INTDOSKIT: An R-Code for Calculation of Dose Coefficients and Studying Their Uncertainties

An R-code, which allows the calculation of the time dependent activity distribution based on ICRP reference models, the number of decays in a commitment period, and the dose coefficients for tissues and organs of the human body, has been developed. R Language was chosen due to its powerful mathematical and statistical modeling features, as well as its graphical capabilities. The developed set of functions and constants (called "INTDOSKIT") can be sourced in R-scripts that define or import the models and calculations to be performed. The code has been tested on models of several radionuclides and was successfully validated against reference data taken from ICRP OIR Data Viewer software. Furthermore, the code has been tested and verified on the modeling of the radioactivity of decay chains using data of the 233 Ra model presented by Höllriegl and colleagues. The results of calculations with INTDOSKIT demonstrated that the code is able to reproduce the ICRP bioassay data and dose coefficients. Deviations are a few percent only and are due mainly to rounding in the original data. Lastly, the code is able to handle uncertainty and sensitivity studies as demonstrated by the results in a pilot study of injection of 241 Am, which estimated geometric standard deviations (GSD) for dose coefficients ranging between 1.25 (bone-surface) and 1.66 (testes); these results are consistent with those obtained from similar studies done by other researchers who reported GSD values ranging from 1.13 to 1.73.