title: [[¹¹C]choline as a pharmacodynamic marker for docetaxel therapy. Response assessment in a LNCaP prostate cancer xenograft mouse model].
abstract: The AIM of this study was to determine whether [¹¹C]choline can be used for docetaxel therapy response assessment in a LNCaP-prostate cancer xenograft mouse model using [¹¹C]choline small-animal PET/CT.
  
  
  METHODS
  The androgen-dependent human prostate cancer cell line LNCaP was implanted subcutaneously into the left flanks of 17 SCID-mice, 12.5 mg testosterone platelets were implanted in the neck wrinkle. All mice were injected 4-6 weeks after xenograft implantation with 37 MBq [¹¹C]choline via the tail vein. Dynamic imaging was performed for 60 minutes with a small-animal PET/CT scanner. After the first [¹¹C]choline PET/CT imaging 8 mice were subsequently injected intravenously with docetaxel twice (days 1 and 5) at a dose of 3 mg/kg body weight. 8 mice were treated with PBS as a control. [¹¹C]choline PET/CT imaging was performed on day 7, 14 and 21 after treatment. Image analysis was performed using tumor/muscle (T/M) ratios (ROI(T)/ROI(M) = T/M ratio).
  
  
  RESULTS
  All LNCaP tumours could be visualized by [¹¹C]choline PET/CT. Before treatment the mean T/M ratio was 2.0 ± 0.2 in the docetaxel-treated group and 1.9 ± 0.2 in the control group (p = 0.837). There was a reduction in the mean [¹¹C]choline uptake after docetaxel treatment of the tumours of the LNCaP cell line as early as 1 week after initiation of therapy (T/M(mean) ratio 1.5 ± 0.2 after one week, 1.3 ± 0.2 after 2 weeks and 1.4 ± 0.2 after 3 weeks). There was no decrease in [¹¹C]choline uptake in the control group.
  
  
  CONCLUSIONS
  Our results show that [¹¹C]choline has the potential for use in the early monitoring of the therapeutic effect of docetaxel in a LNCaP prostate cancer xenograft animal model.
authors: Klinik für Nuklearmedizin, Klinikum rechts der Isar der Technischen Universität München.
authors: S
authors: S
authors: Schwarzenböck
authors: D
authors: D
authors: Sachs
authors: M
authors: M
authors: Souvatzoglou
authors: T
authors: T
authors: Schuster
authors: R
authors: R
authors: Nawroth
authors: G
authors: G
authors: Weirich
authors: U
authors: U
authors: Treiber
authors: H-J
authors: HJ
authors: Wester
authors: S
authors: S
authors: Ziegler
authors: M
authors: M
authors: Schwaiger
authors: R
authors: R
authors: Senekowitsch-Schmidtke
authors: B J
authors: BJ
authors: Krause
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D045744:Cell Line, Tumor; D002794:Choline / Q000493:pharmacokinetics*; D000077143:Docetaxel; D008297:Male; D051379:Mice; D016513:Mice, SCID; D049268:Positron-Emission Tomography / Q000379:methods*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000378:metabolism; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D043823:Taxoids / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D043823:Taxoids; D000077143:Docetaxel; D002794:Choline