[Place of nuclear medicine methods in thyroid diagnosis]

Since the introduction of precise and easily accessible methods of measuring the level of T4 and T3 in serum, the use of isotopes to assess thyroid function can no longer be advocated. Moreover, the recent growth in knowledge concerning the pathogenesis of thyroid diseases indicates that not even scintigraphic imaging of the thyroid gland contributes substantially to therapeutic decisions in routine situations such as Graves' disease and most euthyroid and hyperthyroid nodular goiters. The use of isotopes in clinical thyroidology should therefore be restricted to the fairly few cases where it is essential for diagnostic and therapeutic decisions, such as, for example, in planning 131I-therapy of postoperative goiter recurrences. A critical review of the indications is presented. Isotopes continue, however, to expand our knowledge of the pathogenesis of thyroid diseases in clinical research.