^(153)Sm-EDTMP治疗骨转移病例的三维剂量计算——蒙特卡罗和S因子计算方法的比较  

Three-dimensional Dose Calculation of 153Sm-EDTMP in Treating Bone Metastasis——Comparison of Monte Carlo and S Value Calculation Methods

作　　者：陈立新[1] 刘小伟[2] 干峰[2] 唐强[2] 游日安[1] 张伟光[1] 樊卫[1] 

机构地区：[1]华南肿瘤学国家重点实验室 [2]中山大学理工学院,广东广州510275

出　　处：《癌症》2006年第11期1399-1405,共7页Chinese Journal of Cancer

基　　金：广州市重点科技攻关基金(No.2002XZ-J200131);广东省自然科学基金(No.031563);高等学校博士点基金(No.20050558034)~~

摘　　要：背景与目的:个体化核素治疗的三维吸收剂量计算是目前核医学感兴趣的问题。基于三维功能成像和器质成像计算三维吸收剂量,现主要采用S因子计算方法、点源卷积计算方法和蒙特卡罗直接模拟计算方法。本研究比较蒙特卡罗和基于体素的S因子计算方法,探索核素治疗中三维吸收剂量的计算。方法:基于蒙特卡罗程序包EGS4构建的三维剂量计算程序,计算核素153Sm的体素S因子;对1例采用153Sm-EDTMP治疗的鼻咽癌骨转移患者,测量其注射药物0、0.5、2、3.5、5和6h后排尿的核素活度,通过测量数据进行拟合计算其累积活度;结合患者的SPECT/CT联合扫描融合图像,采用直接蒙特卡罗方法和S因子方法进行了三维吸收剂量计算。结果:吸收剂量计算结果表明:蒙特卡罗和S因子两种计算方法所给出的等剂量分布曲线基本相近,剂量分布主要集中在骨组织内。在两种计算方法下,最大剂量点剂量分别为3.92Gy和3.71Gy,相差5%左右。计算区域的剂量-体积直方图显示:D10(10%体积所包括的最高剂量)分别为2.14Gy和2.00Gy,相差7%;D20则分别为0.58和0.51Gy,相差14%左右。总体来说,S因子方法的计算结果相对于蒙特卡罗方法的计算结果小一些。结论:蒙特卡罗和S因子方法都能够基于核医学影像进行核素治疗三维剂量计算,S因子方法计算误差可能稍大,但不失为一种快捷的剂量评估方法。BACKGROUND ＆ OBJECTIVE. Three-dimensional （3D） dose calculation of radionuclide therapy for specified patients is a research interest in nuclear medicine, of which the main methods include S value calculation method, dose point kernel calculation method, and Monte Carlo （MC） simulation method. This study was to compare 3D absorbed dose calculation of ^153Sm-EDTMP in treating a specified patient with bone metastasis between MC and S value methods. METHODS： A 3D dose calculation program was built based on the MC program EGS4, and the S value of nuclide ^153Sm was calculated. For the specified patient with bone metastasis, ^153Sm activity in excreted urine was measured at 0, 0.5, 2, 3.5, 5 and 6 h after injection of ^153Sm-EDTMP. The accumulative activity is calculated by fitting measurement data. Based on the fusion SPECT/CT images of the patient, 3D absorbed dose is calculated by MC and S value methods. RESULTS： The iso-dose distribution curves of MC and S value calculation results were similar, and the dose was mainly collected in the bone. According to the 2 methods, the maximum doses were 3.92 Gy and 3.71 Gy with a difference of 5%. On the dose-volume histogram of the calculation volume, D10 （the highest dose of the 10% volume） were 2.14 Gy and 2.00 Gy with a difference of 7%; D20 （the highest dose of the 20% volume） were 0.58 Gy and 0.51 Gy with a difference of 14%. In general, the data of S value calculation were smaller than the data of MC calculation. CONCLUSIONS： MC and S value could be used to calculate the 3D dose of radionuclide therapy based on nuclear medical image. S value is a fast and simple method for the dose evaluation although the error of the calculation is relatively bigger.

关 键 词：骨肿瘤/继发性 核素治疗 S因子 蒙特卡罗 剂量 

分 类 号：R730.5[医药卫生—肿瘤]