227Th (α-emitter, half-life 18.7 days) was inhaled by rats from solution in nitrate form. Organ doses were calculated after whole body measurements and measuring of activity concentrations in the organs over a longer incorporation period. An initial deposition of 100 nCi227Th in the lung resulted in mean total doses of 150 rad in lung and 36 rad in bone. The data for kidney and liver were 2 rad and 0.1 rad, respectively.
