APPLICATION OF EPR TOOTH DOSIMETRY FOR VALIDATION OF THE CALCULATED EXTERNAL DOSES: EXPERIENCE IN DOSIMETRY FOR THE TECHA RIVER COHORT.

This study applies EPR tooth dosimetry for validation of external doses calculated with the TRDS-2016. EPR-based external dose in tooth enamel is calculated by subtraction of the contributions of natural and anthropogenic sources from the exposure of interest. These subtracted terms may contribute substantially to the overall uncertainty of the EPR-derived external dose. The validation method strongly depends on the uncertainties. The current study combines the results of a number of previous papers to propagate the uncertainty of EPR-derived external doses. It is concluded that the overall uncertainties of D ≥ 500 mGy are comparable with measurement uncertainties (≤30%); the overall uncertainties of D < 500 mGy become higher as the EPR-dose decreases because they are strongly effected by all other factors of influence. More than 70% of investigated individuals were exposed externally to doses <100 mGy with uncertainties >100%. Therefore, the validation task can be solved only based on statistical approaches. The validation of the TRDS-2016 predictions demonstrates good convergence of group-averages with EPR-based doses. The method for validation of the uncertainty of TRDS-2016 predictions should be also designed based on statistical approaches.