北京市放射治疗防护检测结果与分析

目的：了解北京市^192Ir后装治疗机、^60Co治疗机和医用加速器放射治疗设备及场所的防护状况，探讨放疗防护和管理措施，方法：使用SG102X－γ环境剂量率仪、FJ－347A X－γ剂量仪、PTW－UNIDOS放疗剂量仪和水箱等常规检测工具，分别对不同放疗设备的技术性能和安全防护性能进行测量和分析。结果：各放射治疗室外围辐射剂量水平在本底范围波动（个别点除外）；4台加速器的技术指标合格率100％，^60Co治疗机不合格的技术指标主要是治疗床的等中心和辐射半影区；加速器机头和电子轨道以及床面2m圆内泄漏辐率，准直器的透过率、^60Co治疗机贮源泄漏辐射率检测合格率均为100％；各放疗场所防护设施功能正常，结论：经调试后的放疗设备的防护指标满足相应的国家标准，完善放疗场所的防护设施，加强人员的防护培训，提高他们的安全文化素养，是放射治疗安全防护保障的基础。

Analysis and assessment of radiotherapy protection effect in Beijing

Objective To study the protection status of radiotherapy equipments and their measures and management including 192Ir afterloading therapy apparatus, 60Co therapy apparatus and medical accelerator. Methods Measuring and analyzing the technical performance and safety protection measures of various radiotherapy apparatuses by means of general detecting tools such as SG102 X-7 environmental doserate instrument, FJ-347A X-y dose instrument, PTW-UNIDOS radiotherapy dose instrument, water phantom and so on. Results Radiation dose level outside of all radiotherapy rooms fluctuated within the range of background (except for very few points) . The eligibility ratio of technical guidelines of 4 accelerators was 100% . However, the isocenter of treatment couch and radiation penumbra of 60Co therapy apparatus were not eligible. The eligibility ratio of some guidelines of medical accelerators including leakage radiation rate of the head of apparatus, electron track and permeation ration of collimator, even the leakage radiation of Co therapy apparatus in store phases all could grade as 100%. The protection establishment of all treatment rooms could work correctly. Conclusion The protection guidelines of all radiotherapy apparatuses could meet corresponding national standards after debugging properly. It would be the base of radio therapy safeguard to consummate protection establishment, to reinforce protection training on radiation workers so as to improve their attainment of safety culture.