The distribution of Pb-210 in human bone and its impact on methods for the retrospective estimation of Rn-222 exposure from in vivo measurements

Abstract

It is possible to estimate radon exposure to man retrospectively by the in vivo measurement of the decay product Pb-210, which accumulates in the bones. For in vivo methods, knowledge of the distribution of Pb-210 in the skeleton is needed to determine the optimal site for measurement, the skull or the knee. In this study the activity of Pb-210 in a variety of bone samples from 3 individuals have been measured in vitro using underground gamma-ray spectrometry. The individuals were unlikely to have had elevated intakes of Rn. These measurements give baseline data on the bone massic activity of Pb-210. They show that the massic activity is similar for each of these people and there are similar massic activities of Pb-210 in the skull and the knee of the 2 individuals for which the skull was measured. Additionally for 2 of the individuals trabecular and cortical bone were separated and massic activities were found to be strongly correlated indicating that the Pb-210 is associated with the hydroxyapatite. (C) 2004 Elsevier Ltd. All rights reserved.