The Experts below are selected from a list of 100332 Experts worldwide ranked by ideXlab platform
Nikos Papanikolaou - One of the best experts on this subject based on the ideXlab platform.
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SU‐E‐T‐707: Clinical Evaluation of a New Commercial Dose Calculation Algorithm
Medical Physics, 2011Co-Authors: Carlos Esquivel, Sotirios Stathakis, C. Sath, Alonso N. Gutierrez, J. Dorward, Dimitris Mihailidis, Panayiotis Mavroidis, Nikos PapanikolaouAbstract:Purpose: A new Algorithm, Acuros® XB Advanced Dose Calculation, has been introduced by Varian Medical Systems in the Eclipse planning system for photondose Calculation in external beam radiotherapy. Acuros XB is based on the solution of the linear Boltzmann transport equation (LBTE). In this study we perform a clinical evaluation of the Acuros XB by comparison to other known and tested treatment planning systems and dose Calculation Algorithms. Methods: Twenty (n=20) patients previously planned with the Pinnacle ver.9.0 treatment planning system and calculated using the collapsed cone convolution superposition Algorithm, were recalculated using the Eclipse ver. 10.0 with the Acuros XB dose Calculation Algorithm. A mixture of treatment sites were chosen, including brain,lung,liver, and pelvis. The metrics chosen for the evaluation were DVH, absolute dose difference, and profiles along the axial, sagital and coronal planes at the isocenter Results: Good agreement was observed between the dose Calculations with Acuros and the ones from Pinnacle using the CCCS Algorithm. Differences were mostly detected in inhomogeneous media. Maximum differences of 2.5% were observed for lung patients, while, smaller differences were detected for pelvic, brain, and abdominal cases. Conclusions: The new dose Calculation Algorithm Acuros XB available in Eclipse ver. 10 is in very good agreement with the widely tested and accepted CCCS dose Calculation Algorithm. More extensive testing of the Algorithm might be necessary in order to further evaluate the accuracy of the Calculations.
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SU‐E‐T‐702: Accuracy of a Commercially Available Dose Calculation Algorithm for Small Field Dosimetry
Medical Physics, 2011Co-Authors: Sotirios Stathakis, Carlos Esquivel, Alonso N. Gutierrez, Dimitris Mihailidis, Panayiotis Mavroidis, C. Buckey, P. Myers, Nikos PapanikolaouAbstract:Purpose: To validate the AcurosXB dose Calculation Algorithm for small field dosimetry for high energy photon beams. Methods: Calculations in water phantom of 0.2×0.2×0,2cm3 voxel size with slabs of inhomogeneity materials (air rho=0.0012g/cm3, lung rho =0.2 g/cm3 and bone rho =1.85 g/cm3) were used in this study. Fields sizes ranging from 1×1cm2 to 10×10cm2 and energies of 6, 10 and 18MV were calculated using the Acuros XB dose Calculation Algorithm available in the Eclipse treatment planning system (TPS). The Calculations were compared to the Analytical Anisotropic Algorithm (AAA) also available in Eclipse as well to Collapsed Cone Convolution Superposition (CCCS) Algorithm available in the Pinnacle3 TPS. Comparison between the dose Calculations and Monte Carlo Calculations using EGSnrc\BEAMnrc and EGSnrc\DOSXYZnrc package was also performed. Results: The AcurosXB Calculation Algorithm was in general in good agreement with Monte Carlo Calculations. Discrepancies were observed at the interfaces of the inhomogeneities. Good agreement between CCCS and AcurosXB was also observed for the majority of the cases with discrepancies observed only at the interfaces of the media. The AAA did not successfully calculate the dose for the test geometries when small fields were used. Discrepancies in the order of 50–70% were observed. The AAA overestimated the dose in the low density material and failed to predict the second buildup region accurately for the very small field sizes. Conclusion: In general, the overall degree of accuracy for AcurosXB in the conditions of electronic disequilibrium was in good agreement with Monte Carlo Calculations (within 2%) and comparable with the CCCS Algorithm. The AAA on the other hand failed to accurately predict the dose for the small fields studied in the presence of inhomogeneities
Jerzy Wasniewski - One of the best experts on this subject based on the ideXlab platform.
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PARA - A Recursive Formulation of the Inversion of Symmetric Positive Definite Matrices in Packed Storage Data Format
Lecture Notes in Computer Science, 2002Co-Authors: Bjarne Stig Andersen, John A. Gunnels, Fred G Gustavson, Jerzy WasniewskiAbstract:A new Recursive Packed Inverse Calculation Algorithm for symmetric positive definite matrices has been developed. The new Recursive Inverse Calculation Algorithm uses minimal storage, n(n + 1)/2, and has nearly the same performance as the LAPACK full storage Algorithm using n2 memory words. New recursive packed BLAS needed for this Algorithm have been developed too. Two transformation routines, from the LAPACK packed storage data format to the recursive storage data format were added to the package too.We present performance measurements on several current architectures that demonstrate improvements over the traditional packed routines.
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a recursive formulation of the inversion of symmetric positive definite matrices in packed storage data format
Parallel Computing, 2002Co-Authors: Bjarne Stig Andersen, John A. Gunnels, Fred G Gustavson, Jerzy WasniewskiAbstract:A new Recursive Packed Inverse Calculation Algorithm for symmetric positive definite matrices has been developed. The new Recursive Inverse Calculation Algorithm uses minimal storage, n(n + 1)/2, and has nearly the same performance as the LAPACK full storage Algorithm using n2 memory words. New recursive packed BLAS needed for this Algorithm have been developed too. Two transformation routines, from the LAPACK packed storage data format to the recursive storage data format were added to the package too.We present performance measurements on several current architectures that demonstrate improvements over the traditional packed routines.
Sotirios Stathakis - One of the best experts on this subject based on the ideXlab platform.
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Accuracy of the Small Field Dosimetry Using the Acuros XB Dose Calculation Algorithm within and beyond Heterogeneous Media for 6 MV Photon Beams
International Journal of Medical Physics Clinical Engineering and Radiation Oncology, 2012Co-Authors: Sotirios Stathakis, Carlos Esquivel, Alonso N. Gutierrez, Panayiotis Mavroidis, P. Myers, Luis Alberto Vazquez Quino, O Calvo, Niko PapanikolaouAbstract:Purpose: The dosimetric accuracy of the recently released Acuros XB advanced dose Calculation Algorithm (Varian Medical Systems, Palo Alto, CA) is investigated for single radiation fields incident on homogeneous and heterogeneous geometries, as well as for two arc (VMAT) cases and compared against the analytical anisotropic Algorithm (AAA), the collapsed cone convolution superposition Algorithm (CCCS) and Monte Carlo (MC) Calculations for the same geometries. Methods and Materials: Small open fields ranging from 1 × 1 cm2 to 5 × 5 cm2 were used for part of this study. The fields were incident on phantoms containing lung, air, and bone inhomogeneities. The dosimetric accuracy of Acuros XB, AAA and CCCS in the presence of the inhomogeneities was compared against BEAMnrc/DOSXYZnrc Calculations that were considered as the benchmark. Furthermore, two clinical cases of arc deliveries were used to test the accuracy of the dose Calculation Algorithms against MC. Results: Open field tests in a homogeneous phantom showed good agreement between all dose Calculation Algorithms and MC. The dose agreement was +/?1.5% for all field sizes and energies. Dose Calculation in heterogenous phantoms showed that the agreement between Acuros XB and CCCS was within 2% in the case of lung and bone. AAA Calculations showed deviation of approximately 5%. In the case of the air heterogeneity, the differences were larger for all Calculations Algorithms. The Calculation in the patient CT for a lung and bone (paraspinal targets) showed that all dose Calculation Algorithms predicted the dose in the middle of the target accurately; however, small differences (2% - 5%) were observed at the low dose region. Overall, when compared to MC, the Acuros XB and CCCS had better agreement than AAA. Conclusions: The Acuros XB Calculation Algorithm in the newest version of the Eclipse treatment planning system is an improvement over the existing AAA Algorithm. The results are comparable to CCCS and MC Calculations especially for both stylized and clinical cases. Dose discrepancies were observed for extreme cases in the presence of air inhomogeneities.
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SU‐E‐T‐707: Clinical Evaluation of a New Commercial Dose Calculation Algorithm
Medical Physics, 2011Co-Authors: Carlos Esquivel, Sotirios Stathakis, C. Sath, Alonso N. Gutierrez, J. Dorward, Dimitris Mihailidis, Panayiotis Mavroidis, Nikos PapanikolaouAbstract:Purpose: A new Algorithm, Acuros® XB Advanced Dose Calculation, has been introduced by Varian Medical Systems in the Eclipse planning system for photondose Calculation in external beam radiotherapy. Acuros XB is based on the solution of the linear Boltzmann transport equation (LBTE). In this study we perform a clinical evaluation of the Acuros XB by comparison to other known and tested treatment planning systems and dose Calculation Algorithms. Methods: Twenty (n=20) patients previously planned with the Pinnacle ver.9.0 treatment planning system and calculated using the collapsed cone convolution superposition Algorithm, were recalculated using the Eclipse ver. 10.0 with the Acuros XB dose Calculation Algorithm. A mixture of treatment sites were chosen, including brain,lung,liver, and pelvis. The metrics chosen for the evaluation were DVH, absolute dose difference, and profiles along the axial, sagital and coronal planes at the isocenter Results: Good agreement was observed between the dose Calculations with Acuros and the ones from Pinnacle using the CCCS Algorithm. Differences were mostly detected in inhomogeneous media. Maximum differences of 2.5% were observed for lung patients, while, smaller differences were detected for pelvic, brain, and abdominal cases. Conclusions: The new dose Calculation Algorithm Acuros XB available in Eclipse ver. 10 is in very good agreement with the widely tested and accepted CCCS dose Calculation Algorithm. More extensive testing of the Algorithm might be necessary in order to further evaluate the accuracy of the Calculations.
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SU‐E‐T‐702: Accuracy of a Commercially Available Dose Calculation Algorithm for Small Field Dosimetry
Medical Physics, 2011Co-Authors: Sotirios Stathakis, Carlos Esquivel, Alonso N. Gutierrez, Dimitris Mihailidis, Panayiotis Mavroidis, C. Buckey, P. Myers, Nikos PapanikolaouAbstract:Purpose: To validate the AcurosXB dose Calculation Algorithm for small field dosimetry for high energy photon beams. Methods: Calculations in water phantom of 0.2×0.2×0,2cm3 voxel size with slabs of inhomogeneity materials (air rho=0.0012g/cm3, lung rho =0.2 g/cm3 and bone rho =1.85 g/cm3) were used in this study. Fields sizes ranging from 1×1cm2 to 10×10cm2 and energies of 6, 10 and 18MV were calculated using the Acuros XB dose Calculation Algorithm available in the Eclipse treatment planning system (TPS). The Calculations were compared to the Analytical Anisotropic Algorithm (AAA) also available in Eclipse as well to Collapsed Cone Convolution Superposition (CCCS) Algorithm available in the Pinnacle3 TPS. Comparison between the dose Calculations and Monte Carlo Calculations using EGSnrc\BEAMnrc and EGSnrc\DOSXYZnrc package was also performed. Results: The AcurosXB Calculation Algorithm was in general in good agreement with Monte Carlo Calculations. Discrepancies were observed at the interfaces of the inhomogeneities. Good agreement between CCCS and AcurosXB was also observed for the majority of the cases with discrepancies observed only at the interfaces of the media. The AAA did not successfully calculate the dose for the test geometries when small fields were used. Discrepancies in the order of 50–70% were observed. The AAA overestimated the dose in the low density material and failed to predict the second buildup region accurately for the very small field sizes. Conclusion: In general, the overall degree of accuracy for AcurosXB in the conditions of electronic disequilibrium was in good agreement with Monte Carlo Calculations (within 2%) and comparable with the CCCS Algorithm. The AAA on the other hand failed to accurately predict the dose for the small fields studied in the presence of inhomogeneities
Carlos Esquivel - One of the best experts on this subject based on the ideXlab platform.
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Accuracy of the Small Field Dosimetry Using the Acuros XB Dose Calculation Algorithm within and beyond Heterogeneous Media for 6 MV Photon Beams
International Journal of Medical Physics Clinical Engineering and Radiation Oncology, 2012Co-Authors: Sotirios Stathakis, Carlos Esquivel, Alonso N. Gutierrez, Panayiotis Mavroidis, P. Myers, Luis Alberto Vazquez Quino, O Calvo, Niko PapanikolaouAbstract:Purpose: The dosimetric accuracy of the recently released Acuros XB advanced dose Calculation Algorithm (Varian Medical Systems, Palo Alto, CA) is investigated for single radiation fields incident on homogeneous and heterogeneous geometries, as well as for two arc (VMAT) cases and compared against the analytical anisotropic Algorithm (AAA), the collapsed cone convolution superposition Algorithm (CCCS) and Monte Carlo (MC) Calculations for the same geometries. Methods and Materials: Small open fields ranging from 1 × 1 cm2 to 5 × 5 cm2 were used for part of this study. The fields were incident on phantoms containing lung, air, and bone inhomogeneities. The dosimetric accuracy of Acuros XB, AAA and CCCS in the presence of the inhomogeneities was compared against BEAMnrc/DOSXYZnrc Calculations that were considered as the benchmark. Furthermore, two clinical cases of arc deliveries were used to test the accuracy of the dose Calculation Algorithms against MC. Results: Open field tests in a homogeneous phantom showed good agreement between all dose Calculation Algorithms and MC. The dose agreement was +/?1.5% for all field sizes and energies. Dose Calculation in heterogenous phantoms showed that the agreement between Acuros XB and CCCS was within 2% in the case of lung and bone. AAA Calculations showed deviation of approximately 5%. In the case of the air heterogeneity, the differences were larger for all Calculations Algorithms. The Calculation in the patient CT for a lung and bone (paraspinal targets) showed that all dose Calculation Algorithms predicted the dose in the middle of the target accurately; however, small differences (2% - 5%) were observed at the low dose region. Overall, when compared to MC, the Acuros XB and CCCS had better agreement than AAA. Conclusions: The Acuros XB Calculation Algorithm in the newest version of the Eclipse treatment planning system is an improvement over the existing AAA Algorithm. The results are comparable to CCCS and MC Calculations especially for both stylized and clinical cases. Dose discrepancies were observed for extreme cases in the presence of air inhomogeneities.
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SU‐E‐T‐707: Clinical Evaluation of a New Commercial Dose Calculation Algorithm
Medical Physics, 2011Co-Authors: Carlos Esquivel, Sotirios Stathakis, C. Sath, Alonso N. Gutierrez, J. Dorward, Dimitris Mihailidis, Panayiotis Mavroidis, Nikos PapanikolaouAbstract:Purpose: A new Algorithm, Acuros® XB Advanced Dose Calculation, has been introduced by Varian Medical Systems in the Eclipse planning system for photondose Calculation in external beam radiotherapy. Acuros XB is based on the solution of the linear Boltzmann transport equation (LBTE). In this study we perform a clinical evaluation of the Acuros XB by comparison to other known and tested treatment planning systems and dose Calculation Algorithms. Methods: Twenty (n=20) patients previously planned with the Pinnacle ver.9.0 treatment planning system and calculated using the collapsed cone convolution superposition Algorithm, were recalculated using the Eclipse ver. 10.0 with the Acuros XB dose Calculation Algorithm. A mixture of treatment sites were chosen, including brain,lung,liver, and pelvis. The metrics chosen for the evaluation were DVH, absolute dose difference, and profiles along the axial, sagital and coronal planes at the isocenter Results: Good agreement was observed between the dose Calculations with Acuros and the ones from Pinnacle using the CCCS Algorithm. Differences were mostly detected in inhomogeneous media. Maximum differences of 2.5% were observed for lung patients, while, smaller differences were detected for pelvic, brain, and abdominal cases. Conclusions: The new dose Calculation Algorithm Acuros XB available in Eclipse ver. 10 is in very good agreement with the widely tested and accepted CCCS dose Calculation Algorithm. More extensive testing of the Algorithm might be necessary in order to further evaluate the accuracy of the Calculations.
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SU‐E‐T‐702: Accuracy of a Commercially Available Dose Calculation Algorithm for Small Field Dosimetry
Medical Physics, 2011Co-Authors: Sotirios Stathakis, Carlos Esquivel, Alonso N. Gutierrez, Dimitris Mihailidis, Panayiotis Mavroidis, C. Buckey, P. Myers, Nikos PapanikolaouAbstract:Purpose: To validate the AcurosXB dose Calculation Algorithm for small field dosimetry for high energy photon beams. Methods: Calculations in water phantom of 0.2×0.2×0,2cm3 voxel size with slabs of inhomogeneity materials (air rho=0.0012g/cm3, lung rho =0.2 g/cm3 and bone rho =1.85 g/cm3) were used in this study. Fields sizes ranging from 1×1cm2 to 10×10cm2 and energies of 6, 10 and 18MV were calculated using the Acuros XB dose Calculation Algorithm available in the Eclipse treatment planning system (TPS). The Calculations were compared to the Analytical Anisotropic Algorithm (AAA) also available in Eclipse as well to Collapsed Cone Convolution Superposition (CCCS) Algorithm available in the Pinnacle3 TPS. Comparison between the dose Calculations and Monte Carlo Calculations using EGSnrc\BEAMnrc and EGSnrc\DOSXYZnrc package was also performed. Results: The AcurosXB Calculation Algorithm was in general in good agreement with Monte Carlo Calculations. Discrepancies were observed at the interfaces of the inhomogeneities. Good agreement between CCCS and AcurosXB was also observed for the majority of the cases with discrepancies observed only at the interfaces of the media. The AAA did not successfully calculate the dose for the test geometries when small fields were used. Discrepancies in the order of 50–70% were observed. The AAA overestimated the dose in the low density material and failed to predict the second buildup region accurately for the very small field sizes. Conclusion: In general, the overall degree of accuracy for AcurosXB in the conditions of electronic disequilibrium was in good agreement with Monte Carlo Calculations (within 2%) and comparable with the CCCS Algorithm. The AAA on the other hand failed to accurately predict the dose for the small fields studied in the presence of inhomogeneities
Tomoyoshi Ito - One of the best experts on this subject based on the ideXlab platform.
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Simple and fast Calculation Algorithm for computer-generated hologram with wavefront recording plane
Optics Letters, 2009Co-Authors: Nobuyuki Masuda, Tomoyoshi Ito, Tomoyoshi ShimobabaAbstract:We present a simple and fast Calculation Algorithm for a computer-generated hologram (CGH) by use of wavefront recording plane. The wavefront recording plane is placed between the object data and a CGH. When the wavefront recording plane is placed close to the object, the object light passes through a small region on the wave recording plane. The computational complexity for the object light is very small. We can obtain a CGH to execute diffraction Calculation from the wavefront recording plane to the CGH. The computational complexity is constant. The total computational complexity is dramatically reduced in comparison with conventional CGH Calculations.
