National Library of Energy BETA

Sample records for knife fryburg mondak

  1. Carter Co. Harding Co. Perkins Co. Dunn Co. Dawson Co. Fallon Co.

    U.S. Energy Information Administration (EIA) Indexed Site

    PENNEL BUFFALO LITTLE KNIFE FRYBURG MONDAK PLEVNA LOOKOUT BUTTE E ELKHORN RANCH DICKINSON CADY CREEK MEDICINE POLE HILLS BICENTENNIAL ROOSEVELT BIG STICK ROUGH RIDER MONARCH TREE TOP LOOKOUT BUTTE BUCKHORN MEDORA FLAT TOP BUTTE ELAND DEMORES ASH COULEE WHISKEY JOE GAS CITY DAVIS CREEK WINDY RIDGE POKER JIM PLEVNA S KNUTSON STATE LINE BELL BEAR CREEK ELKHORN RANCH N PIERRE CREEK LONE BUTTE ZENITH MANNING SQUAW GAP AMOR STADIUM HEART S HILINE ASH MARY GAYLORD BULL CREEK HALEY SHORT PINE HILLS W

  2. Carter Co. Harding Co. Perkins Co. Dunn Co. Dawson Co. Fallon Co.

    U.S. Energy Information Administration (EIA) Indexed Site

    BUFFALO PENNEL LITTLE KNIFE FRYBURG MONDAK PLEVNA LOOKOUT BUTTE E ELKHORN RANCH DICKINSON CADY CREEK BICENTENNIAL MEDICINE POLE HILLS BIG STICK ROOSEVELT ROUGH RIDER MONARCH TREE TOP LOOKOUT BUTTE BUCKHORN MEDORA FLAT TOP BUTTE ELAND DEMORES ASH COULEE WHISKEY JOE GAS CITY DAVIS CREEK WINDY RIDGE POKER JIM PLEVNA S KNUTSON BELL STATE LINE BEAR CREEK ELKHORN RANCH N PIERRE CREEK LONE BUTTE ZENITH MANNING SQUAW GAP AMOR HEART S STADIUM HILINE ASH MARY LAKE ILO GAYLORD BULL CREEK HALEY BULLY SHORT

  3. Carter Co. Harding Co. Perkins Co. Dunn Co. Dawson Co. Fallon Co.

    U.S. Energy Information Administration (EIA) Indexed Site

    PENNEL BUFFALO LITTLE KNIFE FRYBURG MONDAK PLEVNA LOOKOUT BUTTE E ELKHORN RANCH DICKINSON CADY CREEK MEDICINE POLE HILLS BICENTENNIAL ROOSEVELT BIG STICK ROUGH RIDER MONARCH TREE TOP LOOKOUT BUTTE BUCKHORN MEDORA FLAT TOP BUTTE ELAND DEMORES ASH COULEE WHISKEY JOE GAS CITY DAVIS CREEK WINDY RIDGE POKER JIM PLEVNA S KNUTSON STATE LINE BELL BEAR CREEK ELKHORN RANCH N PIERRE CREEK LONE BUTTE ZENITH MANNING SQUAW GAP AMOR STADIUM HEART S HILINE ASH MARY GAYLORD BULL CREEK HALEY SHORT PINE HILLS W

  4. Electrosurgical knife

    DOE Patents [OSTI]

    Doss, James D.; Cowan, Robert E.; Newell, Robert H.; McCabe, Charles W.

    1979-01-01

    An electrosurgical knife blade of insulating material having a pair of electrodes adapted to be connected to a radiofrequency generator.

  5. Electrosurgical knife

    DOE Patents [OSTI]

    Doss, J.D.; Cowan, R.E.; Newell, R.H.; McCabe, C.W.

    1975-08-01

    An electrosurgical knife blade of insulating material having a pair of electrodes adapted to be connected to a radiofrequency generator was developed.

  6. Little Knife field - US Williston basin

    SciTech Connect (OSTI)

    Wittstrom, M.D.; Lindsay, R.F. )

    1991-03-01

    Little Knife field is a combination structural and stratigraphic trap located near the structural center of the Williston basin, North Dakota. The field is approximately 12 mi (19.3 km) long and 2.5 to 5.5 mi (4 to 8.9 km) wide. Little Knife was discovered by Gulf Oil in 1976 as part of a regional exploration play involving a transition from impermeable to porous carbonate rocks. In 1987, ultimate recovery from the Mission Canyon (Mississippian) reservoir was estimated to be 97.5 MMBO. This included 57.5 MMBO primary, 27 MMBO secondary, and 13 MMBO tertiary (CO{sub 2}) oil. At present the field is still under primary recovery, since utilization efforts have not been successful. Approximately one-third of Little Knife's 130 ft (39.6 m) oil column is trapped by structural closure beneath a regional anhydrite seal in a north-south-trending anticline. The remaining two-thirds of the oil column is trapped where the reservoir beds change facies from porous dolostones and dolomitic limestones to nonporous limestones. Structural entrapment accounts for approximately 50% (127 MMBO) of the OOIP, but covers only 30% of the producing area. Production is from the upper portions of the Mission Canyon Formation, a regressive, shoaling-upward carbonate-anhydrite sequence deposited in a slowly shrinking epeiric sea. The Mission Canyon in the Little Knife area is divided into six zones that record predominantly cyclic, subtidal deposition. These are overlain by prograding lagoonal, tidal flat, and sabkha beds. The source of Mission Canyon oil is thought to be the Bakken Formation, an organic-rich shale at the base of the Mississippian.

  7. Origin of reservoir fractures in Little Knife field, North Dakota

    SciTech Connect (OSTI)

    Narr, W.; Burrus, R.C.

    1984-09-01

    Thin, vertical, planar fractures observed in the Mission Canyon Formation, at the Little Knife field, are naturally occurring and appear to be extension fractures. The predominant east-west trend of the fractures, measured in oriented core from six wells, parallels the contemporary maximum horizontal compressive stress in the Williston basin. The fractures occur only in carbonate units, but within the carbonates their occurrence is not lithology dependent. Fracture density measured in the cores of the reservoir carbonates averages 1 ft (.3 m) of fracture per 2.3 ft (.7 m) of core. The formation and mineralization of reservoir fractures were the most recent diagenetic events in the Mission Canyon Formation at Little Knife. Study of aqueous and hydrocarbon fluid inclusions associated with the fractures reveals: (1) fractures formed after the strata were buried to at least their present depth of 9,800 ft (2,987 m), which indicates their age is post-Mesozoic; (2) the pore-fluid pressure gradient was normal hydrostatic immediately after, if not during, fracture system development; (3) formation-water salinity has remained fairly constant since fracture initiation; (4) migration of hydrocarbons into the reservoir probably preceded fracture genesis; and (5) methane concentration may have decreased since fracture initiation.

  8. Success in prevention of casing failures opposite salts, Little Knife Field, North Dakota

    SciTech Connect (OSTI)

    Rike, E.A.; Bryant, G.A.; Williams, S.D.

    1986-04-01

    The authors became aware in early 1981 of a severe problem with casing failures opposite salts in the Little Knife Field. A concerted engineering effort was initiated to isolate and to remedy the cause of failures. With the use of a relaxed invert-oil-emulsion drilling fluid and properly designed cementing programs, the problem has been arrested. In the 26 wells drilled in the Little Knife Field since initiation of this drilling program, there have been no instances of casing failure.

  9. Evaluation of the Little Knife CO/sub 2/ minitest

    SciTech Connect (OSTI)

    Suffridge, F.E.; Dauben, D.L.; Pezzullo, J.A.

    1986-04-01

    A joint DOE-Gulf Oil Corporation, nonproducing carbon dioxide minitest was conducted in the Little Knife Field in western North Dakota. At the time of the project, the reservoir was undergoing primary depletion and had no secondary recovery operations underway. The five-acre inverted four-spot tested the applicability of a CO/sub 2/-alternating-with-water injection process to commercially displace oil in the nonflooded Mission Canyon Formation located in the Williston Basin. The nonproducing test was evaluated using time-lapse logging and fluid sampling to monitor fluid movement as injected CO/sub 2/ and water displaced 41/sup 0/ API oil in three observation wells which surrounded a central injector. Numerical simulation studies using the time-lapse logging data provided the basis for estimating pilot performance and evaluating a proposed expansion of the process to a 160-acre pattern. Gulf personnel are to be commended for designing and implementing a state-of-the-art, nonproducing pilot test of the CO/sub 2/ process. Results obtained in the pilot show an optimistic incremental recovery over waterflooding of 8.0 percent of the oil-in-place (OOIP) with an optimistic 1.0 STB of oil production estimated per 5.0 to 8.0 MSCF of injected CO/sub 2/ depending on exclusion or inclusion of Zone W. Assuming a more realistic 1.0 STB of oil recovered per 10.0 MSCF of injected CO/sub 2/, these results still encourage the commercial application of the process to the Little Knife Field upon location of a suitable CO/sub 2/ source. 34 refs., 17 figs., 13 tabs.

  10. Size reduction of high- and low-moisture corn stalks by linear knife grid system

    SciTech Connect (OSTI)

    Womac, A.R. [University of Tennessee; Igathinathane, C. [Mississippi State University (MSU); Sokhansanj, Shahabaddine [ORNL; Narayan, S. [First American Scientific Co.

    2009-04-01

    High- and low-moisture corn stalks were tested using a linear knife grid size reduction device developed for first-stage size reduction. The device was used in conjunction with a universal test machine that quantified shearing stress and energy characteristics for forcing a bed of corn stalks through a grid of sharp knives. No published engineering performance data for corn stover with similar devices are available to optimize performance; however, commercial knife grid systems exist for forage size reduction. From the force displacement data, mean and maximum ultimate shear stresses, cumulative and peak mass-based cutting energies for corn stalks, and mean new surface area-based cutting energies were determined from 4 5 refill runs at two moisture contents (78.8% and 11.3% wet basis), three knife grid spacings (25.4, 50.8, and 101.6 mm), and three bed depths (50.8, 101.6, and 152.4 mm). In general, the results indicated that peak failure load, ultimate shear stress, and cutting energy values varied directly with bed depth and inversely with knife grid spacing. Mean separation analysis established that high- and low-moisture conditions and bed depths 101.6 mm did not differ significantly (P < 0.05) for ultimate stress and cutting energy values, but knife grid spacing were significantly different. Linear knife grid cutting energy requirements for both moisture conditions of corn stalks were much smaller than reported cutting energy requirements. Ultimate shear stress and cutting energy results of this research should aid the engineering design of commercial scale linear knife gird size reduction equipment for various biomass feedstocks.

  11. Success in Prevention of Casing Failures Opposite Salts, Little Knife Field, ND

    SciTech Connect (OSTI)

    Rilke, E.A.

    1984-05-01

    Early in 1981, Gulf became aware of a severe problem with casing failures opposite salts in the Little Knife Field. A concerted effort was initiated at that time to isolate and remedy the cause of failures. By properly designing tubulars, utilizing a relaxed invert oil emulsion drilling fluid, and properly designing cementing programs, the problem has been arrested. In the 22 wells drilled in the Little Knife Field since initiation of this drilling program in 1981, there have been no instances of casing failure.

  12. Gamma Knife Radiosurgery for the Treatment of Cystic Cerebral Metastases

    SciTech Connect (OSTI)

    Ebinu, Julius O.; Lwu, Shelly; Monsalves, Eric; Arayee, Mandana; Chung, Caroline; Laperriere, Normand J.; Kulkarni, Abhaya V.; Goetz, Pablo; Zadeh, Gelareh

    2013-03-01

    Purpose: To assess the role of Gamma Knife radiosurgery (GKRS) in the treatment of nonsurgical cystic brain metastasis, and to determine predictors of response to GKRS. Methods: We reviewed a prospectively maintained database of brain metastases patients treated at our institution between 2006 and 2010. All lesions with a cystic component were identified, and volumetric analysis was done to measure percentage of cystic volume on day of treatment and consecutive follow-up MRI scans. Clinical, radiologic, and dosimetry parameters were reviewed to establish the overall response of cystic metastases to GKRS as well as identify potential predictive factors of response. Results: A total of 111 lesions in 73 patients were analyzed; 57% of lesions received prior whole-brain radiation therapy (WBRT). Lung carcinoma was the primary cancer in 51% of patients, 10% breast, 10% colorectal, 4% melanoma, and 26% other. Fifty-seven percent of the patients were recursive partitioning analysis class 1, the remainder class 2. Mean target volume was 3.3 mL (range, 0.1-23 mL). Median prescription dose was 21 Gy (range, 15-24 Gy). Local control rates were 91%, 63%, and 37% at 6, 12, and 18 months, respectively. Local control was improved in lung primary and worse in patients with prior WBRT (univariate). Only lung primary predicted local control in multivariate analysis, whereas age and tumor volume did not. Lesions with a large cystic component did not show a poorer response compared with those with a small cystic component. Conclusions: This study supports the use of GKRS in the management of nonsurgical cystic metastases, despite a traditionally perceived poorer response. Our local control rates are comparable to a matched cohort of noncystic brain metastases, and therefore the presence of a large cystic component should not deter the use of GKRS. Predictors of response included tumor subtype. Prior WBRT decreased effectiveness of SRS for local control rates.

  13. Williston Basin. Gulf's CO/sub 2/ mini-test at Little Knife being evaluated

    SciTech Connect (OSTI)

    Hess, T.

    1981-10-01

    The Gulf Oil Exploration and Production Co. nonproducing CO/sub 2/ mini-test at Little Knife field is complete and under evaluation. Although Gulf and the Department of Energy, cosponsors of the $5.62-million project in Billings County, North Dakota, say it is premature to draw conclusions, it appears field test results mirror those achieved in laboratory tests. CO/sub 2/ and tracers have shown up in the observation wells. The objective was to show that CO/sub 2/ miscible displacement is potentially a commercial method of recovering crude oil from high-saturation carbonate reservoirs that have not been extensively waterflooded. The mini-test site, 3-144N-98W in Little Knife field, was appropriate because it was representative of the field.

  14. Gamma Knife irradiation method based on dosimetric controls to target small areas in rat brains

    SciTech Connect (OSTI)

    Constanzo, Julie; Paquette, Benoit; Charest, Gabriel; Masson-Côté, Laurence; Guillot, Mathieu

    2015-05-15

    Purpose: Targeted and whole-brain irradiation in humans can result in significant side effects causing decreased patient quality of life. To adequately investigate structural and functional alterations after stereotactic radiosurgery, preclinical studies are needed. The purpose of this work is to establish a robust standardized method of targeted irradiation on small regions of the rat brain. Methods: Euthanized male Fischer rats were imaged in a stereotactic bed, by computed tomography (CT), to estimate positioning variations relative to the bregma skull reference point. Using a rat brain atlas and the stereotactic bregma coordinates obtained from CT images, different regions of the brain were delimited and a treatment plan was generated. A single isocenter treatment plan delivering ≥100 Gy in 100% of the target volume was produced by Leksell GammaPlan using the 4 mm diameter collimator of sectors 4, 5, 7, and 8 of the Gamma Knife unit. Impact of positioning deviations of the rat brain on dose deposition was simulated by GammaPlan and validated with dosimetric measurements. Results: The authors’ results showed that 90% of the target volume received 100 ± 8 Gy and the maximum of deposited dose was 125 ± 0.7 Gy, which corresponds to an excellent relative standard deviation of 0.6%. This dose deposition calculated with GammaPlan was validated with dosimetric films resulting in a dose-profile agreement within 5%, both in X- and Z-axes. Conclusions: The authors’ results demonstrate the feasibility of standardizing the irradiation procedure of a small volume in the rat brain using a Gamma Knife.

  15. SU-E-T-542: Comparison of Stereotactic Radiosurgery (SRS) of Brain Lesions Using Gamma Knife, VMAT, IMRT, and Conformal Arcs

    SciTech Connect (OSTI)

    Li, S; Charpentier, P; Chan, P; Neicu, T; Miyamoto, C

    2014-06-01

    Purpose: To compare dose distributions in stereotactic radiation surgery of brain lesions using gamma Knife, VMAT, conformal arcs, and IMRT in order to provide an optimal treatment. Methods: Dose distributions from single shot of 4C model of Gamma Knife at the helmet collimation sizes of 4, 8, 14, and 18 mm in diameter were compared with full arcs with the square shapes of 4×4 (or 5×5), 8×8 (or 10×10), and spherical shapes of 16 or 20 mm in diameter using EDR3 films in the same gamma knife QA phantom. Plans for ten SRS cases with single and multiple lesions were created in gamma knife plans and Pinnacle plans. The external beam plans had enlarged field size by 2-mm and used single conformal full circle arc for solitary lesion and none coplanar arcs/beams for multiple lesions. Coverage, conformity index, dose to critical organs, and integral dose to the brain and nearby critical structures were compared on all plans. Structures and dose matrices were registered in a Velocity deformable image registration system. Results: Single full circle arc from Elekta beam-modulate MLC (4-mm leaf thickness) and agility MLC (5-mm leaf thickness) have larger penumbra and less flatness than that of Gamma Knife single shot. None-coplanar arcs or beams were required to achieve similar dose distribution. In general, Gamma Knife plans provided significant less integral dose than that of linac-based plans. Benefits of IMRT and VMAT versus gamma Knife and conformal arcs were not significant. Conclusion: Our dose measurement and treatment planning evaluation clearly demonstrated dose distribution differences amount current popular SRS modalities for small solitary and multiple brain lesions. The trend of using MLC shape beams or arcs to replace conventional cones should be revisited in order to keep lower integral dose if the late correlates with some radiation-induced side effects. Pilot grant from Elekta LLC.

  16. Impact of Millimeter-Level Margins on Peripheral Normal Brain Sparing for Gamma Knife Radiosurgery

    SciTech Connect (OSTI)

    Ma, Lijun; Sahgal, Arjun; Larson, David A.; Pinnaduwage, Dilini; Fogh, Shannon; Barani, Igor; Nakamura, Jean; McDermott, Michael; Sneed, Penny

    2014-05-01

    Purpose: To investigate how millimeter-level margins beyond the gross tumor volume (GTV) impact peripheral normal brain tissue sparing for Gamma Knife radiosurgery. Methods and Materials: A mathematical formula was derived to predict the peripheral isodose volume, such as the 12-Gy isodose volume, with increasing margins by millimeters. The empirical parameters of the formula were derived from a cohort of brain tumor and surgical tumor resection cavity cases (n=15) treated with the Gamma Knife Perfexion. This was done by first adding margins from 0.5 to 3.0 mm to each individual target and then creating for each expanded target a series of treatment plans of nearly identical quality as the original plan. Finally, the formula was integrated with a published logistic regression model to estimate the treatment-induced complication rate for stereotactic radiosurgery when millimeter-level margins are added. Results: Confirmatory correlation between the nominal target radius (ie, R{sub T}) and commonly used maximum target size was found for the studied cases, except for a few outliers. The peripheral isodose volume such as the 12-Gy volume was found to increase exponentially with increasing Δ/R{sub T}, where Δ is the margin size. Such a curve fitted the data (logarithmic regression, R{sup 2} >0.99), and the 12-Gy isodose volume was shown to increase steeply with a 0.5- to 3.0-mm margin applied to a target. For example, a 2-mm margin on average resulted in an increase of 55% ± 16% in the 12-Gy volume; this corresponded to an increase in the symptomatic necrosis rate of 6% to 25%, depending on the Δ/R{sub T} values for the target. Conclusions: Millimeter-level margins beyond the GTV significantly impact peripheral normal brain sparing and should be applied with caution. Our model provides a rapid estimate of such an effect, particularly for large and/or irregularly shaped targets.

  17. CO/sub 2/ Minitest, Little Knife Field, ND: A case history

    SciTech Connect (OSTI)

    Thakur, G.C.; Lin, C.J.; Patel, Y.R.

    1984-04-01

    A joint DOE-Gulf Oil Corporation Minitest of CO/sub 2/ miscible flooding was conducted in the Mission Canyon formation of the Little Knife Field, North Dakota. In the five-acre minitest area, a central injection and three observation wells were drilled to form a non-producing, inverted four-spot pattern. A 1:1 CO/sub 2/ WAG injection sequence (preflush water injection, five alternate slugs of CO/sub 2/ and water, and drive water injection) was implemented. Prior to the CO/sub 2/ minitest, a detailed reservoir description of the test area was developed through logging, pulse testing and core analysis. Extensive laboratory work had been performed to determine miscibility pressure, swelling and viscosity reduction effects. The minitest included continuous bottomhole pressure measurement in all test wells and time-lapse logging to monitor saturation changes as alternate slugs of water and CO/sub 2/ passed the observation wells. Fluid samples from the observation wells were collected periodically to check for tracers and fluid composition.

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

    SciTech Connect (OSTI)

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

    2014-02-15

    Purpose: Establish and validate a process of accurately irradiating small animals using the CyberKnife G4 System (version 8.5) with treatment plans designed to irradiate a hemisphere of a mouse brain based on microCT scanner images. Methods: These experiments consisted of four parts: (1) building a mouse phantom for intensity modulated radiotherapy (IMRT) quality assurance (QA), (2) proving usability of a microCT for treatment planning, (3) fabricating a small animal positioning system for use with the CyberKnife's image guided radiotherapy (IGRT) system, and (4)in vivo verification of targeting accuracy. A set of solid water mouse phantoms was designed and fabricated, with radiochromic films (RCF) positioned in selected planes to measure delivered doses. After down-sampling for treatment planning compatibility, a CT image set of a phantom was imported into the CyberKnife treatment planning 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.

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

    SciTech Connect (OSTI)

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

    2014-02-15

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

  20. Clinical Realization of Sector Beam Intensity Modulation for Gamma Knife Radiosurgery: A Pilot Treatment Planning Study

    SciTech Connect (OSTI)

    Ma, Lijun; Mason, Erica; Sneed, Penny K.; McDermott, Michael; Polishchuk, Alexei; Larson, David A.; Sahgal, Arjun

    2015-03-01

    Purpose: To demonstrate the clinical feasibility and potential benefits of sector beam intensity modulation (SBIM) specific to Gamma Knife stereotactic radiosurgery (GKSRS). Methods and Materials: SBIM is based on modulating the confocal beam intensities from individual sectors surrounding an isocenter in a nearly 2π geometry. This is in contrast to conventional GKSRS delivery, in which the beam intensities from each sector are restricted to be either 0% or 100% and must be identical for any given isocenter. We developed a SBIM solution based on available clinical planning tools, and we tested it on a cohort of 12 clinical cases as a proof of concept study. The SBIM treatment plans were compared with the original clinically delivered treatment plans to determine dosimetric differences. The goal was to investigate whether SBIM would improve the dose conformity for these treatment plans without prohibitively lengthening the treatment time. Results: A SBIM technique was developed. On average, SBIM improved the Paddick conformity index (PCI) versus the clinically delivered plans (clinical plan PCI = 0.68 ± 0.11 vs SBIM plan PCI = 0.74 ± 0.10, P=.002; 2-tailed paired t test). The SBIM plans also resulted in nearly identical target volume coverage (mean, 97 ± 2%), total beam-on times (clinical plan 58.4 ± 38.9 minutes vs SBIM 63.5 ± 44.7 minutes, P=.057), and gradient indices (clinical plan 3.03 ± 0.27 vs SBIM 3.06 ± 0.29, P=.44) versus the original clinical plans. Conclusion: The SBIM method is clinically feasible with potential dosimetric gains when compared with conventional GKSRS.

  1. Anatomy of a dolomitized carbonate reservoir - Mission Canyon formation at little Knife field, North Dakota

    SciTech Connect (OSTI)

    Lindsay, R.F.

    1985-05-01

    The Mission Canyon Formation is a regressive, shoaling-upward carbonate to anhydrite sequence deposited in a slowly shrinking epeiric sea. From its base upsection, the formation is mostly subtidal in origin and emergent at its top, and consists of (1) deeper water carbonates, (2) major cycles of open shallow-marine mudstones grading up into skeletal packstone or rainstone, (3) minor cycles of dolomitized transitional open to restricted marine mudstone grading up into skeletal wackestone, (4) dolomitized restricted marine pelletal wackestone or packstone, (5) partially dolomitized marginal marine skeletal wackestone, (6) slightly skeletal, oolitic-pisolitic wackestone, or grainstone barrier-island buildups with storm washover aprons, (7) thin lagoonal limestones, (8) tidal-flat anhydrite, and (9) sabkha anhydrite. The oil is structurally trapped on the north, east, and west, within the northward plunging Little Knife anticline. Facies changes entrap the oil southward; the vertical seal is the overlying anhydrite beds. Closure is less than 100 ft 930 m). Porous, hydrocarbon-bearing beds were deposited as transitional open-to-restricted marine, restricted marine, and marginal marine lime muds. These became porous dolomitic reservoir rock by undergoing three diagenetic changes: (1) anhydrite replacement of skeletal fragments, (2) dolomitization of the muddy matrix, and (3) later, leaching of the anhydrite to create moldic porosity. The reservoir's pore system is composed of moldic pores and three types of dolomite intercrystalline pores-polyhedral, tetrahedral, and interboundary-sheet pores. Pore throats in productive beds are of two general sizes (1.2-1.6..mu.. and 5.2..mu..).

  2. SU-E-T-104: Development of 3 Dimensional Dosimetry System for Gamma Knife

    SciTech Connect (OSTI)

    Yoon, K; Kwak, J; Cho, B; Lee, D; Ahn, S

    2014-06-01

    Purpose: The aim of this study was to develop a new 3 dimensional dosimetry system to verify the dosimetric accuracy of Leksell Gamma Knife-Perfexion (LGK) (Elekta, Norcross, GA). Methods: We designed and manufactured a lightweight dosimetry instrument to be equipped with the head frame to LGK. It consists of a head phantom, a scintillator, a CCD camera and a step motor. The 1010 cm2 sheet of Gd2O3;Tb phosphor or Gafchromic EBT3 film was located at the center of the 16 cm diameter hemispherical PMMA, the head phantom. The additional backscatter compensating material of 1 cm thick PMMA plate was placed downstream of the phosphor sheet. The backscatter plate was transparent for scintillation lights to reach the CCD camera with 12001200 pixels by 5.2 um pitch. With This equipment, 300 images with 0.2 mm of slice gap were acquired under three collimator setups (4mm, 8mm and 16mm), respectively. The 2D projected doses from 3D distributions were compared with the exposured film dose. Results: As all doses normalized by the maximum dose value in 16 mm setup, the relative differences between the equipment dose and film dose were 0.2% for 4mm collimator and 0.5% for 8mm. The acquisition of 300 images by the equipment took less than 3 minutes. Conclusion: The new equipment was verified to be a good substitute to radiochromic film, with which required more time and resources. Especially, the new methods was considered to provide much convenient and faster solution in the 3D dose acquisition for LGK.

  3. Little Knife field CO/sub 2/ minitest, Billings County, North Dakota. Vol. II. Appendices. Final report

    SciTech Connect (OSTI)

    Upton, J.E.

    1983-07-01

    A study of the water injection phase of the Little Knife CO/sub 2/ minitest has been completed using a three-dimensional, three-phase black oil simulator. The study was designed to investigate the water injection requirements for repressurization and the effects of the injection on the reservoir. An accurate reservoir characterization was necessary to accomplish this goal. It is believed that by including a detailed description of reservoir properties and production history, a good reservoir characterization was obtained. Using the resultant reservoir model, several prediction cases were run to simulate the effects of various injection plans on the minitest area. These cases included two injection start up dates and two different future production performance schedules. The following conclusions are drawn, based upon the results of this study: (1) the pressure in the minitest area will be raised above the calculated minimum CO/sub 2/ miscibility pressure of 3400 psig, if water injection is begun on either October 1, 1980 or September 1, 1980; (2) a water injection rate of 1150 STB/D, for fifteen (15) days, will adequately repressure the pilot area if the above dates are observed; (3) the current rate of reservoir fluid withdrawal will not adversely affect the pilot area if the aforementioned injection plan is utilized; (4) water injection in the pilot area will not strongly affect the average reservoir pressure in the D-zone of the Little Knife field. 28 figures, 11 tables.

  4. Enhanced oil recovery by CO/sub 2/ miscible displacement in the Little Knife Field, Billings County, North Dakota

    SciTech Connect (OSTI)

    Desch, J.B.; Larsen, W.K.; Lindsay, R.F.; Nettle, R.L.

    1984-09-01

    A CO/sub 2/ minitest involving the miscible displacement process was conducted in the Mission Canyon formation (lower Mississippian) at Little Knife field, ND. The Mission Canyon is a dolomitized carbonate reservoir at approximately 9,700 to 9,900 ft (2957 to 3018 m) subsurface, which is undergoing primary depletion. Four wells were drilled in an inverted four-spot configuration, covering 5 acres (20 234 m/sup 2/). The central well served as the injection well and was surrounded by three nonproducing observation wells. Oriented cores were cut in each well for detailed reservoir characterization and laboratory testing. In addition, a well test program was conducted that involved two pulse tests and injectivity tests on the individual wells. Results from these tests were used to upgrade two reservoir simulation models. Various parameters within the computer models were modified to determine the most efficient injection plan for the specific reservoir characteristics.

  5. Enhanced oil recovery by CO/sub 2/ miscible displacement in the Little Knife Field, Billings County, North Dakota

    SciTech Connect (OSTI)

    Desch, J.B.; Larsen, W.K.; Lindsay, R.F.; Nettle, R.L.

    1982-01-01

    Gulf Oil Exploration and Production Company, in conjunction with the Department of Energy, has successfully conducted a field test of the CO/sub 2/ miscible displacement process in the Little Knife Field. All project objectives were conceived, implemented, and accomplished as a result of the synergetic cooperation and communication between the various departments within Gulf Oil Corporation and the DOE. The minitest succeeded in establishing water-flood residual-oil saturations. It also succeeded in reducing the waterflood residual-oil saturation to a lower value by CO/sub 2//water injection. Finally, and most importantly, the minitest was successfully characterized, developed, and monitored. Monitoring was accomplished by cased-hole logging, fluid sampling, and simulation modeling. 9 refs.

  6. Little Knife Field CO/sub 2/ minitest, Billings County, North Dakota. Final report. Volume 1. Technical report

    SciTech Connect (OSTI)

    Upton, J.E.

    1983-07-01

    A carbon dioxide minitest was conducted in the Mission Canyon Formation (lower Mississippian) at Little Knife Field, North Dakota. The Mission Canyon is a dolomitized carbonate reservoir which is undergoing primary depletion. Four wells were drilled in an inverted four-spot configuration, covering five acres. The central well served as the injection well and was surrounded by three non-producing observation wells. Oriented cores were cut in each well for detailed reservoir characterization and laboratory testing. In addition, a well test program was conducted which involved two pulse tests and injectivity tests on the individual wells. Results from these tests were used as part of the input data for two reservoir simulation models. Various parameters in the computer models were varied to determine the most efficient injection plan for the specific reservoir characteristics. The pattern sweep efficiency for carbon dioxide approached 52 percent in the minitest area. Displacement efficiency, as indicated by simulation study, was 50 percent of the oil-in-place at the start of the project, compared with an efficiency of 37 percent for waterflood. Thirty-one hundred cubic feet of CO/sub 2/ were required per incremental barrel of displaced oil. The absence of producing wells and the fact that only one zone within the Mission Canyon Formation was flooded, favorably influenced these figures. The Little Knife CO/sub 2/ minitest confirmed, by field testing, the results of laboratory CO/sub 2/ miscible displacement tests. The minitest indicated that the CO/sub 2/ miscible displacement process has technical potential for commercialization in a dolomitized carbonate reservoir that has not been extensively waterflooded and has an indicated high remaining oil saturation. 159 figures, 46 tables.

  7. SU-E-T-476: Quality Assurance for Gamma Knife Perfexion Using the Exradin W1 Plastic Scintillation Detector

    SciTech Connect (OSTI)

    Pino, R; Therriault-Proulx, F; Yang, J; Beddar, S

    2014-06-01

    Purpose: To perform dose profile and output factor measurements for the Exradin W1 plastic scintillation detector (PSD) for the Gamma Knife Perfexion (GKP) collimators in a Lucy phantom and to compare these values to an Exradin A16 ion chamber, EBT3 radiochromic film and treatment planning system (TPS) data. Methods: We used the Exradin W1 PSD which has a small volume, near-water equivalent sensitive element. It has also been shown to be energy independent. This new detector is manufactured and distributed by Standard Imaging, Inc. Measurements were performed for all three collimators (4 mm, 8 mm and 16 mm) for the GKP. The Lucy phantom with the PSD inserted was moved in small steps to acquire profiles in all three directions. EBT3 film was inserted in the Lucy phantom and exposed to a single shot for each collimator. Relative output factors were measured using the three detectors while profiles acquired with the PSD were compared to the ones measured with EBT3 radiochromic film. Results: Measured output factors relative to the largest collimator are as followsCollimator PS EBT3 A1616mm 1.000 1.000 1.0008mm 0.892 0.881 0.8834mm 0.795 0.793 0.727 The nominal (vendor) OFs for GKP are 1.000, 0.900, and 0.814, for collimators 16 mm, 8 mm and 4 mm, respectively. There is excellent agreement between all profiles measured with the PSD and EBT3 as well as with the TPS data provided by the vendor. Conclusion: Output factors measured with the W1 were consistent with the ones measured with EBT3 and A16 ion chamber. Measured profiles are in excellent agreement. The W1 detector seems well suited for beam QA for Gamma Knife due to its dosimetric characteristics. Sam Beddar would like to disclose a NIH/NCI SBIR Phase II grant (2R44CA153824-02A1) with Standard Imaging, Title: “Water-Equivalent Plastic Scintillation Detectors for Small Field Radiotherapy”.

  8. Enhanced oil recovery by CO/sub 2/ miscible displacement in the Little Knife Field, Billings County, North Dakota

    SciTech Connect (OSTI)

    Desch, J.B.; Larsen, W.K.; Lindsay, R.F.; Nettle, R.L.

    1982-01-01

    A CO/sub 2/ minitest employing the miscible displacement process was conducted in the Mission Canyon Formation (lower Mississippian) at Little Knife Field, North Dakota. The Mission Canyon is a dolomitized carbonate reservoir which is undergoing primary depletion. Four wells were drilled in an inverted four-spot configuration, covering five acres. The central well served as the injection well and was surrounded by three non-producing observation wells. A WAG-type injection sequence utilized five alternate slugs of formation water and CO/sub 2/. Preflush injection began December 11, 1980, followed by the WAG slugs from January 7 to March 25, 1981. Drive water injection commenced immediately and was completed on September 24, 1981. Injection rates were maintained at 1150 B/D during water injection and 40 T/D during CO/sub 2/ injection. Tracers were used during the waterflood preflush and with the water during the WAG. A pressure core behind the flood front was obtained to confirm residual-oil saturations in the project interval. Overall rock recovery was excellent, 90%, but sample recovery under reservoir pressure was less than anticipated. Invasion of drilling fluids during coring was checked by introduction of a radioactive tracer into the coring fluid. Project analysis is still ongoing and once completed, the simulation models will be updated and used to predict field-wide applicability. (JMT)

  9. Measurement of relative output factors for the 8 and 4 mm collimators of Leksell Gamma Knife Perfexion by film dosimetry

    SciTech Connect (OSTI)

    Novotny, Josef Jr.; Bhatnagar, Jagdish P.; Quader, Mubina A.; Bednarz, Greg; Lunsford, L. Dade; Huq, M. Saiful

    2009-05-15

    Three types of films, Kodak EDR2, Gafchromic EBT, and Gafchromic MD-V2-55, were used to measure relative output factors of 4 and 8 mm collimators of the Leksell Gamma Knife Perfexion. The optical density to dose calibration curve for each of the film types was obtained by exposing the films to a range of known doses. Ten data points were acquired for each of the calibration curves in the dose ranges from 0 to 4 Gy, 0 to 8 Gy, and 0 to 80 Gy for Kodak EDR2, Gafchromic EBT, and Gafchromic MD-V2-55 films, respectively. For the measurement of relative output factors, five films of each film type were exposed to a known dose. All films were scanned using EPSON EXPRESSION 10000 XL scanner with 200 dpi resolution in 16 bit gray scale for EDR2 film and 48 bit color scale for Gafchromic films. The scanned images were imported in the red channel for both Gafchromic films. The background corrections from an unexposed film were applied to all films. The output factors obtained from film measurements were in a close agreement both with the Monte Carlo calculated values of 0.924 and 0.805 for 8 and 4 mm collimators, respectively. These values are provided by the vendor and used as default values in the vendor's treatment planning system. The largest differences were noted for the Kodak EDR 2 films (-2.1% and -4.5% for 8 and 4 mm collimators, respectively). The best agreement observed was for EBT Gafchromic film (-0.8% and +0.6% differences for 8 and 4 mm collimators, respectively). Based on the present values, no changes in the default relative output factor values were made in the treatment planning system.

  10. A Simple and Efficient Methodology To Improve Geometric Accuracy in Gamma Knife Radiation Surgery: Implementation in Multiple Brain Metastases

    SciTech Connect (OSTI)

    Karaiskos, Pantelis; Moutsatsos, Argyris; Pappas, Eleftherios; Georgiou, Evangelos; Roussakis, Arkadios; Torrens, Michael; Seimenis, Ioannis

    2014-12-01

    Purpose: To propose, verify, and implement a simple and efficient methodology for the improvement of total geometric accuracy in multiple brain metastases gamma knife (GK) radiation surgery. Methods and Materials: The proposed methodology exploits the directional dependence of magnetic resonance imaging (MRI)-related spatial distortions stemming from background field inhomogeneities, also known as sequence-dependent distortions, with respect to the read-gradient polarity during MRI acquisition. First, an extra MRI pulse sequence is acquired with the same imaging parameters as those used for routine patient imaging, aside from a reversal in the read-gradient polarity. Then, “average” image data are compounded from data acquired from the 2 MRI sequences and are used for treatment planning purposes. The method was applied and verified in a polymer gel phantom irradiated with multiple shots in an extended region of the GK stereotactic space. Its clinical impact in dose delivery accuracy was assessed in 15 patients with a total of 96 relatively small (<2 cm) metastases treated with GK radiation surgery. Results: Phantom study results showed that use of average MR images eliminates the effect of sequence-dependent distortions, leading to a total spatial uncertainty of less than 0.3 mm, attributed mainly to gradient nonlinearities. In brain metastases patients, non-eliminated sequence-dependent distortions lead to target localization uncertainties of up to 1.3 mm (mean: 0.51 ± 0.37 mm) with respect to the corresponding target locations in the “average” MRI series. Due to these uncertainties, a considerable underdosage (5%-32% of the prescription dose) was found in 33% of the studied targets. Conclusions: The proposed methodology is simple and straightforward in its implementation. Regarding multiple brain metastases applications, the suggested approach may substantially improve total GK dose delivery accuracy in smaller, outlying targets.

  11. Characterization of radiation beams used to determinate the correction factor for a CyberKnife unit reference field using ionization chambers

    SciTech Connect (OSTI)

    Aragn-Martnez, Nestor Massillon-JL, Guerda; Gmez-Muoz, Arnulfo

    2014-11-07

    This paper aimed to characterize a 6 MV x-ray beam from a Varian iX linear accelerator in order to obtain the correction factors needed by the IAEA/AAPM new formalism{sup 1}. The experiments were performed in a liquid water phantom under different irradiation conditions: a) Calibration of the reference field of 10 cm 10 cm at 90 cm SSD and 10 cm depth was carried out according to the TRS-398 protocol using three ionization chambers (IC) calibrated in different reference laboratory and b) Measurement of the absorbed dose rate at 70 cm SSD and 10 cm depth in a 10 cm 10 cm and 5.4 cm 5.4 cm fields was obtained in order to simulate the CyberKnife conditions where maximum distance between the source and the detector is equal to 80 cm and the maximum field size is 6 cm diameter. Depending where the IC was calibrated, differences between 0.16% and 2.24% in the absorbed dose rate measured in the 10 cm 10 cm field at 90 cm SSD were observed, while for the measurements at 70 cm SSD, differences between 1.27% and 3.88% were obtained. For the 5.4 cm 5.4 cm field, the absorbed dose measured with the three ICs varies between 1.37% and 3.52%. The increase in the difference on the absorbed dose when decreasing the SSD could possibly be associated to scattering radiation generated from the collimators and/or the energy dependence of the ionization chambers to low-energy radiation. The results presented in this work suggest the importance of simulating the CyberKnife conditions using other linear accelerator for obtaining the correction factors as proposed by the IAEA/AAPM new formalism in order to measure the absorbed dose with acceptable accuracy.

  12. Poster Thur Eve 23: Dose and Position Quality Assurance using the RADPOS System for 4D Radiotherapy with CyberKnife

    SciTech Connect (OSTI)

    Marants, R; Vandervoort, E; Cygler, J E

    2014-08-15

    Introduction: RADPOS 4D dosimetry system consists of a microMOSFET dosimeter combined with an electromagnetic positioning sensor, which allows for performing real-time dose and position measurements simultaneously. In this report the use of RADPOS as an independent quality assurance (QA) tool during CyberKnife 4D radiotherapy treatment is described. In addition to RADPOS, GAFCHROMIC films were used for simultaneous dose measurement. Methods: RADPOS and films were calibrated in a Solid Water phantom at 1.5 cm depth, SAD= 80 cm, using 60 mm cone. CT based treatment plan was created for a Solid Water breast phantom containing metal fiducials and RADPOS probe. Dose calculations were performed using iPlan pencil beam algorithm. Before the treatment delivery, GAFCHROMIC film was inserted inside the breast phantom, next to the RADPOS probe. Then the phantom was positioned on the chest platform of the QUASAR, to which Synchrony LED optical markers were also attached. Position logging began for RADPOS and the Synchrony tracking system, the QUASAR motion was initiated and the treatment was delivered. Results: RADPOS position measurements very closely matched the LED marker positions recorded by the Synchrony camera tracking system. The RADPOS measured dose was 2.5% higher than the average film measured dose, which is within the experimental uncertainties. Treatment plan calculated dose was 4.1 and 1.6% lower than measured by RADPOS and film, respectively. This is most likely due to the inferior nature of the dose calculation algorithm. Conclusions: Our study demonstrates that RADPOS system is a useful tool for independent QA of CyberKnife treatments.

  13. A comparative study of small field total scatter factors and dose profiles using plastic scintillation detectors and other stereotactic dosimeters: The case of the CyberKnife

    SciTech Connect (OSTI)

    Morin, J.; Beliveau-Nadeau, D.; Chung, E.; Seuntjens, J.; Theriault, D.; Archambault, L.; Beddar, S.; Beaulieu, L.

    2013-01-15

    Purpose: Small-field dosimetry is challenging, and the main limitations of most dosimeters are insufficient spatial resolution, water nonequivalence, and energy dependence. The purpose of this study was to compare plastic scintillation detectors (PSDs) to several commercial stereotactic dosimeters by measuring total scatter factors and dose profiles on a CyberKnife system. Methods: Two PSDs were developed, having sensitive volumes of 0.196 and 0.785 mm{sup 3}, and compared with other detectors. The spectral discrimination method was applied to subtract Cerenkov light from the signal. Both PSDs were compared to four commercial stereotactic dosimeters by measuring total scatter factors, namely, an IBA dosimetry stereotactic field diode (SFD), a PTW 60008 silicon diode, a PTW 60012 silicon diode, and a microLion. The measured total scatter factors were further compared with those of two independent Monte Carlo studies. For the dose profiles, two commercial detectors were used for the comparison, i.e., a PTW 60012 silicon diode and Gafchromics EBT2. Total scatter factors for a CyberKnife system were measured in circular fields with diameters from 5 to 60 mm. Dose profiles were measured for the 5- and 60-mm cones. The measurements were performed in a water tank at a 1.5-cm depth and an 80-cm source-axis distance. Results: The total scatter factors measured using all the detectors agreed within 1% with the Monte Carlo values for cones of 20 mm or greater in diameter. For cones of 10-20 mm in diameter, the PTW 60008 silicon diode was the only dosimeter whose measurements did not agree within 1% with the Monte Carlo values. For smaller fields (<10 mm), each dosimeter type showed different behaviors. The silicon diodes over-responded because of their water nonequivalence; the microLion and 1.0-mm PSD under-responded because of a volume-averaging effect; and the 0.5-mm PSD was the only detector within the uncertainties of the Monte Carlo simulations for all the cones. The PSDs, the PTW 60012 silicon diode, and the Gafchromics EBT2 agreed within 2% and 0.2 mm (gamma evaluation) for the measured dose profiles except in the tail of the 60-mm cone. Conclusions: Silicon diodes can be used to accurately measure small-field dose profiles but not to measure total scatter factors, whereas PSDs can be used to accurately measure both. The authors' measurements show that the use of a 1.0-mm PSD resulted in a negligible volume-averaging effect (under-response of Almost-Equal-To 1%) down to a field size of 5 mm. Therefore, PSDs are strong candidates to become reference radiosurgery detectors for beam characterization and quality assurance measurements.

  14. Semiquantitative Analysis Using Thallium-201 SPECT for Differential Diagnosis Between Tumor Recurrence and Radiation Necrosis After Gamma Knife Surgery for Malignant Brain Tumors

    SciTech Connect (OSTI)

    Matsunaga, Shigeo; Shuto, Takashi; Takase, Hajime; Ohtake, Makoto; Tomura, Nagatsuki; Tanaka, Takahiro; Sonoda, Masaki

    2013-01-01

    Purpose: Semiquantitative analysis of thallium-201 chloride single photon emission computed tomography ({sup 201}Tl SPECT) was evaluated for the discrimination between recurrent brain tumor and delayed radiation necrosis after gamma knife surgery (GKS) for metastatic brain tumors and high-grade gliomas. Methods and Materials: The medical records were reviewed of 75 patients, including 48 patients with metastatic brain tumor and 27 patients with high-grade glioma who underwent GKS in our institution, and had suspected tumor recurrence or radiation necrosis on follow-up neuroimaging and deteriorating clinical status after GKS. Analysis of {sup 201}Tl SPECT data used the early ratio (ER) and the delayed ratio (DR) calculated as tumor/normal average counts on the early and delayed images, and the retention index (RI) as the ratio of DR to ER. Results: A total of 107 tumors were analyzed with {sup 201}Tl SPECT. Nineteen lesions were removed surgically and histological diagnoses established, and the other lesions were evaluated with follow-up clinical and neuroimaging examinations after GKS. The final diagnosis was considered to be recurrent tumor in 65 lesions and radiation necrosis in 42 lesions. Semiquantitative analysis demonstrated significant differences in DR (P=.002) and RI (P<.0001), but not in ER (P=.372), between the tumor recurrence and radiation necrosis groups, and no significant differences between metastatic brain tumors and high-grade gliomas in all indices (P=.926 for ER, P=.263 for DR, and P=.826 for RI). Receiver operating characteristics analysis indicated that RI was the most informative index with the optimum threshold of 0.775, which provided 82.8% sensitivity, 83.7% specificity, and 82.8% accuracy. Conclusions: Semiquantitative analysis of {sup 201}Tl SPECT provides useful information for the differentiation between tumor recurrence and radiation necrosis in metastatic brain tumors and high-grade gliomas after GKS, and the RI may be the most valuable index for this purpose.

  15. Gamma Knife Stereotactic Radiosurgery as Salvage Therapy After Failure of Whole-Brain Radiotherapy in Patients With Small-Cell Lung Cancer

    SciTech Connect (OSTI)

    Harris, Sunit; Chan, Michael D.; Lovato, James F.; Ellis, Thomas L.; Tatter, Stephen B.; Bourland, J. Daniel; Munley, Michael T.; Guzman, Allan F. de; Shaw, Edward G.; Urbanic, James J.; McMullen, Kevin P.

    2012-05-01

    Purpose: Radiosurgery has been successfully used in selected cases to avoid repeat whole-brain irradiation (WBI) in patients with multiple brain metastases of most solid tumor histological findings. Few data are available for the use of radiosurgery for small-cell lung cancer (SCLC). Methods and Materials: Between November 1999 and June 2009, 51 patients with SCLC and previous WBI and new brain metastases were treated with GammaKnife stereotactic radiosurgery (GKSRS). A median dose of 18 Gy (range, 10-24 Gy) was prescribed to the margin of each metastasis. Patients were followed with serial imaging. Patient electronic records were reviewed to determine disease-related factors and clinical outcomes after GKSRS. Local and distant brain failure rates, overall survival, and likelihood of neurologic death were determined based on imaging results. The Kaplan-Meier method was used to determine survival and local and distant brain control. Cox proportional hazard regression was performed to determine strength of association between disease-related factors and survival. Results: Median survival time for the entire cohort was 5.9 months. Local control rates at 1 and 2 years were 57% and 34%, respectively. Distant brain failure rates at 1 and 2 years were 58% and 75%, respectively. Fifty-three percent of patients ultimately died of neurologic death. On multivariate analysis, patients with stable (hazard ratio [HR] = 2.89) or progressive (HR = 6.98) extracranial disease (ECD) had worse overall survival than patients without evidence of ECD (p = 0.00002). Concurrent chemotherapy improved local control (HR = 89; p = 0.006). Conclusions: GKSRS represents a feasible salvage option in patients with SCLC and brain metastases for whom previous WBI has failed. The status of patients' ECD is a dominant factor predictive of overall survival. Local control may be inferior to that seen with other cancer histological results, although the use of concurrent chemotherapy may help to improve this.

  16. Differential dose volume histograms of Gamma Knife in the presence of inhomogeneities using MRI-polymer gel dosimetry and MC simulation

    SciTech Connect (OSTI)

    Allahverdi Pourfallah, Tayyeb; Allahverdi, Mahmoud; Riahi Alam, Nader; Ay, Mohammad-Reza; Zahmatkesh, Mohammad-Hasan

    2009-07-15

    Polymer gel dosimeters offer a practical solution to 3D dose verification for conventional radiotherapy as well as intensity-modulated and stereotactic radiotherapy. In this study, EGSnrc calculated and PAGAT polymer gel dosimeter measured dose volume histograms (DVHs) for single-shot irradiations of the Gamma Knife (GK) unit were used to investigate the effects of the presence of inhomogeneities on 3D dose distribution. The head phantom was a custom-built 16 cm diameter Plexiglas sphere. Inside the phantom, there is a cubic cutout for inserting the gel vials and another cutout for inserting the inhomogeneities. Following irradiation with the GK unit, the polymer gel phantoms were scanned with a 1.5 T MRI scanner. Comparing the results of measurement in homogeneous and heterogeneous phantoms revealed that inserting inhomogeneities inside the homogeneous phantom did not cause considerable disturbances on dose distribution in irradiation with 8 mm collimator within low isodose levels (<50%), which is essential for the dose sparing of sensitive structures. The results of simulation for homogeneous and inhomogeneous phantoms in irradiation with 18 mm collimator of the GK unit showed 23.24% difference in DVH within 90%-100% relative isodose level and also revealed that a significant part of the target (28.56%) received relative doses higher than the maximum dose, which exceeds the acceptance criterion (5%). Based on these results it is concluded that the presence of inhomogeneities inside the phantom can cause considerable errors in dose calculation within high isodose levels with respect to LGP prediction which assumes that the target is a homogeneous material. Moreover, it is demonstrated that the applied MC code is an accurate and stand-alone tool for 3D evaluation of dose distribution in irradiation with the GK unit, which can provide important, 3D plan evaluation criteria used in clinical practice.

  17. SU-E-T-587: Monte Carlo Versus Ray-Tracing for Treatment Planning Involving CNS Tumors On the MultiPlan System for CyberKnife Radiosurgery

    SciTech Connect (OSTI)

    Forbang, R Teboh

    2014-06-01

    Purpose: MultiPlan, the treatment planning system for the CyberKnife Robotic Radiosurgery system offers two approaches to dose computation, namely Ray-Tracing (RT), the default technique and Monte Carlo (MC), an option. RT is deterministic, however it accounts for primary heterogeneity only. MC on the other hand has an uncertainty associated with the calculation results. The advantage is that in addition, it accounts for heterogeneity effects on the scattered dose. Not all sites will benefit from MC. The goal of this work was to focus on central nervous system (CNS) tumors and compare dosimetrically, treatment plans computed with RT versus MC. Methods: Treatment plans were computed using both RT and MC for sites covering (a) the brain (b) C-spine (c) upper T-spine (d) lower T-spine (e) L-spine and (f) sacrum. RT was first used to compute clinically valid treatment plans. Then the same treatment parameters, monitor units, beam weights, etc., were used in the MC algorithm to compute the dose distribution. The plans were then compared for tumor coverage to illustrate the difference if any. All MC calculations were performed at a 1% uncertainty. Results: Using the RT technique, the tumor coverage for the brain, C-spine (C3–C7), upper T-spine (T4–T6), lower T-spine (T10), Lspine (L2) and sacrum were 96.8%, 93.1%, 97.2%, 87.3%, 91.1%, and 95.3%. The corresponding tumor coverage based on the MC approach was 98.2%, 95.3%, 87.55%, 88.2%, 92.5%, and 95.3%. It should be noted that the acceptable planning target coverage for our clinical practice is >95%. The coverage can be compromised for spine tumors to spare normal tissues such as the spinal cord. Conclusion: For treatment planning involving the CNS, RT and MC appear to be similar for most sites but for the T-spine area where most of the beams traverse lung tissue. In this case, MC is highly recommended.

  18. Predictive Parameters of CyberKnife Fiducial-less (XSight Lung) Applicability for Treatment of Early Non-Small Cell Lung Cancer: A Single-Center Experience

    SciTech Connect (OSTI)

    Bahig, Houda; Campeau, Marie-Pierre; Vu, Toni; Doucet, Robert; Bliveau Nadeau, Dominic; Fortin, Bernard; Roberge, David; Lambert, Louise; Carrier, Jean-Franois; Filion, Edith

    2013-11-01

    Purpose: To determine which parameters allow for CyberKnife fiducial-less tumor tracking in stereotactic body radiation therapy (SBRT) for early-stage non-small cell lung cancer. Methods and Materials: A total of 133 lung SBRT patients were preselected for direct soft-tissue tracking based on manufacturer recommendations (peripherally located tumors ?1.5 cm with a dense appearance) and staff experience. Patients underwent a tumor visualization test to verify adequate detection by the tracking system (orthogonal radiographs). An analysis of potential predictors of successful tumor tracking was conducted looking at: tumor stage, size, histology, tumor projection on the vertebral column or mediastinum, distance to the diaphragm, lung-to-soft tissue ratio, and patient body mass index. Results: Tumor visualization was satisfactory for 88 patients (66%) and unsatisfactory for 45 patients (34%). Median time to treatment start was 6 days in the success group (range, 2-18 days) and 15 days (range, 3-63 days) in the failure group. A stage T2 (P=.04), larger tumor size (volume of 15.3 cm{sup 3} vs 6.5 cm{sup 3} in success and failure group, respectively) (P<.0001), and higher tumor density (0.86 g/cm{sup 3} vs 0.79 g/cm{sup 3}) were predictive of adequate detection. There was a 63% decrease in failure risk with every 1-cm increase in maximum tumor dimension (relative risk for failure = 0.37, CI=0.23-0.60, P=.001). A diameter of 3.6 cm predicted a success probability of 80%. Histology, lung-to-soft tissue ratio, distance to diaphragm, patient's body mass index, and tumor projection on vertebral column and mediastinum were not found to be predictive of success. Conclusions: Tumor size, volume, and density were the most predictive factors of a successful XSight Lung tumor tracking. Tumors >3.5 cm have ?80% chance of being adequately visualized and therefore should all be considered for direct tumor tracking.

  19. Small fields output factors measurements and correction factors determination for several detectors for a CyberKnife{sup Registered-Sign} and linear accelerators equipped with microMLC and circular cones

    SciTech Connect (OSTI)

    Bassinet, C.; Huet, C.; Derreumaux, S.; Baumann, M.; Trompier, F.; Roch, P.; Clairand, I.; Brunet, G.; Gaudaire-Josset, S.; Chea, M.; Boisserie, G.

    2013-07-15

    Purpose: The use of small photon fields is now an established practice in stereotactic radiosurgery and radiotherapy. However, due to a lack of lateral electron equilibrium and high dose gradients, it is difficult to accurately measure the dosimetric quantities required for the commissioning of such systems. Moreover, there is still no metrological dosimetric reference for this kind of beam today. In this context, the first objective of this work was to determine and to compare small fields output factors (OF) measured with different types of active detectors and passive dosimeters for three types of facilities: a CyberKnife{sup Registered-Sign} system, a dedicated medical linear accelerator (Novalis) equipped with m3 microMLC and circular cones, and an adaptive medical linear accelerator (Clinac 2100) equipped with an additional m3 microMLC. The second one was to determine the k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} correction factors introduced in a recently proposed small field dosimetry formalism for different active detectors.Methods: Small field sizes were defined either by microMLC down to 6 Multiplication-Sign 6 mm{sup 2} or by circular cones down to 4 mm in diameter. OF measurements were performed with several commercially available active detectors dedicated to measurements in small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW 31018 microLion liquid chamber, and PTW 60003 natural diamond). Two types of passive dosimeters were used: LiF microcubes and EBT2 radiochromic films.Results: Significant differences between the results obtained by several dosimetric systems were observed, particularly for the smallest field size for which the difference in the measured OF reaches more than 20%. For passive dosimeters, an excellent agreement was observed (better than 2%) between EBT2 and LiF microcubes for all OF measurements. Moreover, it has been shown that these passive dosimeters do not require correction factors and can then be used as reference dosimeters. Correction factors for the active detectors have then been determined from the mean experimental OF measured by the passive dosimeters.Conclusions: Four sets of correction factors needed to apply the new small field dosimetry formalism are provided for several active detectors. A protocol for small photon beams OF determination based on passive dosimeters measurements has been recently proposed to French radiotherapy treatment centers.

  20. Iron aluminide knife and method thereof

    DOE Patents [OSTI]

    Sikka, Vinod K.

    1997-01-01

    Fabricating an article of manufacture having a Fe.sub.3 Al-based alloy cutting edge. The fabrication comprises the steps of casting an Fe.sub.3 Al-based alloy, extruding into rectangular cross section, rolling into a sheet at 800.degree. C. for a period of time followed by rolling at 650.degree. C., cutting the rolled sheet into an article having an edge, and grinding the edge of the article to form a cutting edge.

  1. Iron aluminide knife and method thereof

    DOE Patents [OSTI]

    Sikka, V.K.

    1997-08-05

    Fabricating an article of manufacture having a Fe{sub 3}Al-based alloy cutting edge is discussed. The fabrication comprises the steps of casting an Fe{sub 3}Al-based alloy, extruding into rectangular cross section, rolling into a sheet at 800 C for a period of time followed by rolling at 650 C, cutting the rolled sheet into an article having an edge, and grinding the edge of the article to form a cutting edge. 1 fig.

  2. SU-E-T-476: Quality Assurance for Gamma Knife Perfexion Using...

    Office of Scientific and Technical Information (OSTI)

    due to its dosimetric characteristics. Sam Beddar would like to disclose a NIHNCI SBIR Phase II grant (2R44CA153824-02A1) with Standard Imaging, Title: "Water-Equivalent Plastic...

  3. SU-E-T-476: Quality Assurance for Gamma Knife Perfexion Using...

    Office of Scientific and Technical Information (OSTI)

    States); Therriault-Proulx, F; Yang, J; Beddar, S University of Texas MD Anderson Cancer Center, Houston, TX (United States) 07 ISOTOPES AND RADIATION SOURCES; COLLIMATORS;...

  4. TH-A-9A-06: Inverse Planning of Gamma Knife Radiosurgery Using...

    Office of Scientific and Technical Information (OSTI)

    obtained by solving a constrained integer-linear problem. (4) The shots are placed into ... Subject: 60 APPLIED LIFE SCIENCES; ALGORITHMS; GEOMETRY; KERNELS; NEOPLASMS; OPTIMIZATION; ...

  5. SU-E-T-476: Quality Assurance for Gamma Knife Perfexion Using...

    Office of Scientific and Technical Information (OSTI)

    film was inserted in the Lucy phantom and exposed to a single shot for each collimator. Relative output factors were measured using the three detectors while profiles acquired...

  6. SU-E-T-59: Calculations of Collimator Scatter Factors (Sc) with and Without Custom-Made Build-Up Caps for CyberKnife

    SciTech Connect (OSTI)

    Wokoma, S; Yoon, J; Jung, J; Lee, S

    2014-06-01

    Purpose: To investigate the impact of custom-made build-up caps for a diode detector in robotic radiosurgery radiation fields with variable collimator (IRIS) for collimator scatter factor (Sc) calculation. Methods: An acrylic cap was custom-made to fit our SFD (IBA Dosimetry, Germany) diode detector. The cap has thickness of 5 cm, corresponding to a depth beyond electron contamination. IAEA phase space data was used for beam modeling and DOSRZnrc code was used to model the detector. The detector was positioned at 80 cm source-to-detector distance. Calculations were performed with the SFD, with and without the build-up cap, for clinical IRIS settings ranging from 7.5 to 60 mm. Results: The collimator scatter factors were calculated with and without 5 cm build-up cap. They were agreed within 3% difference except 15 mm cone. The Sc factor for 15 mm cone without buildup was 13.2% lower than that with buildup. Conclusion: Sc data is a critical component in advanced algorithms for treatment planning in order to calculate the dose accurately. After incorporating build-up cap, we discovered differences of up to 13.2 % in Sc factors in the SFD detector, when compared against in-air measurements without build-up caps.

  7. Well test report and CO/sub 2/ injection plan for the Little Knife Field CO/sub 2/ minitest Billings County, North Dakota. First annual report, September 1979-August 1980

    SciTech Connect (OSTI)

    Upton, J.E.

    1981-11-01

    Gulf Oil Exploration and Production Company in conjunction with the Department of Energy is conducting a field test of the CO/sub 2/ miscible displacement process. The project is being conducted in the Mission Canyon Formation (lower Mississippian), a dolomitized carbonate reservoir which is currently in the middle stage of primary depletion. Location of the field is in west-central North Dakota at the approximate center of the Williston Basin. Four wells were drilled in an inverted four-spot configuration within the five-acre minitest. The central well is the injection well surrounded by three non-producing observation wells. Oriented cores were obtained from each well for detailed reservoir characterization and laboratory testing. In addition, pulse and injectivity tests were obtained. Results from these tests were used to upgrade two reservoir simulation models. Various parameters within the models were modified to determine the most efficient injection plan. A WAG-type injection sequence involving alternate slugs of water and CO/sub 2/ will be employed. The test is designed to establish the incremental recovery, over waterflooding, by a miscible CO/sub 2/ flood in an oil reservoir.

  8. Non-reclosing pressure relief device for vacuum systems

    DOE Patents [OSTI]

    Swansiger, W.A.

    1994-02-08

    A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife. 6 figures.

  9. Method Of Making An Ultracapacitor Electrode

    DOE Patents [OSTI]

    Wei, Chang; Jerabek, Elihu Calvin; DeJager, Katherine Dana; LeBlanc, Jr., Oliver Harris

    2003-05-06

    A paste of organic solvent with dissolved organic salt and active carbon is formed and a uniform film of the paste is applied onto a substrate by casting the paste into a clearance between a knife blade and the substrate. The paste is evaporated to form a paste electrode for an ultracapacitor.

  10. Method of making an ultracapacitor electrode

    DOE Patents [OSTI]

    Wei, Chang; Jerabek, Elihu Calvin; DeJager, Katherine Dana; LeBlanc, Jr., Oliver Harris

    2001-10-16

    A paste of organic solvent with dissolved organic salt and active carbon is formed and a uniform film of the paste is applied onto a substrate by casting the paste into a clearance between a knife blade and the substrate. The paste is evaporated to form a paste electrode for an ultracapacitor.

  11. Micromachined electrical cauterizer

    DOE Patents [OSTI]

    Lee, Abraham P.; Krulevitch, Peter A.; Northrup, M. Allen

    1999-01-01

    A micromachined electrical cauterizer. Microstructures are combined with microelectrodes for highly localized electro cauterization. Using boron etch stops and surface micromachining, microneedles with very smooth surfaces are made. Micromachining also allows for precision placement of electrodes by photolithography with micron sized gaps to allow for concentrated electric fields. A microcauterizer is fabricated by bulk etching silicon to form knife edges, then parallelly placed microelectrodes with gaps as small as 5 .mu.m are patterned and aligned adjacent the knife edges to provide homeostasis while cutting tissue. While most of the microelectrode lines are electrically insulated from the atmosphere by depositing and patterning silicon dioxide on the electric feedthrough portions, a window is opened in the silicon dioxide to expose the parallel microelectrode portion. This helps reduce power loss and assist in focusing the power locally for more efficient and safer procedures.

  12. Micromachined electrical cauterizer

    DOE Patents [OSTI]

    Lee, A.P.; Krulevitch, P.A.; Northrup, M.A.

    1999-08-31

    A micromachined electrical cauterizer is disclosed. Microstructures are combined with microelectrodes for highly localized electro cauterization. Using boron etch stops and surface micromachining, microneedles with very smooth surfaces are made. Micromachining also allows for precision placement of electrodes by photolithography with micron sized gaps to allow for concentrated electric fields. A microcauterizer is fabricated by bulk etching silicon to form knife edges, then parallelly placed microelectrodes with gaps as small as 5 {mu}m are patterned and aligned adjacent the knife edges to provide homeostasis while cutting tissue. While most of the microelectrode lines are electrically insulated from the atmosphere by depositing and patterning silicon dioxide on the electric feedthrough portions, a window is opened in the silicon dioxide to expose the parallel microelectrode portion. This helps reduce power loss and assist in focusing the power locally for more efficient and safer procedures. 7 figs.

  13. A high precision, compact electromechanical ground rotation sensor

    SciTech Connect (OSTI)

    Dergachev, V.; DeSalvo, R.; University of Sannio, C.so Garibaldi 107, Benevento 82100 ; Asadoor, M.; Oklahoma State University, 219 Student Union, Stillwater, Oklahoma 74074 ; Bhawal, A.; Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213 ; Gong, P.; School of Industrial and System Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0205 ; Kim, C.; Lottarini, A.; Department of Computer Science, Columbia University, 1214 Amsterdam Avenue, New York, New York 10027 ; Minenkov, Y.; Murphy, C.; University of Melbourne Grattan Street, Parkville VIC 3010 ; O'Toole, A.; Michigan Technological University, 1400 Townsend Dr, Houghton, Michigan 49931 ; Peña Arellano, F. E.; and others

    2014-05-15

    We present a mechanical rotation sensor consisting of a balance pivoting on a tungsten carbide knife edge. These sensors are important for precision seismic isolation systems, as employed in land-based gravitational wave interferometers and for the new field of rotational seismology. The position sensor used is an air-core linear variable differential transformer with a demonstrated noise floor of 1 × 10{sup −11}m/√( Hz ). We describe the instrument construction and demonstrate low noise operation with a noise floor upper bound of 5.7 × 10{sup −9} rad /√( Hz ) at 10 mHz and 6.4 × 10{sup −10} rad /√( Hz ) at 0.1 Hz. The performance of the knife edge hinge is compatible with a behaviorur free of noise from dislocation self-organized criticality.

  14. Apparatus and method for measuring critical current properties of a coated conductor

    DOE Patents [OSTI]

    Mueller, Fred M.; Haenisch, Jens

    2012-07-24

    The transverse critical-current uniformity in a superconducting tape was determined using a magnetic knife apparatus. A critical current I.sub.c distribution and transverse critical current density J.sub.c distribution in YBCO coated conductors was measured nondestructively with high resolution using a magnetic knife apparatus. The method utilizes the strong depression of J.sub.c in applied magnetic fields. A narrow region of low, including zero, magnetic field in a surrounding higher field is moved transversely across a sample of coated conductor. This reveals the critical current density distribution. A Fourier series inversion process was used to determine the transverse J.sub.c distribution in the sample.

  15. WE-B-19A-01: SRT II: Uncertainties in SRT

    SciTech Connect (OSTI)

    Dieterich, S; Schlesinger, D; Geneser, S

    2014-06-15

    SRS delivery has undergone major technical changes in the last decade, transitioning from predominantly frame-based treatment delivery to imageguided, frameless SRS. It is important for medical physicists working in SRS to understand the magnitude and sources of uncertainty involved in delivering SRS treatments for a multitude of technologies (Gamma Knife, CyberKnife, linac-based SRS and protons). Sources of SRS planning and delivery uncertainty include dose calculation, dose fusion, and intra- and inter-fraction motion. Dose calculations for small fields are particularly difficult because of the lack of electronic equilibrium and greater effect of inhomogeneities within and near the PTV. Going frameless introduces greater setup uncertainties that allows for potentially increased intra- and interfraction motion, The increased use of multiple imaging modalities to determine the tumor volume, necessitates (deformable) image and contour fusion, and the resulting uncertainties introduced in the image registration process further contribute to overall treatment planning uncertainties. Each of these uncertainties must be quantified and their impact on treatment delivery accuracy understood. If necessary, the uncertainties may then be accounted for during treatment planning either through techniques to make the uncertainty explicit, or by the appropriate addition of PTV margins. Further complicating matters, the statistics of 1-5 fraction SRS treatments differ from traditional margin recipes relying on Poisson statistics. In this session, we will discuss uncertainties introduced during each step of the SRS treatment planning and delivery process and present margin recipes to appropriately account for such uncertainties. Learning Objectives: To understand the major contributors to the total delivery uncertainty in SRS for Gamma Knife, CyberKnife, and linac-based SRS. Learn the various uncertainties introduced by image fusion, deformable image registration, and contouring variation. Learn a variety of strategies for dealing with uncertainty, including margin recipes and explicit visualization of uncertainty. Understand how the assessment of PTV margins differs from regular fractionation (van Herk recipe) for 15 fraction deliveries.

  16. Coating and curing apparatus and methods

    DOE Patents [OSTI]

    Brophy, Brenor L; Maghsoodi, Sina; Neyman, Patrick J; Gonsalves, Peter R; Hirsch, Jeffrey G; Yang, Yu S

    2015-02-24

    Disclosed are coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly systems and methods for skin curing sol-gel coatings deposited onto the surface of glass substrates using a high temperature air-knife are disclosed.

  17. Experimental comparison of seven commercial dosimetry diodes for measurement of stereotactic radiosurgery cone factors

    SciTech Connect (OSTI)

    Dieterich, Sonja; Sherouse, George W.

    2011-07-15

    Purpose: The purpose of this work is to assess the variation in performance of various commercially available dosimetry diodes for quantitative small field dosimetry, specifically by intercomparing measurements of SRS cone factors. Methods: Measurements were made in 6 MV photon beams with fixed SRS cones for two accelerator-based SRS systems: a Varian Clinac iX (Varian/Zmed cones) at 600 MU/min and a CyberKnife model G4 at 800 MU/min. Measurements were made at 1.5 cm depth in water using the IBA Dosimetry ''blue phantom'' 3D scanning system, controlled by omnipro-accept software. Source-to-detector distance was 100 cm for the Clinac, 80 cm for the CyberKnife. Two normalization methods were used for the Clinac, one directly referenced to diode measurements in a 10 cm x 10 cm square field and the other indirectly by ''daisy-chaining'' diode measurements to ion chamber measurement in the 10 cm x 10 cm reference field through an intermediate 4 cm x 4 cm square field. CyberKnife factors were referenced directly to measurements in the 60 mm reference field. Seven commercial diodes were evaluated: PTW TN60008, TN60012, TN60016, TN60017; IBA Dosimetry SFD; Sun Nuclear EDGE; Exradin SD1 (first generation prototype). Results: With the exception of the SFD, all the evaluated devices yielded surprisingly consistent results. Standard deviations of Clinac factors for four diodes (SD1, EDGE, TN60008, and TN60012) ranged from approximately 0.50% at 30 mm to 2.0% at 5 mm cones size when referenced directly to the 10 cm x 10 cm measurement. The daisy-chaining strategy reduced the standard deviation to approximately 0.30% at 30 mm and 1.9% at 5 mm. Standard deviations for the same four diodes in the CyberKnife beam ranged up to approximately 1.0% at 5 mm. Conclusions: The inter-detector variation is small and appears to be systematic with detector packaging, more inherent filtration producing flatter curves for both the relatively hard Clinac beam and the softer CyberKnife beam. The daisy-chain strategy appears to be of limited value for most of the diodes, but does bring the SFD results into significantly better agreement with the others.

  18. Imaging, cutting, and collecting instrument and method

    DOE Patents [OSTI]

    Tench, Robert J.; Siekhaus, Wigbert J.; Balooch, Mehdi; Balhorn, Rodney L.; Allen, Michael J.

    1995-01-01

    Instrumentation and techniques to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution, to cut-off identified parts of such objects, to move around and manipulate such cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM, such that plural cantilevers are used with either sharp-tips or knife-edges thereon. In addition, the invention can be utilized for measuring hardness of materials.

  19. Variable diameter wind turbine rotor blades

    DOE Patents [OSTI]

    Jamieson, Peter McKeich; Hornzee-Jones, Chris; Moroz, Emilian M.; Blakemore, Ralph W.

    2005-12-06

    A system and method for changing wind turbine rotor diameters to meet changing wind speeds and control system loads is disclosed. The rotor blades on the wind turbine are able to adjust length by extensions nested within or containing the base blade. The blades can have more than one extension in a variety of configurations. A cable winching system, a hydraulic system, a pneumatic system, inflatable or elastic extensions, and a spring-loaded jack knife deployment are some of the methods of adjustment. The extension is also protected from lightning by a grounding system.

  20. Design Strategies for Optically-Accessible, High-Temperature, High-Pressure Reactor

    SciTech Connect (OSTI)

    S. F. Rice; R. R. Steeper; C. A. LaJeunesse; R. G. Hanush; J. D. Aiken

    2000-02-01

    The authors have developed two optical cell designs for high-pressure and high-temperature fluid research: one for flow systems, and the other for larger batch systems. The flow system design uses spring washers to balance the unequal thermal expansions of the reactor and the window materials. A typical design calculation is presented showing the relationship between system pressure, operating temperature, and torque applied to the window-retaining nut. The second design employs a different strategy more appropriate for larger windows. This design uses two seals: one for the window that benefits from system pressure, and a second one that relies on knife-edge, metal-to-metal contact.

  1. Design strategies for optically-accessible, high-temperature, high-pressure reactor

    SciTech Connect (OSTI)

    S. F. Rice; R. R. Steeper; C. A. LaJeunesse; R. G. Hanush; J. D. Aiken

    2000-02-01

    The authors have developed two optical cell designs for high-pressure and high-temperature fluid research: one for flow systems, and the other for larger batch systems. The flow system design uses spring washers to balance the unequal thermal expansions of the reactor and the window materials. A typical design calculation is presented showing the relationship between system pressure, operating temperature, and torque applied to the window-retaining nut. The second design employs a different strategy more appropriate for larger windows. This design uses two seals: one for the window that benefits from system pressure, and a second one that relies on knife-edge, metal-to-metal contact.

  2. The Stanford Automated Mounter: Pushing the limits of sample exchange at the SSRL macromolecular crystallography beamlines

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

    Russi, Silvia; Song, Jinhu; McPhillips, Scott E.; Cohen, Aina E.

    2016-02-24

    The Stanford Automated Mounter System, a system for mounting and dismounting cryo-cooled crystals, has been upgraded to increase the throughput of samples on the macromolecular crystallography beamlines at the Stanford Synchrotron Radiation Lightsource. This upgrade speeds up robot maneuvers, reduces the heating/drying cycles, pre-fetches samples and adds an air-knife to remove frost from the gripper arms. As a result, sample pin exchange during automated crystal quality screening now takes about 25 s, five times faster than before this upgrade.

  3. Municipal waste processing apparatus

    DOE Patents [OSTI]

    Mayberry, John L.

    1989-01-01

    Municipal waste materials are processed by crushing the materials so that pieces of noncombustible material are smaller than a selected size and pieces of combustible material are larger than the selected size. The crushed materials are placed on a vibrating mesh screen conveyor belt having openings which pass the smaller, noncombustible pieces of material, but do not pass the larger, combustible pieces of material. Consecutive conveyors may be connected by an intermediate vibratory plate. An air knife can be used to further separate materials based on weight.

  4. Fermilab Today | Result of the Week Archive | 2010

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

    0 Dec. 16, 2010 Subatomic color Dec. 9, 2010 Living flavorfully with biases Dec. 2, 2010 Searching for new particles Nov. 18, 2010 Top quark mass measured by CDF to a 0.7 percent accuracy Nov. 11, 2010 No sting in study of three "b"s Nov. 4, 2010 Improved CDF Higgs search: No event left behind Oct. 28, 2010 A better way to sharpen a knife Oct. 21, 2010 Measurement of W spin from CDF top quark decays Oct. 14, 2010 Spokespersons’ perspective: The Tevatron and an opportunity to answer

  5. An experimental apparatus for diffraction-limites soft x-ray nanofocusing

    SciTech Connect (OSTI)

    Merthe, Daniel; Goldberg, Kenneth; Yashchuk, Valeriy; Yuan, Sheng; McKinney, Wayne; Celestre, Richard; Mochi, Iacopo; Macdougall, James; Morrison, Gregory; Rakawa, Senajith; Anderson, Erik; Smith, Brian; Domning, Edward; Warwick, Tony; Padmore, Howard

    2011-10-21

    Realizing the experimental potential of high-brightness, next generation synchrotron and free-electron laser light sources requires the development of reflecting x-ray optics capable of wavefront preservation and high-resolution nano-focusing. At the Advanced Light Source (ALS) beamline 5.3.1, we are developing broadly applicable, high-accuracy, in situ, at-wavelength wavefront measurement techniques to surpass 100-nrad slope measurement accuracy for diffraction-limited Kirkpatrick-Baez (KB) mirrors. The at-wavelength methodology we are developing relies on a series of wavefront-sensing tests with increasing accuracy and sensitivity, including scanning-slit Hartmann tests, grating-based lateral shearing interferometry, and quantitative knife-edge testing. We describe the original experimental techniques and alignment methodology that have enabled us to optimally set a bendable KB mirror to achieve a focused, FWHM spot size of 150 nm, with 1 nm (1.24 keV) photons at 3.7 mrad numerical aperture. The predictions of wavefront measurement are confirmed by the knife-edge testing.The side-profiled elliptically bent mirror used in these one-dimensional focusing experiments was originally designed for a much different glancing angle and conjugate distances. This work demonstrates that high-accuracy, at-wavelength wavefront-slope feedback can be used to optimize the pitch, roll, and mirror-bending forces in situ, using procedures that are deterministic and repeatable.

  6. Experimental determination of radiated internal wave power without pressure field data

    SciTech Connect (OSTI)

    Lee, Frank M.; Morrison, P. J. [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 787121192 (United States)] [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 787121192 (United States); Paoletti, M. S.; Swinney, Harry L. [Physics Department, The University of Texas at Austin, Austin, Texas 787121192 (United States)] [Physics Department, The University of Texas at Austin, Austin, Texas 787121192 (United States)

    2014-04-15

    We present a method to determine, using only velocity field data, the time-averaged energy flux (J) and total radiated power P for two-dimensional internal gravity waves. Both (J) and P are determined from expressions involving only a scalar function, the stream function ?. We test the method using data from a direct numerical simulation for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream function method agree to within 0.5% with results obtained using pressure and velocity data from the numerical simulation. The results for the radiated power computed from the stream function agree well with power computed from the velocity and pressure if the starting point for the stream function computation is on a solid boundary, but if a boundary point is not available, care must be taken to choose an appropriate starting point. We also test the stream function method by applying it to laboratory data for tidal flow past a knife edge, and the results are found to agree with the direct numerical simulation. The supplementary material includes a Matlab code with a graphical user interface that can be used to compute the energy flux and power from two-dimensional velocity field data.

  7. Systematic measurements of whole-body dose distributions for various treatment machines and delivery techniques in radiation therapy

    SciTech Connect (OSTI)

    Haelg, Roger A.; Besserer, Juergen; Schneider, Uwe

    2012-12-15

    Purpose: Contemporary radiotherapy treatment techniques, such as intensity-modulated radiation therapy and volumetric modulated arc therapy, could increase the radiation-induced malignancies because of the increased beam-on time, i.e., number of monitor units needed to deliver the same dose to the target and the larger volume irradiated with low doses. In this study, whole-body dose distributions from typical radiotherapy patient plans using different treatment techniques and therapy machines were measured using the same measurement setup and irradiation intention. Methods: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The dose distributions from 6 MV beams were compared in terms of treatment technique (3D-conformal, intensity-modulated radiation therapy, volumetric modulated arc therapy, helical TomoTherapy, stereotactic radiotherapy, hard wedges, and flattening filter-free radiotherapy) and therapy machine (Elekta, Siemens and Varian linear accelerators, Accuray CyberKnife and TomoTherapy). Results: Close to the target, the doses from intensity-modulated treatments (including flattening filter-free) were below the dose from a static treatment plan, whereas the CyberKnife showed a larger dose by a factor of two. Far away from the treatment field, the dose from intensity-modulated treatments showed an increase in dose from stray radiation of about 50% compared to the 3D-conformal treatment. For the flattening filter-free photon beams, the dose from stray radiation far away from the target was slightly lower than the dose from a static treatment. The CyberKnife irradiation and the treatment using hard wedges increased the dose from stray radiation by nearly a factor of three compared to the 3D-conformal treatment. Conclusions: This study showed that the dose outside of the treated volume is influenced by several sources. Therefore, when comparing different treatment techniques, the dose ratios vary with distance to the isocenter. The effective dose outside the treated volume of intensity-modulated treatments with or without flattening filter was 10%-30% larger when compared to 3D-conformal radiotherapy. This dose increase is much lower than the monitor unit scaled effective dose from a static treatment.

  8. Imaging, cutting, and collecting instrument and method

    DOE Patents [OSTI]

    Tench, R.J.; Siekhaus, W.J.; Balooch, M.; Balhorn, R.L.; Allen, M.J.

    1995-10-31

    Instrumentation and techniques are described to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution. This instrument and method are also used to cut-off identified parts of objects, to move around and manipulate the cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM. The plural cantilevers are used with either sharp-tips or knife-edges. In addition, the invention can be utilized for measuring the hardness of materials. 10 figs.

  9. Design and initial characterization of a compact, ultra high vacuum compatible, low frequency, tilt accelerometer

    SciTech Connect (OSTI)

    OToole, A. E-mail: riccardo.desalvo@gmail.com; Pea Arellano, F. E.; Rodionov, A. V.; Kim, C.; Shaner, M.; Asadoor, M.; Sobacchi, E.; Dergachev, V.; DeSalvo, R. E-mail: riccardo.desalvo@gmail.com; Bhawal, A.; Gong, P.; Lottarini, A.; Minenkov, Y.; Murphy, C.

    2014-07-15

    A compact tilt accelerometer with high sensitivity at low frequency was designed to provide low frequency corrections for the feedback signal of the Advanced Laser Interferometer Gravitational Wave Observatory active seismic attenuation system. It has been developed using a Tungsten Carbide ceramic knife-edge hinge designed to avoid the mechanical 1/f noise believed to be intrinsic in polycrystalline metallic flexures. Design and construction details are presented; prototype data acquisition and control limitations are discussed. The instrument's characterization reported here shows that the hinge is compatible with being metal-hysteresis-free, and therefore also free of the 1/f noise generated by the dislocation Self-Organized Criticality in the metal. A tiltmeter of this kind will be effective to separate the ground tilt component from the signal of horizontal low frequency seismometers, and to correct the ill effects of microseismic tilt in advanced seismic attenuation systems.

  10. Microfabricated high-bandpass foucault aperture for electron microscopy

    DOE Patents [OSTI]

    Glaeser, Robert; Cambie, Rossana; Jin, Jian

    2014-08-26

    A variant of the Foucault (knife-edge) aperture is disclosed that is designed to provide single-sideband (SSB) contrast at low spatial frequencies but retain conventional double-sideband (DSB) contrast at high spatial frequencies in transmission electron microscopy. The aperture includes a plate with an inner open area, a support extending from the plate at an edge of the open area, a half-circle feature mounted on the support and located at the center of the aperture open area. The radius of the half-circle portion of reciprocal space that is blocked by the aperture can be varied to suit the needs of electron microscopy investigation. The aperture is fabricated from conductive material which is preferably non-oxidizing, such as gold, for example.

  11. Schlieren technique applied to the arc temperature measurement in a high energy density cutting torch

    SciTech Connect (OSTI)

    Prevosto, L.; Mancinelli, B.; Artana, G.; Kelly, H.

    2010-01-15

    Plasma temperature and radial density profiles of the plasma species in a high energy density cutting arc have been obtained by using a quantitative schlieren technique. A Z-type two-mirror schlieren system was used in this research. Due to its great sensibility such technique allows measuring plasma composition and temperature from the arc axis to the surrounding medium by processing the gray-level contrast values of digital schlieren images recorded at the observation plane for a given position of a transverse knife located at the exit focal plane of the system. The technique has provided a good visualization of the plasma flow emerging from the nozzle and its interactions with the surrounding medium and the anode. The obtained temperature values are in good agreement with those values previously obtained by the authors on the same torch using Langmuir probes.

  12. Phase-shifting point diffraction interferometer focus-aid enhanced mask

    DOE Patents [OSTI]

    Naulleau, Patrick

    2000-01-01

    A phase-shifting point diffraction interferometer system (PS/PDI) employing a PS/PDI mask that includes a PDI focus aid is provided. The PDI focus aid mask includes a large or secondary reference pinhole that is slightly displaced from the true or primary reference pinhole. The secondary pinhole provides a larger capture tolerance for interferometrically performing fine focus. With the focus-aid enhanced mask, conventional methods such as the knife-edge test can be used to perform an initial (or rough) focus and the secondary (large) pinhole is used to perform interferometric fine focus. Once the system is well focused, high accuracy interferometry can be performed using the primary (small) pinhole.

  13. SU-E-T-409: Intensity Modulated Robotic Radiotherapy

    SciTech Connect (OSTI)

    Wang, B; Jin, L; Li, J; Chen, L; Ma, C; Fan, J; Zhang, C

    2014-06-01

    Purpose: As compared with the IRIS-based models, the MLC-based CyberKnife system allows more efficient treatment delivery due to its improved coverage of large lesions and intensity modulation. The treatment delivery efficiency is mainly determined by the number of selected nodes. This study aimed to demonstrate that relatively small sets of optimally selected nodes could produce high-quality plans. Methods: The full body path of the CyberKnife system consists of 110 nodes, from which we selected various sets for 4 prostate cancer cases using our in-house beamselection software. With the selected nodes we generated IMRT plans using our in-house beamlet-based inverse-planning optimization program. We also produced IMRT plans using the MultiPlan treatment planning system (version 5.0) for the same cases. Furthermore, the nodes selected by MultiPlan were used to produce plans with our own optimization software so that we could compare the quality of the selected sets of nodes. Results: Our beam-selection program selected one node-set for each case, with the number of nodes ranging from 23 to 34. The IMRT plans based on the selected nodes and our in-house optimization program showed adequate target coverage, with favorable critical structure sparing for the cases investigated. Compared with the plans using the nodes selected by MultiPlan, the plans generated with our selected beams provided superior rectum/bladder sparing for 75% of the cases. The plans produced by MultiPlan with various numbers of nodes also suggested that the plan quality was not compromised significantly when the number of nodes was reduced. Conclusion: Our preliminary results showed that with beamletbased planning optimization, one could produce high-quality plans with an optimal set of nodes for MLC-based robotic radiotherapy. Furthermore, our beam-selection strategy could help further improve critical structure sparing.

  14. SU-E-T-492: Implementing a Method for Brain Irradiation in Rats Utilizing a Commercially Available Radiosurgery Irradiator

    SciTech Connect (OSTI)

    Cates, J; Drzymala, R

    2014-06-01

    Purpose: The purpose of the study was to implement a method for accurate rat brain irradiation using the Gamma Knife Perfexion unit. The system needed to be repeatable, efficient, and dosimetrically and spatially accurate. Methods: A platform (“rat holder”) was made such that it is attachable to the Leskell Gamma Knife G Frame. The rat holder utilizes two ear bars contacting bony anatomy and a front tooth bar to secure the rat. The rat holder fits inside of the Leskell localizer box, which utilizes fiducial markers to register with the GammaPlan planning system. This method allows for accurate, repeatable setup.A cylindrical phantom was made so that film can be placed axially in the phantom. We then acquired CT image sets of the rat holder and localizer box with both a rat and the phantom. Three treatment plans were created: a plan on the rat CT dataset, a phantom plan with the same prescription dose as the rat plan, and a phantom plan with the same delivery time as the rat plan. Results: Film analysis from the phantom showed that our setup is spatially accurate and repeatable. It is also dosimetrically accurate, with an difference between predicted and measured dose of 2.9%. Film analysis with prescription dose equal between rat and phantom plans showed a difference of 3.8%, showing that our phantom is a good representation of the rat for dosimetry purposes, allowing for +/- 3mm diameter variation. Film analysis with treatment time equal showed an error of 2.6%, which means we can deliver a prescription dose within 3% accuracy. Conclusion: Our method for irradiation of rat brain has been shown to be repeatable, efficient, and accurate, both dosimetrically and spatially. We can treat a large number of rats efficiently while delivering prescription doses within 3% at millimeter level accuracy.

  15. Mirror monochromator

    SciTech Connect (OSTI)

    Mankos, Marian; Shadman, Khashayar

    2014-12-02

    In this SBIR project, Electron Optica, Inc. (EOI) is developing a mirror electron monochromator (MirrorChrom) attachment to new and retrofitted electron microscopes (EMs) for improving the energy resolution of the EM from the characteristic range of 0.2-0.5 eV to the range of 10-50 meV. This improvement will enhance the characterization of materials by imaging and spectroscopy. In particular, the monochromator will refine the energy spectra characterizing materials, as obtained from transmission EMs [TEMs] fitted with electron spectrometers, and it will increase the spatial resolution of the images of materials taken with scanning EMs (SEMs) operated at low voltages. EOIs MirrorChrom technology utilizes a magnetic prism to simultaneously deflect the electron beam off the axis of the microscope column by 90 and disperse the electrons in proportional to their energies into a module with an electron mirror and a knife-edge. The knife-edge cuts off the tails of the energy distribution to reduce the energy spread of the electrons that are reflected, and subsequently deflected, back into the microscope column. The knife-edge is less prone to contamination, and thereby charging, than the conventional slits used in existing monochromators, which improves the reliability and stability of the module. The overall design of the MirrorChrom exploits the symmetry inherent in reversing the electron trajectory in order to maintain the beam brightness a parameter that impacts how well the electron beam can be focused downstream onto a sample. During phase I, EOI drafted a set of candidate monochromator architectures and evaluated the trade-offs between energy resolution and beam current to achieve the optimum design for three particular applications with market potential: increasing the spatial resolution of low voltage SEMs, increasing the energy resolution of low voltage TEMs (beam energy of 5-20 keV), and increasing the energy resolution of conventional TEMs (beam energy of 80-120 keV). Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key monochromator components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded into a model describing the key electron-optical parameters of the complete monochromator. The simulations reveal that the mirror monochromator can reduce the energy spread of a Schottky electron source, an established electron emitter used widely in EMs, to 10 meV for practical beam current values and that further reduction of the energy spread down to 3 meV is possible for low current applications with a Cold Field Emitter (an electron source with 10x the brightness of a Schottky source). MirrorChroms can be designed and built to attach to different types of TEMs and SEMs, thus making them suitable for enhancing the study of the structure, composition, and bonding states of new materials at the nanoscale to advance material science research in the field of nanotechnology as well as biomedical research.

  16. SU-E-T-629: Feasibility Study of Treating Multiple Brain Tumors with Large Number of Noncoplanar IMRT Beams

    SciTech Connect (OSTI)

    Dong, P; Ma, L

    2014-06-15

    Purpose: To study the feasibility of treating multiple brain tumors withlarge number of noncoplanar IMRT beams. Methods: Thirty beams are selected from 390 deliverable beams separated by six degree in 4pi space. Beam selection optimization is based on a column generation algorithm. MLC leaf size is 2 mm. Dose matrices are calculated with collapsed cone convolution and superposition method in a 2 mm by 2mm by 2 mm grid. Twelve brain tumors of various shapes, sizes and locations are used to generate four plans treating 3, 6, 9 and 12 tumors. The radiation dose was 20 Gy prescribed to the 100% isodose line. Dose Volume Histograms for tumor and brain were compared. Results: All results are based on a 2 mm by 2 mm by 2 mm CT grid. For 3, 6, 9 and 12 tumor plans, minimum tumor doses are all 20 Gy. Mean tumor dose are 20.0, 20.1, 20.1 and 20.1 Gy. Maximum tumor dose are 23.3, 23.6, 25.4 and 25.4 Gy. Mean ventricles dose are 0.7, 1.7, 2.4 and 3.1 Gy.Mean subventricular zone dose are 0.8, 1.3, 2.2 and 3.2 Gy. Average Equivalent uniform dose (gEUD) values for tumor are 20.1, 20.1, 20.2 and 20.2 Gy. The conformity index (CI) values are close to 1 for all 4 plans. The gradient index (GI) values are 2.50, 2.05, 2.09 and 2.19. Conclusion: Compared with published Gamma Knife treatment studies, noncoplanar IMRT treatment plan is superior in terms of dose conformity. Due to maximum limit of beams per plan, Gamma knife has to treat multiple tumors separately in different plans. Noncoplanar IMRT plans theoretically can be delivered in a single plan on any modern linac with an automated couch and image guidance. This warrants further study of using noncoplanar IMRT as a viable treatment solution for multiple brain tumors.

  17. Preliminary Results Of A 600 Joules Small Plasma Focus Device

    SciTech Connect (OSTI)

    Lee, S. H.; Yap, S. L.; Wong, C. S.

    2009-07-07

    Preliminary results of a 600 J (3.7 muF, 18 kV) Mather type plasma focus device operated at low pressure will be presented. The discharge is formed between a solid anode with length of 6 cm and six symmetrically and coaxially arranged cathode rods of same lengths. The cathode base is profiled in a knife-edge design and a set of coaxial plasma gun are attached to it in order to initiate the breakdown and enhance the current sheath formation. The experiments have been performed in argon gas under a low pressure condition of several microbars. The discharge current and the voltage across the electrodes during the discharge are measured with high voltage probe and current coil. The current and voltage characteristics are used to determine the possible range of operating pressure that gives good focusing action. At a narrow pressure regime of 9.0+-0.5 mubar, focusing action is observed with good reproducibility. Preliminary result of ion beam energy is presented. More work will be carried out to investigate the radiation output.

  18. High resolution transmission electron microscopy of melamine-formaldehyde aerogels and silica aerogels

    SciTech Connect (OSTI)

    Ruben, G.C. (Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences)

    1991-09-01

    The goal of the high resolution transmission electron microscopy (HRTEM) was to image the structure of two tetramethyl orthosilicate (TMOS) and two melamine-formaldehyde (MF) aerogels at the single polymer chain level{sup 1,2}. With this level of structural resolution we hoped to interrelate each aerogel's structure with its physical properties and its method of synthesis. Conventional single-step base catalysed TMOS aerogels show strings of spheroidal particles linked together with minimal necking. The spheroidal particles range from 86--132 {Angstrom} and average 113{plus minus}10 {Angstrom} in diameter{sup 2}. In contrast the TMOS aerogels reported on here were made by a two step method. After extended silica chains are grown in solution under acidic conditions with a substoichiometric amount of water, the reaction is stopped and the methanol hydrolysed from TMOS is removed. Then base catalysis and additional water are added to cause gel formation is a nonalcoholic solvent. The MF aerogels were prepared for HRTEM by fracturing them on a stereo microscope stage with razor knife so that fractured pieces with smooth flat surfaces could be selected for platinum-carbon replication. The two silica (TMOS) aerogels were both transparent and difficult to see. These aerogels were fractured on a stereo microscope stage with tweezers. 6 refs., 4 figs.

  19. Core based stress measurements: A guide to their application. Topical report, July 1991--June 1993

    SciTech Connect (OSTI)

    Warpinski, N.R.; Teufel, L.W.; Lorenz, J.C.; Holcomb, D.J.

    1993-06-01

    This report is a summary and a guide to core-based stress measurements. It covers anelastic strain recovery, circumferential velocity anistropy, differential strain curve analysis, differential wave velocity analysis, petrographic examination of microcracks, overcoring of archieved core, measurements of the Kaiser effect, strength anisotropy tests, and analysis of coring-induced fractures. The report begins with a discussion of the stored energy within rocks, its release during coring, and the subsequent formation of relaxation microcracks. The interogation or monitoring of these microcracks form the basis for most of the core-based techniques (except for the coring induced fractures). Problems that can arise due to coring or fabric are also presented, Coring induced fractures are discussed in some detail, with the emphasis placed on petal (and petal-centerline) fractures and scribe-knife fractures. For each technique, a short description of the physics and the analysis procedures is given. In addition, several example applications have also been selected (where available) to illustrate pertinent effects. This report is intended to be a guide to the proper application and diagnosis of core-based stress measurement procedures.

  20. Fail safe controllable output improved version of the electromechanical battery

    DOE Patents [OSTI]

    Post, R.F.

    1999-01-19

    Mechanical means are provided to control the voltages induced in the windings of a generator/motor. In one embodiment, a lever is used to withdraw or insert the entire stator windings from the cavity where the rotating field exists. In another embodiment, voltage control and/or switching off of the output is achievable with a variable-coupling generator/motor. A stator is made up of two concentric layers of windings, with a larger number of turns on the inner layer of windings than the outer layer of windings. The windings are to be connected in series electrically, that is, their voltages add vectorially. The mechanical arrangement is such that one or both of the windings can be rotated with respect to the other winding about their common central axis. Another improved design for the stator assembly of electromechanical batteries provides knife switch contacts that are in electrical contact with the stator windings. The operation of this embodiment depends on the fact that an abnormally large torque will be exerted on the stator structure during any short-circuit condition. 4 figs.

  1. X-ray tests of a two-dimensional stigmatic imaging scheme with variable magnifications

    SciTech Connect (OSTI)

    Lu, J.; Bitter, M.; Hill, K. W.; Delgado-Aparicio, L. F.; Efthimion, P. C.; Pablant, N. A.; Beiersdorfer, P.; Caughey, T. A.; Brunner, J.

    2014-11-15

    A two-dimensional stigmatic x-ray imaging scheme, consisting of two spherically bent crystals, one concave and one convex, was recently proposed [M. Bitter et al., Rev. Sci. Instrum. 83, 10E527 (2012)]. The Bragg angles and the radii of curvature of the two crystals of this imaging scheme are matched to eliminate the astigmatism and to satisfy the Bragg condition across both crystal surfaces for a given x-ray energy. In this paper, we consider more general configurations of this imaging scheme, which allow us to vary the magnification for a given pair of crystals and x-ray energy. The stigmatic imaging scheme has been validated for the first time by imaging x-rays generated by a micro-focus x-ray source with source size of 8.4 ?m validated by knife-edge measurements. Results are presented from imaging the tungsten L?1 emission at 8.3976 keV, using a convex Si-422 crystal and a concave Si-533 crystal with 2d-spacings of 2.21707 and 1.65635 and radii of curvature of 500 1 mm and 823 1 mm, respectively, showing a spatial resolution of 54.9 ?m. This imaging scheme is expected to be of interest for the two-dimensional imaging of laser produced plasmas.

  2. Impact of cycle chemistry on fossil-fueled high pressure boilers - BHEL approach and experience

    SciTech Connect (OSTI)

    Somu, M.; Gourishankar, S.

    1995-01-01

    Cycle chemistry in high pressure boilers plays an important role as far as availability and reliability of the boilers are concerned. Up keep of proper cycle chemistry is a stupendous task and care must be taken, right from design stage to commissioning and operation of the boilers. It calls for selection of proper design, method of manufacture of critical components and practicing proper procedures during commissioning and regular operation of boilers. Control of cycle chemistry is important from the view point of proper quality of steam and prevention of corrosion. The corrosion is like a double edged knife which reduces the boiler availability on one side and steam quality on the other. The steam quality dictates the efficiency of the turbine. Apart from the internal and external Water Treatment practices, selection of proper deaerator, sizing of drum, steam loading, selection of appropriate drum internals etc. help achieve the desired cycle chemistry. The impact of such cycle chemistry, selection of equipment, Water Treatment practice and operational practices are presented in this paper, in the back drop of BHEL`s design, fabrication and operational guidelines and experience on high pressure boilers. The critical components in the pre-boiler circuit as well as in the main circuit are assessed from the point of view of appropriate water chemistry parameters.

  3. A laboratory based system for Laue micro x-ray diffraction

    SciTech Connect (OSTI)

    Advanced Light Source; Tamura, Nobumichi; Lynch, P.A.; Stevenson, A.W.; Liang, D.; Parry, D.; Wilkins, S.; Tamura, N.

    2007-02-28

    A laboratory diffraction system capable of illuminating individual grains in a polycrystalline matrix is described. Using a microfocus x-ray source equipped with a tungsten anode and prefigured monocapillary optic, a micro-x-ray diffraction system with a 10 mum beam was developed. The beam profile generated by the ellipsoidal capillary was determined using the"knife edge" approach. Measurement of the capillary performance, indicated a beam divergence of 14 mrad and a useable energy bandpass from 5.5 to 19 keV. Utilizing the polychromatic nature of the incident x-ray beam and application of the Laue indexing software package X-Ray Micro-Diffraction Analysis Software, the orientation and deviatoric strain of single grains in a polycrystalline material can be studied. To highlight the system potential the grain orientation and strain distribution of individual grains in a polycrystalline magnesium alloy (Mg 0.2 wt percent Nd) was mapped before and after tensile loading. A basal (0002) orientation was identified in the as-rolled annealed alloy; after tensile loading some grains were observed to undergo an orientation change of 30 degrees with respect to (0002). The applied uniaxial load was measured as an increase in the deviatoric tensile strain parallel to the load axis (37 References).

  4. Fail safe controllable output improved version of the Electromechanical battery

    DOE Patents [OSTI]

    Post, Richard F. (Walnut Creek, CA)

    1999-01-01

    Mechanical means are provided to control the voltages induced in the windings of a generator/motor. In one embodiment, a lever is used to withdraw or insert the entire stator windings from the cavity where the rotating field exists. In another embodiment, voltage control and/or switching off of the output is achievable with a variable-coupling generator/motor. A stator is made up of two concentric layers of windings, with a larger number of turns on the inner layer of windings than the outer layer of windings. The windings are to be connected in series electrically, that is, their voltages add vectorially. The mechanical arrangement is such that one or both of the windings can be rotated with respect to the other winding about their common central axis. Another improved design for the stator assembly of electromechanical batteries provides knife switch contacts that are in electrical contact with the stator windings. The operation of this embodiment depends on the fact that an abnormally large torque will be exerted on the stator structure during any short-circuit condition.

  5. In-depth survey report: control technology for falling solids at Cincinnati Paint and Varnish, Cincinnati, Ohio

    SciTech Connect (OSTI)

    Heitbrink, W.A.

    1988-04-01

    A visit was made to the Cincinnati Paint and Varnish Company, Cincinnati, Ohio, to determine the effectiveness of control measures used to contain dust generated during the manufacturing of custom coatings. Dust arose when 50 pound bags of different powdered materials, titanium dioxide, talc, and crystalline silica, were emptied into 600-gallon mixing tanks by a worker. The worker slit the bags with a knife, lifted the bag, poured the contents into the mixer, and returned the empty bags to the floor. Exterior surfaces of the bags were dusty; handling them released some dust into the atmosphere. A slot hood was used to capture dust generated during the operation. Air velocity toward th slot hood along the lip of the tank where the bags were emptied ranged from 50 to 100 feet per minute. The total dust concentrations determined for crystalline silica during this operation averaged 3.0mg/cum. During a revisit to the site this worker's exposure was below 0.15mg/cum for a time-weighted average of less than 0.004 mg/m/sup 3/. The difference in liquid level in the tank at the time each powdered ingredient was added may have significantly affected the amount of dust released. Measurements of the actual process indicated that the silica had to fall almost 1 meter before reaching any liquid in the mixing tank whereas the talc had to fall only 25 centimeters.

  6. Integration of Functional MRI and White Matter Tractography in Stereotactic Radiosurgery Clinical Practice

    SciTech Connect (OSTI)

    Pantelis, Evaggelos; Papadakis, Nikolaos; Verigos, Kosmas; Stathochristopoulou, Irene; Antypas, Christos; Lekas, Leonidas; Tzouras, Argyrios; Georgiou, Evangelos; Salvaras, Nikolaos

    2010-09-01

    Purpose: To study the efficacy of the integration of functional magnetic resonance imaging (fMRI) and diffusion tensor imaging tractography data into stereotactic radiosurgery clinical practice. Methods and Materials: fMRI and tractography data sets were acquired and fused with corresponding anatomical MR and computed tomography images of patients with arteriovenous malformation (AVM), astrocytoma, brain metastasis, or hemangioma and referred for stereotactic radiosurgery. The acquired data sets were imported into a CyberKnife stereotactic radiosurgery system and used to delineate the target, organs at risk, and nearby functional structures and fiber tracts. Treatment plans with and without the incorporation of the functional structures and the fiber tracts into the optimization process were developed and compared. Results: The nearby functional structures and fiber tracts could receive doses of >50% of the maximum dose if they were excluded from the planning process. In the AVM case, the doses received by the Broadmann-17 structure and the optic tract were reduced to 700 cGy from 1,400 cGy and to 1,200 cGy from 2,000 cGy, respectively, upon inclusion into the optimization process. In the metastasis case, the motor cortex received 850 cGy instead of 1,400 cGy; and in the hemangioma case, the pyramidal tracts received 780 cGy instead of 990 cGy. In the astrocytoma case, the dose to the motor cortex bordering the lesion was reduced to 1,900 cGy from 2,100 cGy, and therefore, the biologically equivalent dose in three fractions was delivered instead. Conclusions: Functional structures and fiber tracts could receive high doses if they were not considered during treatment planning. With the aid of fMRI and tractography images, they can be delineated and spared.

  7. Linear Accelerator-Based Radiosurgery Alone for Arteriovenous Malformation: More Than 12 Years of Observation

    SciTech Connect (OSTI)

    Matsuo, Takayuki Kamada, Kensaku; Izumo, Tsuyoshi; Hayashi, Nobuyuki; Nagata, Izumi

    2014-07-01

    Purpose: Although radiosurgery is an accepted treatment method for intracranial arteriovenous malformations (AVMs), its long-term therapeutic effects have not been sufficiently evaluated, and many reports of long-term observations are from gamma-knife facilities. Furthermore, there are few reported results of treatment using only linear accelerator (LINAC)-based radiosurgery (LBRS). Methods and Materials: Over a period of more than 12 years, we followed the long-term results of LBRS treatment performed in 51 AVM patients. Results: The actuarial obliteration rates, after a single radiosurgery session, at 3, 5, 10, and 15 years were 46.9%, 54.0%, 64.4%, and 68.0%, respectively; when subsequent radiosurgeries were included, the rates were 46.9%, 61.3%, 74.2%, and 90.3%, respectively. Obliteration rates were significantly related to target volumes ≥4 cm{sup 3}, marginal doses ≥12 Gy, Spetzler-Martin grades (1 vs other), and AVM scores ≥1.5; multivariate analyses revealed a significant difference for target volumes ≥4 cm{sup 3}. The postprocedural actuarial symptomatic radiation injury rates, after a single radiation surgery session, at 5, 10, and 15 years were 12.3%, 16.8%, and 19.1%, respectively. Volumes ≥4 cm{sup 3}, location (lobular or other), AVM scores ≥1.5, and the number of radiosurgery were related to radiation injury incidence; multivariate analyses revealed significant differences associated with volumes ≥4 cm{sup 3} and location (lobular or other). Conclusions: Positive results can be obtained with LBRS when performed with a target volume ≤4 cm{sup 3}, an AVM score ≤1.5, and ≥12 Gy radiation. Bleeding and radiation injuries may appear even 10 years after treatment, necessitating long-term observation.

  8. SU-E-T-563: A Fast and Quantative Picket-Fence Test of a Submillimeter Patient Positioning System for Stereotactic Radiosurgery

    SciTech Connect (OSTI)

    Ma, L; Perez-Andujar, A; Chiu, J; McGuinness, C

    2014-06-01

    Purpose: Picket-fence test is a qualitative TG142-recommended quality assurance (QA) test for multileaf collimators. In study, we adopted the same concept and developed a fast but quantatitive QA test for an automatic patient positioning system that requires submilleter accuracy for a radiosurgical treatment. Methods: A piece of radiochromic film was first placed inside a spherical solid water phantom and then irradiated with a sequenence of linearly placed shots of same collimator size (e.g. 4-mm) via the Leskell Gamma Knife Perfexion system (PFX). The shots were positioned with either equal or non-equal gaps of approximately 4 mm to 8 mm depending on the location of the region of interest. A pattern recognization program was developed and then applied to measure the gap spacing between two adjacent shots. The measured distance was then compared with the initial preset values for the test. Results: By introducing variable systematic and random shifts of 0.1 mm to 0.5 mm to the shot sequence, the maximum gap variation from the described test was found to be 0.35 mm or less. On average the positioning uncertainty for the PFX delivery system was found to be 0.10.2 mm. No significant difference in the positioning uncertainty was noted for the centrally aligned shot sequence locations versus the peripherally aligned shot sequence locations. Conclusion: A new quantitative picket-fence type test was developed and demonstrated for routine QA of the submillimeter PFX patient positioning sytem. This test also enables independent verification of any patient-specific shot positioning for a critical treatment such as a tumor in brainstem. Dr Ma is currently on the board of international society of stereotactic Radiosurgery.

  9. SU-E-T-568: Improving Normal Brain Sparing with Increasing Number of Arc Beams for Volume Modulated Arc Beam Radiosurgery of Multiple Brain Metastases

    SciTech Connect (OSTI)

    Hossain, S; Hildebrand, K; Ahmad, S; Larson, D; Ma, L; Sahgal, A

    2014-06-01

    Purpose: Intensity modulated arc beams have been newly reported for treating multiple brain metastases. The purpose of this study was to determine the variations in the normal brain doses with increasing number of arc beams for multiple brain metastases treatments via the TrueBeam Rapidarc system (Varian Oncology, Palo Alto, CA). Methods: A patient case with 12 metastatic brain lesions previously treated on the Leksell Gamma Knife Perfexion (GK) was used for the study. All lesions and organs at risk were contoured by a senior radiation oncologist and treatment plans for a subset of 3, 6, 9 and all 12 targets were developed for the TrueBeam Rapidarc system via 3 to 7 intensity modulated arc-beams with each target covered by at least 99% of the prescribed dose of 20 Gy. The peripheral normal brain isodose volumes as well as the total beam-on time were analyzed with increasing number of arc beams for these targets. Results: All intensisty modulated arc-beam plans produced efficient treatment delivery with the beam-on time averaging 0.6–1.5 min per lesion at an output of 1200 MU/min. With increasing number of arc beams, the peripheral normal brain isodose volumes such as the 12-Gy isodose line enclosed normal brain tissue volumes were on average decreased by 6%, 11%, 18%, and 28% for the 3-, 6-, 9-, 12-target treatment plans respectively. The lowest normal brain isodose volumes were consistently found for the 7-arc treatment plans for all the cases. Conclusion: With nearly identical beam-on times, the peripheral normal brain dose was notably decreased when the total number of intensity modulated arc beams was increased when treating multiple brain metastases. Dr Sahgal and Dr Ma are currently serving on the board of international society of stereotactic radiosurgery.

  10. Long-term elemental dry deposition fluxes measured around Lake Michigan with an automated dry deposition sampler

    SciTech Connect (OSTI)

    Shahin, U. Yi, S.M.; Paode, R.D.; Holsen, T.M.

    2000-05-15

    Long-term measurements of mass and elemental dry deposition (MG, Al, V, Cr, Mn, Ni, Co, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, and Pb) were made with an automated dry deposition sampler (Eagle II) containing knife-edge surrogate surfaces during the Lake Michigan Mass Balance/Mass Budget Study. Measurements were made over a roughly 700-day period in Chicago, IL; in South Haven and Sleeping Bear Dunes, MI; and over Lake Michigan on the 68th Street drinking water intake cribs from December 1993 to October 1995. Average mass fluxes in Chicago, South Haven, Sleeping Bear Dunes, and the 68th Street crib were 65, 10, 3.6, and 12 mg m{sup {minus}2} day{sup {minus}1}, respectively. Primarily crustal elemental fluxes were significantly smaller than the mass fluxes but higher than primarily anthropogenic elemental fluxes. For example, the average elemental flux of Al in Chicago, South Haven, Sleeping Bear Dunes, and the 68th Street crib were 1.0, 0.34, 0.074, and 0.34 mg m{sup {minus}2}day{sup {minus}1}, respectively. The average Pb fluxes in Chicago, South Haven, Sleeping Bear Dunes, and the 68th Street crib were 0.038, 0.023, 0.035, and 0.032 mg m{sup {minus}2}day{sup {minus}1}, respectively. The measured fluxes at the various sites were used to calculate the dry deposition loadings to the lake. These estimated fluxes were highest for Mg and lowest for Cd.

  11. Dosimetric verification of stereotactic radiosurgery/stereotactic radiotherapy dose distributions using Gafchromic EBT3

    SciTech Connect (OSTI)

    Cusumano, Davide; Fumagalli, Maria L.; Marchetti, Marcello; Fariselli, Laura; De Martin, Elena

    2015-10-01

    Aim of this study is to examine the feasibility of using the new Gafchromic EBT3 film in a high-dose stereotactic radiosurgery and radiotherapy quality assurance procedure. Owing to the reduced dimensions of the involved lesions, the feasibility of scanning plan verification films on the scanner plate area with the best uniformity rather than using a correction mask was evaluated. For this purpose, signal values dispersion and reproducibility of film scans were investigated. Uniformity was then quantified in the selected area and was found to be within 1.5% for doses up to 8 Gy. A high-dose threshold level for analyses using this procedure was established evaluating the sensitivity of the irradiated films. Sensitivity was found to be of the order of centiGray for doses up to 6.2 Gy and decreasing for higher doses. The obtained results were used to implement a procedure comparing dose distributions delivered with a CyberKnife system to planned ones. The procedure was validated through single beam irradiation on a Gafchromic film. The agreement between dose distributions was then evaluated for 13 patients (brain lesions, 5 Gy/die prescription isodose ~80%) using gamma analysis. Results obtained using Gamma test criteria of 5%/1 mm show a pass rate of 94.3%. Gamma frequency parameters calculation for EBT3 films showed to strongly depend on subtraction of unexposed film pixel values from irradiated ones. In the framework of the described dosimetric procedure, EBT3 films proved to be effective in the verification of high doses delivered to lesions with complex shapes and adjacent to organs at risk.

  12. TU-F-BRE-04: Development of a High-Resolution EPID Based Dosimetry Strategy for Radiosurgery QA

    SciTech Connect (OSTI)

    Han, B; Ding, A; Xing, L; Wang, L

    2014-06-15

    Purpose: To systematically investigate a high spatial-resolution (0.2mm) electronic portal imaging device (EPID) for CyberKnife (CK) based radiosurgery system quality assurance (QA). Methods: An EPID-based dosimetric measurement technique is applied to CK output measurement and field size verification. A Monte Carlo (MC) simulated pixel-to-pixel EPID response specific to CK is used to convert a raw EPID-measured image of a radiosurgery field into water-based dose distribution. The output factors are measured using EPID for radiosurgery fields formed by fixed and variable aperture (Iris) cones. Circular fields of 5, 7.5, 10, 15, 30 and 60mm diameters are measured and compared with diode measurements. The equivalent diameters are determined by analyzing the area received dose greater than half maximum. Results: For both fixed and Iris cones, the EPID measured output factors of circular fields of 5mm to 60mm diameters are in good agreement with the radiosurgery diode measurements. The mean output differences are 1.0% and 1.5% for fixed and Iris cone respectively. The max differences are 2.2% for the 15mm fixed cone, and 1.8% for the 10mm Iris field. The equivalent diameters derived from the EPID measurements are in good agreement comparing to the water scan result with mean differences of 0.210.09mm and 0.020.22mm for fixed and Iris cone, respectively. The high detector density EPID is able to measure the whole radiation field and identify the field edge and center. Therefore, there is no need to align the detector center perfectly at field center and the setup time is greatly reduced for QA. Conclusion: The high spatial-resolution EPID is proved to be an accurate and efficient dosimetric tool for radiosurgery QA and especially useful in Cyberknife QA for variable aperture collimators.

  13. Development of Pneumatic Aerodynamic Devices to Improve the Performance, Economics, and Safety of Heavy Vehicles

    SciTech Connect (OSTI)

    Robert J. Englar

    2000-06-19

    Under contract to the DOE Office of Heavy Vehicle Technologies, the Georgia Tech Research Institute (GTRI) is developing and evaluating pneumatic (blown) aerodynamic devices to improve the performance, economics, stability and safety of operation of Heavy Vehicles. The objective of this program is to apply the pneumatic aerodynamic aircraft technology previously developed and flight-tested by GTRI personnel to the design of an efficient blown tractor-trailer configuration. Recent experimental results obtained by GTRI using blowing have shown drag reductions of 35% on a streamlined automobile wind-tunnel model. Also measured were lift or down-load increases of 100-150% and the ability to control aerodynamic moments about all 3 axes without any moving control surfaces. Similar drag reductions yielded by blowing on bluff afterbody trailers in current US trucking fleet operations are anticipated to reduce yearly fuel consumption by more than 1.2 billion gallons, while even further reduction is possible using pneumatic lift to reduce tire rolling resistance. Conversely, increased drag and down force generated instantaneously by blowing can greatly increase braking characteristics and control in wet/icy weather due to effective ''weight'' increases on the tires. Safety is also enhanced by controlling side loads and moments caused on these Heavy Vehicles by winds, gusts and other vehicles passing. This may also help to eliminate the jack-knifing problem if caused by extreme wind side loads on the trailer. Lastly, reduction of the turbulent wake behind the trailer can reduce splash and spray patterns and rough air being experienced by following vehicles. To be presented by GTRI in this paper will be results developed during the early portion of this effort, including a preliminary systems study, CFD prediction of the blown flowfields, and design of the baseline conventional tractor-trailer model and the pneumatic wind-tunnel model.

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

    SciTech Connect (OSTI)

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

    2014-02-15

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

  15. Phase II Trial of Radiosurgery to Magnetic Resonance Spectroscopy-Defined High-Risk Tumor Volumes in Patients With Glioblastoma Multiforme

    SciTech Connect (OSTI)

    Einstein, Douglas B.; Wessels, Barry; Bangert, Barbara; Fu, Pingfu; Nelson, A. Dennis; Cohen, Mark; Sagar, Stephen; Lewin, Jonathan; Sloan, Andrew; Zheng Yiran; Williams, Jordonna; Colussi, Valdir; Vinkler, Robert; Maciunas, Robert

    2012-11-01

    Purpose: To determine the efficacy of a Gamma Knife stereotactic radiosurgery (SRS) boost to areas of high risk determined by magnetic resonance spectroscopy (MRS) functional imaging in addition to standard radiotherapy for patients with glioblastoma (GBM). Methods and Materials: Thirty-five patients in this prospective Phase II trial underwent surgical resection or biopsy for a GBM followed by SRS directed toward areas of MRS-determined high biological activity within 2 cm of the postoperative enhancing surgical bed. The MRS regions were determined by identifying those voxels within the postoperative T2 magnetic resonance imaging volume that contained an elevated choline/N-acetylaspartate ratio in excess of 2:1. These voxels were marked, digitally fused with the SRS planning magnetic resonance image, targeted with an 8-mm isocenter per voxel, and treated using Radiation Therapy Oncology Group SRS dose guidelines. All patients then received conformal radiotherapy to a total dose of 60 Gy in 2-Gy daily fractions. The primary endpoint was overall survival. Results: The median survival for the entire cohort was 15.8 months. With 75% of recursive partitioning analysis (RPA) Class 3 patients still alive 18 months after treatment, the median survival for RPA Class 3 has not yet been reached. The median survivals for RPA Class 4, 5, and 6 patients were 18.7, 12.5, and 3.9 months, respectively, compared with Radiation Therapy Oncology Group radiotherapy-alone historical control survivals of 11.1, 8.9, and 4.6 months. For the 16 of 35 patients who received concurrent temozolomide in addition to protocol radiotherapeutic treatment, the median survival was 20.8 months, compared with European Organization for Research and Treatment of Cancer historical controls of 14.6 months using radiotherapy and temozolomide. Grade 3/4 toxicities possibly attributable to treatment were 11%. Conclusions: This represents the first prospective trial using selective MRS-targeted functional SRS combined with radiotherapy for patients with GBM. This treatment is feasible, with acceptable toxicity and patient survivals higher than in historical controls. This study can form the basis for a multicenter, randomized trial.

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

    SciTech Connect (OSTI)

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

    2013-01-01

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

  17. Automated treatment planning for a dedicated multi-source intra-cranial radiosurgery treatment unit accounting for overlapping structures and dose homogeneity

    SciTech Connect (OSTI)

    Ghobadi, Kimia; Ghaffari, Hamid R.; Aleman, Dionne M.; Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario M5T 3M6; Techna Institute, University Health Network, Ontario M5G 1P5 ; Jaffray, David A.; Department of Radiation Oncology, University of Toronto, Ontario M5S 3E2; Department of Medical Biophysics, University of Toronto, Ontario M5G 2M9; Institute of Biomaterial and Biomedical Engineering, University of Toronto, Ontario M5S 2J7; Techna Institute, University Health Network, Ontario M5G 1P5; Ontario Cancer Institute, Ontario M5G 0A3 ; Ruschin, Mark; Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2

    2013-09-15

    Purpose: The purpose of this work is to advance the two-step approach for Gamma Knife{sup } Perfexion (PFX) optimization to account for dose homogeneity and overlap between the planning target volume (PTV) and organs-at-risk (OARs).Methods: In the first step, a geometry-based algorithm is used to quickly select isocentre locations while explicitly accounting for PTV-OARs overlaps. In this approach, the PTV is divided into subvolumes based on the PTV-OARs overlaps and the distance of voxels to the overlaps. Only a few isocentres are selected in the overlap volume, and a higher number of isocentres are carefully selected among voxels that are immediately close to the overlap volume. In the second step, a convex optimization is solved to find the optimal combination of collimator sizes and their radiation duration for each isocentre location.Results: This two-step approach is tested on seven clinical cases (comprising 11 targets) for which the authors assess coverage, OARs dose, and homogeneity index and relate these parameters to the overlap fraction for each case. In terms of coverage, the mean V{sub 99} for the gross target volume (GTV) was 99.8% while the V{sub 95} for the PTV averaged at 94.6%, thus satisfying the clinical objectives of 99% for GTV and 95% for PTV, respectively. The mean relative dose to the brainstem was 87.7% of the prescription dose (with maximum 108%), while on average, 11.3% of the PTV overlapped with the brainstem. The mean beam-on time per fraction per dose was 8.6 min with calibration dose rate of 3.5 Gy/min, and the computational time averaged at 205 min. Compared with previous work involving single-fraction radiosurgery, the resulting plans were more homogeneous with average homogeneity index of 1.18 compared to 1.47.Conclusions: PFX treatment plans with homogeneous dose distribution can be achieved by inverse planning using geometric isocentre selection and mathematical modeling and optimization techniques. The quality of the obtained treatment plans are clinically satisfactory while the homogeneity index is improved compared to conventional PFX plans.

  18. Delayed Complications in Patients Surviving at Least 3 Years After Stereotactic Radiosurgery for Brain Metastases

    SciTech Connect (OSTI)

    Yamamoto, Masaaki; Department of Neurosurgery, Tokyo Women's Medical University Medical Center East, Tokyo ; Kawabe, Takuya; Department of Neurosurgery, Kyoto Prefectural University of Medicine Graduate School of Medical Sciences, Kyoto ; Higuchi, Yoshinori; Sato, Yasunori; Nariai, Tadashi; Barfod, Bierta E.; Kasuya, Hidetoshi; Urakawa, Yoichi

    2013-01-01

    Purpose: Little is known about delayed complications after stereotactic radiosurgery in long-surviving patients with brain metastases. We studied the actual incidence and predictors of delayed complications. Patients and Methods: This was an institutional review board-approved, retrospective cohort study that used our database. Among our consecutive series of 2000 patients with brain metastases who underwent Gamma Knife radiosurgery (GKRS) from 1991-2008, 167 patients (8.4%, 89 women, 78 men, mean age 62 years [range, 19-88 years]) who survived at least 3 years after GKRS were studied. Results: Among the 167 patients, 17 (10.2%, 18 lesions) experienced delayed complications (mass lesions with or without cyst in 8, cyst alone in 8, edema in 2) occurring 24.0-121.0 months (median, 57.5 months) after GKRS. The actuarial incidences of delayed complications estimated by competing risk analysis were 4.2% and 21.2% at the 60th month and 120th month, respectively, after GKRS. Among various pre-GKRS clinical factors, univariate analysis demonstrated tumor volume-related factors: largest tumor volume (hazard ratio [HR], 1.091; 95% confidence interval [CI], 1.018-1.154; P=.0174) and tumor volume {<=}10 cc vs >10 cc (HR, 4.343; 95% CI, 1.444-12.14; P=.0108) to be the only significant predictors of delayed complications. Univariate analysis revealed no correlations between delayed complications and radiosurgical parameters (ie, radiosurgical doses, conformity and gradient indexes, and brain volumes receiving >5 Gy and >12 Gy). After GKRS, an area of prolonged enhancement at the irradiated lesion was shown to be a possible risk factor for the development of delayed complications (HR, 8.751; 95% CI, 1.785-157.9; P=.0037). Neurosurgical interventions were performed in 13 patients (14 lesions) and mass removal for 6 lesions and Ommaya reservoir placement for the other 8. The results were favorable. Conclusions: Long-term follow-up is crucial for patients with brain metastases treated with GKRS because the risk of complications long after treatment is not insignificant. However, even when delayed complications occur, favorable outcomes can be expected with timely neurosurgical intervention.

  19. SU-E-T-224: Is Monte Carlo Dose Calculation Method Necessary for Cyberknife Brain Treatment Planning?

    SciTech Connect (OSTI)

    Wang, L; Fourkal, E; Hayes, S; Jin, L; Ma, C

    2014-06-01

    Purpose: To study the dosimetric difference resulted in using the pencil beam algorithm instead of Monte Carlo (MC) methods for tumors adjacent to the skull. Methods: We retrospectively calculated the dosimetric differences between RT and MC algorithms for brain tumors treated with CyberKnife located adjacent to the skull for 18 patients (total of 27 tumors). The median tumor sizes was 0.53-cc (range 0.018-cc to 26.2-cc). The absolute mean distance from the tumor to the skull was 2.11 mm (range - 17.0 mm to 9.2 mm). The dosimetric variables examined include the mean, maximum, and minimum doses to the target, the target coverage (TC) and conformality index. The MC calculation used the same MUs as the RT dose calculation without further normalization and 1% statistical uncertainty. The differences were analyzed by tumor size and distance from the skull. Results: The TC was generally reduced with the MC calculation (24 out of 27 cases). The average difference in TC between RT and MC was 3.3% (range 0.0% to 23.5%). When the TC was deemed unacceptable, the plans were re-normalized in order to increase the TC to 99%. This resulted in a 6.9% maximum change in the prescription isodose line. The maximum changes in the mean, maximum, and minimum doses were 5.4 %, 7.7%, and 8.4%, respectively, before re-normalization. When the TC was analyzed with regards to target size, it was found that the worst coverage occurred with the smaller targets (0.018-cc). When the TC was analyzed with regards to the distance to the skull, there was no correlation between proximity to the skull and TC between the RT and MC plans. Conclusions: For smaller targets (< 4.0-cc), MC should be used to re-evaluate the dose coverage after RT is used for the initial dose calculation in order to ensure target coverage.

  20. Predictors of Individual Tumor Local Control After Stereotactic Radiosurgery for Non-Small Cell Lung Cancer Brain Metastases

    SciTech Connect (OSTI)

    Garsa, Adam A.; Badiyan, Shahed N.; DeWees, Todd; Simpson, Joseph R.; Huang, Jiayi; Drzymala, Robert E.; Barani, Igor J.; Dowling, Joshua L.; Rich, Keith M.; Chicoine, Michael R.; Kim, Albert H.; Leuthardt, Eric C.; Robinson, Clifford G.

    2014-10-01

    Purpose: To evaluate local control rates and predictors of individual tumor local control for brain metastases from non-small cell lung cancer (NSCLC) treated with stereotactic radiosurgery (SRS). Methods and Materials: Between June 1998 and May 2011, 401 brain metastases in 228 patients were treated with Gamma Knife single-fraction SRS. Local failure was defined as an increase in lesion size after SRS. Local control was estimated using the Kaplan-Meier method. The Cox proportional hazards model was used for univariate and multivariate analysis. Receiver operating characteristic analysis was used to identify an optimal cutpoint for conformality index relative to local control. A P value <.05 was considered statistically significant. Results: Median age was 60 years (range, 27-84 years). There were 66 cerebellar metastases (16%) and 335 supratentorial metastases (84%). The median prescription dose was 20 Gy (range, 14-24 Gy). Median overall survival from time of SRS was 12.1 months. The estimated local control at 12 months was 74%. On multivariate analysis, cerebellar location (hazard ratio [HR] 1.94, P=.009), larger tumor volume (HR 1.09, P<.001), and lower conformality (HR 0.700, P=.044) were significant independent predictors of local failure. Conformality index cutpoints of 1.4-1.9 were predictive of local control, whereas a cutpoint of 1.75 was the most predictive (P=.001). The adjusted Kaplan-Meier 1-year local control for conformality index ≥1.75 was 84% versus 69% for conformality index <1.75, controlling for tumor volume and location. The 1-year adjusted local control for cerebellar lesions was 60%, compared with 77% for supratentorial lesions, controlling for tumor volume and conformality index. Conclusions: Cerebellar tumor location, lower conformality index, and larger tumor volume were significant independent predictors of local failure after SRS for brain metastases from NSCLC. These results warrant further investigation in a prospective setting.

  1. Evaluation of a CdTe semiconductor based compact gamma camera for sentinel lymph node imaging

    SciTech Connect (OSTI)

    Russo, Paolo; Curion, Assunta S.; Mettivier, Giovanni; Esposito, Michela; Aurilio, Michela; Caraco, Corradina; Aloj, Luigi; Lastoria, Secondo

    2011-03-15

    Purpose: The authors assembled a prototype compact gamma-ray imaging probe (MediPROBE) for sentinel lymph node (SLN) localization. This probe is based on a semiconductor pixel detector. Its basic performance was assessed in the laboratory and clinically in comparison with a conventional gamma camera. Methods: The room-temperature CdTe pixel detector (1 mm thick) has 256x256 square pixels arranged with a 55 {mu}m pitch (sensitive area 14.08x14.08 mm{sup 2}), coupled pixel-by-pixel via bump-bonding to the Medipix2 photon-counting readout CMOS integrated circuit. The imaging probe is equipped with a set of three interchangeable knife-edge pinhole collimators (0.94, 1.2, or 2.1 mm effective diameter at 140 keV) and its focal distance can be regulated in order to set a given field of view (FOV). A typical FOV of 70 mm at 50 mm skin-to-collimator distance corresponds to a minification factor 1:5. The detector is operated at a single low-energy threshold of about 20 keV. Results: For {sup 99m}Tc, at 50 mm distance, a background-subtracted sensitivity of 6.5x10{sup -3} cps/kBq and a system spatial resolution of 5.5 mm FWHM were obtained for the 0.94 mm pinhole; corresponding values for the 2.1 mm pinhole were 3.3x10{sup -2} cps/kBq and 12.6 mm. The dark count rate was 0.71 cps. Clinical images in three patients with melanoma indicate detection of the SLNs with acquisition times between 60 and 410 s with an injected activity of 26 MBq {sup 99m}Tc and prior localization with standard gamma camera lymphoscintigraphy. Conclusions: The laboratory performance of this imaging probe is limited by the pinhole collimator performance and the necessity of working in minification due to the limited detector size. However, in clinical operative conditions, the CdTe imaging probe was effective in detecting SLNs with adequate resolution and an acceptable sensitivity. Sensitivity is expected to improve with the future availability of a larger CdTe detector permitting operation at shorter distances from the patient skin.

  2. Implementing Strategies for Drying and Pressing Wood Without Emissions Controls

    SciTech Connect (OSTI)

    Sujit Banerjee; Terrance Conners

    2007-09-07

    Drying and pressing wood for the manufacture of lumber, particleboard, oriented strand board (OSB), veneer and medium density fiberboard (MDF) release volatile organic compounds (VOCs) into the atmosphere. These emissions require control equipment that are capital-intensive and consume significant quantities of natural gas and electricity. The objective of our work was to understand the mechanisms through which volatile organic compounds are generated and released and to develop simple control strategies. Of the several strategies developed, two have been implemented for OSB manufacture over the course of this study. First, it was found that increasing final wood moisture by about 2-4 percentage points reduced the dryer emissions of hazardous air pollutants by over 70%. As wood dries, the escaping water evaporatively cools the wood. This cooling tapers off wood when the wood is nearly dry and the wood temperature rises. Thermal breakdown of the wood tissue occurs and VOCs are released. Raising the final wood moisture by only a few percentage points minimizes the temperature rise and reduces emissions. Evaporative cooling also impacts has implications for VOC release from wood fines. Flaking wood for OSB manufacture inevitable generates fines. Fines dry out rapidly because of their high surface area and evaporative cooling is lost more rapidly than for flakes. As a result, fines emit a disproportionate quantity of VOCs. Fines can be reduced in two ways: through screening of the green furnish and through reducing their generation during flaking. The second approach is preferable because it also increased wood yield. A procedure to do this by matching the sharpness angle of the flaker knife to the ambient temperature was also developed. Other findings of practical interests are as follows: Dielectric heating of wood under low-headspace conditions removes terpenes and other extractives from softwood; The monoterpene content in trees depend upon temperature and seasonal effects; Method 25A emissions from lumber drying can be modeled from a knowledge of the airflow through the kiln; A heat transfer model shows that VOCs released during hot-pressing mainly originate from the surface of the board; and Boiler ash can be used to adsorb formaldehyde from air streams.

  3. SU-E-J-258: Inter- and Intra-Fraction Setup Stability and Couch Change Tolerance for Image Guided Radiation Therapy

    SciTech Connect (OSTI)

    Teboh, Forbang R; Agee, M; Rowe, L; Creasy, T; Schultz, J; Bell, R; Wong, J; Armour, E

    2014-06-01

    Purpose: Immobilization devices combine rigid patient fixation as well as comfort and play a key role providing the stability required for accurate radiation delivery. In the setup step, couch re-positioning needed to align the patient is derived via registration of acquired versus reference image. For subsequent fractions, replicating the initial setup should yield identical alignment errors when compared to the reference. This is not always the case and further couch re-positioning can be needed. An important quality assurance measure is to set couch tolerances beyond which additional investigations are needed. The purpose of this work was to study the inter-fraction couch changes needed to re-align the patient and the intra-fraction stability of the alignment as a guide to establish the couch tolerances. Methods: Data from twelve patients treated on the Accuray CyberKnife (CK) system for fractionated intracranial radiotherapy and immobilized with Aquaplast RT, U-frame, F-Head-Support (Qfix, PA, USA) was used. Each fraction involved image acquisitions and registration with the reference to re-align the patient. The absolute couch position corresponding to the approved setup alignment was recorded per fraction. Intra-fraction set-up corrections were recorded throughout the treatment. Results: The average approved setup alignment was 0.030.28mm, 0.150.22mm, 0.060.31mm in the L/R, A/P, S/I directions respectively and 0.000.35degrees, 0.030.32degrees, 0.080.45degrees for roll, pitch and yaw respectively. The inter-fraction reproducibility of the couch position was 6.65mm, 10.55mm, and 4.77mm in the L/R, A/P and S/I directions respectively and 0.82degrees, 0.71degrees for roll and pitch respectively. Intra-fraction monitoring showed small average errors of 0.210.21mm, 0.000.08mm, 0.230.22mm in the L/R, A/P, S/I directions respectively and 0.030.12degrees, 0.040.25degrees, and 0.130.15degrees in the roll, pitch and yaw respectively. Conclusion: The inter-fraction reproducibility should serve as a guide to couch tolerances, specific to a site and immobilization. More patients need to be included to make general conclusions.

  4. Final Report on "Development and Testing of Advanced Accelerator Structures and Technologies at 11.424 GHz"

    SciTech Connect (OSTI)

    Gold, Steven H.

    2013-10-13

    This is the final report on the research program ?Development and Testing of Advanced Accelerator Structures and Technologies at 11.424 GHz,? which was carried out by the Naval Research Laboratory (NRL) under Interagency Agreement DE?AI02?01ER41170 with the Department of Energy. The period covered by this report is 15 July 2010 ? 14 July 2013. The program included two principal tasks. Task 1 involved a study of the key physics issues related to the use of high gradient dielectric-loaded accelerating (DLA) structures in rf linear accelerators and was carried out in collaboration with Argonne National Laboratory (ANL) and Euclid Techlabs LLC. Task 2 involved a study of high power active microwave pulse compressors and was carried out in collaboration with Omega-P, Inc. and the Institute of Applied Physics of the Russian Academy of Sciences in Nizhny Novgorod. The studies under Task 1 were focused on rf-induced multipactor and breakdown in externally driven DLA structures at the 200-ns timescale. Suppression of multipactor and breakdown are essential to the practical application of dielectric structures in rf linear accelerators. The structures that were studied were developed by ANL and Euclid Techlabs and their performance was evaluated at high power in the X-band Magnicon Laboratory at NRL. Three structures were designed, fabricated, and tested, and the results analyzed in the first two years of the program: a clamped quartz traveling-wave (TW) structure, a externally copper-coated TW structure, and an externally copper-coated dielectric standing-wave (SW) structure. These structures showed that rf breakdown could be largely eliminated by eliminating dielectric joints in the structures, but that the multipactor loading was omnipresent. In the third year of the program, the focus of the program was on multipactor suppression using a strong applied axial magnetic field, as proposed by Chang et al. [C. Chang et al., J. Appl. Phys. 110, 063304 (2011).], and a successful experiment was carried out that demonstrated suppression of multipactor in the uniform-field region of a TW DLA structure. However, in accordance with theory, the multipactor was enhanced in regions of the structure with lower values of axial magnetic field. Under Task 2, there were two two-month experimental runs at NRL that were used to characterize the performance of high power two-channel dual-mode active microwave pulse compressor configurations that used electron-beam triggered switch cavities. The pulse compressors were designed and fabricated by Omega-P, Inc. and the Russian Institute of Applied Physics and tested in the Magnicon Laboratory at NRL. These pulse compressors made use of an electron beam discharge from a cylindrical knife-edged Mo cathode coated with a CVD diamond film that was driven by a ?100 kV, 100 ns high voltage pulse. The electron beam was used to change the resonant frequency of the switch cavities in order to create the output microwave pulse. The compressor channels included a TE01 input and output section and a TE02 energy storage cavity, followed by a switch assembly that controlled the coupling between the TE01 and TE02 modes. In the initial state, the switch cavity was in resonance, the reflection from the cavity was out of phase, and the mode conversion was only ~2-3%, allowing the energy storage cavity to fill. When the electron beam was discharged into the switch cavity, the cavity was shifted out of resonance, causing the phase of the reflection to change by ~?. As a result of the change in the reflection phase, the mode coupling in the conical taper was greatly increased, and could approach ~100%, permitting the energy storage cavity to empty in one cavity round trip time of the TE02 mode to produce a high power output pulse. The second experiment runs demonstrated a 190 MW, ~20 ns compressed pulse at 25.7 gain and ~50% efficiency, using a 7.4 MW, 1 ?s drive pulse from the magnicon. The success of this experiment suggests a path to future high gain active versions of the SLED 2 pulse compressor at SLAC.