title: Biodistribution and radiation dosimetry of the serotonin 5-HT₆ ligand [¹¹C]GSK215083 determined from human whole-body PET.
abstract: OBJECTIVE
  We measured the whole-body distribution of IV-injected [¹¹C]GSK215083, a new 5-HT₆ antagonist PET tracer, as a function of time in adult subjects, in order to determine the radiation exposure.
  
  
  METHODS
  After injection with a single bolus of [¹¹C]GSK215083 (range 330-367 MBq; mean 346 MBq), PET emission data were acquired for approximately 120 min in six subjects (three males and three females). Five organs were identified as exhibiting uptake above background. For these, regions of interest were delineated on emission images, and time-activity curves (TAC) generated. Residence times were calculated as the area under the curve of the TAC, normalized to injected activities and standard values of organ volumes. Dosimetry calculations were then performed using the computer program OLINDA/EXM 1.0.
  
  
  RESULTS
  The mean effective dose averaged over both males and females (deviation) was estimated to be 7.7 ± 1.0 μSv/MBq (male 7.0 ± 0.4; female 8.5 ± 0.6). For the effective dose equivalent, the corresponding values are 7.8 ± 1.2 μSv/MBq (male 6.8 ± 0.5; female 8.9 ± 0.1). The organ receiving the highest dose was the lung, with an average equivalent dose of 25.6 ± 6.9 μSv/MBq (male 20.8 ± 5.6; female 30.4 ± 4.4).
  
  
  CONCLUSIONS
  The estimated radiation dose for [¹¹C]GSK215083 is consistent with those for other neuroreceptor ligands labeled with carbon-11. The somewhat higher dose estimate for females compared to males may reflect the difference in observed residence times and representative differences in the male and female phantoms used for dosimetry calculations. Based on conventionally accepted dose limits, [¹¹C]GSK215083 may be used for multiple PET scans in the same subject.
authors.affiliation: GlaxoSmithKline Clinical Imaging Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Comley
authors.forename: Cristian
authors.initials: C
authors.lastname: Salinas
authors.forename: Romina
authors.initials: R
authors.lastname: Mizrahi
authors.forename: Irina
authors.initials: I
authors.lastname: Vitcu
authors.forename: Alvina
authors.initials: A
authors.lastname: Ng
authors.forename: William
authors.initials: W
authors.lastname: Hallett
authors.forename: Nicholas
authors.initials: N
authors.lastname: Keat
authors.forename: Alan A
authors.initials: AA
authors.lastname: Wilson
authors.forename: Eugenii A
authors.initials: EA
authors.lastname: Rabiner
authors.forename: Marc
authors.initials: M
authors.lastname: Laruelle
authors.forename: Sylvain
authors.initials: S
authors.lastname: Houle
mesh_terms: D000293:Adolescent; D000328:Adult; D002250:Carbon Radioisotopes; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008024:Ligands; D008297:Male; D009928:Organ Specificity / Q000187:drug effects; D049268:Positron-Emission Tomography / Q000379:methods*; D011804:Quinolines / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D011874:Radiometry / Q000379:methods*; D011985:Receptors, Serotonin / Q000378:metabolism*; D013450:Sulfones / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D013997:Time Factors; D014018:Tissue Distribution / Q000187:drug effects; D051598:Whole Body Imaging / Q000379:methods*; D055815:Young Adult
chemical_list: D002250:Carbon Radioisotopes; C571031:GSK215083; D008024:Ligands; D011804:Quinolines; D011985:Receptors, Serotonin; D013450:Sulfones; C097216:serotonin 6 receptor
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