移动式加速器术中放射治疗的辐射防护与安全评价  

Assessment on the radiation protection and safety of Intra-operative radiotherapy (IORT) with a mobile accelerator

作　　者：马永忠[1,2] 万玲[1,2] 娄云[1,2] 李慧娟[1,2] 王宏芳[1,2] 冯泽臣[1,2] 

机构地区：[1]北京市疾病预防控制中心 [2]北京市预防医学研究中心,100013

出　　处：《首都公共卫生》2012年第5期197-202,共6页Capital Journal of Public Health

基　　金：北京市预防医学公益应用研究项目(编号:2012-BJCDC-06)

摘　　要：目的评估移动式加速器术中放射治疗(IORT)的辐射防护与安全状况,为IORT临床应用中的辐射安全提供指导。方法以某医院拟用的1台MOBETRON移动式加速器及其场所为研究目标,确定IORT的工作负荷及场所外围人员的年剂量管理目标值,估算极端情况下IORT室外围的辐射水平和人员所受的剂量,核算IORT治疗场所的辐射屏蔽。结果该IORT治疗室在仅采用相当于普通X射线诊断装置的屏蔽条件下,治疗室外与靶不同距离关注位置的剂量率为:东墙外35～78μSv/h;南墙外89μSv/h,西墙外70～84μSv/h,北墙外75～106μSv/h;IORT室楼下普通治疗室64μSv/h,室顶外围空间为45μSv/h。估算出年累积出束5h时场所外围职业人员的年剂量最高为0.53mSv,公众所受年剂量低于0.1mSv,均满足剂量管理目标值的要求。加速器IORT设备及场所设置有相应的安全联锁、防护设施与管理措施,可有效制约设备运行照射时人员误入和误留IORT室的风险。结论在普通手术室中施行移动式加速器IORT时,在工作负荷极小的条件下采取针对低能辐射的屏蔽防护可达到剂量管理目标要求,但应相对固定IORT场所,并根据工作负荷和剂量率控制要求对治疗室增设相应的屏蔽。Objective To assess the radiation protection and safety of Intra-operative radiotherapy （IORT） with a mobile accelerator, and to provide guidance of radiation safety for clinical application of IORT. Methods A Mobetron mobile accelerator and its working room of a hospital were determined as the research object. After the workloads of JORT and annual dose goals were confirmed, the radiation level surrounding the IORT room and the doses received by the personnel were calculated When the irradiation condition was set in the worst scenarios, In addition, the radiation shielding of IORT room were checked. Results Under the radiation protection of the IORT room being designed as the same shielding structure as the room of an ordinary X-ray diagnostic device, the dose rates were calculated as follows： 35 -78 trSv/h outside east wall, 89 IxSv/h outside south wall, 70 -84 p.Sv/h outside west wall and 75 - 106 μSv/h outside north wall. The maximum rate of the general treatment room below the IORT room was 64 μSv/h and the dose rate of the space above the treatment room was 45 μSv/h. At the same time, it was shown that all the annual doses calculated from 5 h of cumulative beam-on time met the requirement of dose goal for the highest annual dose received by occupational radiation staff were 0.53 mSv, and the annual doses of public were lower than 0. 1 mSv. The radiation safety settings including some corresponding safety facilities, available protection apparatus and effective management measures were employed to prevent operators from entering or staying in IORT room incorrectly. Conclusion The dose management goal of IORT with a mobile accelerator operated in an ordinary operating room could be achieved with infinitesimal radiotherapy workload, but the IORT spot should be fixed and the treatment room should be added with relevant shielding materials in terms of actual workload and controlling requirement of dose rate.

关 键 词：移动式加速器 术中放射治疗(IORT) 辐射防护 辐射屏蔽 

分 类 号：R14[医药卫生—公共卫生与预防医学]