基于实验与蒙特卡罗模拟法探究125I粒子间剂量衰减  

Monte Carlo simulation and experimental investigation of 125I interseed dose attenuation

作　　者：李志[1] 姜杉[1] 杨志永[1] 白红升 张兴福 

机构地区：[1]天津大学机械工程学院,300072 [2]天津赛德生物制药有限公司

出　　处：《中华放射医学与防护杂志》2015年第5期389-392,共4页Chinese Journal of Radiological Medicine and Protection

基　　金：国家自然科学基金（51175373）;天津市科技支撑重大项目（12ZCDZSYl0600）

摘　　要：目的 研究多颗125I放射性粒子间剂量衰减规律.方法 利用Geant 4软件包进行蒙特卡罗模拟单颗粒子和多颗粒子周围剂量分布,将模拟结果与TG43-U1报告中推荐剂量计算方法所得结果进行对比,并利用实验测得数据验证蒙特卡罗模拟结果.结果 单颗粒子周围剂量分布的蒙特卡罗模拟结果与TG43-U1计算和实验结果差值分别在±3％和±5％以内.多颗粒子的蒙特卡罗模拟结果对比TG43-U1线性叠加结果,粒子间剂量衰减为3.8％ ～ 13.2％,平均剂量衰减为7.2％,实验所得结果与蒙特卡罗模拟结果差值在6％以内.结论 空间中存在多颗放射性125I粒子时,由于粒子间的相互影响导致7％左右的剂量衰减,其最大值可超过13％,在人体组织中剂量衰减值会更大.因此,利用TG43-U1方法进行线性叠加计算临床中的剂量分布不够精确.Objective To investigate the interseed dose attenuation for multiple 125I seeds.Methods Monte Carlo simulation was done by Geant 4 to investigate the dose distribution of single seed and multiple seeds.The results were compared with the dose calculation method from TG43-U1 and examined by experiments.Results The difference of single seed dose distribution between Monte Carlo method and line source model was ±3%.The difference between Monte Carlo method and experiment result was ±5%.The interseed dose attenuation of multiple seeds at the interesting points was 3.8% to 13.2% and the average interseed dose attenuation was 7.2%.The difference of experiment result and Monte Carlo result was less than 6%.Conclusions The interseed attenuation is about 7% and the maximum value may be larger than 13% for multiple seeds.The interseed dose attenuation may be larger in tissue.So it is not accurate to calculate the dose distribution by using TG43-U1.

关 键 词：近距离放疗 125I粒子 剂量衰减 GEANT 4 蒙特卡罗 

分 类 号：R730.55[医药卫生—肿瘤]