Recovery of CFUc in rat bone marrow after prolonged fractionated irradiation with various total doses

The rate and the degree of recovery of committed precursors of granulocytes and monocytes (CFUc) following long-term fractionated irradiation were a function of a cumulative radiation dose. In rats exposed to doses of 9.7 and 19.4 Gy the number of CFUc of myelokaryocytes and granulocytes of blood reached the control values after 1-3 months. The increase in CFUc of animals exposed to a dose of 29.1 Gy was transient and did not provide the recovery of granulocytopoiesis.