调强放疗三维剂量验证系统精度测试及临床应用研究  

A clinical test and application research of IMRT 3D dose verification system

作　　者：邢晓汾[1] 褚薛刚[1] 崔桐[1] 郑旭亮[1] 郭瑞嵩[1] 

机构地区：[1]山西省肿瘤医院放射治疗中心,太原030013

出　　处：《中华放射医学与防护杂志》2014年第6期427-430,共4页Chinese Journal of Radiological Medicine and Protection

摘　　要：目的 测试三维剂量验证系统CompassR测量重建及独立计算剂量的精度,评估其临床应用可行性.方法 设计一系列宽度分别为2、1、0.5 cm的条纹状射野,并选取11例肺部调强放疗（IMRT）计划,使用胶片和电离室对被测系统的平面剂量分布和特定点绝对剂量进行验证测试;使用CompassR对IMRT模体计划做基于解剖信息的三维剂量验证,验证体积γ通过率、平均剂量偏差等参数.结果 条纹状射野测试,与胶片测量相比,被测系统重建和计算剂量γ通过率大于90％（选用3％/3 mm、2％/2 mm标准）,宽度为0.5 cm射野在半影区内γ通过率略差,被测系统重建和计算剂量曲线与胶片测量的曲线最大偏离分别3.21％和2.70％;IMRT计划特定点绝对剂量偏差在3％以内,最大偏差发生在肺部,IMRT计划等中心平面测量重建与胶片测量的γ通过率平均为（94.65±1.93）％（选用3％/3 mm标准）;三维剂量验证结果,靶区及危及器官的体积γ通过率均大于90％,平均剂量的偏差＜1％.结论 测试系统剂量精度可满足IMRT计划验证要求,并能给出与患者解剖结构相关的体积剂量误差与位置误差的信息,有利于评估其对临床的影响.Objective To test the accuracy of a three-dimensional dose verification system CompassR,which reconstructing dose distribution based on measurements and independent dose calculation,and to evaluate the feasibility of its application in clinical intensity-modulated radiotherapy （IMRT） quality assure.Methods A set of square-wave chart patterns of 2 cm,1 cm and 0.5 cm gaps was designed and 11 completed IMRT lung plans were selected for the test.EDR2 film and the ionization chamber were used for test and verifying of plane dose distribution and some special points dose of CompassR.The IMRT phantom plans were verified by CompassR with three-dimension based on anatomical information.Parameters including the volume γ pass rate and the average dose deviation were tested using dose volume histograms.Results In square-wave chart patterns test,the dose distribution reconstructed and calculated by CompassR coincided with the measurement using film.The γ pass rates （3%/3 mm,2%/2 mm） exceeded 90%.When the width of field is 0.5 cm,the γ pass rate was a little lower on account of the penumbra zone.Compared to the dose distribution profile which was measured by film,the maximum deviations of the dose distribution profile which was reconstructed and calculated by CompassR were 3.21% and 2.70%.The absolute dose deviation of specific point in the IMRT plans was less than 3%,the maximum deviation occurred in the lung.Compared to film,the averageγpass rates on the isocenter plain in IMRT plan were （94.65 ＋ 1.93）% （3%/3 mm） which was reconstructed by CompassR.In three-dimensional dose verification,the volume γ pass rates of targets and risk organs were not less than 90%,and the deviation of average dose was less than 1%.Conclusions Accuracy of the tested system satisfies the demand of IMRT dose verification.CompassR could provide information of volumetric dosimetry and anatomical location of dose error,which is benefit for evaluating the clinical value of verification result.

关 键 词：调强放疗 质量保证 三维剂量验证 剂量学 

分 类 号：R144[医药卫生—公共卫生与预防医学]