Bayesian estimation of dose-rate effectiveness factors

A Bayesian statistical method was developed to estimate the parameters for the following survival model characterized by the probability density f(t,d)=αλ^{α&iotaα-1&e&rho&betade-(λ&iota)αe&rho&betad} Computer programs were developed in "Mathematica" (10) to calculate the posterior densities for the model parameters α, &beta, λ, and &rho. The data used in the analyses came from BALB/c female mice exposed to ¹³⁷Cs gamma radiation (5,6). The doses ranged from 0 to 2 Gy with dose rates from 0.083 Gy/day to 0.4 Gy/min (5,6). The data were generated at the Biology division of Oak Ridge National Lab (ORNL) and supplied by ORNL and the National Radiobiology Archives. The parameter &rho describes the effect of dose-rate on the induction of cancer in mice. The derived posterior density for p describes the remaining uncertainty about the parameter after updating. This thesis describes the first direct estimation of a dose-rate effectiveness factor (DREF) using the techniques of Bayesian parameter estimation and gives the first quantitative description of the uncertainty of this factor in terms of a probability density.