Estimating radiation dose from time to emesis and lymphocyte depletion.

Lymphocyte depletion kinetics and time to emesis have previously been shown to correlate with radiation dose. However, the method for estimating dose from lymphocyte counts was cumbersome, and a tabulation of estimated dose vs. time to emesis published by the International Atomic Energy Agency did not agree well with a regression of data from many (>100) radiation accident cases. The time-to-emesis data have been reanalyzed, and the new regression corroborates the previously published table. Also, dose estimation from post-exposure lymphocyte counts has been simplified and no longer requires serial calculations. Instead, dose can be estimated by a simple table lookup, given the ratio of two lymphocyte counts and the time between blood samples.