高能医用直线加速器感生放射性辐射场特点和防护研究  

A study of the protection against induced radioactivity from high-energy medical linear accelerator and its characteristics

作　　者：王志斌[1] 向莹[1] 温涵泳[1] 吕扬阳[1] 刀鸿威[1] 

机构地区：[1]中国人民解放军广州军区疾病预防控制中心,广东省广州市510507

出　　处：《职业与健康》2014年第13期1758-1760,共3页Occupation and Health

摘　　要：目的通过现场监测高能医用直线加速器感生放射性辐射场分布及其变化,提出针对性的防护措施。方法模拟放射治疗环境,监测高能医用直线加速器感生放射性随能量、射线类型、出束剂量、照射野面积、距离和时间的变化。结果高能光子线的感生放射性辐射水平随出束剂量的增加而升高(r=0.996,P>0.05);随出束停止时间的增加而迅速下降,5 min下降最快;有随着照射野面积的增大而变小的趋势;没有按照与距离平方成反比的规律衰减。高能电子线的感生放射性在停机后迅速消失。结论放疗工作人员在应用高能加速器对患者进行治疗结束后,只需要对高能光子线产生的感生放射性进行防护;通过缩短给患者摆位的时间、合理推迟进入机房的时间和采取合理安排高低能射线照射方式及加强机房内部通风等措施,尽可能减少感生放射性危害。[ Objective] To find specific measures for protection by monitoring radiation field distribution and variation of induced radioactivity from high-energy medical linear accelerator. [ Methods ] Through simulating the working environment of radiotherapy technician, the induced radioactivity variation of high-energy medical hnear accelerator under different conditions of energy, radiation type, dose, beam field area, distance and time. [ Results ] The induced radioactivity level of high-energy photons was increased with increasing dose （ r = 0.996,P 〉 0.05）, and was decreased with time increase and significantly in first 5 minutes, decreased with beam field area increasing. The induced radioactivity was not influenced by the square of distance. The induced radioactivity of high-energy electrons disappeared rapidly after accelerator shutdown. [ Conclusion ] It is necessary to take measures to protect against the induced radioactivity by high-energy photons after treatment on patients with accelerator. Through shortening the positioning time, delaying entering, reasonable arrangement of high and low radiation machine and effective ventilation, the induced radioactivity can be minimized.

关 键 词：高能医用加速器 感生放射性 辐射防护 

分 类 号：R144[医药卫生—公共卫生与预防医学]