医用直线加速器机房辐射屏蔽分析

Analysis of the shielding design for medical linear accelerator room

为评估机房辐射防护水平,依据机器的运行上限参数,运用相关文献报道的计算方法,对X射线初级和次级屏蔽层以及加速器防护门的屏蔽能力进行估算和分析。结果表明:加速器机房四周墙体(除迷路内墙外)和天棚的设计厚度均大于理论计算厚度,表明机房的相应屏蔽层厚度设计可以满足15 MeV X射线加速器的防护标准及选定的剂量管理目标值;此外,机房防护门需增加8.3 mm铅和6.9 cm含硼聚乙烯才能分别满足对X射线和中子的屏蔽要求。

This paper is to evaluate and inspect the protective ability of the shielding walls and door with various thickness against the primary and secondary radiation coming from X-rays transferred by use of a medical accelerator according to the optimized parameters. The result indicates that the calculated thickness of the wall （except labyrinth interior wall） and accelerator facility roof could fit both the protection criterion and desired value of dose management for 15 MeV X-rays. Furthermore, the protective door should be added with a Pb layer of 8.3 mm and a polyethylene containing boron layer of 6.9 cm to meet the shielding requirement of X-rays and neutron, respectively.