PRELIMINARY EXPERIENCE WITH DOUBLE-PHASE SPECT USING TC-99M SESTAMIBIIN PATIENTS WITH HYPERPARATHYROIDISM

Background. There is a continual search for a better imaging modality for parathyroid pathology, In recent years, Tc-99m sestamibi has been proposed as an alternative to TI-201 for parathyroid scintigraphy, The purpose of this study is to assess the usefulness of a double-phase T c-99m sestamibi SPECT technique for parathyroid imaging, Methods. Sixt y-one consecutive patients with hyperparathyroidism were studied, Sixt een had previously undergone unsuccessful surgery for hyperparathyroid ism. SPECT imaging of the neck and chest was performed at 15 minutes a nd again at 2 hours after 20-25 mCi of Tc-99m sestamibi was given intr avenously, A positive scan was defined as a region of increased focal uptake that persisted on the delayed images. Results. When compared wi th surgical findings, double-phase sestamibi SPECT correctly identifie d 55% (26/47) of the parathyroid adenomas in the previously unoperated group, and 91% (10/11) of the parathyroid adenomas in the reoperative group, Double-phase sestamibi SPECT was negative in 92% (109/118) of the normal parathyroid glands in the previously unoperated group, and in 88% (15/17) in the reoperative group, Conclusions. These preliminar y data suggest that double-phase Tc-99m sestamibi SPECT is a promising procedure for the preoperative detection and localization of hyperfun ctioning parathyroid tissue, especially in patients with recurrent or persistent postoperative hyperparathyroidism.