The usefulness of Tc-99m tetrofosmin scintigraphy in the diagnosis and localization of hyperfunctioning parathyroid glands

Purpose: The aim of the work was to study the diagnostic value of Tc-99m te trofosmin to localize anomalous parathyroid glands in patients with hyperpa rathyroid disease. Methods: We studied 31 patients, 19 with primary and 12 with secondary hype rparathyroid disease. Five of these patients were renal graft recipients. A ll patients underwent surgery. Each patient was injected with 555 to 740 MB q (15 to 20 mCi) Tc-99m tetrafosmin. Subsequently, radionuclide images were acquired 15 and 120 minutes after injection using a low-energy, all-purpos e, parallel-hole collimator. Pertechnetate thyroid scintigraphy was obtaine d in nine cases (24 to 48 h later) when the thyroid activity made it diffic ult to identify the parathyroid glands. Results: All cases showed tracer uptake as early as 15 minutes after inject ion. In the group of patients with primary hyperparathyroid disease, 15 sho wed focal uptake in a parathyroid gland, and surgery revealed an adenoma in the same location. In one patient with hyperplasia, scintigraphy identifie d only two of four diseased glands. In the three remaining cases, scintigra phy showed focal uptake in the lower parathyroid gland, whereas at surgery the abnormal gland was located in the upper pole. In the secondary hyperpar athyroidism group, seven patients showed diffuse tracer uptake in two or mo re glands, and histologic analysis confirmed hyperplasia in all of them. Fi ve cases showed focal uptake, with three evaluated after surgery (uptake in the only remaining gland); one of them was a renal graft recipient, and th e remaining patient had chronic renal failure and was receiving hemodialysi s. Conclusions: Our results suggest that Tc-99m tetrofosmin may be a suitable tracer for preoperative detection and screening of anomalous parathyroid gl ands. The earlier images at 15 minutes were better than those at 120 minute s. Tc-99m tetrofosmin is; cleared more slowly from the normal thyroid than is Tc-99m sestamibi, and both of these tracers may give better results than the old pertechnetate Tl-201 subtraction technique.