title: Optimal duration of PET studies with 18F-fluoroethyl-diprenorphine.
abstract: The tracer 6-O-(2-(18)F-fluoroethyl)-6-O-desmethyldiprenorphine (18F-FDPN) provides enhanced flexibility to PET studies of the opioidergic system because the label has a longer half-life than the label of 11C-diprenorphine. Here we evaluated the ideal length of PET studies with 18F-FDPN.
  
  
  METHODS
  18F-FDPN binding kinetics were quantified with protocols of different lengths by use of a 1-tissue or a 2-tissue compartment model for different volumes of interest. Furthermore, the effects of scanning duration were assessed by parametric analyses.
  
  
  RESULTS
  A 90-min protocol resulted in less than 10% bias in distribution volume (DV) relative to the full-length protocol. Correlation analyses of the DV estimates for the full-length protocol and the shortened protocols showed good replication of DV estimates for regions with both low and high levels of binding at schedules of up to 90 min.
  
  
  CONCLUSIONS
  Data sampling in dynamic 18F-FDPN PET acquisitions should not be shorter than 90 min to maintain reliable estimates of DV.
authors.affiliation: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany. h.boecker@lrz.tu-muenchen.de
authors.forename: Henning
authors.initials: H
authors.lastname: Boecker
authors.forename: Till
authors.initials: T
authors.lastname: Sprenger
authors.forename: Gjermund
authors.initials: G
authors.lastname: Henriksen
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Toelle
authors.forename: Mary E
authors.initials: ME
authors.lastname: Spilker
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology; D004174:Diprenorphine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D008024:Ligands; D008297:Male; D015233:Models, Statistical; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D012044:Regression Analysis; D013997:Time Factors
chemical_list: C411951:6-O-(2-(18F)fluoroethyl)-6-O-desmethyldiprenorphine; D008024:Ligands; D019275:Radiopharmaceuticals; D004174:Diprenorphine