医用加速器机房迷路辐射水平的测量与分析

Measurement and analysis of radiation levels in mazes of medical accelerator rooms

目的 通过医用加速器机房迷路内辐射水平的测量与分析,为职业照射的控制提供科学依据,为理论模拟计算积累实验数据.方法 利用剂量率仪测量加速器机房迷路内的辐射水平,并对测量结果进行理论分析.结果 医用加速器机房出入口处杂散X-γ射线剂量率与机头朝向有关.并随照射野的减小而降低;杂散中子剂量率水平主要取决于加速器粒子的能量和输出剂量,随照射野的变化不明显.同时,医用加速器机房出入口处杂散X-γ射线和中子剂量率与医用加速器机房迷路的辐射防护设计密切相关.结论 合理改善医用加速器机房迷路的辐射防护设计是降低医用加速器机房出入口处X-γ射线和中子剂量率水平的行之有效的措施.

Objective To provide scientific basis for occupational exposure controls and to accumulate experimental data for Monte Carlo simulations by means of measuring and analyzing radiation levels in mazes of medical accelerator loom.Methods The radiation levels in mazes of medical accelerator rooms were measured using dose rate meters,and the results were analyzed.Results At room entrances,the dose rate levels of X-γray are related to medical accelerator head orientations and reduced with the decrease of the sizes of exposure fields.They are mainly decided by the energes of accelerated particles and output doses for neutron dose rate levels which change insignificantly with the sizes of exposure fields.They are closely related with radiation protection design of medical accelerator room mazes.Conclusions It is an effective measure of decreasing X-γray and neutron dose rote levels at medical accelerator loom entrances by improving radiation protection design of medical aceelerotor room mazes.