Radioiodine treatment of hyperthyroidism at the Tikur Anbessa Hospital

Thirty-four hyperthyroid patients selected on preset criteria for radioiodine therapy were given low dose radioiodine-131 (I-131) in the Nuclear Medicine Unit of the Tikur Anbessa Hospital as a preferential alternative to repeat or protracted administration of antithyroid drugs, or surgery. The dose chosen was 85 uCi per gram of thyroid tissue based on the 24 hour uptake of a test dose of I-131. The age range of the patients was 18 to 68 years, female to male ratio was 7.5:1 and 80% of the females were in the reproductive age group. Twenty-five patients had multinodular goiter, four had persistent hyperthyroidism after surgery, and five had recurrent Graves' disease. Estimated thyroid gland weight was from 3.5 to 51.4 grams and the amount of I-131 administered was from 0.2 to 4.9 mCi. Only 11 of the 34 patents became euthyroid after a single dose of I-131, 14 required one or more repeat doses and only six of those became euthyroid making a total of 17 (50%) responders. The low dose regimen we used in this study, though economical in a situation of limited I-131 supply, resulted in a high failure rate of 50%. This shows the need to formulate a better dosage scheme that can benefit the majority of patients by optimizing the prospects of the resolution of hyperthyroidism with a single dose of radioiodine.