某医院直线加速器机房防护门改造实例分析

目的 改造直线加速器机房防护门,降低防护门外的中子辐射剂量水平,减少对人员的危害。方法 根据理论计算的结果,在原防护门防护材料的基础上增加聚乙烯防护材料,以减少门外的中子辐射。结果 增加聚乙烯材料之前防护门外30 cm处的中子辐射剂量水平为2.54~3.83 μSv/h,防护门改造之后防护门外30 cm处的中子辐射剂量水平低于仪器探测下限。结论 对电子标称能量大于10 MeV的医用电子直线加速器进行防护门的设计时需要考虑中子的危害,富含低原子序数的材料适用于对中子的屏蔽。

Example Analysis of the Linear Accelerator Protective Door Reconstruction of A Hospital

Objective To reconstruct the door of linear accelerator room for reducing the outside dose level of neutron shield door to reduce the harm to people. Methods According to the theoretical calculation results, to increase polyethylene based on the original door protection materials to reduce the neutron radiation outside. Results Prior to addition of polyethylene materials, neutron radiation dose level outside the door at 30cm were 2.54~3.83 μSv/h. After the reconstruction of the shield door, neutron radiation dose level outside were below the instrument detection limit. Conclusion When the electron nominal energy greater than 10 MeV, design of door of medical electron linear accelerator must consider the reduce of thought about the harm of neutron, materials with low atomic number were suitable for the neutron shielding.