title: Whole-Body Distribution and Radiation Dosimetry of 11C-Elacridar and 11C-Tariquidar in Humans.
abstract: (11)C-elacridar and (11)C-tariquidar are new PET tracers to assess the transport activity of P-glycoprotein (adenosine triphosphate-binding cassette subfamily B, member 1 [ABCB1]) and breast cancer resistance protein (adenosine triphosphate-binding cassette subfamily G, member 2 [ABCG2]). This study investigated the whole-body distribution and radiation dosimetry of both radiotracers in humans.
  
  
  METHODS
  Twelve healthy volunteers (6 women, 6 men) underwent whole-body PET/CT imaging over the 90 min after injection of either (11)C-elacridar or (11)C-tariquidar. Radiation doses were calculated with OLINDA/EXM software using adult reference phantoms.
  
  
  RESULTS
  Biodistribution was consistent with a major elimination route of hepatobiliary excretion, which may be mediated by ABCB1 and ABCG2. High radioactivity uptake was seen in liver, followed by spleen and kidneys, whereas brain uptake was lowest. Effective doses were 3.41 ± 0.06 μSv/MBq for (11)C-elacidar and 3.62 ± 0.11 μSv/MBq for (11)C-tariquidar.
  
  
  CONCLUSIONS
  Our data indicate that both (11)C-elacridar and (11)C-tariquidar are safe radiotracers, for which an injected activity of 400 MBq corresponds to a total effective dose of approximately 1.5 mSv.
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria martin.m.bauer@meduniwien.ac.at.
authors.forename: Martin
authors.initials: M
authors.lastname: Bauer
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria Health and Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria; and.
authors.forename: Matthias
authors.initials: M
authors.lastname: Blaickner
authors.affiliation: Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Cécile
authors.initials: C
authors.lastname: Philippe
authors.affiliation: Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wadsak
authors.affiliation: Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Marcus
authors.initials: M
authors.lastname: Hacker
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Zeitlinger
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria Health and Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria; and Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Langer
mesh_terms: D000166:Acridines / Q000032:analysis* / Q000493:pharmacokinetics*; D000328:Adult; D002250:Carbon Radioisotopes; D006801:Humans; D008657:Metabolic Clearance Rate; D009928:Organ Specificity; D049268:Positron-Emission Tomography / Q000379:methods*; D011804:Quinolines / Q000032:analysis* / Q000493:pharmacokinetics*; D011829:Radiation Dosage; D019275:Radiopharmaceuticals / Q000032:analysis / Q000493:pharmacokinetics; D044005:Tetrahydroisoquinolines / Q000032:analysis* / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014915:Whole-Body Counting / Q000379:methods*
chemical_list: D000166:Acridines; D002250:Carbon Radioisotopes; D011804:Quinolines; D019275:Radiopharmaceuticals; D044005:Tetrahydroisoquinolines; C402343:tariquidar; C083501:Elacridar
keywords: 11C-elacridar; 11C-tariquidar; P-glycoprotein; breast cancer resistance protein; radiation dosimetry