title: Human biodistribution and dosimetry of iodine-123-fluoroalkyl analogs of beta-CIT.
abstract: Two new N-omega-fluoroalkyl analogs of [123I]2beta-carbomethoxy-3beta-(4-iodophenyl)tropane ([123I]beta-CIT), the fluoroethyl and fluoropropyl compounds ([123I]FE-CIT and [123I]FP-CIT, respectively), have been shown to have faster kinetics and better selectivity for the dopamine transporter than [123I]beta-CIT. We examined the organ biodistribution and radiation safety of these two compounds in six healthy volunteers who received an injection with each of the two compounds 2 weeks apart. Data were obtained on the Strichman 860 whole-body scanner. Transmission scans were obtained in all subjects prior to the injection of the radiotracer with a line source and used to derive organ-specific attenuation correction factors. Whole-body planar images were acquired every hour for the first 6 h, and at 24 h. Attenuation-corrected regional conjugate counts were converted into units of activity using a calibration factor obtained for each subject by dividing whole-body conjugate decay-corrected counts from the first acquisition by the injected activity. Radiation dose estimates were on average higher for [123I]CIT-FE than for [123I]CIT-FP, with the lower large intestine receiving the highest exposure: 0.15+/-13% mGy/MBq (mean +/-COV) and 0.12+/-14% mGy/MBq for [123I]FE-CIT and [123I]FP-CIT, respectively, followed by the upper large intestine and the spleen.
authors.affiliation: Department of Psychiatry, Yale University School of Medicine and VA Medical Center, West Haven, Conn., USA.
authors.forename: A
authors.initials: A
authors.lastname: Abi-Dargham
authors.forename: R B
authors.initials: RB
authors.lastname: Innis
authors.forename: G
authors.initials: G
authors.lastname: Wisniewski
authors.forename: R M
authors.initials: RM
authors.lastname: Baldwin
authors.forename: J L
authors.initials: JL
authors.lastname: Neumeyer
authors.forename: J P
authors.initials: JP
authors.lastname: Seibyl
mesh_terms: D000328:Adult; D002352:Carrier Proteins / Q000378:metabolism; D003042:Cocaine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000652:urine; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics / Q000652:urine; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011485:Protein Binding; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics* / Q000652:urine; D011880:Radiotherapy Planning, Computer-Assisted; D014018:Tissue Distribution
chemical_list: D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D019275:Radiopharmaceuticals; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine