Distribution of the femoral colony-forming cells in 226Ra-injected mice.

Distribution of damage caused by the retained 226-Ra to the femoral haemopoiesis has been studied in mice injected with 0.02 and/or 0.09 muCi of 226-Ra/g. The exocolonizing test and the 59-Fe uptake in recipient spleens have been used. Non-uniform radiation effect has been observed in the bone marrow cellularity as well as in the CFU counts within 10 weeks after nuclide injection. The lowest depression appears in the distal femoral ends. The changes are not so serious in the proximal parts and are only moderate in the shafts. The results have been discussed from several standpoints.