[sup 222]Rn alpha dose to organs other than lung

Description/Abstract

The alpha dose to cells in tissues or organs other theft the lung has been calculated using the solubility coefficients for [sup 222] Rn measured in human tissue. The annual alpha dose equivalent f rom [sup 222] Rn and decay products in most tissues is a maximum of 30% of the annual average natural background dose equivalent (1 mSv) for external and internally deposited nuclides. The dose to the small population of lymphocytes located in or under the bronchial epithelium is a special case and their annual dose equivalent is essentially the same as that to basal cells in bronchial epithelium (200 mSv) for continuous exposure to 200 Bq M[sup [minus]3]. The significance of this dose is uncertain because the only excess cancer observed in follow up studies of underground miners with high [sup 222] Rn exposure is bronchogenic carcinoma.