In-vivo measurements of Pb-210 to determine cumulative exposure to radon daughters: A pilot study

The feasibility of measuring Pb-210 in vivo in the skulls of those individuals who have resided in homes with above average levels of radon/radon daughters, has now been successfully demonstrated. These values, when incorporated into metabolic models of Pb-210 in the body including other related physical parameters, can be used for the calculation of a realistic estimate of a resident's cumulative exposure to radon and its' decay products. Data are presented for 26 subjects exposed to higher than average concentrations of radon i.e. ranging from 10 to 120 pCi/l, for various periods of time. Their skeletal Pb-210 burdens are compared to measurement results of a population of individuals presumed to have been exposed to values which are more representative of average levels i.e. <1pCi/1. Results of a study to determine the biological retention of Pb-210 in the human skeleton for use in the metabolic model relating skull burdens of this nuclide to cumulative radon/daughter exposure, are also described. At the present time, our measurements, made over a period of 10 years, of an individual with a significant Pb-210 burden, indicate a biological half-time of approximately 57 years and an effective half-life of 16 years. 4 refs., 11 figs.