A METHOD FOR ESTIMATING OCCUPATIONAL RADIATION-DOSE TO INDIVIDUALS, USING WEEKLY DOSIMETRY DATA

Statistical analyses of data from epidemiological studies of workers e xposed to radiation have been based on recorded annual radiation doses . It is usually assumed that the annual doses are known exactly, altho ugh it is generally recognized that the data contain uncertainty due t o measurement error and bias. We propose the use of a probability dist ribution to describe an individual's dose during a specific period and develop statistical methods for estimating this distribution. The met hods take into account the ''measurement error'' that is produced by t he dosimetry system and the bias that was introduced by policies of re cording doses below a threshold as zero. The method is applied to a sa mple of dose histories over the period 1945 to 1955 obtained from hard -copy dosimetry records at Oak Ridge National Laboratory (ORNL). The r esult of this evaluation raises serious questions about the validity o f the historical personnel dosimetry data that are currently being use d in studies of the effects of low doses in nuclear industry workers. In particular, it appears that there was a systematic underestimation of doses for ORNL workers. This may result in biased estimates of dose -response coefficients and their standard errors. (C) 1997 by Radiatio n Research Society.