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目的:分别根据中、外放射治疗机房辐射屏蔽标准，对低能医用电子直线加速器机房设计方案进行对比，为修订和完善现行国家标准提供参考。方法:按照美国国家辐射防护与测量委员会(NCRP)151号报告、英国电离辐射法规(IRR)17号和国家标准GBZ/T 201，对于一个每日平均治疗125例患者(90%为调强放疗技术)的6 MV X射线医用电子直线加速器机房，分别设计机房屏蔽方案，对比关注点(主束次屏蔽区A、B点、主束主屏蔽区C、D点、侧墙次屏蔽点E、室顶主屏蔽点F和室顶次屏蔽点G)所需的混凝土屏蔽厚度、治疗室内使用面积、室内层高和室顶承重。结果:按照NCRP 151号报告和IRR 17号法规，计算得到的A、B、C、D、E、F和G点所需的混凝土屏蔽厚度分别为79、105、136、166、104、137、76 cm和94、126、183、189、119、175、92 cm。而按照我国标准GBZ/T 201计算得到的相应关注点所需的混凝土屏蔽厚度是最厚的，特别是主束主屏蔽厚度的增加明显，分别为117、133、207、227、121、175、94 cm。与此同时，与NCRP 151号报告计算得到的屏蔽方案相比，治疗室内使用面积、室内层高显著降低，分别减小11.24%和7.13%，室顶承重增加更为明显(25.20%)。结论:与NCRP 151号报告和IRR 17号法规相比，按照我国现行屏蔽标准所推荐的计算方法和评价指标计算得到的屏蔽厚度是最大的，特别是现行国家标准中要求的瞬时剂量当量率评价指标会显著增加主屏蔽区所需的屏蔽厚度。“,”Objective:To calculate and compare the three shielding schemes for a low energy medical linear accelerator according to different Chinese and foreign radiation shielding standards, with a view to provide reference for revising and improving the Chinese national standards.Methods:For a regular bunker with 6 MV X-ray linear accelerator to treat an average of 125 patients (90% with IMRT technology) per day, the corresponding shielding schemes are calculated according to NCRP report 151(America), IRR 17 legislation (British) and Chinese national standard GBZ/T 201, respectively. The concrete shielding thickness required for the points of concern, and their influence on the indoor usable area, the indoor floor height, and the roof load-bearing in each scheme were evaluated and compared.Results:The values of concrete shielding thickness required for points A and B (secondary barrier of the primary wall), C and D (primary barrier of the primary wall), E(secondary barrier of the side wall), F(primary barrier of the roof) and G(secondary barrier of the roof) according to NCRP 151 report and IRR 17 legislation were 79, 105, 136, 166, 104, 137, 76 cm and 94, 126, 183, 189, 119, 175, 92 cm, respectively. The values of concrete shielding thickness according to the Chinese national standard GBZ/T 201 for these points were 117, 133, 207, 227, 121, 175, 94 cm, respectively, significantly higher than the foreign values, especially about the primary beam. At the same time, GBZ/T standard were significantly decreased the indoor usable area and floor height of the treatment room were 11.24% and 7.13%, respectively, less than those calculated under NCRP report 115, especially with the roof load-bearing increased by 25.20%.Conclusions:GBZ/T achieved the thickest shielding requirement, especially, the primary shielding were significantly increased according to the instantaneous dose rate limit required by the current national standard.