OBJECTIVETo determine the radioactivities in parathyroid and near tissues during radioguided parathyroidectomy in patients with hyperparathyroidism and the utility of parathyroidectomy in patients with negative (99m)Tc-sestamibi scans.

METHODSBetween August 2010 and August 2011, 21 patients underwent radioguided parathyroidectomy for hyperthyroidism. The levels of parathyroid hormone (PTH) and serum calcium before and after surgery were detected respectively. In vivo and ex vivo radioactivities in parathyroid and near tissues were examined. According to the radioactivity in parathyroid, the patients were divided into two groups, positive group and negative group. All data was descriptively analyzed and underwent a t test and an analysis of variance.

RESULTSIn all patients both PTH and calcium levels decreased significantly after parathyroidectomy when compared to those before surgery (t' = 17.71 and t = 10.00, respectively, P < 0.001). In vivo and ex vivo radioactivities in enlarged parathyroid glands were higher than those in thyroid and fat tissue (F = 75.25 and 37.81, respectively, P < 0.001). In vivo and ex vivo radioactivities of the enlarged parathyroid with negative sestamibi scans were significantly greater than background radioactivity.

CONCLUSIONSThere are significant differences in (99m)Tc-sestamibi radioactivities among enlarged parathyroid glands, thyroid glands and fat tissues. This radioguided technique is helpful to identify abnormal parathyroid gland in patients with hyperparathyroidism during parathyroidectomy.