The use of thallium-201 and technetium-99m subtraction scintigraphy for the localisation of parathyroid adenomas.

Parathyroid adenomas account for approximately 85% of cases of primary hyperparathyroidism. Several preoperative localisation techniques exist to aid the surgeon during neck exploration, with varying degrees of success. We report on the results of a modification of the established technique of thallium and technetium subtraction scintigraphy. The operative findings of 60 patients undergoing neck exploration for parathyroid adenoma were correlated with preoperative thallium and technetium subtraction scintigraphy scans. The radio-isotopes were administered in the reverse order to conventional administration, resulting in enhanced imaging. The adenomatous glands were correctly localised in all cases. The 100% sensitivity of this modified scanning technique supports a strategy of unilateral scan-directed neck exploration.