Development of Improved Methods of Dose Reconstruction for Atomic Veterans
D.C. Kocher; A.I. Apostoaei; and J.R. Trabalka (SENES Oak Ridge, Inc.)
This presentation gives an overview of work for the Defense Threat Reduction Agency (DTRA) that was undertaken in response to a review of DTRA's dose reconstruction program for atomic veterans by a National Research Council committee. The main purpose is to provide DTRA with improved methods of estimating credible upper bounds (at least upper 95% credibility limits) of radiation doses to atomic veterans for use by the Department of Veterans Affairs (VA) in adjudicating claims for compensation for cancers. We generally evaluate uncertainty in dose assessment models using probability distributions of model parameters to represent their uncertainty and Monte Carlo sampling techniques to propagate parameter uncertainties and generate probability distributions of model output. Specific areas of work include: (1) an evaluation of options for reporting atomic veterans' doses to facilitate use by the VA of the Interactive RadioEpidemiological Program (IREP) to estimate upper 99% credibility limits of probability of causation (PC) of cancers; (2) development and evaluation of models to estimate contamination of skin and clothing by descending or resuspended fallout or by contact with contaminated ground or other surfaces and resulting electron doses to skin; (3) an analysis of potential effects of fractionation of radionuclides in fallout on estimates of dose from inhalation or ingestion or from external exposure to contaminated ground; (4) an analysis of uncertainty in estimates of inhalation dose in scenarios involving resuspension of previously deposited fallout by the blast wave produced by a nuclear detonation; (5) development of screening doses corresponding to a PC of 50% at the upper 99% credibility limit for all cancers considered in IREP to facilitate streamlining of dose reconstructions; and (6) development of tools to communicate information to atomic veterans on radiation risk, PC, and use of dose estimates in adjudicating claims for compensation.