title: Hybrid microPET imaging for dosimetric applications in mice: improvement of activity quantification in dynamic microPET imaging for accelerated dosimetry applied to 6-[18 F]fluoro-L-DOPA and 2-[18 F]fluoro-L-tyrosine.
abstract: OBJECTIVE
  Dynamic microPET imaging has advantages over traditional organ harvesting, but is prone to quantification errors in small volumes. Hybrid imaging, where microPET activities are cross-calibrated using post scan harvested organs, can improve quantification. Organ harvesting, dynamic imaging and hybrid imaging were applied to determine the human and mouse radiation dosimetry of 6-[18 F]fluoro-L-DOPA and 2-[18 F]fluoro-L-tyrosine and compared.
  
  
  METHODS
  Two-hour dynamic microPET imaging was performed with both tracers in four separate mice for 18 F-FDOPA and three mice for 18 F-FTYR. Organ harvesting was performed at 2, 5, 10, 30, 60 and 120 min post tracer injection with n = 5 at each time point for 18 F-FDOPA and n = 3 at each time point for 18 F-FTYR. Human radiation dosimetry projected from animal data was calculated for the three different approaches for each tracer using OLINDA/EXM. S-factors for the MOBY phantom were used to calculate the animal dosimetry.
  
  
  RESULTS
  Correlations between dose estimates based on organ harvesting and imaging was improved from r = 0.997 to r = 0.999 for 18 F-FDOPA and from r = 0.985 to r = 0.996 (p < 0.0001 for all) for 18 F-FTYR by using hybrid imaging.
  
  
  CONCLUSIONS
  Hybrid imaging yields comparable results to traditional organ harvesting while partially overcoming the limitations of pure imaging. It is an advantageous technique in terms of number of animals needed and labour involved.
authors.affiliation: Cyclotron Research Centre, University of Liege, Allée du 6 Août, Building B30, Sart Tilman, 4000, Liege, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Bretin
authors.forename: T
authors.initials: T
authors.lastname: Mauxion
authors.forename: G
authors.initials: G
authors.lastname: Warnock
authors.forename: M A
authors.initials: MA
authors.lastname: Bahri
authors.forename: L
authors.initials: L
authors.lastname: Libert
authors.forename: C
authors.initials: C
authors.lastname: Lemaire
authors.forename: A
authors.initials: A
authors.lastname: Luxen
authors.forename: M
authors.initials: M
authors.lastname: Bardiès
authors.forename: A
authors.initials: A
authors.lastname: Seret
authors.forename: A
authors.initials: A
authors.lastname: Plenevaux
mesh_terms: D000818:Animals; D004295:Dihydroxyphenylalanine / Q000008:administration & dosage / Q000378:metabolism*; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D049268:Positron-Emission Tomography / Q000379:methods*; D014018:Tissue Distribution; D014443:Tyrosine / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D005462:Fluorine Radioisotopes; D014443:Tyrosine; D004295:Dihydroxyphenylalanine