3H-TDR labelling of osteoprogenitor cells after 226RA incorporation in mice.

The time course of 3H-TDR labelling index of osteoprogenitor cells and the doses in endosteum of lumbar vertebra and distal femoral epiphysis were autoradiographically determined in young female mice after single injections of 19.7 and 55.9 micronCi/kg body weight of 226Ra. The selected bone areas were examined in animals killed 2 hours to 28 days after the injection of nuclide. It was ascertained that changes in the relative labelling index are depending on the absorbed doses of alpha radiation. The possible relevance of these experimental findings for the explanation of the osteosarcoma induction and localization is discussed.