title: Biodistribution and radiation dosimetry of [18F]F-PEB in nonhuman primates.
abstract: BACKGROUND
  The metabotropic glutamate receptor subtype 5 (mGluR5) is distributed throughout the central nervous system (CNS), and has been suggested to be a potential target for several CNS disorders suchas Parkinson's disease, pain, anxiety, depression, schizophrenia, and addiction. We report here on the rhesus monkey biodistribution and radiation dosimetry of [18F]3-fluoro-5-[(pyridine-3-yl)ethynyl]benzonitrile, [18F]F-PEB, a mGluR5 positron emission tomography (PET) radiotracer.
  
  
  METHODS
  Three male and two female rhesus monkeys were imaged using the Discovery ST PET/computed tomography scanner. A total of 25 whole body PET emissions were acquired over 3 h (23 emissions in one subject). Regions of interest were drawn in the brain, lungs, heart, liver, spleen, bladder, and testes. The absorbed radiation dose was calculated using OLINDA v1.
  
  
  RESULTS
  At the end of the imaging session, 45% of the [18F]F-PEB activity had been excreted by the liver and into the gastrointestinal tract and 10% had been excreted into the urinary bladder. When extrapolating to the adult human, the largest absorbed radiation doses were located in the upper large intestine (males: 0.18 mGy/MBq, females: 0.20 mGy/MBq) and small intestine (males: 0.16 mGy/MBq, females: 0.19 mGy/MBq). Effective radiation dose was 0.033 mSv/MBq for males and 0.034 mSv/MBq for females, similar to many other [18F] ligands.
  
  
  CONCLUSIONS
  The effective radiation dose of [18F]F-PEB obtained from rhesus is similar to many other clinically utilized [18F] ligands.
authors.affiliation: Imaging Department, Merck Research Laboratories, West Point, Pennsylvania 19486-004, USA. marie_belanger@merck.com
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Bélanger
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Krause
authors.forename: Christine
authors.initials: C
authors.lastname: Ryan
authors.forename: Sandra
authors.initials: S
authors.lastname: Sanabria-Bohorquez
authors.forename: Wenping
authors.initials: W
authors.lastname: Li
authors.forename: Terence G
authors.initials: TG
authors.lastname: Hamill
authors.forename: Hugh Donald
authors.initials: HD
authors.lastname: Burns