title: Use of an isotopic somatostatin receptor probe to image gut endocrine tumors.
abstract: OBJECTIVE
  To evaluate the effectiveness of indium In 111 pentetate (diethylenetriaminepentaacetic acid [DTPA]-D-Phe-labeled octreotide scintigraphy in the localization of gastroenteropancreatic neuroendocrine lesions, and to identify covert lesions, determine multicentricity, define the distribution of metastases, confirm complete removal of tumor postoperatively, and evaluate the efficacy of therapeutic embolization.
  
  
  METHODS
  Unmasked comparison.
  
  
  METHODS
  Tertiary care referral center.
  
  
  METHODS
  We studied 28 patients over a 12-month period. Biochemical evidence of a gastroenteropancreatic tumor was present in 13 patients. Octreoscan 111 was employed in four patients with an ambiguous biochemical diagnosis of gastroenteropancreatic tumor. Postoperative examination to document complete tumor removal was undertaken in seven patients. In one patient, Octreoscan 111 was used to evaluate the efficacy of therapeutic embolization.
  
  
  METHODS
  [111In]DTPA-D-Phe-octreotide scintigraphy.
  
  
  METHODS
  Identification of somatostatin receptor-bearing neuroendocrine tumors.
  
  
  RESULTS
  Intravenous administration of [111In]DTPA-D-Phe-octreotide followed by whole-body gamma camera scintigraphy resulted in the localization of gastroenteropancreatic neuroendocrine tumors with 75% sensitivity, 100% specificity, 100% positive predictive value, 63% negative predictive value, and 82% overall accuracy.
  
  
  CONCLUSIONS
  While Octreoscan 111 has been shown to localize the majority of amine precursor uptake and decarboxylation system (APUD) cell tumors as well as various other somatostatin-positive tumors, this technique may also be useful in a number of other circumstances. These include prediction of tumors that will respond to octreotide therapy, identification of covert metastases, intraoperative identification of tumors, and postoperative surveillance. Use of an alternative isotope may provide a vehicle for the administration of local therapeutic radiation to tumor cells. The precise efficacy of Octreoscan 111 in the identification of lesions smaller than 3 cm with low-density somatostatin-2 receptor expression remains to be determined.
authors.affiliation: Department of Surgery, Yale University School of Medicine, New Haven, Conn, USA.
authors.forename: I M
authors.initials: IM
authors.lastname: Modlin
authors.forename: E
authors.initials: E
authors.lastname: Cornelius
authors.forename: G P
authors.initials: GP
authors.lastname: Lawton
mesh_terms: D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000737:chemistry / Q000000981:diagnostic imaging*; D004379:Duodenal Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging*; D005260:Female; D015408:Gastrinoma / Q000737:chemistry / Q000000981:diagnostic imaging*; D006801:Humans; D007205:Indium Radioisotopes; D007340:Insulinoma / Q000737:chemistry / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000031:analogs & derivatives*; D010190:Pancreatic Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging*; D004369:Pentetic Acid / Q000031:analogs & derivatives*; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000032:analysis*; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging*
chemical_list: D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; C071632:SDZ 215-811; D004369:Pentetic Acid; D015282:Octreotide