Dual isotope parathyroid imaging.

Eleven patients who had clinical and biochemical evidence of primary hyperparathyroidism were studied using dual isotope technetium-thallium parathyroid subtraction imaging. The parathyroid scans correctly identified all surgically proven parathyroid adenomas. Three abnormal foci also were identified that were not parathyroid adenomas. These were caused by adenocarcinoma metastatic to a lymph node, primary papillary carcinoma of the thyroid, and parathyroid hyperplasia. This report also demonstrates the importance of surgically examining all abnormal sites of uptake.