Differentiation of Benign From Malignant Nodules by Accumulation of Tc-99m Pertechnetate Using Tl-201 Delayed Scans

摘要

Thyroid carcinoma usually is characterized by a nonfunctioning or "cold" nodule depicted on the Tc-99m scan. Twelve patients with functioning "hot" thyroid nodules underwent thyroidectomy (nine hemithyroidectomies, two nodulectomies, and one subtotal thyroidectomy). Histologic examination revealed that five patients (42) had malignant nodules (papillary carcinoma in two and follicular carcinoma in three). Of the seven patients with benign nodules, five had follicular adenoma and two had adenomatous hyperplasia. Tl-201 scanning (early and delayed) was performed at the same time as Tc-99m scanning. Only one of the seven benign nodules showed accumulation on the delayed Tl-201 scan, whereas all five malignant nodules showed accumulation. The delayed Tl-201 scan is useful for the differentiation of benign from malignant nodules that show accumulation of Tc-99m pertechnetate.