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 beavy 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.