[Imaging of somatostatin receptor using 111In-pentetreotide]

Recently radiolabeled somatostatin analog, [111In]pentetreotide, was developed and its usefulness for the diagnosis and localization of neuroendocrine tumors has been described. In this paper, we reported the results of [111In]pentetreotide scintigraphy in four patients with gastroenteropancreatic endocrine tumors. Two patients with metastatic gastrinoma, one patient with gastric carcinoid, and one patient suspected with gastrinoma, were injected with 119-156 MBq of [111In]pentetreotide. Planar and SPECT images were obtained 4, 24, and 48 hours postinjection. Both primary and metastatic tumors were well visualized in patients with metastatic gastrinoma. Especially in one patient small liver metastases which were not detected by CT or MRI were imaged. We could not obtain positive images in the other two patients. Four-hour or 24-hr images were better than 48-hr images because of higher count density and lower gut activity. No significant adverse effect were seen in any patient. [111In]pentetreotide scintigraphy is a useful procedure for the localization of gastroenteropancreatic endocrine tumors.