由染色体畸变率计算剂量的方法

ESTIMATION OF DOSE FROM CHROMOSOME ABERRATION RATE

本文介绍了根据正确判读的染色体畸变数估算剂量的有关方法、技巧及相应的BASIC机算程序。讨论了目前国内常规判读方法中存在的漏检可能较大的情况及其防止的措施。对用有照射时间修正因子G的剂量-效应曲线,估算剂量及其置信区间和在(n、γ)混合照射时的剂量估算方法,以及对通过泊松分布参数检验判断低LET辐射局部急性照射并估算其剂量的方法作了较详细的介绍。考察了在混合辐射照射中是否计入n与γ产生的次损伤间的作用对所估剂量造成的差异。对剂量-效应标准曲线的拟合,强调了它作正确的加权拟合,并应与公认值比较;还给出了畸变率y拟合的变导系数σ_y/y随剂量D和照射时间T的变化。 在附录Ⅰ和Ⅱ中,分别给出了按微剂量学双元作用原理对染色体畸变率产额公式的推导和次损伤数随时间的变化过程。附录Ⅲ给出了由两种类型的染色体畸变率估算剂量的方法。 附录Ⅳ给出了一个简单的由畸变率估算剂量的机算程序和另一个包含由畸变率估算剂量和由实验点拟合标准曲线的较完备的机算程序。后者,采用了紧缩的数据贮存技巧,并可按不同参量的顺序主从排队印出结果。在标准曲线的拟合程序中,包括对拟合残差的检验,并能对输入的剂量D和照射时间T给出相应的畸变率及其标准差;还设有产生模拟“实验结果”

In this article, the methods and skills of evaluating dosefrom correctly scored shromsome aberration rate are presented, andsupplemented with corresponding BASIC computer code. The possibility andpreventive measures of excessive probability of missing score of theaberrations in some of the current routine score methods are discussed.The use of dose-effect relationship with exposure time correction factor G inevaluating doses and their confidence intervals,dose estimation in mixedn-γ exposure, and identification of high by nonuniform acute exposure tolow LET radiation and its dose estimation are discussed in more detail.The difference of estimated dose due to whether the interaction betweensubleisoms produced by n and γ have been taken into account is examined.In fitting the standard dose-aberration rate curve,proper weighting ofexperiment points and comparison with commonly accepted values areemphasised, and the coefficient of variation σ_y /y of the aberration rate yas a function of dose and exposure time is given. In appendix I and Ⅱ,the dose-aberration rate formula is derived from dual action theory,andthe time variation of subleisom is illustrated and in appendix Ⅲ,theestimation of dose from scores of two different types of aberations (ofother related score) is illustrated,.Two computer codes are given in appendixⅣ,one is a simple code, the other a complete code, including the fittingof standard curve.The skills of using compressed data storage,and theproduction of simulated adata'for testing the curve fitting procedure arealso given.