Another challenge in dose reconstructions for atomic veterans is that some of the models and supporting data used to estimate dose, especially in cases of intakes of radionuclides by inhalation or ingestion, represent standard assumptions that were developed for purposes of radiation protection. In radiation protection, which is concerned with controlling exposures and evaluating compliance with dose limits for workers or the public, standard models and databases used to estimate internal dose are assumed to apply to everyone, without uncertainty. However, dose reconstructions for atomic veterans focus on estimating actual doses to specific persons. It is important that uncertainties in standard models used in radiation protection be acknowledged and properly taken into account in dose reconstructions for specific veterans in the context of a compensation program.
Regulations governing the NTPR program specify that the veteran will be given the benefit of the doubt in estimating dose. Specifically, as stated in 38 CFR 3.102:
When, after careful consideration of all procurable and assembled data, a reasonable doubt arises regarding service origin, the degree of disability, or any other point, such doubt will be resolved in favor of the claimant. By reasonable doubt is meant one which exists because of an approximate balance of positive and negative evidence which does not satisfactorily prove or disprove a claim. It is a substantial doubt and one within the range of probability as distinguished from pure speculation or remote possibility. It is not a means of reconciling actual conflict or a contradiction in the evidence. Mere suspicion or doubt as to the truth of any statements submitted, as distinguished from impeachment or contradiction by evidence or known facts, is not justifiable basis for denying the application of the reasonable doubt doctrine if the entire, complete record otherwise warrants invoking this doctrine. The reasonable doubt doctrine is also applicable even in the absence of official records, particularly if the basic incident allegedly arose under combat, or similarly strenuous conditions, and is consistent with the probable results of such known hardships.
Thus, if there are matters of dispute or a lack of important information about conditions of exposure, plausible assumptions that give the highest estimates of dose should be used in dose reconstructions for atomic veterans. It is not intended that doses be estimated on the basis of assumptions that are beyond reason. Rather, as stated above, assumptions should be “within the range of probability as distinguished from pure speculation or remote possibility.” Nonetheless, the need to give the veteran the benefit of the doubt can place considerable demands on the definition of exposure scenarios, the selection of parameter values used in models to estimate dose, and the methods used to account for uncertainty in estimates of dose. The demands are greater if a veteran engaged in unusual activities.