In-111-pentetreotide scintigraphy in the detection of insulinomas: Importance of SPECT imaging

The aim of this study was to determine whether the systematic use of SPECT can increase the reported low sensitivity of somatostatin receptor scintigr aphy (SRS) in detecting insulinomas. Methods: Fourteen patients were evalua ted. After In-111-pentetreotide injection (similar to 250 MBq intravenously ), abdominal SPECT images were obtained at 4 h and multiple planar images w ere obtained at 4 and 24 h. MRI and CT were performed within 1 mo of SRS, S ixteen tumors were histologically verified after surgery in 14 patients. Re sults: SPECT revealed 14 lesions in 12 patients (sensitivity, 87.5%), both planar SRS and MRI revealed 7 tumors in 7 patients (sensitivity, 43.8%), an d CT revealed only 5 lesions in 4 patients (sensitivity, 31.3%). Moreover, in 4 patients SPECT was the only examination with positive findings. Conclu sion: SPECT at 4 h is mandatory for preoperative detection of insulinomas u sing SRS because the images are more sensitive than planar images and are s uperior to images from other conventional methods.