四川省7台加速器调强放疗靶体积和危及器官剂量及二维剂量分布验证方法研究  

Verification of doses to PTV and OAR and 2D dose distribution in IMRT for 7 accelerators in Sichuan province

作　　者：刘冉[1] 马桥[1] 刘德明[1] 李长虹[1] 薛娴[2] 罗素明[2] Liu Ran;Ma Qiao;Liu Deming;Li Changhong;Xue Xian;Luo Suming(Institute of Occupational Health and Radiological Health,Sichuan Center for Disease Control and Prevention,Chengdu 610041,China;Key Laboratory of Radiological Protection and Nuclear Emergency,China CDC,National Institute for Radiological Protection,Chinese Center for Disease Control and Prevention,Beijing 100088,China)

机构地区：[1]四川省疾病预防控制中心职业与辐射卫生所,成都610041 [2]中国疾病预防控制中心辐射防护与核安全医学所辐射防护与核应急中国疾病预防控制中心重点实验室,北京100088

出　　处：《中华放射医学与防护杂志》2020年第2期145-149,共5页Chinese Journal of Radiological Medicine and Protection

基　　金：IAEA资助项目(CRP/17821);四川省科技支撑计划项目(2012SZ0179);四川省卫生与计划生育委员会科研课题(16PJ398)。

摘　　要：目的研究用放射性免冲洗胶片(film)和热释光剂量计(TLD)测量调强放射治疗(IMRT)靶体积(PTV)、危及器官(OAR)剂量和二维剂量分布验证方法。方法选择7台医用直线加速器(瓦里安、医科达、西门子),国际原子能机构(IAEA)提供的聚苯乙烯专用模体,经CT扫描,影像传给放射治疗计划系统(TPS)制定治疗计划,能量6 MV X射线束,按治疗计划对模体实施照射。照射后的TLD和胶片邮寄到中国疾病预防控制中心辐射防护与核安全医学所二级标准剂量学实验室测量和估算。结果IAEA要求,对靶体积和危及器官剂量,TLD测量值与TPS计划剂量值的相对偏差应为±7.0%。靶体积结果:5台加速器的的相对偏差在-4.0%~3.4%范围内,符合要求,2台加速器的相对偏差在-7.0%~10.6%范围内,不符合要求。危及器官结果:4台加速器的相对偏差在-5.6%~3.3%范围内,符合要求,3台加速器的相对偏差在-20.8%~11.5%范围内,不符合要求。IAEA要求,二维剂量分布3 mm/3%通过率应≥90%。5台加速器的通过率在91.8%~98.5%范围内,符合要求,2台加速器的通过率分别为45.0%和77.0%,不符合要求。结论用TLD和放射性免冲洗胶片验证调强放射治疗靶体积、危及器官和二维剂量分布通过率,方法可行,可推广大范围运用到质量核查中,也可用于医院内部核查。Objective To study a method for verifying the doses to PTV and OAR as well as the 2D dose distribution arising from IMRT through using radiochromic films and TLDs.Methods Totally 7 medical electronic linear accelerators from Varian,Siemens and Elekta were selected.The polystyrene phantom provided by IAEA was conducted with CT scan.After irradiation with 6 MV X-rays,the TLDs and films were returned to the secondary standard dosimetry laboratory of China CDC for measurement and estimation.Results According to the IAEA requirements,the relative deviations between TLD-measured and TPS-planned values for PTV and OAR doses were both within±7.0%.For PTV,the measured relative deviations for 5 accelerators were in the range of-4.0%to 3.4%,consistent with the IAEA requirements,whereas the values for the other 2 accelerators were in the range of-7.0%to 10.6%,not consistent with the requirements.For OAR,the values for 4 accelerators were in the range of-5.6%to 3.3%,consistent with the IAEA requirements,whereas the values for the other 3 accelerators were in the range of-20.8%to 11.5%,not meeting the requirements.As required by the IAEA,the 2D dose distribution 3 mm/3%pass rate should be higher than 90%.The measured values for 5 accelerators were in the range of 91.8%to 98.5%,consistent with the requirements,whereas the values measured for the other 2 were 45.0%and 77.0%respectively,not meeting the requirements.Conclusions It is feasible for using TLDs and radiochromic films to verify the doses to PTV and OAR and the 2D dose distribution in IMRT.This method should be applied to not only quality verification but also hospital internal audit to the extent possible.

关 键 词：调强放疗 免冲洗胶片 靶体积 危及器官 二维剂量分布 

分 类 号：R730[医药卫生—肿瘤]