Radioactive iodine (131I) has been used for half a century and proved effective in treating hyperthyroidism. It is safe, cheap and relatively free from side effects. Iodine-131 is used in most cases of nodular toxic goitre and regarded as the treatment of choice for patients with Graves' disease who do not remit following a course of antithyroid drugs (1, 2). Although large surveys among European (3) and American (4) thyroidologists have disclosed some differences in attitude, this treatment is increasingly used. In fact, many thyroidologists have come to the conclusion that antithyroid drugs aiming at inducing remission of the hyperthyroidism should be reserved for young patients and those with normal or only slightly increased thyroid size. In Denmark this would limit the use of antithyroid drugs—for the purpose of inducing remission—to not more than 25% of the patients with hyperthyroidism (5, 6).
Recently, renewed interest in the treatment of