三维治疗计划系统计算125I放射性胆道支架表面径向剂量分布  

Calculation of the surface radial dose distribution of radioactive biliary stent loaded with nsI seeds by treatment planning system

作　　者：姚丽红[1] 林蕾[1] 孙海涛[1] 王俊杰[1] 周付根[2] 颜学庆[3] 滕皋军[4] 郭金和[4] 

机构地区：[1]北京大学第三医院放疗科,100191 [2]北京航空航天大学图像中心 [3]北京大学物理学院重离子物理研究所 [4]东南大学附属中大医院放射科

出　　处：《中华医学杂志》2016年第9期727-730,共4页National Medical Journal of China

摘　　要：目的应用计算机三维治疗计划系统计算不同长度125I放射性胆道支架在不同粒子活度下的表面径向剂量分布。方法用有机玻璃和固体石蜡制成实验体模，待支架固定好后，行cT扫描，将扫描图像传入治疗计划系统，制作验证计划，计算支架表面的径向剂量分布。结果支架长度（F=3189．160，P〈0．01）和125I粒子活度（F=811．509，P〈0．01）均可显著影响放射性支架的径向累积剂量分布。径向累积剂量（dose）（Gy）与支架长度（length）（cm）、125I粒子活度（activity）（mCi）和测量点距离支架的中心距离（distance）（cm）满足回归方程：indose=2．565＋0．208length＋1．502activity-0．738distance（F=4929．279，P〈0．05）。结论应根据治疗目的，结合患者病变长度，参照剂量表或拟合公式，选用适合活度的放射性125I粒子。本研究测量结果具有较小的不确定性，可为临床应用提供剂量学参考。Objective To study the surface radial dose distribution of different length radioactive biliary stems in different activity of 125I seeds by treatment planning system. Methods After a radioactive biliary stent was positioned in measurement phantom, which were made of solid paraffin and polymethyl methacrylate, a CT scan was performed to get the stent images. The images were then transferred to the treatment planning system for planning. The maximum dose level slice nearest to the center of the stent was selected to calculate the surface radial dose distribution. Results The length of the stents （F = 3 189. 160, P〈0. 01） and the activity of the 125I seeds （F = 811. 509,P 〈 0. 01 ） can both significantly affect the cumulative radial dose distribution of the radioactive stent. Radial cumulative dose dose （ Gy）, stent length （cm）, 125I seeds activity （mCi） and distance from the stent surface （cm） meet the regression equation： In dose = 2. 565 ＋ 0. 208 length ＋ 1. 502 activity - 0. 738 distance （ F = 4 929. 279, P 〈 0. 05 ）. Conclusions The choice of suitable activity of radioactive 125I should be based on treatment purpose in combination with the length and diameter of lesion and also with reference to the dose table. The measurement results are with smaller uncertainty, which can provide reference for the clinical application of dosimetry.

关 键 词：放射治疗计划 计算机辅助 支架 辐射剂量 

分 类 号：R730.55[医药卫生—肿瘤]