【摘要】 目的:使用蒙特卡罗方法模拟清华大学自主研制的同源双束医用加速器,为今后研究该设备KV级能量在放射治疗中成像剂量分布奠定基础。方法:(1)借助蒙卡BEAMnrc程序模拟加速器机头得到相空间文件。(2)以该相空间文件为源,使用蒙卡DOSXYZnrc程序计算水模体中百分深度剂量(percent depth dose,PDD)和离轴比(off axis ratio,OAR),采用MATLAB编程提取剂量数据显示于EXCEL。(3)分析蒙卡模拟参数对结果的影响。(4)对比实测调整模拟参数。结果:蒙卡模拟所得水模体中PDD和OAR曲线与实测有很好的吻合,得到加速器机头模型。结论:医用加速器KV级能量蒙卡模拟与高能有明显不同;要得到合适的该加速器蒙卡模型,需要选择合适的电子束能量和电子空间密度分布;该模拟所得加速器模型可用于成像剂量分布等后续研究。更多还原

【Abstract】 Objective:To apply Monte Carlo method in simulating the Homo-Source Dual-Beam medical accelerator developed by Tsinghua University and lay the foundation for future researches on the Accelerator’s KV energy dose distribution in an image-guided radiotherapy procedure.Methods:(1)Using Monte Carlo’s BEAMnrc program for simulating the head of Tsinghua Homo-Source Dual-Beam Medical Accelerator we obtained the Phase Space file which would be used as the source for the next step.(2) Using Monte Carlo’s DOSXYZnrc program we calculated the percent depth dose(PDD) and off axis ratio(OAR),dealt the dose data by MATLAB program and displayed them in EXCEL.(3) Analyzed the impact of the Monte Carlo simulated parameters on the final outcome was analyzed.(4)Compared the PDD and OAR calculated with the measured of identical condition.Results:The PDD and OAR in water phantom simulated using Monte Carlo method were well matched with those measured in the actual experiments and the Accelerator’s Monte Carlo model was achieved.Conclusions:The Accelerator’s Monte Carlo simulated parameters of KV energy are apparently different from that of High-energy.To obtain the accurate Accelerator’s Monte Carlo model,it is important to choose proper electron beam energy and electron space density distribution.The Accelerator’s Monte Carlo model can be used in future researches on the image dose distribution.更多还原