Quantification of low-level radiation exposure by conventional chromosome aberration analysis

Chromosome dosimetry, in its conventional form largely based on scoring of dicentrics and ring chromosomes in human blood lymphocytes, is the most widely distributed and reliable biological technique in radiological protection to estimate individual whole-body doses of about 100 mGy of low-LET radiation. Attempts to detect and quantify effects even of lower acute doses or protracted and chronic exposures have been repeatedly performed and the results revealed inherent limitations of this approach. Most relevant items, such as extrapolating from high-dose to low-dose effects, the influence of background frequency of dicentrics on the dose estimates, dose accumulation and concomitant temporal decline of the yields of unstable dicentrics or the statistical analyses of the data and their implications for quantifying low-level radiation exposure will be discussed in this report.