快速蒙特卡洛模拟调强放疗剂量计算的研究

Fast Monte Caro simulation for dose calculation in intensity-modulated radiotherapy

目的:提高蒙特卡洛模拟速度并应用于临床调强放疗剂量计算。方法:运用BEAMnrc程序建立Varian_EDGE加速器6 MV FF与FFF模式束流模型,在DOSXYZnrc程序的基础上开发并行运算的Par-DOSXYZnrc(PDMC)剂量计算程序,与SYNCJAWS、SYNCHDMLC组件实现同步调强放疗剂量计算,并利用仿真模体和临床病例对该方法的精确性与运算效率进行评估。结果:PDMC与DOSXYZnrc的剂量分布一致,与加速器测量值的偏差小于1%。PDMC在6核处理器中效率提升10.5倍以上,能够在0.74 h内完成调强放疗剂量计算,其效率随处理器核心数增加而增长。结论:建立的PDMC能保证临床调强放疗病例剂量计算的准确性,同时提高的效率可满足临床调强放疗剂量计算的时间需求。

Objective To improve the speed of Monte Carlo simulation and apply it into the dose calculation in intensity-modulated radiotherapy （IMRT）. Methods Varian_EDGE linear accelerator 6 MV flattening filter and flattening filter free radiation source model were built with the use of BEAMnrc program. Then we developed a software-package PDMC with the foundation of DOSXYZnrc which is combined with SYNCJAWS and SYNCVMLC modules to achieve the synchronous IMRT dose calculation. Finally, the simulation phantoms and clinical cases were used to evaluate the accuracy and calculation efficiency of the proposed method. Results PDMC was in excellent agreement to DOSXYZnrc in terms of dose distributions, and the differences with linear accelerator measurements were less than 1%. The operating efficiency of PDMC implemented on 6-cores CUP had increased by 10.5 times, and the IMRT dose verification was completed in 0.74 h. With the increase of CPU-cores, the calculation efficiency was increasingly improved. Conclusion PDMC can guarantee the accuracy of the dose calculation in IMRT and improve calculation efficiency, satisfying the time requirements for IMRT dose calculation.