Abstract
It is assumed that trace amounts of ionic indium-111 are specifically bound to serum transferrin and then in part distributed to the erythroid line in active bone marrow when injected intravenously in the form of 111In-chloride at acid pH. Because of this metabolic manner similar, i f not identical, to iron, 111In-chloride can be used clinically for a bone marrow-imaging agent.
Clinical studies were undertaken in 23 patients with malignant diseases, such as malignant lymphoma, seminoma, esophageal cancer, uterine cervix carcinoma, etc., who were to receive irradiation in the bone marrow of verteblar column. Scintigrams were obtained with a dual probe scanner at 48 hr after injection of 1 mCi of 111In-chloride.
The acute and chronic effects of hematopoiesis of focal irradiation to the bone marrow was evaluated with serial scintigraphic studies. The total number of studies were thirty-one, and the period of examination ranged from 1 month to 5 year following radiotherapy.
These studies have demonstrated that in the irradiated bone marrow the accumulation of indium-111 was markedly inhibited early at 600-1, 000 rads, but that of 99mTc-sulfur colloid not suppressed as yet. These earlier inhibitions of accumulation in the irradiated bone marrow were common phenomenon of all cases, which appears to be coincident with reduction of early precursors at 400-600 rads and complete disappearance of all nucleated cells at 1, 000 cads.
Of 8 cases receiving less than 2, 000 rads to the bone marrow, only two showed recovery of bone marrow-uptake after radiotherapy, while in the remaining 15 cases who received more than 2, 000 rads the irradiated bone marrow-uptake has not as yet recovered.
Thus, practically, it appears that the scintigraphy of bone marrow with 111In-chloride provides a useful measure of hematopoietic elements. The exact distribution for carrier-free ionic indium, however, has not as yet been solved, and there are several differences between the physiology of injected indium and iron. As a consequence, further investigations of metabolism and distribution are needed for clinical application.
