

E-Print Network 3.0 - abdominal computed tomography Sample Search...  

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

aortic aneurysm (AAA) from computed tomography angiography (CTA) images. Output data (3-D model) form... angiography (DSA), computed ... Source: Loncaric, Sven - Faculty of...

375

Software-defined Radio Based Wireless Tomography: Experimental Demonstration and Verification  

SciTech Connect (OSTI)

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.

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

2015-01-01T23:59:59.000Z

376

Cone beam x-ray luminescence computed tomography: A feasibility study  

SciTech Connect (OSTI)

Purpose: The appearance of x-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging by x ray. In the previous XLCT system, the sample was irradiated by a sequence of narrow x-ray beams and the x-ray luminescence was measured by a highly sensitive charge coupled device (CCD) camera. This resulted in a relatively long sampling time and relatively low utilization of the x-ray beam. In this paper, a novel cone beam x-ray luminescence computed tomography strategy is proposed, which can fully utilize the x-ray dose and shorten the scanning time. The imaging model and reconstruction method are described. The validity of the imaging strategy has been studied in this paper. Methods: In the cone beam XLCT system, the cone beam x ray was adopted to illuminate the sample and a highly sensitive CCD camera was utilized to acquire luminescent photons emitted from the sample. Photons scattering in biological tissues makes it an ill-posed problem to reconstruct the 3D distribution of the x-ray luminescent sample in the cone beam XLCT. In order to overcome this issue, the authors used the diffusion approximation model to describe the photon propagation in tissues, and employed the sparse regularization method for reconstruction. An incomplete variables truncated conjugate gradient method and permissible region strategy were used for reconstruction. Meanwhile, traditional x-ray CT imaging could also be performed in this system. The x-ray attenuation effect has been considered in their imaging model, which is helpful in improving the reconstruction accuracy. Results: First, simulation experiments with cylinder phantoms were carried out to illustrate the validity of the proposed compensated method. The experimental results showed that the location error of the compensated algorithm was smaller than that of the uncompensated method. The permissible region strategy was applied and reduced the reconstruction error to less than 2 mm. The robustness and stability were then evaluated from different view numbers, different regularization parameters, different measurement noise levels, and optical parameters mismatch. The reconstruction results showed that the settings had a small effect on the reconstruction. The nonhomogeneous phantom simulation was also carried out to simulate a more complex experimental situation and evaluated their proposed method. Second, the physical cylinder phantom experiments further showed similar results in their prototype XLCT system. With the discussion of the above experiments, it was shown that the proposed method is feasible to the general case and actual experiments. Conclusions: Utilizing numerical simulation and physical experiments, the authors demonstrated the validity of the new cone beam XLCT method. Furthermore, compared with the previous narrow beam XLCT, the cone beam XLCT could more fully utilize the x-ray dose and the scanning time would be shortened greatly. The study of both simulation experiments and physical phantom experiments indicated that the proposed method was feasible to the general case and actual experiments.

Chen Dongmei; Zhu Shouping; Yi Huangjian; Zhang Xianghan; Chen Duofang; Liang Jimin [School of Life Sciences and Technology, Xidian University, Xi'an 710071 (China); Tian Jie [School of Life Sciences and Technology, Xidian University, Xi'an 710071 (China); Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, Beijing 100190 (China)

2013-03-15T23:59:59.000Z

377

Validation of Plaster Endocast Morphology Through 3D CT Image Analysis  

E-Print Network [OSTI]

Validation of Plaster Endocast Morphology Through 3D CT Image Analysis P. Thomas Schoenemann,1 by creating endo- casts out of rubber latex shells filled with plaster. The extent to which the method questions. Pairs of virtual endocasts (VEs) created from high-resolution CT scans of corresponding latex/plaster

Schoenemann, P. Thomas

378

Siemens AG, CT IC 4, H.-G. Zimmermann1 CORPORATETECHNOLOGY  

E-Print Network [OSTI]

© Siemens AG, CT IC 4, H.-G. Zimmermann1 CORPORATETECHNOLOGY System Identification & Forecasting with Advanced Neural Networks Principles, Techniques, Applications Hans Georg Zimmermann Siemens AG Email : Hans_Georg.Zimmermann@siemens.com © Siemens AG, CT IC 4, H.-G. Zimmermann2 CORPORATETECHNOLOGY . . . . ! " i ii wxw 0 w1 wn xn x1 Distinct

Schmidhuber, Juergen

379

Bone Surface Reconstruction From CT/MR Images Using Fast Marching and Level Set Methods1)  

E-Print Network [OSTI]

Bone Surface Reconstruction From CT/MR Images Using Fast Marching and Level Set Methods1) Istv surfaces reconstructed from MR volumes are shown. 1 Outline of the project One of our current projects steps of bone surface reconstruction from CT/MR slice images. 2 Main steps of reconstruction 2.1

Chetverikov, Dmitry

380

Multi-atlas Segmentation in Head and Neck CT Scans Amelia M. Arbisser  

E-Print Network [OSTI]

Multi-atlas Segmentation in Head and Neck CT Scans by Amelia M. Arbisser B.S., Computer Science of Engineering Thesis Committee #12;2 #12;Multi-atlas Segmentation in Head and Neck CT Scans by Amelia M, we employ an atlas of labeled training images. We register each of these images to the unlabeled

Golland, Polina

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

AUTOMATIC HEART ISOLATION FOR CT CORONARY VISUALIZATION USING G. Funka-Lea1  

E-Print Network [OSTI]

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

Boykov, Yuri

382

CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1  

E-Print Network [OSTI]

CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1 , A. Moreno1-based registration of CT (at two different instants of the breathing cycle, intermediate expirations) and PET images in order to simulate the instant in the breathing cycle most similar to the PET image and guarantee

Paris-Sud XI, Université de

383

CT-FIRE (V1.3 Beta2) User's Manual, LOCI @ UW-Madison CT-FIRE V1.3 Beta2 User's Manual (November 6 2014)  

E-Print Network [OSTI]

CT-FIRE (V1.3 Beta2) User's Manual, LOCI @ UW-Madison 1 CT-FIRE V1.3 Beta2 User's Manual (November straightness. Using #12;CT-FIRE (V1.3 Beta2) User's Manual, LOCI @ UW-Madison 2 the advanced output control-processing. Major features of the versions Version 1.3 Beta2 (newest): The primary change in CT-FIRE V1.3 Beta2

Yavuz, Deniz

384

3D Reconstruction of Intricate Archean Microbial Structures Using Neutron Computed Tomography and Serial SectioningIN43B-0331 Abstract Project Goals  

E-Print Network [OSTI]

Tomography and Serial SectioningIN43B-0331 Abstract Project Goals Background Methods Neutron Computed using both serial sectioning and neutron computed tomography (NCT). Reconstruction techniques vary mechanisms for ancient microbial communities Neutron Computed Tomography Serial Sectioning Samples were

Hamann, Bernd

385

Reduction of radiation dose to radiosensitive organs and its tradeoff with image quality in Computed Tomography  

E-Print Network [OSTI]

retrospective review”. Pediatric Radiology, 2010 May;40(5):pediatric CT: effect of technical factors and phantom size and shape. Radiology

Zhang, Di

2012-01-01T23:59:59.000Z

386

Hemangioma of the Interatrial Septum: CT and MRI Features  

SciTech Connect (OSTI)

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.

Hrabak-Paar, Maja, E-mail: majahrabak@gmail.com [University Hospital Center Zagreb, University of Zagreb School of Medicine, Department of Diagnostic and Interventional Radiology (Croatia); Huebner, Marisa [University Hospital Mainz (Germany); Stern-Padovan, Ranka; Lusic, Mario [University Hospital Center Zagreb, University of Zagreb School of Medicine, Department of Diagnostic and Interventional Radiology (Croatia)

2011-02-15T23:59:59.000Z

387

Monitoring internal organ motion with continuous wave radar in CT  

SciTech Connect (OSTI)

Purpose: To avoid motion artifacts in medical imaging or to minimize the exposure of healthy tissues in radiation therapy, medical devices are often synchronized with the patient's respiratory motion. Today's respiratory motion monitors require additional effort to prepare the patients, e.g., mounting a motion belt or placing an optical reflector on the patient's breast. Furthermore, they are not able to measure internal organ motion without implanting markers. An interesting alternative to assess the patient's organ motion is continuous wave radar. The aim of this work is to design, implement, and evaluate such a radar system focusing on application in CT.Methods: The authors designed a radar system operating in the 860 MHz band to monitor the patient motion. In the intended application of the radar system, the antennas are located close to the patient's body inside the table of a CT system. One receive and four transmitting antennas are used to avoid the requirement of exact patient positioning. The radar waves propagate into the patient's body and are reflected at tissue boundaries, for example at the borderline between muscle and adipose tissue, or at the boundaries of organs. At present, the authors focus on the detection of respiratory motion. The radar system consists of the hardware mentioned above as well as of dedicated signal processing software to extract the desired information from the radar signal. The system was evaluated using simulations and measurements. To simulate the radar system, a simulation model based on radar and wave field equations was designed and 4D respiratory-gated CT data sets were used as input. The simulated radar signals and the measured data were processed in the same way. The radar system hardware and the signal processing algorithms were tested with data from ten volunteers. As a reference, the respiratory motion signal was recorded using a breast belt simultaneously with the radar measurements.Results: Concerning the measurements of the test persons, there is a very good correlation (?= 0.917) between the respiratory motion phases received by the radar system and the external motion monitor. Our concept of using an array of transmitting antennas turned out to be widely insensitive to the positioning of the test persons. A time shift between the respiratory motion curves recorded with the radar system and the motion curves from the external respiratory monitor was observed which indicates a slight difference between internal organ motion and motion detected by the external respiratory monitor. The simulations were in good accordance with the measurements.Conclusions: A continuous wave radar operating in the near field of the antennas can be used to determine the respiratory motion of humans accurately. In contrast to trigger systems used today, the radar system is able to measure motion inside the body. If such a monitor was routinely available in clinical CT, it would be possible optimizing the scan start with respect to the respiratory state of the patient. Breathing commands would potentially widely be avoided, and as far as uncooperative patients or children are concerned, less sedation might be necessary. Further applications of the radar system could be in radiation therapy or interventional imaging for instance.

Pfanner, Florian [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany)] [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany); Maier, Joscha [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Allmendinger, Thomas; Flohr, Thomas [Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany)] [Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany); Kachelrieß, Marc [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen, Germany and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

2013-09-15T23:59:59.000Z

388

Remote Tomography Via von Neumann-Arthurs-Kelly Interaction  

E-Print Network [OSTI]

Teleportation usually involves entangled particles 1,2 shared by Alice and Bob, Bell-state measurement on particle 1 and system particle by Alice, classical communication to Bob, and unitary transformation by Bob on particle 2. We propose a novel method: interaction-based remote tomography. Alice arranges an entanglement generating von Neumann-Arthurs-Kelly interaction between the system and two apparatus particles, and then teleports the latter to Bob. Bob reconstructs the unknown initial state of the system not received by him by quadrature measurements on the apparatus particles .

S. M. Roy; Abhinav Deshpande; Nitica Sakharwade

2013-08-23T23:59:59.000Z

389

Pulsed homodyne Gaussian quantum tomography with low detection efficiency  

E-Print Network [OSTI]

Pulsed homodyne quantum tomography usually requires a high detection efficiency limiting its applicability in quantum optics. Here, it is shown that the presence of low detection efficiency ($<50\\%$) does not prevent the tomographic reconstruction of quantum states of light, specifically, of Gaussian type. This result is obtained by applying the so-called "minimax" adaptive reconstruction of the Wigner function to pulsed homodyne detection. In particular, we prove, by both numerical and real experiments, that an effective discrimination of different Gaussian quantum states can be achieved. Our finding paves the way to a more extensive use of quantum tomographic methods, even in physical situations in which high detection efficiency is unattainable.

Martina Esposito; Fabio Benatti; Roberto Floreanini; Stefano Olivares; Francesco Randi; Kelvin Titimbo; Marco Pividori; Fabio Novelli; Federico Cilento; Fulvio Parmigiani; Daniele Fausti

2014-02-19T23:59:59.000Z

390

Tomography increases key rates of quantum-key-distribution protocols  

E-Print Network [OSTI]

We construct a practically implementable classical processing for the BB84 protocol and the six-state protocol that fully utilizes the accurate channel estimation method, which is also known as the quantum tomography. Our proposed processing yields at least as high key rate as the standard processing by Shor and Preskill. We show two examples of quantum channels over which the key rate of our proposed processing is strictly higher than the standard processing. In the second example, the BB84 protocol with our proposed processing yields a positive key rate even though the so-called error rate is higher than the 25% limit.

Shun Watanabe; Ryutaroh Matsumoto; Tomohiko Uyematsu

2008-07-22T23:59:59.000Z

391

Localization of Competing Metals (Ni, Co, and Zn) in Alyssum using micro-XRF and Tomography. (3564)  

E-Print Network [OSTI]

Localization of Competing Metals (Ni, Co, and Zn) in Alyssum using micro-XRF and Tomography. (3564 and observed metal localization in root and shoot tissue using synchrotron based micro-XRF and tomography

Sparks, Donald L.

392

Analysis of hydraulic tomography using temporal moments of drawdown recovery data  

E-Print Network [OSTI]

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

Daniels, Jeffrey J.

393

Hydraulic conductivity imaging from 3-D transient hydraulic tomography at several pumping/observation densities  

E-Print Network [OSTI]

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

Barrash, Warren

394

Electrical impedance tomography and Calderon's Department of Mathematics, University of Washington, Seattle, WA 98195, USA  

E-Print Network [OSTI]

Electrical impedance tomography and Calder´on'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

Uhlmann, Gunther

395

WIND TOMOGRAPHY IN BINARY SYSTEMS O.Knill, R.Dgani and M.Vogel  

E-Print Network [OSTI]

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

Knill, Oliver

396

High-Resolution Optical Coherence Tomography-Guided Laser Ablation of Surgical Tissue1  

E-Print Network [OSTI]

High-Resolution Optical Coherence Tomography-Guided Laser Ablation of Surgical Tissue1 Stephen A Hospital, Boston, Massachusetts 02114 Submitted for publication September 17, 1998 Background. Optical coherence tomography (OCT) is a compact high-speed imaging technology which uses infrared light to acquire

Boppart, Stephen

397

3-D Electrical Resistivity Tomography for Cliff Stability Assessment at Pointe du Hoc in Normandy, France  

E-Print Network [OSTI]

purposes. The objective of this study is to apply advanced 3?D resistivity tomography toward a detailed site stability assessment with special attention to the two at-risk buildings. 3?D resistivity tomography datasets at Pointe du Hoc in the presence...

Udphuay, Suwimon

2010-01-14T23:59:59.000Z

398

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

399

Determining both sound speed and internal source in thermo- and photo-acoustic tomography  

E-Print Network [OSTI]

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.

Hongyu Liu; Gunther Uhlmann

2015-02-04T23:59:59.000Z

400

STUDY OF TRANS-RECTAL NEAR-INFRARED DIFFUSE OPTICAL TOMOGRAPHY CONCURRENT  

E-Print Network [OSTI]

STUDY OF TRANS-RECTAL NEAR-INFRARED DIFFUSE OPTICAL TOMOGRAPHY CONCURRENT WITH TRANS of the requirements for the Degree of DOCTOR OF PHILOSOPHY May, 2010 #12;ii STUDY OF TRANS-RECTAL NEAR-INFRARED supported by the project Trans-rectal Near-Infrared Optical Tomography for Prostate Imaging from DOD

Piao, Daqing

Note: This page contains sample records for the topic "tomography ct scanners" from the National Library of EnergyBeta (NLEBeta).
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401

Using computerized tomography to determine ionospheric structures. Part 1, Notivation and basic approaches  

SciTech Connect (OSTI)

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.

Vittitoe, C.N.

1993-08-01T23:59:59.000Z

402

Spatially-Adaptive Reconstruction in Computed Tomography Based on Statistical Learning  

E-Print Network [OSTI]

, there exist techniques which require projections data only in the All authors are with the Computer Science1 Spatially-Adaptive Reconstruction in Computed Tomography Based on Statistical Learning Joseph a direct reconstruction algorithm for Computed Tomography, based on a local fusion of a few preliminary

Zibulevsky, Michael

403

Limited Angle Tomography of Sparse Images from Noisy Data using TLS MUSIC Algorithm  

E-Print Network [OSTI]

1 Limited Angle Tomography of Sparse Images from Noisy Data using TLS MUSIC Algorithm Andrew E The limited angle tomography problem is to recon- struct an image x(y, z) from its projections p(t, ) p-shaped region. This has applications to med- ical imaging and non-destructive evaluation where projection data

Yagle, Andrew E.

404

BRAIN TUMOR VASCULAR NETWORK SEGMENTATION FROM MICRO-TOMOGRAPHY Xavier Descombes1  

E-Print Network [OSTI]

BRAIN TUMOR VASCULAR NETWORK SEGMENTATION FROM MICRO-TOMOGRAPHY Xavier Descombes1 , Franck for the systematic 3D analysis of supra- cellular structures such as micro-vascular networks [1, 2]. Since, France ABSTRACT Micro-tomography produces high resolution images of bio- logical structures

405

Investigating the stratigraphy of an alluvial aquifer using crosswell seismic traveltime tomography  

E-Print Network [OSTI]

can be used in situations where surface seismic reflection has failed e.g., Liberty et al., 1999Investigating 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

Barrash, Warren

406

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)

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.

Maier, Joscha, E-mail: joscha.maier@dkfz.de [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)

2014-05-15T23:59:59.000Z

407

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)

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.

Prabhakar, Ramachandran, E-mail: Ramachandran.Prabhakar@petermac.org [Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); RMIT University, Melbourne (Australia); Oates, Richard; Jones, Daryl [Radiation Therapy Services, Peter MacCallum Cancer Centre, Melbourne (Australia); Kron, Tomas [Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); RMIT University, Melbourne (Australia); Cramb, Jim [Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Foroudi, Farshad [Radiation Therapy Services, Peter MacCallum Cancer Centre, Melbourne (Australia); Geso, Moshi [RMIT University, Melbourne (Australia); Gill, Suki [Radiation Therapy Services, Peter MacCallum Cancer Centre, Melbourne (Australia)

2014-04-01T23:59:59.000Z

408

Quantifying the debonding of inclusions through tomography and computational homology.  

SciTech Connect (OSTI)

This report describes a Laboratory Directed Research and Development (LDRD) project to use of synchrotron-radiation computed tomography (SRCT) data to determine the conditions and mechanisms that lead to void nucleation in rolled alloys. The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) has provided SRCT data of a few specimens of 7075-T7351 aluminum plate (widely used for aerospace applications) stretched to failure, loaded in directions perpendicular and parallel to the rolling direction. The resolution of SRCT data is 900nm, which allows elucidation of the mechanisms governing void growth and coalescence. This resolution is not fine enough, however, for nucleation. We propose the use statistics and image processing techniques to obtain sub-resolution scale information from these data, and thus determine where in the specimen and when during the loading program nucleation occurs and the mechanisms that lead to it. Quantitative analysis of the tomography data, however, leads to the conclusion that the reconstruction process compromises the information obtained from the scans. Alternate, more powerful reconstruction algorithms are needed to address this problem, but those fall beyond the scope of this project.

Lu, Wei-Yang; Johnson, George C. (University of California, Berkeley, Berkeley, CA); Mota, Alejandro; Foulk, James W., III; Jin, Huiqing

2010-09-01T23:59:59.000Z

409

Our Next Two Steps for Fukushima Daiichi Muon Tomography  

SciTech Connect (OSTI)

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.

Miyadera, Haruo [Los Alamos National Laboratory

2012-04-11T23:59:59.000Z

410

LMFBR fuel bundle distortion characterization using neutron tomography and potting  

SciTech Connect (OSTI)

A standard liquid metal fast breeder reactor (LMFBR) subassembly used in the Experimental Breeder Reactor II (EBRII) was investigated for fuel bundle distortion by both nondestructive and destructive methods, and the results from both methods were compared. The nondestructive method employed neutron tomography to reconstruct the locations of fuel elements through the use of a maximum entropy reconstruction algorithm known as MENT. The destructive method consisted of ''potting'' (a technique that embeds and permanently fixes the fuel elements in a solid matrix) the subassembly and then cutting and polishing the individual sections. The comparison indicated that the tomography reconstruction provided good results in describing the bundle geometry and spacer-wire locations, with the overall resolution being on the order of a spacer-wire diameter. A dimensional consistency check indicated that the element and spacer-wire dimensions were accurately reproduced in the reconstruction. It was found that in situ fuel elements deform axially in a helical spiral and that the reconstruction was able to identify this helical distortion to within approximately half of a spacerwire diameter.

Betten, P.R.; Tow, D.M.

1984-05-01T23:59:59.000Z

411

CT effective dose per dose length product using ICRP 103 weighting factors  

SciTech Connect (OSTI)

Purpose: To generate effective dose per unit dose length product (E/DLP) conversion factors incorporating ICRP Publication 103 tissue weighting factors. Methods: Effective doses for CT examinations were obtained using the IMPACT Dosimetry Calculator using all 23 dose data sets that are offered by this spreadsheet. CT examinations were simulated for scans performed along the patient long axis for each dosimetry data set using a 4 cm beam width ranging from the upper thighs to top of the head. Five basic body regions (head, neck, chest, abdomen, and pelvis), as well as combinations of the regions (head/neck, chest/abdomen, abdomen/pelvis, and chest/abdomen/pelvis) and whole body CT scans were investigated. Correction factors were generated that can be applied to convert E/DLP conversion factors based on ICRP 60 data to conversion factors that are valid for ICRP 103 data (i.e., E{sub 103}/E{sub 60}). Results: Use of ICRP 103 weighting factors increase effective doses for head scans by {approx}11%, for chest scans by {approx}20%, and decrease effective doses for pelvis scans by {approx}25%. Current E/DLP conversion factors are estimated to be 2.4 {mu}Sv/mGy cm for head CT examinations and range between 14 and 20 {mu}Sv/mGy cm for body CT examinations. Conclusions: Factors that enable patient CT doses to be adjusted to account for ICRP 103 tissue weighting factors are provided, which result in E/DLP factors that were increased in head and chest CT, reduced in pelvis CT, and showed no marked change in neck and abdomen CT.

Huda, Walter; Magill, Dennise; He Wenjun [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina 29425 (United States); Department of Bioengineering, Clemson-MUSC Bioengineering Program, Clemson University, Charleston, South Carolina 29425 (United States)

2011-03-15T23:59:59.000Z

412

Reconstruction from a flexible number of projections in cone-beam computed tomography via active shape models  

E-Print Network [OSTI]

Reconstruction from a flexible number of projections in cone-beam computed tomography via active, and limited view computed tomography. 1. INTRODUCTION In recent years, cone beam computed tomography (CBCT a limited set of projections. Evaluations were performed using simulations with Shepp-Logan phantoms

Corso, Jason J.

413

MR-Guided Freehand Biopsy of Liver Lesions With Fast Continuous Imaging Using a 1.0-T Open MRI Scanner: Experience in 50 Patients  

SciTech Connect (OSTI)

The purpose of this study was to assess a new open system with a field-strength of 1.0 T for the feasibility of liver biopsy using the freehand technique with fast continuous imaging. Fifty patients with focal liver lesions measuring 5 to 30 mm in diameter were included in the study. Guidance and monitoring was performed using a 1.0-T open magnetic resonance (MR) scanner (Panorama HFO; Philips Healthcare, Best, The Netherlands). With fast continuous imaging using a T1-weighted (T1W) gradient echo (GRE) sequence after administration of gadolinium (Gd)-EOB-DTPA, the needle was placed into the lesion. An interface for interactive dynamic viewing in two perpendicular planes prevented needle deviations T2-weighted turbo spin echo (TSE) fat-suppressed sequence was added to rule out postinterventional hematoma or biloma. All lesions were visible on the interventional images. Biopsy was technically successful, and solid specimens were obtained in all cases. Forty-six patients showed a histopathologic pattern other than native liver tissue, thus confirming correct position of the needle. Time between determination of the lesion and performance of the control scan was on average 18 min. No major complications were recorded. MR guidance with the new 1-T open system must be considered an attractive alternative for liver punction. An interface for dynamic imaging of needle guidance and T1W-GRE imaging with administration of Gd-EOB-DTPA for contrast enhancement allows the pinpoint puncture of liver lesions.

Fischbach, Frank, E-mail: frank.fischbach@med.ovgu.de [Otto von Guericke University, Department of Radiology, Medical School (Germany); Bunke, Juergen [Philips Healthcare (Germany); Thormann, Markus; Gaffke, Gunnar; Jungnickel, Kerstin [Otto von Guericke University, Department of Radiology, Medical School (Germany); Smink, Jouke [Philips Healthcare (Germany); Ricke, Jens [Otto von Guericke University, Department of Radiology, Medical School (Germany)

2011-02-15T23:59:59.000Z

414

Cardiac C-arm computed tomography using a 3D + time ROI reconstruction method with spatial and temporal regularization  

SciTech Connect (OSTI)

Purpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition. Methods: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization. Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction. Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection.

Mory, Cyril, E-mail: cyril.mory@philips.com [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France) [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Auvray, Vincent; Zhang, Bo [Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France)] [Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Grass, Michael; Schäfer, Dirk [Philips Research, Röntgenstrasse 24–26, D-22335 Hamburg (Germany)] [Philips Research, Röntgenstrasse 24–26, D-22335 Hamburg (Germany); Chen, S. James; Carroll, John D. [Department of Medicine, Division of Cardiology, University of Colorado Denver, 12605 East 16th Avenue, Aurora, Colorado 80045 (United States)] [Department of Medicine, Division of Cardiology, University of Colorado Denver, 12605 East 16th Avenue, Aurora, Colorado 80045 (United States); Rit, Simon [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France) [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France); Université Lyon 1 (France); Centre Léon Bérard, 28 rue Laënnec, F-69373 Lyon (France); Peyrin, Françoise [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France) [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); X-ray Imaging Group, European Synchrotron, Radiation Facility, BP 220, F-38043 Grenoble Cedex (France); Douek, Philippe; Boussel, Loïc [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France) [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France); Université Lyon 1 (France); Hospices Civils de Lyon, 28 Avenue du Doyen Jean Lépine, 69500 Bron (France)

2014-02-15T23:59:59.000Z

415

Breast Patient Setup Error Assessment: Comparison of Electronic Portal Image Devices and Cone-Beam Computed Tomography Matching Results  

SciTech Connect (OSTI)

Purpose: To quantify the differences in setup errors measured with the cone-beam computed tomography (CBCT) and electronic portal image devices (EPID) in breast cancer patients. Methods and Materials: Repeat CBCT scan were acquired for routine offline setup verification in 20 breast cancer patients. During the CBCT imaging fractions, EPID images of the treatment beams were recorded. Registrations of the bony anatomy for CBCT to planning CT and EPID to digitally reconstructed-radiographs (DRRs) were compared. In addition, similar measurements of an anthropomorphic thorax phantom were acquired. Bland-Altman and linear regression analysis were performed for clinical and phantom registrations. Systematic and random setup errors were quantified for CBCT and EPID-driven correction protocols in the EPID coordinate system (U, V), with V parallel to the cranial-caudal axis and U perpendicular to V and the central beam axis. Results: Bland-Altman analysis of clinical EPID and CBCT registrations yielded 4 to 6-mm limits of agreement, indicating that both methods were not compatible. The EPID-based setup errors were smaller than the CBCT-based setup errors. Phantom measurements showed that CBCT accurately measures setup error whereas EPID underestimates setup errors in the cranial-caudal direction. In the clinical measurements, the residual bony anatomy setup errors after offline CBCT-based corrections were {Sigma}{sub U} = 1.4 mm, {Sigma}{sub V} = 1.7 mm, and {sigma}{sub U} = 2.6 mm, {sigma}{sub V} = 3.1 mm. Residual setup errors of EPID driven corrections corrected for underestimation were estimated at {Sigma}{sub U} = 2.2mm, {Sigma}{sub V} = 3.3 mm, and {sigma}{sub U} = 2.9 mm, {sigma}{sub V} = 2.9 mm. Conclusion: EPID registration underestimated the actual bony anatomy setup error in breast cancer patients by 20% to 50%. Using CBCT decreased setup uncertainties significantly.

Topolnjak, Rajko [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Sonke, Jan-Jakob, E-mail: j.sonke@nki.n [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Nijkamp, Jasper; Rasch, Coen; Minkema, Danny; Remeijer, Peter; Vliet-Vroegindeweij, Corine van [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

2010-11-15T23:59:59.000Z

416

E-Print Network 3.0 - angiographic c-arm ct Sample Search Results  

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

of GPU-Based Cone Beam Computed Tomography. Summary: . 5. Reconstruction of CBCT data from mobile C-arm units by using NVIDIA devices is presented in 6... ., Riabkov, D.,...

417

Iterative image-domain decomposition for dual-energy CT  

SciTech Connect (OSTI)

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 (Catphan©600) 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.

Niu, Tianye; Dong, Xue; Petrongolo, Michael; Zhu, Lei, E-mail: leizhu@gatech.edu [Nuclear and Radiological Engineering and Medical Physics Programs, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)] [Nuclear and Radiological Engineering and Medical Physics Programs, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2014-04-15T23:59:59.000Z

418

Temporal and spectral imaging with micro-CT  

SciTech Connect (OSTI)

Purpose: Micro-CT is widely used for small animal imaging in preclinical studies of cardiopulmonary disease, but further development is needed to improve spatial resolution, temporal resolution, and material contrast. We present a technique for visualizing the changing distribution of iodine in the cardiac cycle with dual source micro-CT. Methods: The approach entails a retrospectively gated dual energy scan with optimized filters and voltages, and a series of computational operations to reconstruct the data. Projection interpolation and five-dimensional bilateral filtration (three spatial dimensions + time + energy) are used to reduce noise and artifacts associated with retrospective gating. We reconstruct separate volumes corresponding to different cardiac phases and apply a linear transformation to decompose these volumes into components representing concentrations of water and iodine. Since the resulting material images are still compromised by noise, we improve their quality in an iterative process that minimizes the discrepancy between the original acquired projections and the projections predicted by the reconstructed volumes. The values in the voxels of each of the reconstructed volumes represent the coefficients of linear combinations of basis functions over time and energy. We have implemented the reconstruction algorithm on a graphics processing unit (GPU) with CUDA. We tested the utility of the technique in simulations and applied the technique in an in vivo scan of a C57BL/6 mouse injected with blood pool contrast agent at a dose of 0.01 ml/g body weight. Postreconstruction, at each cardiac phase in the iodine images, we segmented the left ventricle and computed its volume. Using the maximum and minimum volumes in the left ventricle, we calculated the stroke volume, the ejection fraction, and the cardiac output. Results: Our proposed method produces five-dimensional volumetric images that distinguish different materials at different points in time, and can be used to segment regions containing iodinated blood and compute measures of cardiac function. Conclusions: We believe this combined spectral and temporal imaging technique will be useful for future studies of cardiopulmonary disease in small animals.

Johnston, Samuel M.; Johnson, G. Allan; Badea, Cristian T. [Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710 (United States)

2012-08-15T23:59:59.000Z

419

RIS-M-2586 ELASTIC-PLASTIC FRACTURE MECHANICS ANALYSIS OF A CT-SPECIMEN  

E-Print Network [OSTI]

RISÃ?-M-2586 ELASTIC-PLASTIC FRACTURE MECHANICS ANALYSIS OF A CT-SPECIMEN - A TWO-DIMENSIONAL APPROACH Gunner C. Larsen Abstract. This report documents the results obtained from an elastic-plastic

420

Finite Element Analysis of Ballistic Penetration of Plain Weave Twaron CT709® Fabrics: A Parametric Study  

E-Print Network [OSTI]

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...

Gogineni, Sireesha

2011-10-21T23:59:59.000Z

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421

MicroCT of Coronary Stents: Staining Techniques for 3-D Pathological Analysis  

E-Print Network [OSTI]

for the degree of MASTER OF SCIENCE May 2011 Major Subject: Biomedical Engineering MicroCT of Coronary Stents: Staining Techniques for 3-D Pathological Analysis Copyright 2011 Stephen Daniel Darrouzet... ABSTRACT MicroCT of Coronary Stents: Staining Techniques for 3-D Pathological Analysis. (May 2011) Stephen Daniel Darrouzet, B.S., Texas A&M Unversity Chair of Advisory Committee: Dr. Fred Clubb, Jr. In the area of translational research...

Darrouzet, Stephen 1987-

2011-04-21T23:59:59.000Z

422

Iterative methods for dose reduction and image enhancement in tomography  

DOE Patents [OSTI]

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.

Miao, Jianwei; Fahimian, Benjamin Pooya

2012-09-18T23:59:59.000Z

423

3D Jet Tomography of the Twisted Color Glass Condensate  

E-Print Network [OSTI]

Jet Tomography is proposed as a new test of Color Glass Condensate (CGC) initial conditions in non-central $A+A$ collisions. The $k_{T}$ factorized CGC formalism is used to calculate the rapidity twist in the reaction plane of both the bulk low $p_T 6$ GeV partons. Unlike conventional perturbative QCD, the initial high $p_{T}$ CGC gluons are shown to be twisted even further away from the beam axis than the the low $p_T$ bulk at high rapidities $|\\eta|>2$. Differential directed flow $v_{1}(p_{T}>6,|\\eta|>2)$ is proposed to test this novel high $p_T$ rapidity twist predicted by the CGC model.

A. Adil; M. Gyulassy; T. Hirano

2005-09-23T23:59:59.000Z

424

Electrical resistance tomography from measurements inside a steel cased borehole  

DOE Patents [OSTI]

Electrical resistance tomography (ERT) produced from measurements taken inside a steel cased borehole. A tomographic inversion of electrical resistance measurements made within a steel casing was then made for the purpose of imaging the electrical resistivity distribution in the formation remotely from the borehole. The ERT method involves combining electrical resistance measurements made inside a steel casing of a borehole to determine the electrical resistivity in the formation adjacent to the borehole; and the inversion of electrical resistance measurements made from a borehole not cased with an electrically conducting casing to determine the electrical resistivity distribution remotely from a borehole. It has been demonstrated that by using these combined techniques, highly accurate current injection and voltage measurements, made at appropriate points within the casing, can be tomographically inverted to yield useful information outside the borehole casing.

Daily, William D. (Livermore, CA); Schenkel, Clifford (Walnut Creek, CA); Ramirez, Abelardo L. (Pleasanton, CA)

2000-01-01T23:59:59.000Z

425

Temporoparietal cortex in aphasia. Evidence from positron emission tomography  

SciTech Connect (OSTI)

Forty-four aphasic patients were examined with (F18)-fluorodeoxyglucose positron emission tomography in a resting state to determine whether consistent glucose metabolic abnormalities were present. Ninety-seven percent of subjects showed metabolic abnormalities in the angular gyrus, 89% in the supramarginal gyrus, and 87% in the lateral and transverse superior temporal gyrus. Pearson product moment correlations were calculated between regional metabolic measures and performance on the Western Aphasia Battery. No significant correlations were found between the Western Aphasia Battery scores and right hemisphere metabolic measures. Most left hemisphere regions correlated with more than one score from the Western Aphasia Battery. Temporal but not frontal regions had significant correlations to the comprehension score. The left temporoparietal region was consistently affected in these subjects, suggesting that common features in the aphasias were caused by left temporoparietal dysfunction, while behavioral differences resulted from (1) the extent of temporoparietal changes, and (2) dysfunction elsewhere in the brain, particularly the left frontal and subcortical areas.

Metter, E.J.; Hanson, W.R.; Jackson, C.A.; Kempler, D.; van Lancker, D.; Mazziotta, J.C.; Phelps, M.E. (National Institute of Aging, Baltimore, MD (USA))

1990-11-01T23:59:59.000Z

426

A support vector machine classifier reduces interscanner variation in the HRCT classification of regional disease pattern in diffuse lung disease: Comparison to a Bayesian classifier  

SciTech Connect (OSTI)

Purpose: To investigate the effect of using different computed tomography (CT) scanners on the accuracy of high-resolution CT (HRCT) images in classifying regional disease patterns in patients with diffuse lung disease, support vector machine (SVM) and Bayesian classifiers were applied to multicenter data. Methods: Two experienced radiologists marked sets of 600 rectangular 20 Multiplication-Sign 20 pixel regions of interest (ROIs) on HRCT images obtained from two scanners (GE and Siemens), including 100 ROIs for each of local patterns of lungs-normal lung and five of regional pulmonary disease patterns (ground-glass opacity, reticular opacity, honeycombing, emphysema, and consolidation). Each ROI was assessed using 22 quantitative features belonging to one of the following descriptors: histogram, gradient, run-length, gray level co-occurrence matrix, low-attenuation area cluster, and top-hat transform. For automatic classification, a Bayesian classifier and a SVM classifier were compared under three different conditions. First, classification accuracies were estimated using data from each scanner. Next, data from the GE and Siemens scanners were used for training and testing, respectively, and vice versa. Finally, all ROI data were integrated regardless of the scanner type and were then trained and tested together. All experiments were performed based on forward feature selection and fivefold cross-validation with 20 repetitions. Results: For each scanner, better classification accuracies were achieved with the SVM classifier than the Bayesian classifier (92% and 82%, respectively, for the GE scanner; and 92% and 86%, respectively, for the Siemens scanner). The classification accuracies were 82%/72% for training with GE data and testing with Siemens data, and 79%/72% for the reverse. The use of training and test data obtained from the HRCT images of different scanners lowered the classification accuracy compared to the use of HRCT images from the same scanner. For integrated ROI data obtained from both scanners, the classification accuracies with the SVM and Bayesian classifiers were 92% and 77%, respectively. The selected features resulting from the classification process differed by scanner, with more features included for the classification of the integrated HRCT data than for the classification of the HRCT data from each scanner. For the integrated data, consisting of HRCT images of both scanners, the classification accuracy based on the SVM was statistically similar to the accuracy of the data obtained from each scanner. However, the classification accuracy of the integrated data using the Bayesian classifier was significantly lower than the classification accuracy of the ROI data of each scanner. Conclusions: The use of an integrated dataset along with a SVM classifier rather than a Bayesian classifier has benefits in terms of the classification accuracy of HRCT images acquired with more than one scanner. This finding is of relevance in studies involving large number of images, as is the case in a multicenter trial with different scanners.

Chang, Yongjun; Lim, Jonghyuck; Kim, Namkug; Seo, Joon Beom [Department of Radiology, University of Ulsan College of Medicine, 388-1 Pungnap2-dong, Songpa-gu, Seoul 138-736 (Korea, Republic of); Lynch, David A. [Department of Radiology, National Jewish Medical and Research Center, Denver, Colorado 80206 (United States)

2013-05-15T23:59:59.000Z

427

Thermal stability of curved ray tomography for corrosion monitoring  

SciTech Connect (OSTI)

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 175°C. 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.

Willey, C. L. [Department of Aerospace Engineering and Engineering Mechanics, University o