The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
W Bolch - One of the best experts on this subject based on the ideXlab platform.
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SU‐FF‐I‐51: Effect of Subcutaneous Fat On Abdominal CT Dosimetry: Monte Carlo Study
Medical Physics, 2007Co-Authors: Choonsik Lee, Daniel Lodwick, W BolchAbstract:Purpose: To investigate the effect of abdominal subcutaneous fat on organ and effective doses in abdominal computed tomography(CT) examination by using deformable hybrid anthropomorphic Phantoms and MCNPX2.5. Methods and Material: A hybrid anthropomorphic computational Phantom representing a newborn reference patient was employed in this study to illustrate use of deformable Phantoms for patient‐specific dosimetry. The hybrid Phantom is currently the most advanced computational Phantom incorporating the best features of conventional stylized and voxel Phantoms, which include parameter‐based flexibility and improved anatomical realism, respectively. Based on the template Phantom of which the abdominal circumference was 36 cm, two more Phantoms having abdominal circumferences of 33 and 39 cm were generated by manipulating control points on the abdominal surfaces. Three Phantoms were then incorporated into MCNPX2.5 code where helical fan beams from SOMATOM Sensation 16 helical multi‐slice CT scanner were modeled. A CTcollimator setting of 12 mm and a tube potential of 100 kVp, both commonly used in pediatric CT scans, were simulated for illustrative calculations. Absorbed doses for major organ doses were calculated in each of the three newborn Phantoms. The normalized organ absorbed doses for a total of 9 major organs were calculated and compared to each other. Results: As waist circumference increases, the thickness of abdominal subcutaneous fat increases correspondingly which causes a decrease in the organ absorbed dose for CT beams, especially, for the small intestinal wall (−5.8%) and kidney (−7.3%). Conclusion: Even though the effect of fat thickness on organ dose was not significant in newborn Phantom, higher correlation would be observed in older and larger Phantoms. The authors are working on a series of pediatric Phantoms so that a more systematic investigation on the effect of abdominal subcutaneous fat on CTdosimetry could be performed in the future.
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su ff i 51 effect of subcutaneous fat on abdominal ct dosimetry monte carlo study
Medical Physics, 2007Co-Authors: Choonsik Lee, Daniel Lodwick, W BolchAbstract:Purpose: To investigate the effect of abdominal subcutaneous fat on organ and effective doses in abdominal computed tomography(CT) examination by using deformable hybrid anthropomorphic Phantoms and MCNPX2.5. Methods and Material: A hybrid anthropomorphic computational Phantom representing a newborn reference patient was employed in this study to illustrate use of deformable Phantoms for patient‐specific dosimetry. The hybrid Phantom is currently the most advanced computational Phantom incorporating the best features of conventional stylized and voxel Phantoms, which include parameter‐based flexibility and improved anatomical realism, respectively. Based on the template Phantom of which the abdominal circumference was 36 cm, two more Phantoms having abdominal circumferences of 33 and 39 cm were generated by manipulating control points on the abdominal surfaces. Three Phantoms were then incorporated into MCNPX2.5 code where helical fan beams from SOMATOM Sensation 16 helical multi‐slice CT scanner were modeled. A CTcollimator setting of 12 mm and a tube potential of 100 kVp, both commonly used in pediatric CT scans, were simulated for illustrative calculations. Absorbed doses for major organ doses were calculated in each of the three newborn Phantoms. The normalized organ absorbed doses for a total of 9 major organs were calculated and compared to each other. Results: As waist circumference increases, the thickness of abdominal subcutaneous fat increases correspondingly which causes a decrease in the organ absorbed dose for CT beams, especially, for the small intestinal wall (−5.8%) and kidney (−7.3%). Conclusion: Even though the effect of fat thickness on organ dose was not significant in newborn Phantom, higher correlation would be observed in older and larger Phantoms. The authors are working on a series of pediatric Phantoms so that a more systematic investigation on the effect of abdominal subcutaneous fat on CTdosimetry could be performed in the future.
Choonsik Lee - One of the best experts on this subject based on the ideXlab platform.
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SU‐FF‐I‐51: Effect of Subcutaneous Fat On Abdominal CT Dosimetry: Monte Carlo Study
Medical Physics, 2007Co-Authors: Choonsik Lee, Daniel Lodwick, W BolchAbstract:Purpose: To investigate the effect of abdominal subcutaneous fat on organ and effective doses in abdominal computed tomography(CT) examination by using deformable hybrid anthropomorphic Phantoms and MCNPX2.5. Methods and Material: A hybrid anthropomorphic computational Phantom representing a newborn reference patient was employed in this study to illustrate use of deformable Phantoms for patient‐specific dosimetry. The hybrid Phantom is currently the most advanced computational Phantom incorporating the best features of conventional stylized and voxel Phantoms, which include parameter‐based flexibility and improved anatomical realism, respectively. Based on the template Phantom of which the abdominal circumference was 36 cm, two more Phantoms having abdominal circumferences of 33 and 39 cm were generated by manipulating control points on the abdominal surfaces. Three Phantoms were then incorporated into MCNPX2.5 code where helical fan beams from SOMATOM Sensation 16 helical multi‐slice CT scanner were modeled. A CTcollimator setting of 12 mm and a tube potential of 100 kVp, both commonly used in pediatric CT scans, were simulated for illustrative calculations. Absorbed doses for major organ doses were calculated in each of the three newborn Phantoms. The normalized organ absorbed doses for a total of 9 major organs were calculated and compared to each other. Results: As waist circumference increases, the thickness of abdominal subcutaneous fat increases correspondingly which causes a decrease in the organ absorbed dose for CT beams, especially, for the small intestinal wall (−5.8%) and kidney (−7.3%). Conclusion: Even though the effect of fat thickness on organ dose was not significant in newborn Phantom, higher correlation would be observed in older and larger Phantoms. The authors are working on a series of pediatric Phantoms so that a more systematic investigation on the effect of abdominal subcutaneous fat on CTdosimetry could be performed in the future.
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su ff i 51 effect of subcutaneous fat on abdominal ct dosimetry monte carlo study
Medical Physics, 2007Co-Authors: Choonsik Lee, Daniel Lodwick, W BolchAbstract:Purpose: To investigate the effect of abdominal subcutaneous fat on organ and effective doses in abdominal computed tomography(CT) examination by using deformable hybrid anthropomorphic Phantoms and MCNPX2.5. Methods and Material: A hybrid anthropomorphic computational Phantom representing a newborn reference patient was employed in this study to illustrate use of deformable Phantoms for patient‐specific dosimetry. The hybrid Phantom is currently the most advanced computational Phantom incorporating the best features of conventional stylized and voxel Phantoms, which include parameter‐based flexibility and improved anatomical realism, respectively. Based on the template Phantom of which the abdominal circumference was 36 cm, two more Phantoms having abdominal circumferences of 33 and 39 cm were generated by manipulating control points on the abdominal surfaces. Three Phantoms were then incorporated into MCNPX2.5 code where helical fan beams from SOMATOM Sensation 16 helical multi‐slice CT scanner were modeled. A CTcollimator setting of 12 mm and a tube potential of 100 kVp, both commonly used in pediatric CT scans, were simulated for illustrative calculations. Absorbed doses for major organ doses were calculated in each of the three newborn Phantoms. The normalized organ absorbed doses for a total of 9 major organs were calculated and compared to each other. Results: As waist circumference increases, the thickness of abdominal subcutaneous fat increases correspondingly which causes a decrease in the organ absorbed dose for CT beams, especially, for the small intestinal wall (−5.8%) and kidney (−7.3%). Conclusion: Even though the effect of fat thickness on organ dose was not significant in newborn Phantom, higher correlation would be observed in older and larger Phantoms. The authors are working on a series of pediatric Phantoms so that a more systematic investigation on the effect of abdominal subcutaneous fat on CTdosimetry could be performed in the future.
Jeremy Sung - One of the best experts on this subject based on the ideXlab platform.
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Comparison of the St. Petersburg Phantom with a BOMAB Phantom in the ORTEC StandFast whole body counter: a Monte Carlo simulation.
Health Physics, 2008Co-Authors: Gary H. Kramer, Kevin Capello, Jeremy SungAbstract:Three sizes of the St. Petersburg Phantom have been compared to six sizes of BOMAB Phantoms measured by a virtual StandFast whole body counter using Monte Carlo simulations to investigate if the counting efficiencies are equivalent. This work shows that previously published data comparing the Reference Man sized Phantom at 662 keV is supported; however, the simulations also show that the smaller sized St. Petersburg Phantoms do not agree well with BOMAB Phantoms. It is concluded that, compared with BOMAB Phantoms, the St. Petersburg Phantoms are system dependent and that they should be validated over a wide photon energy range against corresponding BOMAB Phantoms prior to their use for calibrating whole body counters.
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Monte Carlo comparison of the St Petersburg Phantom with a BOMAB Phantom in the HML's whole-body counter.
Radiation Protection Dosimetry, 2007Co-Authors: Gary H. Kramer, Kevin Capello, Jeremy SungAbstract:Three sizes of the St Petersburg Phantom have been compared to six sizes of BOMAB Phantoms measured by a virtual whole-body counter similar to the one in use in the Human Monitoring Laboratory using Monte Carlo simulations. The previously published data comparing the St Petersburg Reference Man sized Phantom with a similar sized Bottle Manikin Absorber Phantoms (BOMAB) Phantom at 662 keV is supported; however, the simulations also show that the smaller sized St Petersburg Phantoms do not agree well with smaller BOMAB Phantoms. It is concluded that the St Petersburg Phantoms are system dependent meaning that all sizes of the St Petersburg Phantoms should be experimentally compared over a wide photon energy range against corresponding BOMAB Phantoms to validate their use for calibrating whole-body counters.
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The LLNL voxel Phantom: comparison with the physical Phantom and previous virtual Phantoms.
Health physics, 2007Co-Authors: Gary H. Kramer, Kevin Capello, Jeremy SungAbstract:-The Human Monitoring Laboratory has created a voxel Phantom from computer tomography scans of the Lawrence Livermore National Laboratory (LLNL) torso Phantom for use in Monte Carlo simulations. The voxel Phantom has been compared to the previously developed mathematical Phantom using Monte Carlo simulations and both virtual Phantoms have been compared to physical measurement of the LLNL Phantom. The voxel Phantom agreed well with the others, except at very low photon energies (i.e., 17.5 keV), with predicted counting efficiencies being within 2% of the counting efficiencies from the other two Phantoms at 59.5 keV and above. The mathematical Phantom performs similarly to the voxel Phantom, but much faster, so it is an excellent alternative if computer power is lacking. The voxel Phantom of the LLNL Phantom is available from the authors, on request.
Gary H. Kramer - One of the best experts on this subject based on the ideXlab platform.
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Voxel Phantoms: the new ICRP computational Phantoms: how do they compare?
Health physics, 2012Co-Authors: Kevin Capello, Stephanie A. Kedzior, Gary H. KramerAbstract:Two new voxel Phantoms, ICRP Adult Female (AF) and ICRP Adult Male (AM), have been compared with BOMAB (BOttle Mannikin ABsorber) Phantoms and other voxel Phantoms of similar size (NORMAN and VIP-Man) using Monte Carlo simulations to assess their counting efficiencies in a whole body counter. The results show that the ICRP Phantoms, compared with NORMAN and VIP-Man, had counting efficiencies that ranged from 3% to 59% higher over the energy range 122 keV to 1,836 keV, a trend that is also exhibited by the comparable BOMAB Phantoms. A comparison of all the voxel Phantoms' results to those of the BOMAB Phantom corresponding to reference man shows that the NORMAN and VIP-Man have mostly lower counting efficiencies, whereas the ICRP Phantoms have higher counting efficiencies than the PM (Phantom Male) BOMAB Phantom. This could be due to differences in the internal structure of each of the voxel Phantoms. As expected, the ICRP AF (female voxel) had the highest efficiency due to being the smallest of all the Phantoms.
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Comparison of the St. Petersburg Phantom with a BOMAB Phantom in the ORTEC StandFast whole body counter: a Monte Carlo simulation.
Health Physics, 2008Co-Authors: Gary H. Kramer, Kevin Capello, Jeremy SungAbstract:Three sizes of the St. Petersburg Phantom have been compared to six sizes of BOMAB Phantoms measured by a virtual StandFast whole body counter using Monte Carlo simulations to investigate if the counting efficiencies are equivalent. This work shows that previously published data comparing the Reference Man sized Phantom at 662 keV is supported; however, the simulations also show that the smaller sized St. Petersburg Phantoms do not agree well with BOMAB Phantoms. It is concluded that, compared with BOMAB Phantoms, the St. Petersburg Phantoms are system dependent and that they should be validated over a wide photon energy range against corresponding BOMAB Phantoms prior to their use for calibrating whole body counters.
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The NORMAN Phantom vs. the BOMAB Phantom: are they different?
Health physics, 2008Co-Authors: Gary H. Kramer, Kevin Capello, Quoc PhanAbstract:-This paper describes the implementation of the NORMAN Phantom with the Human Monitoring Laboratory's Monte Carlo simulator, the problems that were encountered, and their solution. The NORMAN Phantom has been compared with the reference man BOMAB Phantom in three different whole body counting geometries: a scanning detector system (WBC1), and two stand-up whole body counters (WBC2, WBC3) that have different reference points for their counting geometry. The average agreement (taken over all energies) of the two Phantoms is approximately a factor of 1.15 on any given counting system. For the first two systems (WBC1, WBC2) the BOMAB has the highest counting efficiency, whereas it is reversed on the third system (WBC3). Considering the differences between the two Phantoms, the agreement is good.
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Monte Carlo comparison of the St Petersburg Phantom with a BOMAB Phantom in the HML's whole-body counter.
Radiation Protection Dosimetry, 2007Co-Authors: Gary H. Kramer, Kevin Capello, Jeremy SungAbstract:Three sizes of the St Petersburg Phantom have been compared to six sizes of BOMAB Phantoms measured by a virtual whole-body counter similar to the one in use in the Human Monitoring Laboratory using Monte Carlo simulations. The previously published data comparing the St Petersburg Reference Man sized Phantom with a similar sized Bottle Manikin Absorber Phantoms (BOMAB) Phantom at 662 keV is supported; however, the simulations also show that the smaller sized St Petersburg Phantoms do not agree well with smaller BOMAB Phantoms. It is concluded that the St Petersburg Phantoms are system dependent meaning that all sizes of the St Petersburg Phantoms should be experimentally compared over a wide photon energy range against corresponding BOMAB Phantoms to validate their use for calibrating whole-body counters.
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The LLNL voxel Phantom: comparison with the physical Phantom and previous virtual Phantoms.
Health physics, 2007Co-Authors: Gary H. Kramer, Kevin Capello, Jeremy SungAbstract:-The Human Monitoring Laboratory has created a voxel Phantom from computer tomography scans of the Lawrence Livermore National Laboratory (LLNL) torso Phantom for use in Monte Carlo simulations. The voxel Phantom has been compared to the previously developed mathematical Phantom using Monte Carlo simulations and both virtual Phantoms have been compared to physical measurement of the LLNL Phantom. The voxel Phantom agreed well with the others, except at very low photon energies (i.e., 17.5 keV), with predicted counting efficiencies being within 2% of the counting efficiencies from the other two Phantoms at 59.5 keV and above. The mathematical Phantom performs similarly to the voxel Phantom, but much faster, so it is an excellent alternative if computer power is lacking. The voxel Phantom of the LLNL Phantom is available from the authors, on request.
Daniel Lodwick - One of the best experts on this subject based on the ideXlab platform.
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SU‐FF‐I‐51: Effect of Subcutaneous Fat On Abdominal CT Dosimetry: Monte Carlo Study
Medical Physics, 2007Co-Authors: Choonsik Lee, Daniel Lodwick, W BolchAbstract:Purpose: To investigate the effect of abdominal subcutaneous fat on organ and effective doses in abdominal computed tomography(CT) examination by using deformable hybrid anthropomorphic Phantoms and MCNPX2.5. Methods and Material: A hybrid anthropomorphic computational Phantom representing a newborn reference patient was employed in this study to illustrate use of deformable Phantoms for patient‐specific dosimetry. The hybrid Phantom is currently the most advanced computational Phantom incorporating the best features of conventional stylized and voxel Phantoms, which include parameter‐based flexibility and improved anatomical realism, respectively. Based on the template Phantom of which the abdominal circumference was 36 cm, two more Phantoms having abdominal circumferences of 33 and 39 cm were generated by manipulating control points on the abdominal surfaces. Three Phantoms were then incorporated into MCNPX2.5 code where helical fan beams from SOMATOM Sensation 16 helical multi‐slice CT scanner were modeled. A CTcollimator setting of 12 mm and a tube potential of 100 kVp, both commonly used in pediatric CT scans, were simulated for illustrative calculations. Absorbed doses for major organ doses were calculated in each of the three newborn Phantoms. The normalized organ absorbed doses for a total of 9 major organs were calculated and compared to each other. Results: As waist circumference increases, the thickness of abdominal subcutaneous fat increases correspondingly which causes a decrease in the organ absorbed dose for CT beams, especially, for the small intestinal wall (−5.8%) and kidney (−7.3%). Conclusion: Even though the effect of fat thickness on organ dose was not significant in newborn Phantom, higher correlation would be observed in older and larger Phantoms. The authors are working on a series of pediatric Phantoms so that a more systematic investigation on the effect of abdominal subcutaneous fat on CTdosimetry could be performed in the future.
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su ff i 51 effect of subcutaneous fat on abdominal ct dosimetry monte carlo study
Medical Physics, 2007Co-Authors: Choonsik Lee, Daniel Lodwick, W BolchAbstract:Purpose: To investigate the effect of abdominal subcutaneous fat on organ and effective doses in abdominal computed tomography(CT) examination by using deformable hybrid anthropomorphic Phantoms and MCNPX2.5. Methods and Material: A hybrid anthropomorphic computational Phantom representing a newborn reference patient was employed in this study to illustrate use of deformable Phantoms for patient‐specific dosimetry. The hybrid Phantom is currently the most advanced computational Phantom incorporating the best features of conventional stylized and voxel Phantoms, which include parameter‐based flexibility and improved anatomical realism, respectively. Based on the template Phantom of which the abdominal circumference was 36 cm, two more Phantoms having abdominal circumferences of 33 and 39 cm were generated by manipulating control points on the abdominal surfaces. Three Phantoms were then incorporated into MCNPX2.5 code where helical fan beams from SOMATOM Sensation 16 helical multi‐slice CT scanner were modeled. A CTcollimator setting of 12 mm and a tube potential of 100 kVp, both commonly used in pediatric CT scans, were simulated for illustrative calculations. Absorbed doses for major organ doses were calculated in each of the three newborn Phantoms. The normalized organ absorbed doses for a total of 9 major organs were calculated and compared to each other. Results: As waist circumference increases, the thickness of abdominal subcutaneous fat increases correspondingly which causes a decrease in the organ absorbed dose for CT beams, especially, for the small intestinal wall (−5.8%) and kidney (−7.3%). Conclusion: Even though the effect of fat thickness on organ dose was not significant in newborn Phantom, higher correlation would be observed in older and larger Phantoms. The authors are working on a series of pediatric Phantoms so that a more systematic investigation on the effect of abdominal subcutaneous fat on CTdosimetry could be performed in the future.
