title: A restricted access material for rapid analysis of [(11)C]-labeled radiopharmaceuticals and their metabolites in plasma.
abstract: BACKGROUND
  Analysis of the radioactive components in plasma taken during positron emission tomography (PET) measurements is often vital for the correct quantification of the PET data. The described high-performance liquid chromatography (HPLC) method has been developed to provide a fast, sensitive and robust method for the measurement of plasma samples from PET studies using [(11)C]-labeled radiopharmaceuticals.
  
  
  METHODS
  Unadulterated plasma samples were analyzed directly, following a simple filtration, by the use of a small extraction column, containing a restricted access material, combined with a monolithic analysis column in a column-switching HPLC system.
  
  
  RESULTS
  Up to 4 ml of plasma was analyzed by this method within 4.5-7 min in a fully automated process. Because of the rapid analysis, a large number of samples could be analyzed during a 90-min PET scan. The extraction column could be used for analysis of up to 500 ml of plasma before replacement was required.
  
  
  CONCLUSIONS
  The described method is fast and robust and the large sample volumes allow for accurate determination of the radioactive components in plasma even at 90 min after injection of a [(11)C]-labeled radiopharmaceutical.
authors.affiliation: The PET & Cyclotron Unit and The Lundbeck Centre for Integrated Molecular Brain Imaging, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark. nic@pet.rh.dk
authors.forename: Nic
authors.initials: N
authors.lastname: Gillings
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D002250:Carbon Radioisotopes / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D019275:Radiopharmaceuticals / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014462:Ultrafiltration / Q000379:methods*
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals