Alpha-hit, cellular dose, cell transformation and inactivation probability distributions of radon progenies in the bronchial epithelium.

A fluid dynamics based model has been used to determine the deposition patterns of inhaled radon daughters in a realistic approach of the bronchial airway geometry. The interaction of the emitted alpha particles with epithelial cells has been analyzed by applying a complex hit probability model (Bronchial Alpha Hit Model). The biological response of the hit cells has been calculated by the Probability-Per-Unit-Track-Length Model, which relates the probability of a specific biological effect to the track length of alpha particles as a function of the particles' LET. The models mentioned above form a complex lung-radon interaction description. The calculations indicate that compared to the average values the transformation and cell killing probabilities are higher at bronchial carinal ridges. In addition, a considerable number of cells possessing a not negligible transformation and cell killing probabilities can also be found in the outer sides of the central zone.