Recently, micronuclei scoring has been performed to estimate doses delivered to the lungs after heterogenous irradiation induced after inhalation of radon and its progeny. These studies were limited to the deep lung after either extraction of alveolar macrophages (AM) by lavage (Taya et al., 1994, Johnson and Newton, 1994) or enzymatic dissociation of lung cells to initiate fibroblast cultures (Khan et al., 1994). Dose estimates were performed after comparison with micronuclei formation induced in vitro by irradiation with alpha particles
