氚内照射剂量估算方法的讨论

Discussion on dose estimation methods for internal exposure to tritiumm

目的为氚内照射剂量估算方法的选择和方法所适用的工作场景及剂量准确评估提供重要依据。方法比较尿氚浓度监测的2种方法估算待积有效剂量的过程和公式,解释空气氚浓度监测法的局限性,从适用范围、测量方法等方面,对比分析上述方法。结果利用空气氚浓度监测和尿氚浓度监测法估算人员3和10的待积有效剂量大小相反;E(τ)^(1)比E(τ)^(3)高的百分比绝对值的平均数为29.6%,E(τ)^(2)比E(τ)^(3)的值为72.4%,参考人氚剂量估算法的结果与空气中氚浓度监测法计算的结果一致性更好,利用空气氚浓度监测法偏向于低估氚的待积有效剂量。结论建议使用尿氚浓度监测法估算待积有效剂量,不建议使用空气氚浓度监测;采用参考人氚剂量估算法或是尿氚活度浓度积分法,应结合个人代谢情况、工作环境和摄入时间明确与否等多个因素而定,另外应按时、多次采尿样监测。

Objective To discuss the selection of dose estimation methods for internal exposure to tritium,their applicable working scenarios,and accurate dose estimation.Methods We compared the process and formula of two methods of urine tritium concentration monitoring in estimating the committed effective dose,explained the limitations of the atmospheric tritium concentration monitoring method,and compared the three methods from the aspects of the application scope and measurement methods.Results The atmospheric tritium concentration monitoring and urine tritium concentration monitoring methods provided opposite results of the magnitude of the committed effective doses for persons 3 and 10.The mean of the absolute values of the percentages by which E(τ)^(1)values were higher than E(τ)^(3)values was 29.6%,and that of E(τ)^(2)higher than E(τ)^(3)was 72.4%.The consistency between the reference man-based tritium dose estimation method and the atmospheric tritium concentration monitoring method was better.The atmospheric tritium concentration monitoring method tended to underestimate the committed effective dose of tritium.Conclusion We suggest urine tritium concentration monitoring for estimating the committed effective dose,rather than atmospheric tritium concentration monitoring.The use of the reference man-based tritium dose estimation method or urine tritium activity concentration integration method should be based on individual metabolic conditions,working environment,and intake time,and urine sampling should be on time and repeated for monitoring.