A Comparison of the Response to Injected Radioactive Phosphorus and to X-rays in the Haematopoietic Tissue of Rats

Summary

The radiation response of haematopoietic tissue in rats following the administration of ³²P is compared with the response to acute whole-body x-irradiation in terms of the radiation dose to different tissues, using thick-section autoradiography for measuring the radiation dose to the bone-marrow in the animals treated with ³²P. Changes in the peripheral blood picture and results of ⁵⁹Fe tracer studies in splenectomized and intact rats are presented.

In spite of considerable differences in the conditions of irradiation, a number of similarities in the response of haematopoietic tissue are obtained with these two methods of irradiation. It is suggested that there is little or no dose-rate effect over the range ∼ 30 r/min to ∼ 0·2 rads/min for this tissue. A considerably earlier recovery of erythropoiesis in the spleen after ³²P than after x-irradiation is demonstrated.