A code to investigate complex metabolic models for dose calculation.
A code, DOSEDAY/DOSEYEAR, was developed as a research tool for calculating dose in humans from internally deposited radionuclides, using the International Commission on Radiation Protection (ICRP) Publication 30 compartmental scheme as a framework and ICRP Publication 30 values for default compartmental rate constants. This framework can be varied to investigate new rate constants, fractionation, recycling pathways, and other metabolic information. The compartmental model described in ICRP Publication 30 cannot easily be solved analytically; approximate solutions are generally used. The code calculates the numerical solution to a system of 70 simultaneous, stiff differential equations describing the compartmental model. Step sizes for numerical integration were determined internally by the code to insure stability, and a material balance was calculated for comparison with inputs, which provided a self-contained verification system. The code contains modules for calculating activity and decay in each compartment and for converting these values to dose. Using numerical integration techniques allowed researchers to use recycling compartments (i.e., as proposed for I) and to calculate dose over any time period. DOSEDAY/DOSEYEAR calculates dose for inhalation, ingestion, and injection intake pathways. Chronic intake may also be calculated, using a selected equational form to describe intake (i.e., sinusoidal, representing diurnal Rn exposure; linear, representing 1-d exposure to a constant source; etc.). The code is operational on any personal computer which supports compiled BASIC and thus provides researchers with a readily implemented problem-solving tool to investigate metabolic models.