Estimated absorbed dose in tissues and radiation effects in Japanese Thorotrast patients

The absorbed dose in the liver, spleen and bone marrow of Thorotrast patients was estimated for 71 autopsy cases. 232Th amounts in tissues were determined from measurements of 228Ac gamma-rays and the activity ratio of 228Ac to 232Th. In calculating the absorbed dose, Kaul's data were used as values of the steady state activity ratio between 232Th and its daughters and the self-absorption of alpha-rays in Thorotrast aggregates. The autopsy cases in which the cumulative dose was estimated consisted of 45 cases of malignant hepatic tumor, 12 cases of liver cirrhosis, 7 cases of blood disease and 7 cases of other diseases. The estimated absorbed doses in the organs were presented and the relationship between the dose and radiation effects on organ tissues was discussed.