Microdosimetry of Alpha-irradiated Lung

Abstract

Measurements have been made on the fractions of tissue affected and distributions of energy deposited when rat and human lung are irradiated by alpha particles. Thin sections of alveolar tissue were examined in an image analyser and an imaginary 239PuO2 particle was placed in an alveolar sac. The hypothetical alpha particles were followed to the ends of their tracks so the effects of the material's real structure could be examined in detail. It is shown that a fair comparison exists with results previously obtained with hamster lung. In addition, the measurements actually made with human lung correlate well with predictions based on the rat lung measurements. Finally, it is confirmed that the approximation of a uniform, structureless lung is a poor one.