RESUMO
OBJECTIVE: The aim of this study was to compare the efficacy of low-dose and high-dose (99m)Tc 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 METHODS: The 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 (99m)Tc MIBI in the surgical suite 10 min before incision. Group 2 included 30 patients who were intravenously administered a high dose (15 mCi) of (99m)Tc 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. RESULTS: All 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 (99m)Tc MIBI protocols in the intraoperative localization of adenomas in patients with PHPT were 100%. CONCLUSION: In the light of these findings, we conclude that low-dose (99m)Tc 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 (99m)Tc MIBI. Moreover, the low-dose protocol does not have the disadvantages of high-dose protocol.