[Thallium scintigraphy of the thyroid as an alternative procedure for the demonstration of functionally silent thyroid tissue].

The efficacy of 201-thallium thyroid scintigraphy in nonvisualization of one or both thyroid lobes on 123I scan was evaluated prospectively in 38 patients with benign thyroid disease. In 17 of the 18 patients with autonomous toxic adenoma (Plummer's disease) the suppressed thyroid tissue was visualized by 201Tl scintigraphy. In one patient this method failed. A further 7 patients had partially decompensated adenomas demonstrated by both 123I and 201Tl scintigraphy. Homogeneous 201Tl uptake was observed in all 9 patients with bilateral subacute thyroiditis and depressed iodine uptake. Likewise, visualization of the thyroid was possible in the 3 patients with iodine blockade. 201Tl scintigraphy of the thyroid has substantial advantages over TSH stimulation and can be performed in all cases with diminished or suspended iodine metabolism.