Alpha hit frequency due to radon decay products in human lung cells

Purpose: To calculate the hit probabilities by alpha -particles emitted by radon progeny for basal and secretory cell nuclei in the epithelium of the human tracheobronchial tree. Materials and methods: The equilibrium activities on the surface of airway tubes were calculated using the ICRP66 model. The stopping-power and ranges of alpha -particles in tissue were adopted from ICRU49. A semi-analytical method for determining the alpha -particle fluence rate in tissue was appli ed. The distributions of secretory and basal cells throughout the tracheobr onchial tree were as given by Mercer et al. (1991). Results: The probability to hit basal cell nuclei is three-to-four times sm aller than for secretory cell nuclei in the bronchial region (BB), However, the total number of traversed basal cel nuclei is grater because of the la rger volume abundance of basal cells in BB. The total number of secretory c ell nuclei hit in the bronchiolar region (bb) is larger than that in BB bec ause the volume abundance of secretory cells in bb is larger than that in B B. Conclusions: Basal cells are more sensitive to alpha -radiation than secret ory cells. This finding is based on the analysis of the relative number of cell hits and the relative frequencies of lung cancer induction in BB and b b.