title: Structure of a physiologically based biokinetic model for use in 14C and organically bound tritium dosimetry.
abstract: Physiologically based biokinetic (PBBK) dosimetry models for beta emitters such as 3H and 14C must include rapid turnover compartments which, while they may be minor in terms of dose commitment, can dominate bioassay measurements at early times after intake. In this paper, a consistent PBBK model structure will be described for use in dose assessments for organic 14C and organically bound tritium (OBT), and also for 14CO2, based on the literature of human carbon metabolism, and on direct measurements of human excretion. CO3/HCO3- is a central compartment in carbon metabolism. The 14CO2 biokinetic model described in ICRP Publication 80 for the calculation of dose coefficients was found to omit early components of excretion necessary for the accurate interpretation of bioassay results. Recommendations on the requirements on dosimetry models for intakes of 14C and OBT are made.
authors.affiliation: Radiation Protection Division, Ontario Power Generation, Inc., 700 University Avenue, Toronto, M5G 1X6, Canada. david.whillans@opg.com
authors.forename: D W
authors.initials: DW
authors.lastname: Whillans
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis / Q000493:pharmacokinetics; D001610:Beta Particles; D002250:Carbon Radioisotopes / Q000032:analysis / Q000493:pharmacokinetics* / Q000652:urine*; D003198:Computer Simulation; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D008168:Lung / Q000378:metabolism*; D008954:Models, Biological; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D015203:Reproducibility of Results; D015656:Respiratory Mechanics / Q000502:physiology; D012680:Sensitivity and Specificity; D014316:Tritium / Q000032:analysis / Q000493:pharmacokinetics* / Q000652:urine*
chemical_list: D000396:Air Pollutants, Radioactive; D002250:Carbon Radioisotopes; D014316:Tritium