微型电离室测量多叶准直器小野输出因子方法研究  

Research on the measurement method of micro ionization chamber for small field output factor of MLC

作　　者：罗素明[1] 何志坚[1] 袁继龙[1] 杨春勇[2] 刘冉[3] 孙刚涛[4] 胡传朋 张乙眉[2] 马桥[3] 周文珊[4] 贾陈志 LUO Su-ming;HE Zhi-jian;YUAN Ji-long(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;不详)

机构地区：[1]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 [2]江苏省疾病预防控制中心,江苏南京210009 [3]四川省疾病预防控制中心,四川成都610041 [4]湖北省疾病预防控制中心,湖北武汉430079 [5]河南省职业病防治研究院,河南郑州450052

出　　处：《中国医学装备》2020年第8期46-51,共6页China Medical Equipment

基　　金：国际原子能机构资助项目(CPR/17821)“放射治疗剂量与复杂先进技术质量控制方法研究”。

摘　　要：目的:对A16型微型电离室和60019型宝石微型电离室在测量多叶准直器(MLC)小野输出因子的方法进行研究。方法:选择江苏、湖北、四川、河南4省区27家医院的28台不同型号加速器,采用A16型微型电离室和60019型宝石微型电离室对其进行测量,将两种电离室分别放入水下10 cm,源皮距离(SSD)为100 cm,MLC形成照射野6 cm×6 cm、4 cm×4 cm、3 cm×3 cm和2 cm×2 cm,每个野照射监督单位为300 MU,分别计算每个野输出因子,并与国际原子能机构(IAEA)推荐的出版输出因子3 cm×3 cm和2 cm×2 cm小野时的相对偏差±2.0%和±3.0%进行比较。结果:照射野为3 cm×3 cm时,28台加速器中A16型微型电离室和60019型宝石微型电离室测量与国际出版输出因子相对偏差均为0.1%~2.5%,A16型微型电离室测量3台西门子加速器为0.1%~0.9%,11台瓦里安加速器为-0.1%~2.2%,14台医科达加速器为0.1%~2.5%;60019型宝石微型电离室测量3台西门子加速器为0.1%~1.0%,11台瓦里安加速器为-0.2%~2.5%,14台医科达加速器为0.1%^-1.8%。照射野为2 cm×2 cm时,28台加速器中A16型微型电离室和60019型宝石微型电离室测量相对偏差均为0.1%^-2.2%;A16型微型电离室测量3台西门子加速器为0.5%~3.0%,11台瓦里安加速器为-0.2%^-2.2%,14台医科达加速器为0.0%~2.2%;60019型宝石微型电离室测量3台西门子加速器为0.1%~0.5%,11台瓦里安加速器为0.1%^-2.1%,14台医科达加速器为0.0%~2.2%,均符合IAEA要求。结论:A16型微型电离室和60019型宝石微型电离室测量的有效灵敏体积小,适合用于调强放射治疗MLC形成的小野输出因子,数据准确且测量方便,电离室无需刻度,是测量MLC小野首选电离室。Objective: To research the measure method of A16 micro ionization chamber and the 60019 gem micro ionization chamber for output factor of small field of multi-leaf collimator(MLC). Methods: 28 accelerators of different models were selected from 27 hospitals in Jiangsu, Hubei, Sichuan and Henan provinces, and A16 micro ionization chamber and 60019 gem micro ionization chamber were adopted to implement measure for them. The two kinds of ionization chambers were respectively placed at 10 cm against water surface, and the source skin distance(SSD) was 100 cm, and MLC formed 4 radiation fields included 6 cm×6 cm, 4 cm×4 cm, 3 cm×3 cm and 2 cm×2 cm. And the radiation supervision unit of each field was 300 MU. And the output factor of each field was calculated respectively, and these output factors were compared with relative deviations(±2.0% and ±3.0%) of publication output factors of small fields(3 cm×3 cm, 2 cm×2 cm) which were recommended by international atomic energy agency(IAEA). Results: The relative deviations between measure values of A16 ionization chamber or 60019 gem micro ionization chamber of 28 accelerators and output factor value of international publication were 0.1%-2.5% when radiation field was 3 cm×3 cm. The results of A16 micro ionization chamber indicated that the relative deviation of 3 Siemens accelerators was 0.1%-0.9%, and that of 11 Varian accelerators was-0.1%-2.2%, and that of 14 Elekta accelerators was 0.1%-2.5%. And the results of 60019 gem micro ionization chamber indicated that the relative deviation of 3 Siemens accelerators was 0.1%-1.0%, and that of 11 Varian accelerators was-0.2%-2.5%, and that of 14 Elekta accelerators was 0.1%--1.8%. When the radiation field was 2 cm × 2 cm, the relative deviations both of A16 micro ionization chamber and gem ionization chamber of 28 accelerators were 0.1%--2.2%, and the results of A16 micro ionization chamber indicated that the relative deviation of 3 Siemens accelerators was 0.5%-3.0%, and that of 11 Varian accelerators was-0.2%--2.2%,

关 键 词：微型电离室 多叶准直器(MLC)小野 测量输出因子 国际出版输出因子 

分 类 号：R144.1[医药卫生—公共卫生与预防医学]