title: First clinical evidence that imaging with somatostatin receptor antagonists is feasible.
abstract: Preclinical studies have indicated that somatostatin receptor (sst)-expressing tumors demonstrate higher uptake of radiolabeled sst antagonists than of sst agonists. In this study, we evaluated whether imaging with sst antagonists was feasible in patients.
  
  
  METHODS
  Biodistribution and tumor uptake of the sst antagonist (111)In-DOTA-pNO(2)-Phe-c(DCys-Tyr-DTrp-Lys-Thr-Cys)DTyrNH(2) ((111)In-DOTA-BASS) were studied in 5 patients with metastatic thyroid carcinoma or neuroendocrine tumors. Findings were compared with (111)In-pentetreotid ((111)In-DTPA-octreotide) scan.
  
  
  RESULTS
  No adverse effects of (111)In-DOTA-BASS (20 μg) were observed. (111)In-DOTA-BASS detected 25 of 28 lesions, whereas (111)In-DTPA-octreotide detected only 17 of 28 lesions. In the same patient, (111)In-DOTA-BASS showed higher tumor and lower renal uptake than (111)In-DTPA-octreotide (3.5 ± 2.8 percentage injected activity [%IA] vs. 1.0 ± 0.99%IA and 1.5 ± 0.3 %IA vs. 2.3 ± 0.7 %IA) at 4 h after injection.
  
  
  CONCLUSIONS
  Imaging of neuroendocrine tumors with sst antagonists is clinically feasible. The favorable human biodistribution data suggest that sst antagonists could significantly affect peptide receptor-mediated imaging and therapy.
authors.affiliation: Department of Nuclear Medicine, University Hospital Freiburg, Freiburg, Germany. damian.wild@uniklinik-freiburg.de
authors.forename: Damian
authors.initials: D
authors.lastname: Wild
authors.forename: Melpomeni
authors.initials: M
authors.lastname: Fani
authors.forename: Martin
authors.initials: M
authors.lastname: Behe
authors.forename: Ingo
authors.initials: I
authors.lastname: Brink
authors.forename: Jean E F
authors.initials: JE
authors.lastname: Rivier
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Reubi
authors.forename: Helmut R
authors.initials: HR
authors.lastname: Maecke
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Weber
mesh_terms: D000368:Aged; D056831:Coordination Complexes / Q000009:adverse effects; D004701:Endocrine Gland Neoplasms / Q000000981:diagnostic imaging; D005240:Feasibility Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods*; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging; D015282:Octreotide / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D004369:Pentetic Acid / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D010456:Peptides, Cyclic / Q000009:adverse effects; D011446:Prospective Studies; D011874:Radiometry; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017481:Receptors, Somatostatin / Q000037:antagonists & inhibitors*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging; D014018:Tissue Distribution; D051598:Whole Body Imaging
chemical_list: C562072:111In-DOTA-p-nitrophenylalanyl-cyclo(cysteinyl-tyrosyl-tryptophyl-lysyl-threonyl-cysteinyl)tyrosinamide; C497824:111In-octreotide, DTPA(0)-; D056831:Coordination Complexes; D010456:Peptides, Cyclic; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; D004369:Pentetic Acid; D015282:Octreotide