In recent years,graphics processing units(GPUs)have been applied to accelerate Monte Carlo(MC)simulations for proton dose calculation in radiotherapy.Nonetheless,current GPU platforms,such as Compute Unified Device Ar...In recent years,graphics processing units(GPUs)have been applied to accelerate Monte Carlo(MC)simulations for proton dose calculation in radiotherapy.Nonetheless,current GPU platforms,such as Compute Unified Device Architecture(CUDA)and Open Computing Language(OpenCL),suffer from cross-platform limitation or relatively high programming barrier.However,the Taichi toolkit,which was developed to overcome these difficulties,has been successfully applied to high-performance numerical computations.Based on the class II condensed history simulation scheme with various proton-nucleus interactions,we developed a GPU-accelerated MC engine for proton transport using the Taichi toolkit.Dose distributions in homogeneous and heterogeneous geometries were calculated for 110,160,and 200 MeV protons and were compared with those obtained by full MC simulations using TOPAS.The gamma passing rates were greater than 0.99 and 0.95 with criteria of 2 mm,2%and 1 mm,1%,respectively,in all the benchmark tests.Moreover,the calculation speed was at least 5800 times faster than that of TOPAS,and the number of lines of code was approximately 10 times less than those of CUDA or OpenCL.Our study provides a highly accurate,efficient,and easy-to-use proton dose calculation engine for fast prototyping,beamlet calculation,and education purposes.展开更多
This study mainly focused on the key technologies,the photon dose calculation based on the Monte Carlo Finite-Size Pencil Beam(MCFSPB)model in the Accurate Radiotherapy System(ARTS).In the MCFSPB model,the acquisition...This study mainly focused on the key technologies,the photon dose calculation based on the Monte Carlo Finite-Size Pencil Beam(MCFSPB)model in the Accurate Radiotherapy System(ARTS).In the MCFSPB model,the acquisition of pencil beam kernel is one of the most important technologies.In this study,by analyzing the demerits of the clinical pencil beam dose calculation methods,a new pencil beam kernel model was developed based on the Monte Carlo(MC)simulation and the technology of medical accelerator energy spectrum reconstruction.which greatly improved the accuracy of calculated result.According to the axial symmetry principle,only part of simulation results was used for the data of pencil beam kernel,which greatly reduced the data quantity of the pencil beam and reduced calculated time.Based on the above studies,the MCFSPB method was designed and implemented by the Visual C++development tool.With several tests including the comparisons among the American Association of Physicists in Medicine(AAPM)No.55 Report sample and the ion chamber measurement of lung-simulating inhomogeneous phantom in clinical treatment plan,the results showed that the maximum error of most calculated point was less than 0.5%in the homogeneous phantom and less than 3%in the heterogeneous phantom.This method met the clinical criteria,and would be expected to be used as a fast and accurate dose engine for clinic TPS.展开更多
<div style="text-align:justify;"> <span style="font-family:Verdana;">The purpose of this study was to evaluate a planning strategy based on Acuros with density override in comparison wi...<div style="text-align:justify;"> <span style="font-family:Verdana;">The purpose of this study was to evaluate a planning strategy based on Acuros with density override in comparison with AAA without and with the override. Ten lung-tumor patients were selected with each PTV size around 2 - 4 cm and were imaged using slow scan, followed by four-dimensional (4D) imag</span><span style="font-family:Verdana;">ing limited to the target. On each phase-specific image, gross tumor </span><span style="font-family:Verdana;">volume (GTV) was contoured. Summed over all phases, an integrated GTV (iGTV) was generated and copied to the slow scan. A treatment plan was created using a dynamic-conformal-arc technique with AAA to prescribe 60 Gy to 95% of PTV (iGTV + 0.5 cm). Each AAA-based plan was regenerated by overriding the density of the setup margin of PTV by GTV density (modeling tumor-position uncertainty). It was also regenerated with Acuros and the override. The three plans were validated in 4D dose to PTV, after similarly overriding PTV density (phase-specific), accurately calculating with Acuros, and summing the phase-specific plans through organ/dose registration. The Acuros-based plan with the override, the AAA-based plan, and the AAA-based plan with the override provided 4D PTV doses of 63.9, 67.9, and 62 Gy at D95%, respectively, averaged over all patients. The override with Acuros and AAA produced lesser 4D doses, closer to the associated 3D doses, respectively, than that without the override, with better conformity and inhomogeneity. With the override in common, Acuros provided a greater dose to PTV than that by AAA. The Acuros with the override, which was more accurate than the AAA without the override, is clinically recommended.</span> </div>展开更多
Objective:To optimize targeted beta therapy for liver lesions in adult male phantom by comparing the efficacy and safety profiles of five different beta-emitting radionuclides:90Y,166Ho,153Sm,47Sc,and 177Lu.Methods:Th...Objective:To optimize targeted beta therapy for liver lesions in adult male phantom by comparing the efficacy and safety profiles of five different beta-emitting radionuclides:90Y,166Ho,153Sm,47Sc,and 177Lu.Methods:This study includes Monte Carlo simulations of the behavioral characteristics of five different beta emitters that have current or potential use in targeted beta therapy.The energy loss of beta particles moving within the material through ionization or chemical processes,the energy transferred to the material,the energy lost by beta particles along the distance traveled within the tissue,and consequently,the stopping power are calculated using the Bethe-Bloch formula.The CSDA(continuous slowing-down approximation)range of beta particles within the tissue is examined using ESTAR and GEANT codes,while the stopping power of the tissue is investigated using FLUKA,ESTAR,and GEANT codes.Tissue dose calculations for the target organ are obtained using the IDAC-Dose2.1 and MIRDcalc simulation programs,using parameters such as absorbed dose per accumulated activity(S-factor)and specific absorbed fraction(SAF).Additionally,dose and flux values are obtained using the PHITS program.Results:The behaviors and dose contribution of beta particles in liver tissue have been addressed in various ways.90Y,which has the highest average beta energy,was observed to provide a higher absorbed dose value in the liver compared to other beta-emitting isotopes,while the lowest absorbed dose was observed with 177Lu.In other organs,it has been observed that 90Y and 47Sc contribute to a higher absorbed dose compared to other betaemitting isotopes.Conclusions:This study emphasizes the complexity and significance of targeted beta therapy optimization.展开更多
基金supported by the National Natural Science Foundation of China (Nos.11735003,11975041,and 11961141004)。
文摘In recent years,graphics processing units(GPUs)have been applied to accelerate Monte Carlo(MC)simulations for proton dose calculation in radiotherapy.Nonetheless,current GPU platforms,such as Compute Unified Device Architecture(CUDA)and Open Computing Language(OpenCL),suffer from cross-platform limitation or relatively high programming barrier.However,the Taichi toolkit,which was developed to overcome these difficulties,has been successfully applied to high-performance numerical computations.Based on the class II condensed history simulation scheme with various proton-nucleus interactions,we developed a GPU-accelerated MC engine for proton transport using the Taichi toolkit.Dose distributions in homogeneous and heterogeneous geometries were calculated for 110,160,and 200 MeV protons and were compared with those obtained by full MC simulations using TOPAS.The gamma passing rates were greater than 0.99 and 0.95 with criteria of 2 mm,2%and 1 mm,1%,respectively,in all the benchmark tests.Moreover,the calculation speed was at least 5800 times faster than that of TOPAS,and the number of lines of code was approximately 10 times less than those of CUDA or OpenCL.Our study provides a highly accurate,efficient,and easy-to-use proton dose calculation engine for fast prototyping,beamlet calculation,and education purposes.
基金the National Natural Science Foundation of China under grant No.30900386&No.81101132the Anhui Provincial Natural Science Foundation under grant No.11040606Q55.
文摘This study mainly focused on the key technologies,the photon dose calculation based on the Monte Carlo Finite-Size Pencil Beam(MCFSPB)model in the Accurate Radiotherapy System(ARTS).In the MCFSPB model,the acquisition of pencil beam kernel is one of the most important technologies.In this study,by analyzing the demerits of the clinical pencil beam dose calculation methods,a new pencil beam kernel model was developed based on the Monte Carlo(MC)simulation and the technology of medical accelerator energy spectrum reconstruction.which greatly improved the accuracy of calculated result.According to the axial symmetry principle,only part of simulation results was used for the data of pencil beam kernel,which greatly reduced the data quantity of the pencil beam and reduced calculated time.Based on the above studies,the MCFSPB method was designed and implemented by the Visual C++development tool.With several tests including the comparisons among the American Association of Physicists in Medicine(AAPM)No.55 Report sample and the ion chamber measurement of lung-simulating inhomogeneous phantom in clinical treatment plan,the results showed that the maximum error of most calculated point was less than 0.5%in the homogeneous phantom and less than 3%in the heterogeneous phantom.This method met the clinical criteria,and would be expected to be used as a fast and accurate dose engine for clinic TPS.
文摘<div style="text-align:justify;"> <span style="font-family:Verdana;">The purpose of this study was to evaluate a planning strategy based on Acuros with density override in comparison with AAA without and with the override. Ten lung-tumor patients were selected with each PTV size around 2 - 4 cm and were imaged using slow scan, followed by four-dimensional (4D) imag</span><span style="font-family:Verdana;">ing limited to the target. On each phase-specific image, gross tumor </span><span style="font-family:Verdana;">volume (GTV) was contoured. Summed over all phases, an integrated GTV (iGTV) was generated and copied to the slow scan. A treatment plan was created using a dynamic-conformal-arc technique with AAA to prescribe 60 Gy to 95% of PTV (iGTV + 0.5 cm). Each AAA-based plan was regenerated by overriding the density of the setup margin of PTV by GTV density (modeling tumor-position uncertainty). It was also regenerated with Acuros and the override. The three plans were validated in 4D dose to PTV, after similarly overriding PTV density (phase-specific), accurately calculating with Acuros, and summing the phase-specific plans through organ/dose registration. The Acuros-based plan with the override, the AAA-based plan, and the AAA-based plan with the override provided 4D PTV doses of 63.9, 67.9, and 62 Gy at D95%, respectively, averaged over all patients. The override with Acuros and AAA produced lesser 4D doses, closer to the associated 3D doses, respectively, than that without the override, with better conformity and inhomogeneity. With the override in common, Acuros provided a greater dose to PTV than that by AAA. The Acuros with the override, which was more accurate than the AAA without the override, is clinically recommended.</span> </div>
文摘Objective:To optimize targeted beta therapy for liver lesions in adult male phantom by comparing the efficacy and safety profiles of five different beta-emitting radionuclides:90Y,166Ho,153Sm,47Sc,and 177Lu.Methods:This study includes Monte Carlo simulations of the behavioral characteristics of five different beta emitters that have current or potential use in targeted beta therapy.The energy loss of beta particles moving within the material through ionization or chemical processes,the energy transferred to the material,the energy lost by beta particles along the distance traveled within the tissue,and consequently,the stopping power are calculated using the Bethe-Bloch formula.The CSDA(continuous slowing-down approximation)range of beta particles within the tissue is examined using ESTAR and GEANT codes,while the stopping power of the tissue is investigated using FLUKA,ESTAR,and GEANT codes.Tissue dose calculations for the target organ are obtained using the IDAC-Dose2.1 and MIRDcalc simulation programs,using parameters such as absorbed dose per accumulated activity(S-factor)and specific absorbed fraction(SAF).Additionally,dose and flux values are obtained using the PHITS program.Results:The behaviors and dose contribution of beta particles in liver tissue have been addressed in various ways.90Y,which has the highest average beta energy,was observed to provide a higher absorbed dose value in the liver compared to other beta-emitting isotopes,while the lowest absorbed dose was observed with 177Lu.In other organs,it has been observed that 90Y and 47Sc contribute to a higher absorbed dose compared to other betaemitting isotopes.Conclusions:This study emphasizes the complexity and significance of targeted beta therapy optimization.
