A Comparison between High Ablative Versus Usual Dosages of Iodine-131 in Inducing Hypothyroidism After One Year of Therapy in Hyperthyroid Patients

  • Thamer S Flayyeh
Keywords: hyperthyroidism, ablative dose, RAI-131.


Background: Radioactive iodine-131 therapy is highly effective in treating patients with hyperthyroidism. An ablative dose is preferred by a number of endocrinologists, and, a fixed dose protocol seems to be better than a calculated dose in real practice.

Objective: To check for hypothyroidism in hyperthyroid patients one year after RAI therapy, comparing between the results of high ablative versus usual dosages of RAI-131.

 Methods:  This study included 174 hyperthyroid patients, 101 males and 73 females, divided into 2 groups, the first consisted of 162 patients given a usual fixed dose of RAI while the second consisted of 12 patients given a high fixed ablative dose of RAI. The study lasted about 2 years from August 2000 till July 2002 in the Specialized Centre for Endocrinology & Diabetes, Baghdad.

Results: Out of 162 patients in the first group, 11 patients (6.8%), developed hypothyroidism compared to 4 patients out of 12 (33.3% )  in the second group ( p < 0.05).

 Conclusion: A high ablative dose RAI has a better outcome regarding hypothyroidism than a usual dose, although, endocrinologists have different opinions regarding this issue.