title: Biodistribution and radiation dosimetry in humans of a new PET ligand, (18)F-PBR06, to image translocator protein (18 kDa).
abstract: As a PET biomarker for inflammation, translocator protein (18 kDa) (TSPO) can be measured with an (18)F-labeled aryloxyanilide, (18)F-N-fluoroacetyl-N-(2,5-dimethoxybenzyl)-2-phenoxyaniline ((18)F-PBR06), in the human brain. The objective of this study was to estimate the radiation absorbed doses of (18)F-PBR06 based on biodistribution data in humans.
  
  
  METHODS
  After the injection of (18)F-PBR06, images were acquired from head to thigh in 7 healthy humans. Urine was collected at various time points. Radiation absorbed doses were estimated by the MIRD scheme.
  
  
  RESULTS
  Moderate to high levels of radioactivity were observed in organs with high densities of TSPO and in organs of metabolism and excretion. Bone had low levels of radioactivity. The effective dose was 18.5 muSv/MBq.
  
  
  CONCLUSIONS
  The effective dose of (18)F-PBR06, compared with other (18)F radioligands, was moderate. This radioligand had negligible defluorination, as indirectly assessed by bone radioactivity. Doses to the gallbladder wall and spleen may limit the amount of permissible injected radioactivity.
authors.affiliation: Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-2035, USA.
authors.forename: Yota
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kimura
authors.forename: Fabrice G
authors.initials: FG
authors.lastname: Siméon
authors.forename: Leah P
authors.initials: LP
authors.lastname: Dickstein
authors.forename: Victor W
authors.initials: VW
authors.lastname: Pike
authors.forename: Robert B
authors.initials: RB
authors.lastname: Innis
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujita
mesh_terms: D000083:Acetanilides / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D000328:Adult; D001711:Biotransformation; D001794:Blood Pressure / Q000187:drug effects; D001842:Bone and Bones / Q000378:metabolism; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography; D011874:Radiometry; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D018079:Receptors, GABA / Q000378:metabolism*; D015656:Respiratory Mechanics / Q000187:drug effects; D014018:Tissue Distribution
chemical_list: D000083:Acetanilides; C538798:N-fluoroacetyl-N-(2,5-dimethoxybenzyl)-2-phenoxyaniline; D019275:Radiopharmaceuticals; D018079:Receptors, GABA; C499229:TSPO protein, human