某医院电子加速器建设项目屏蔽防护分析

Analysis on shielding protection of electron accelerator project in a hospital

目的对某医院电子加速器建设项目屏蔽防护进行职业病危害分析和评价。方法选取广东省某三甲医院电子加速器建设项目作为评价对象,采用451P电离室巡测仪和6150AD6/H+6150AD-n中子巡视仪对直线加速器工作场所进行防护检测。通过理论计算和现场检测两种方法,将所得数据与标准要求进行比较。结果该项目加速器机房外30 cm处周围剂量当量率在0.15~0.95μSv/h,低于限值要求。结合工作人员和公众在机房外各区域居留因子估算得出:工作人员周剂量最大值为1.75μSv;公众周剂量最大值为2.31μSv,均低于标准限值要求。结论该电子加速器建设项目屏蔽防护能满足国家标准要求,在正常情况下发生放射损伤的可能性较小。结合理论计算法和现场检测法共同验证了该医院电子加速器机房屏蔽防护是可行的。同时,也验证了利用理论计算法给出的屏蔽设计方案能从源头上控制射线泄漏。

Objective To analyze and evaluate the occupational disease hazard of the shielding protection of electron accelerator project in a hospital. Methods An electronic accelerator construction project of a thrid level hospital in Guangdong province was selected as the evaluation object. 451P ionization chamber scanning instrument and 6150AD6/H＋615OAD-n neutron patrol instrument were used to detect and protect the workplace of linear accelerator. Data come from both theoretical calculation and field test method were compared with the standard requirement. Results The ambient dose equivalent rate at 30 cm outside the electron accelerator room was 0.15-0.95 txSv/h, which was lower than the standard limit. Combined with regional factor of the staff and the public residence outside the room, it was estimated that the weeks maximum dose of staff and public were 1.75 lxSv and 2.31 ~Sv, which were lower than the standard limit. Conclusion The radiation protection level of the electron accelerator project in the hospital is qualified according to the national standards. The possibility of radiation injury is low under normal operation. Combined with theoretical calculation and field test, it is proved that the shielding of electronic accelerator room in the hospital is feasible. At the same time, it is also proved that the shielding design can be used to control the radiation leakage from the source.