Thallium-technetium parathyroid scan. A useful noninvasive technique for localization of abnormal parathyroid tissue.

We studied the usefulness of the thallium-technetium scan in 60 patients with suspected parathyroid disorders. The scan correctly localized abnormal parathyroid tissue in 82% of patients with surgically proved primary hyperparathyroidism due to a single adenoma and in 60% of patients operated on for primary hyperplasia. The scan was particularly useful in patients who had undergone previous neck explorations, since it successfully identified residual adenomatous or hyperplastic tissue in six of seven patients. False-positive images were consistently produced in all patients with coexisting thyroid disease. We conclude that the thallium-technetium scan is useful for localizing abnormal parathyroid tissue. We recommend its routine use in patients with persistent or recurrent hypercalcemia following neck exploration for primary hyperparathyroidism who have no evidence of thyroid disorders.