title: Reproducibility of [11C]choline-positron emission tomography and effect of trastuzumab.
abstract: OBJECTIVE
  This study sought to evaluate the reproducibility of [(11)C]choline-positron emission tomography and the effect of trastuzumab in breast cancer.
  
  
  METHODS
  Twenty-one patients with newly diagnosed and recurrent breast cancer stage II-IV had a baseline dynamic [(11)C]choline-PET scan, 10 patients had a second [(11)C]choline-PET scan to examine reproducibility, and 6 patients had a second scan within a month after trastuzumab. Analysis of [(11)C]choline uptake was measured as the semiquantitative standardized uptake value at 30 and 60 minutes (SUV(30) and SUV(60)), and quantitatively as the net irreversible retention of the radiotracer at steady-state (Ki) and plasma to tissue exchange at 60 minutes (IRF60min).
  
  
  RESULTS
  Breast tumor lesions in all patients were visualized by [(11)C]choline PET. The difference in tumor versus normal tissue uptake was significant for SUV(30), SUV(60), Ki, and IRF60 minutes (Wilcoxon P < 0.0001). At 60 minutes postinjection, 15.1 +/- 2.16% of plasma radioactivity was due to unmetabolized [(11)C]choline radioactivity. [(11)C]Choline uptake was reproducible in breast tumor lesions (r(2) = 0.9 for SUV, 0.9 for Ki, and 0.8 for IRF60). Early responses to trastuzumab measured by [(11)C]choline-PET were significant in three lesions occurring in two patients who responded clinically.
  
  
  CONCLUSIONS
  [(11)C]Choline-PET uptake variables can be reproducibly assessed. Initial studies show that trastuzumab decreases [(11)C]choline uptake.
authors.affiliation: Department of Cancer Medicine, Imperial College, London, UK.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Kenny
authors.forename: Kaiyumars B
authors.initials: KB
authors.lastname: Contractor
authors.forename: Rainer
authors.initials: R
authors.lastname: Hinz
authors.forename: Justin
authors.initials: J
authors.lastname: Stebbing
authors.forename: Carlo
authors.initials: C
authors.lastname: Palmieri
authors.forename: Jie
authors.initials: J
authors.lastname: Jiang
authors.forename: Sami
authors.initials: S
authors.lastname: Shousha
authors.forename: Adil
authors.initials: A
authors.lastname: Al-Nahhas
authors.forename: R Charles
authors.initials: RC
authors.lastname: Coombes
authors.forename: Eric O
authors.initials: EO
authors.lastname: Aboagye
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D002794:Choline / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D002794:Choline; D000068878:Trastuzumab