Effect of high 131I doses on the bone uptake and retention of 90Sr and 90Y.

The uptake and retention of 90Sr and 90Y in mouse bones after injections of the two nuclides in equilibrium were examined after heavy thyroid irradiations from 131I deposited in the glands. The radiation doses to the thyroid glands as well as the gross doses to the femurs and humeri of the mice were calculated. The radiation destruction of the thyroid tissues had no effect on the bone weights nor on the skeletal metabolism of 90Sr. The uptake of 90Y was, however, depressed after thyroidal irradiation but reached the same bone concentration as 90Sr at about 30 days after the administration of the nuclides, i.e. at a time when the corresponding equilibrium between 90Sr and 90Y in the bones was reached in mice without a thyroidal irradiation.