title: Radiation dosimetry estimates for the PET serotonin transporter probe 11C-DASB determined from whole-body imaging in non-human primates.
abstract: The radiotracer 3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile labelled in the N-methyl position (11C-DASB) is a selective radioligand for the in vivo quantification of serotonin transporters (SERTs) using positron emission tomography (PET). The current study quantified the distribution of activity in two rhesus monkeys after the injection of approximately 333 MBq (9 mCi) 11C-DASB. Whole-body images were acquired at 22 time points for a total of 120 min following injection of the radioligand. Source organs were identified at each time point from both tomographic images (using multiple regions of interest on each tomograph for each organ) and a single planar image (using a single region of interest for each organ). The peak activities in planar images in the five identified source organs (expressed as per cent injected dose (ID)) were lungs (24% ID at 1.5 min), kidneys (6.5% ID at 4 min), liver (8% ID at 3 min), brain (4% ID at 5 min) and spleen (0.42% ID at 3 min). Mono-exponential fitting of activity overlying the bladder suggested that approximately 14% of activity was excreted via the urine. The radiation burden to the body was calculated from residence times of these source organs and then scaled to corresponding human values. The calculated effective dose from tomographic and planar images was 6.0 and 6.4 microGy x MBq(-1) (22.3 and 23.7 mrad x mCi(-1)), respectively. The planar analysis was much easier to perform, and generally yielded slightly higher (i.e., more conservative) estimates of radiation burden than the tomographic analysis. The estimated radiation burden of 11C-DASB is relatively modest and would allow multiple scans per research subject per year.
authors.affiliation: Molecular Imaging Branch, National Institute of Mental Health, Bethesda, Maryland 20892-0135, USA. TipreD@intra.nimh.nih.gov
authors.forename: D N
authors.initials: DN
authors.lastname: Tipre
authors.forename: J Q
authors.initials: JQ
authors.lastname: Lu
authors.forename: M
authors.initials: M
authors.lastname: Fujita
authors.forename: M
authors.initials: M
authors.lastname: Ichise
authors.forename: D
authors.initials: D
authors.lastname: Vines
authors.forename: R B
authors.initials: RB
authors.lastname: Innis
mesh_terms: D000814:Aniline Compounds / Q000493:pharmacokinetics* / Q000652:urine; D000818:Animals; D001822:Body Burden; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics / Q000652:urine; D002352:Carrier Proteins / Q000378:metabolism*; D008253:Macaca mulatta; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008657:Metabolic Clearance Rate; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009928:Organ Specificity; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000652:urine; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D050486:Serotonin Plasma Membrane Transport Proteins; D013440:Sulfides / Q000493:pharmacokinetics* / Q000652:urine; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed / Q000379:methods
chemical_list: C412822:3-amino-4-(2-dimethylaminomethylphenylsulfanyl)benzonitrile; D000814:Aniline Compounds; D002250:Carbon Radioisotopes; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D019275:Radiopharmaceuticals; D050486:Serotonin Plasma Membrane Transport Proteins; D013440:Sulfides