Fate of the iodine radioisotopes in the human and estimation of the radiation exposure

Fate of the iodine isotopes and resulting organ exposures have been studied using the four-compartment model proposed by BROWNELL to account for the metabolism of this element. Mathematical equations have been established for this model from biological data accepted in the human. They have been used to calculate the amounts of iodine-131 in the thyroid and in the remaining body as a function of time in case of a single or a chronic contamination; in this latter case three phases have been considered: rise, equilibrium and decrease after removal of the contaminating source. The importance of the daily stable iodine intake from the food has been emphasized. Some of these theoretical results have been checked by experiments on eight volunteers. Calculations have been extended to nine other iodine isotopes in order to determine the exposure doses of the thyroid and the remaining body for a single or a chronic contamination; maximum permissible concentrations in water and in air have also been computed. It appears that some I.C.R.P. recommendations for maximum permissible body burden must be revised. © 1965 Health Physics Society.