放射性粒子源近距离治疗的Monte Carlo模拟

Monte Carlo simulation of radiated seed source brachytherapy

放射性光子源如103Pd和125I已被广泛用于前列腺和眼睛的植入治疗中。本文使用MCNP4C软件计算美国医学物理学家协会(American association of physicists in medicine,AAPM)推荐的103Pd和125I的剂量学特征。由AAPM推荐的剂量学参量如剂量率常数、径向剂量函数、各项异性函数通过Monte Carlo计算得到,在材料固体水WT1(solid water)中,125I的剂量率常数为0.99,103Pd的为0.682,而在材料Water中,125I剂量率为1.01。与前研究工作者Reners的计算结果相比125I的剂量率一致,而103Pd剂量率和各向异性函数结果相差较大,这些差异是使用不同Monte Carlo代码截面数据引起的。

This work presents calculations of the dosimetric parameters as recommended by the AAPM for 103Pd and 125I seeds widely used for brachytherapy applications such as prostate cancer and eye treatments.The dosimetry parameters dose constant,radial dose function,and anisotropy function recommended by AAPM are calculated using the Monte Carlo method.In WT1,the calculated dose rate constant for 125I is 0.99 and for 103Pd is 0.682.In water,the calculated dose rate constant for 125I is 1.01.These results compare well with previous studies.The agreement for the anisotropy function and the dose rate constant of 103Pd is poorer.The discrepancies may come from the different cross-section data utilized in the different Monte Carlo codes.