Validation of the TOPAS Monte-Carlo Code of the Off-Field Dose of a 6 MV Synergy Linac  

作　　者：Kodjo Joel Fabrice N’Guessan Ibrahima Sakho Bogbé D. L. H. Gogon Kodjo Joel Fabrice N’Guessan;Ibrahima Sakho;Bogbé D. L. H. Gogon(Department of Physics and Chemistry, Faculty of Sciences and Technology, Iba Der Thiam University of This, This, Senegal;International Cancer Center of Dakar, Dakar, Senegal;Department of Physics, Faculty of Sciences and Technology, Flix Houphouet Boigny University of Abidjan, Abidjan, Cte dIvoire)

机构地区：[1]Department of Physics and Chemistry, Faculty of Sciences and Technology, Iba Der Thiam University of This, This, Senegal [2]International Cancer Center of Dakar, Dakar, Senegal [3]Department of Physics, Faculty of Sciences and Technology, Flix Houphouet Boigny University of Abidjan, Abidjan, Cte dIvoire

出　　处：《Journal of Biosciences and Medicines》2024年第7期38-54,共17页生物科学与医学（英文）

摘　　要：The risk of radiation-induced second cancer and the late tissue loss due to Off-field doses in radiotherapy remain a serious concern. Monte Carlo (MC) simulation is currently one of the most accurate methods for calculating these doses. MC simulation model based on the Particle Simulation Tool (TOPAS) has been developed to simulate the off-field dose of an Elekta Synergy linear accelerator (Linac) emitting 6 MV photons. Measurements were taken in a water phantom using an ionization chamber to validate this model. The Percentage Depth Dose (PDD) at the depth of 0.0, 5.0, 10.0 and 15.0 cm from the beam axis for a 10 × 10 cm2 field size was measured and simulated. Off-field dose profiles at the depth of 1.5 (dmax), 5.0 and 10.0 cm for field sizes of 5 × 5, 10 × 10, 15 × 15, and 20 × 20 cm2 respectively were measured and simulated. Comparison of measured and simulated off-field dose values showed a good agreement. The average gamma passing rate of the PDDs and profiles curves for off-field doses were 87.5% and 98.11% respectively. The local dose difference based on the PDD curve between the measured and simulated was less than 6.0 % for all locations. For all field size considered in this study, the average difference between profile curves for off-field dose measured and simulated was 9.1%. PDDs and Profiles curves for off-field dose simulation uncertainties were less than 2.0% and 1.0% respectively. TOPAS-MC simulation model developed is a good representation of our 6 MV Linac Elekta Synergy for assessing off-field dose, which would be the primary cause of some secondary cancers.The risk of radiation-induced second cancer and the late tissue loss due to Off-field doses in radiotherapy remain a serious concern. Monte Carlo (MC) simulation is currently one of the most accurate methods for calculating these doses. MC simulation model based on the Particle Simulation Tool (TOPAS) has been developed to simulate the off-field dose of an Elekta Synergy linear accelerator (Linac) emitting 6 MV photons. Measurements were taken in a water phantom using an ionization chamber to validate this model. The Percentage Depth Dose (PDD) at the depth of 0.0, 5.0, 10.0 and 15.0 cm from the beam axis for a 10 × 10 cm2 field size was measured and simulated. Off-field dose profiles at the depth of 1.5 (dmax), 5.0 and 10.0 cm for field sizes of 5 × 5, 10 × 10, 15 × 15, and 20 × 20 cm2 respectively were measured and simulated. Comparison of measured and simulated off-field dose values showed a good agreement. The average gamma passing rate of the PDDs and profiles curves for off-field doses were 87.5% and 98.11% respectively. The local dose difference based on the PDD curve between the measured and simulated was less than 6.0 % for all locations. For all field size considered in this study, the average difference between profile curves for off-field dose measured and simulated was 9.1%. PDDs and Profiles curves for off-field dose simulation uncertainties were less than 2.0% and 1.0% respectively. TOPAS-MC simulation model developed is a good representation of our 6 MV Linac Elekta Synergy for assessing off-field dose, which would be the primary cause of some secondary cancers.

关 键 词：Radiotherapy Off-Field Dose Secondary Cancer TOPAS-MC Simulation DOSIMETRY 

分 类 号：TL5[核科学技术—核技术及应用]