LOCALIZATION OF NEUROENDOCRINE TUMORS WITH [IN-111] DTPA-OCTREOTIDE SCINTIGRAPHY (OCTREOSCAN) - A COMPARATIVE-STUDY WITH CT AND MR-IMAGING

A wide variety of neuroendocrine tumours express somatostatin receptor s, and can be visualized by radiolabelled somatostatin analogue scinti graphy. To investigate the value of [In-111]-octreotide scintigraphy ( Octreoscan), 48 patients (37 with proven carcinoid, pancreatic endocri ne and medullary carcinoma of thyroid tumours, 11 with neuroendocrine syndromes multiple endocrine neoplasia (MEN-I) and Zollinger-Ellison s yndrome (ZES) were examined with In-111-DTPA-D-Phe(1)-octreotide. Scin tigrams were obtained at 24 and 48 h, and the results were compared wi th CT and magnetic resonance imaging (MRI), Thirty-five of 48 patients had positive [In-111]-octreotide scintigraphy (23/25 (92%) carcinoids , 8/9 (89%) PETs, 4/11 (36%) MEN-I & ZES). Of the 42 lesions located b y conventional imaging techniques, 37 (88%) were also identified by Oc treoscan. Unexpected lesions (40 sites), not detected by CT or MR imag ing were found in 24/48 (50%) patients. [In-111]-octreotide scintigrap hy has a higher sensitivity for tumour detection, and is superior to M R imaging and CT scanning in the identification of previously unsuspec ted extraliver and lymph node metastases. It may also be helpful for t he localization of clinically suspected tumours in patients with MEN-I and ZES.