The recovery of iron uptake in erythropoietic bone marrow following large field radiotherapy.
Large X-ray fields, such as those used to irradiate major lymph-node areas in the treatment of lymphomas, often irradiate large areas of haemopoietic bone marrow. The absorbed doses received by the marrow are close to the tolerance level. Quantitative scanning of the bone marrow, using 52Fe and a digital whole-body scanner, has been carried out in a series of 22 patients treated by radiotherapy up to nine years previously in order to assess the extent and recovery of their erythropoietic marrow. The results showed large variations from patient to patient; in some patients the iron uptake in the marrow returned to near normal levels in two to three years, while in others the uptake remained suppressed after seven to eight years. The tolerance dose for the bone marrow appeared to be about 1100 ret. There was some evidence of a more rapid recovery of erythropoietic function in males than females, but no evidence to show that age of patient, type of disease or whether chemotherapy had been used influenced the results. Patients who showed a decreased iron uptake in an irradiated region of marrow generally showed a compensating increased uptake in unirradiated regions, which in some cases was associated with anaemia.