Application of high precision EPR dosimetry with teeth for reconstruction of doses to Chernobyl populations

An acute need for reliable dose estimates calls for development and implementation of high precision retrospective dosimetric techniques. Among others, maybe the most preferable approach is EPR dosimetry using tooth enamel as a natural lifetime dosemeter. During the past eight years a vast experience in the field of EPR dosimetry has been accumulated in SCRM. In this research, the main effort was put into providing the highest achievable accuracy and reproducibility of results as well as on reduction of labour intensity for the analyses. The technique developed in SCRM comprises sophisticated sample preparation procedures, analysis of EPR spectra using a Mn2+:MgO spectrometric standard, and individual calibration of dose response for each sample. Methods for taking into account confounding factors (e.g. medical X ray exposure, UV light effects and nonlinearity of dose-response curves) and assessment of overall uncertainty of dose estimation were also developed. A systematic approach to EPR dosimetry of an exposed population also includes efforts on acquisition of teeth from Chernobyl clean-up workers on a national scale. So far, samples from more than 700 individuals have been collected in Ukraine, and doses to more than 300 liquidators have been reconstructed. Application of this EPR dosimetric system allowed verification of Chernobyl dosimetry and provided on-going biomedical research with reliable retrospective dose estimates.