动态旋转体部伽玛刀辐射剂量学蒙特卡罗模拟研究

摘要

目的:在同一蒙特卡罗(MC)模拟平台上,对不同型号的动态旋转体部伽玛刀辐射剂量学进行MC模拟研究.方法:①根据体部伽玛刀聚焦照射模式,选择代表机型,即OUR-QGD型体部伽玛刀和LUNA全身伽玛刀;②基于EGSnrc分别进行MC建模;③利用EBT3胶片和160 mm有机玻璃球模体测量焦点处剂量分布进行MC模型验证;④利用验证的模型进行剂量学研究.结果:OUR-QGD型体部伽玛刀和LUNA全身伽玛刀的MC模型模拟结果分别与对应的实验测量进行对比,不同准直器条件下,剂量分布半高宽偏差均≤1 mm,MC模拟的输出因子和厂商数据对比,偏差均在±4%之内,并进一步对偏差进行了分析.结论:动态旋转体部伽玛刀辐射剂量学MC模拟研究,基本可以为目前临床使用的不同机型体部伽玛刀的辐射剂量学质量控制提供重要参考和依据.%Objective:To study radiation dosimetry of stereotactic gamma ray radiotherapy system with dynamic rotating of different types on the same platform of Monte Carlo simulation.Methods: 1)OUR-QGD stereotactic gamma ray radiotherapy system and LUNA whole body gamma ray radiotherapy system were selected as the representative model according to the focus mode of stereotactic gamma ray radiotherapy system. 2)MC modeling were implemented based on EGSnrc, respectively. 3)The distributions of dosage at focus were detected by using EBT3 film and 160 mm mode of plexiglass sphere so as to verify MC mode. 4)The relative research of dosimetry was implemented by using the verified mode. Results: The simulation results of the Monte Carlo model of the OUR-QGD stereotactic gamma ray radiotherapy systems and LUNA whole body gamma ray radiotherapy systems were compared with the corresponding result of experimental measurements, respectively. Under the different conditions of collimator, all of the Full Width at Half Maximum(FWHM) deviation of the dose distribution was less than or equal to 1 mm. And the result of the comparison between output factor of MC simulation and data from manufactory revealed that all of deviation were in ±4%, and the deviations were further analyzed.Conclusion: The research of Monte carlo simulation of radiation dosimetry about stereotactic gamma ray radiotherapy system with dynamic rotation can provide important reference and basis for quality control of radiation dosimetry of stereotactic gamma ray radiotherapy system of different type in clinical application at present.