PREOPERATIVE SCINTIGRAPHIC AND INTRAOPERATIVE SCINTIMETRIC LOCALIZATION OF PARATHYROID ADENOMA WITH CATIONIC TC-99M COMPLEXES AND A HAND-HELD GAMMA-PROBE

Aim: The aim of our study was to evaluate the possibility of in intrao perative scintimetric detection of parathyroid adenomas with Tc-99m la belled tracers for its usefulness in dystopic or ectopic adenomas. Met hods: 12 women with biochemically confirmed hyperparathyroidism were i ncluded in our study. After injection of 370 MBq Tc-99m tetrofosmin e. g. sestamibi, preoperative scintigraphy (double phase study and SPECT) was performed and T/NT ratios were evaluated for early, delayed and S PECT images. Surgery was performed using a hand-held gamma-probe after preoperative injection of 555-925 MBq Tc-99m tetrofosmin e.g. sestami bi. Count rates (cts/10 sec) were measured and used for calculating in situ-and ex situ-T/NT ratios. Results: In 9 out of 12 patients, adeno ma could be detected on static images. Mean T/NT ratios for Tc-99m tet rofosmin were 1.29 for early and 1.23 for delayed images, respectively 1.39 and 1.23 for early and delayed Tc-99m sestamibi scan. Three case s could only be detected with SPECT reconstruction. 11 of 12 parathyro id adenomas could be confirmed intraoperatively. Conclusion: SPECT wit h Tc-99m labelled cationic complexes showed advantages in detection, p recise localization and contrast over static scintigraphy and should t herefore be performed at least in cases with poor or no uptake on stat ic images to avoid failures in detection of deeply sited, dislocated g lands or adenomas with low uptake. Intraoperative localization and con firmation of parathyroid adenoma with Tc-9gm-labelled cationic complex es and a gamma probe is possible and may be useful in case of dys- or ectopic adenoma by influencing surgical approach and operating time.