title: In Vivo Evaluation of a Bombesin Analogue Labeled with Ga-68 and Co-55/57.
abstract: The purpose of this study was to apply an analogue of bombesin, NOTA-AMBA, labeled with Co-55 or Ga-68, for preclinical imaging of prostate cancer.
  
  
  
  The peptide NOTA-AMBA was labeled with Ga-68 or Co-55 by microwave irradiation. Biodistribution in xenograft mice (PC3) was performed at 1, 4, and 24 h (only cobalt at 24 h) using a fixed amount of peptide. Four weeks post-inoculation, xenograft mice were positron emission tomography/X-ray computed tomography scanned after tail vein injection of [(68)Ga]NOTA-AMBA or [(55)Co]NOTA-AMBA.
  
  
  
  Labeling with Ga-68 and Co-55/57 was achieved in yields greater than 90 %. A radiochemical purity (RCP) of 95 and 90 % were obtained for Ga-68 and Co-55, respectively. Both radiopeptides showed high uptake in the intestines, stomach, pancreas, and in the tumor ([(68)Ga]NOTA-AMBA, 10.3 %ID/g at 1 h to 6.4 %ID/g at 4 h; [(57)Co]NOTA-AMBA, 8.2 %ID/g at 1 h to 5.3%ID/g at 24 h). Normal tissue cleared over time improving tumor-to-background ratios.
  
  
  
  NOTA-AMBA was labeled in high yields and RCP with Ga-68 and Co-55/57. High tumor uptake in a subcutaneous mouse prostate cancer model was observed. At 24 h, [(55/57)Co]NOTA-AMBA showed better tumor-to-organ ratios than [(68)Ga]NOTA-AMBA at both 1 and 4 h post-injection. Hence, for imaging, [(55)Co]NOTA-AMBA was found to be superior compared to [(68)Ga]NOTA-AMBA.
authors.affiliation: Department of Nuclear Medicine, Odense University Hospital, Sdr. Boulevard 29, 5000, Odense, Denmark. Johan.Dam@rsyd.dk.
authors.forename: Johan Hygum
authors.identifier: 0000-0001-6577-7011
authors.initials: JH
authors.lastname: Dam
authors.affiliation: Department of Nuclear Medicine, Odense University Hospital, Sdr. Boulevard 29, 5000, Odense, Denmark.
authors.forename: Birgitte Brinkmann
authors.initials: BB
authors.lastname: Olsen
authors.affiliation: Department of Nuclear Medicine, Odense University Hospital, Sdr. Boulevard 29, 5000, Odense, Denmark.
authors.forename: Christina
authors.initials: C
authors.lastname: Baun
authors.affiliation: Department of Nuclear Medicine, Odense University Hospital, Sdr. Boulevard 29, 5000, Odense, Denmark.|Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Poul-Flemming
authors.initials: PF
authors.lastname: Høilund-Carlsen
authors.affiliation: Department of Nuclear Medicine, Odense University Hospital, Sdr. Boulevard 29, 5000, Odense, Denmark.|Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Helge
authors.initials: H
authors.lastname: Thisgaard
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D001839:Bombesin / Q000031:analogs & derivatives*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D003037:Cobalt Radioisotopes / Q000737:chemistry*; D005710:Gallium Radioisotopes / Q000737:chemistry*; D006801:Humans; D020128:Inhibitory Concentration 50; D008297:Male; D016513:Mice, SCID; D010455:Peptides / Q000097:blood / Q000737:chemistry; D049268:Positron-Emission Tomography; D055550:Protein Stability; D019275:Radiopharmaceuticals / Q000737:chemistry*; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed; D023041:Xenograft Model Antitumor Assays
chemical_list: D003037:Cobalt Radioisotopes; D005710:Gallium Radioisotopes; D010455:Peptides; D019275:Radiopharmaceuticals; D001839:Bombesin
keywords: AMBA; Bombesin; Cobalt-55; Gallium-68; PET; Positron emission tomography; Prostate cancer