The purpose of this work is to study the correlation between the accumulation of 147Pm in bone and its possible mutagenic effect in organism. When given i.v. to male rats

147Pm was selectively localized in skeleton. The retention data in bone were well described by an exponential expression. It caused marked chromosome aberrations in bone marrow cells. There was positive relationship between chromosome aberration rates and the amount of 147Pm administered. Most of the chromosome aberrations induced by 147Pm were of chromatid type. Chromatid deletions were predominant accompanied with a few chromosome aberrations.