Risk Assessment with Subjectively Derived Doses

In situations involving radiation exposure and acute inhalation exposure of chemicals, among others, actual exposure to a target organ is not available. Instead, interdisciplinary teams build complex, often differential equation–based models relating a measure of exposure to actual exposure at a target organ. These complex models are themselves filled with uncertainties, e.g., in transition rates from one site to the next, in environmental measures, etc. The uncertainties then impact analysis of dose–response. Uncertainties can be quantified either subjectively or empirically, but in either case, the result is that the models provide not an actual target–organ dose, but a distribution for this dose. Although many might base analysis on a representative value of the target–organ dose, we argue that the fact that these mechanistic models give a distribution for target–organ dose is easily accommodated in a statistical dose–response analysis.