title: A compartmental model for biokinetics and dosimetry of 18F-choline in prostate cancer patients.
abstract: PET with (18)F-choline ((18)F-FCH) is used in the diagnosis of prostate cancer and its recurrences. In this work, biodistribution data from a recent study conducted at Skåne University Hospital Malmö were used for the development of a biokinetic and dosimetric model.
  
  
  METHODS
  The biodistribution of (18)F-FCH was followed for 10 patients using PET up to 4 h after administration. Activity concentrations in blood and urine samples were also determined. A compartmental model structure was developed, and values of the model parameters were obtained for each single patient and for a reference patient using a population kinetic approach. Radiation doses to the organs were determined using computational (voxel) phantoms for the determination of the S factors.
  
  
  RESULTS
  The model structure consists of a central exchange compartment (blood), 2 compartments each for the liver and kidneys, 1 for spleen, 1 for urinary bladder, and 1 generic compartment accounting for the remaining material. The model can successfully describe the individual patients' data. The parameters showing the greatest interindividual variations are the blood volume (the clearance process is rapid, and early blood data are not available for several patients) and the transfer out from liver (the physical half-life of (18)F is too short to follow this long-term process with the necessary accuracy). The organs receiving the highest doses are the kidneys (reference patient, 0.079 mGy/MBq; individual values, 0.033-0.105 mGy/MBq) and the liver (reference patient, 0.062 mGy/MBq; individual values, 0.036-0.082 mGy/MBq). The dose to the urinary bladder wall of the reference patient varies between 0.017 and 0.030 mGy/MBq, depending on the assumptions on bladder voiding.
  
  
  CONCLUSIONS
  The model gives a satisfactory description of the biodistribution of (18)F-FCH and realistic estimates of the radiation dose received by the patients.
authors.affiliation: Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Neuherberg, Germany.
authors.forename: Augusto
authors.initials: A
authors.lastname: Giussani
authors.forename: Tilman
authors.initials: T
authors.lastname: Janzen
authors.forename: Helena
authors.initials: H
authors.lastname: Uusijärvi-Lizana
authors.forename: Federico
authors.initials: F
authors.lastname: Tavola
authors.forename: Maria
authors.initials: M
authors.lastname: Zankl
authors.forename: Marie
authors.initials: M
authors.lastname: Sydoff
authors.forename: Anders
authors.initials: A
authors.lastname: Bjartell
authors.forename: Sigrid
authors.initials: S
authors.lastname: Leide-Svegborn
authors.forename: Marcus
authors.initials: M
authors.lastname: Söderberg
authors.forename: Sören
authors.initials: S
authors.lastname: Mattsson
authors.forename: Christoph
authors.initials: C
authors.lastname: Hoeschen
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Cantone
mesh_terms: D000368:Aged; D002794:Choline / Q000493:pharmacokinetics*; D005462:Fluorine Radioisotopes; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D011874:Radiometry; D011877:Radionuclide Imaging; D014018:Tissue Distribution; D001743:Urinary Bladder / Q000528:radiation effects
chemical_list: D005462:Fluorine Radioisotopes; D002794:Choline