The Effectiveness of Low- Dose Versus High- Dose 99m Tc MIBI Protocols for Radioguided Surgery in Patients with Primary Hyperparathyroidism

Abstract

ObjectiveThe aim of this study was to compare the efficacy of low-dose and high-dose Tc-99m methoxy isobutyl isonitrile (MIBI) protocols in intraoperative localization of parathyroid adenomas by means of a gamma probe in patients with primary hyperparathyroidism (PHPT).Patients and methodsThe study included 62 patients with PHPT who were divided into two groups. Group 1 consisted of 32 patients who were injected with a low dose (1 mCi) of Tc-99m MIBI in the surgical suite 10 min before incision. Group 2 included 30 patients who were intravenously administered a high dose (15 mCi) of Tc-99m MIBI 2 h before surgery. With the aid of a gamma probe, intraoperative localization of parathyroid adenomas was performed in both groups of patients who underwent minimally invasive parathyroidectomy. All lesions thought to be parathyroid adenomas were excised and subsequently evaluated histopathologically.ResultsAll parathyroid adenomas in both groups were localized and excised by means of an intraoperative gamma probe. The sensitivity, specificity, and accuracy of low-dose and high-dose Tc-99m MIBI protocols in the intraoperative localization of adenomas in patients with PHPT were 100%.ConclusionIn the light of these findings, we conclude that low-dose Tc-99m MIBI may be preferred to intraoperative identification of parathyroid adenomas by means of a gamma probe in PHPT patients because it appears to be as effective as high-dose Tc-99m MIBI. Moreover, the low-dose protocol does not have the disadvantages of high-dose protocol.