医用直线加速器治疗室中子辐射水平监测结果及分析  

The level of Neutron Radiation of the Medical Electronic Linear Accelerator Treatment Room

作　　者：马桥[1,2] 黄伟旭 刘明哲[4] 刘冉[1,2] 贺良国[1,2] 胡波 张伦[1,2] 刘德明 MA Qiao;HUANG Weixu;LIU Mingzhe;LIU Ran;HE Liangguo;HU Bo;ZHANG Lun;LIU Deming(Sichuan Center for Disease Control and Prevention,Chengdu 610041,Sichuan Province,China;The Center for Radiological Technology Service Quality Control of Sichuan Province,Chengdu 610041,Sichuan Province,China;The Hospital for Occupational Disease Prevention and Control of Guangdong Province,Institute of Radiological Health,Guangzhou 510399,Guangdong Province,China;Provincial Key Laboratory of Applied Nuclear Techniques in Geosciences,Chengdu University of Technology,Chengdu 610059,Sichuan Province,China)

机构地区：[1]四川省疾病预防控制中心,成都610041 [2]四川省放射卫生技术服务质量控制中心,成都610041 [3]广东省职业病防治院放射卫生防护所,广州510399 [4]成都理工大学地学核技术四川省重点实验室,成都610059

出　　处：《职业卫生与病伤》2019年第6期331-335,共5页Occupational Health and Damage

基　　金：国家自然科学基金（项目编号：U19A2086、1274109）;四川省科技计划（项目编号：2019YFS0435）;四川省科技支撑计划项目（项目编号：2012SZ0179）;四川省卫生健康委员会重点科研课题（项目编号：16PJ398）

摘　　要：目的通过对某18MeV医用电子直线加速器治疗室中子剂量率进行监测,了解高能射线出束时治疗室内外中子辐射水平,为中子辐射防护提供依据。方法参照标准GBZ126-2011,利用FH40G-FHT752型中子剂量仪对治疗室内外因高能X射线光核反应产生的中子剂量率进行监测。结果治疗室外中子泄露辐射方面,机房四周屏蔽体、电缆孔和操作位等处测量结果为0.05~0.08μSvh^-1,机房门在未做中子防护时,15MV X射线和9~18 MeV电子射线出束时机房门外中子辐射剂量率为0.40~2.7μSvh^-1;治疗室内,M区和患者测试平面区的中子剂量率测量,距机头由近及远时,辐射剂量率先增高,后降低,距机头0~200 cm范围内,周围剂量当量率为3.67~18.8μSvh^-1;以加速器加速轨道为轴,1 m处360°范围内中子剂量率为20.4~23.4μSvh^-1。结论医用加速器高能射线出束时,治疗室内M区和患者测试平面区的中子辐射水平及机房门的中子辐射防护问题不容忽视。Objective To measure the level of neutron radiation of the medical electronic linear accelerator treatment room so as to understand the characteristics of photonuclear reaction and provide basis for the neutron radiation protection.Methods According to the standard of GBZ126-2011,the FH40G-FHT752 neutron dosimeter was used to monitor the neutron dose rate generated by high energy X-ray photonuclear reaction in the treatment room.Results The measurement results out of the radiation shielding room,computer room,cable shield around the hole and the operating position ranged from 0.05μSvh-1 to 0.08μSvh^-1.When the 15 MV X ray and 9~18 MeV electron beam were launching,the dose rate of outside the door without the protection was 0.40~2.7μSvh^-1.As for the neutron dose rate for M area and patient test plane area of the radiation shielding room,the radiation dose increases first and then decreases when the distance to medical electron linear accelerator was from the near to far.Within the range of 0~200 cm from the accelerator,the dose rate was 3.67~18.8μSvh^-1.Using the accelerating track as the axis,the dose rate was 20.4~23.4μSvh^-1 within 1m around 360°of the aixs.Conclusion The neutron radiation level in the M zone of the treatment room and the test plane zone of the patient,as well as the door in the treatment room,should not be ignored.

关 键 词：医用电子直线加速器 光核反应 韧致辐射 中子 

分 类 号：R146[医药卫生—公共卫生与预防医学]