title: In vivo imaging of cellular proliferation in renal cell carcinoma using 18F-fluorothymidine PET.
abstract: OBJECTIVE
  The ability to measure cellular proliferation non-invasively in renal cell carcinoma may allow prediction of tumour aggressiveness and response to therapy. The aim of this study was to evaluate the uptake of 18F-fluorothymidine (FLT) PET in renal cell carcinoma (RCC), and to compare this to 18F-fluorodeoxyglucose (FDG), and to an immunohistochemical measure of cellular proliferation (Ki-67).
  
  
  METHODS
  Twenty seven patients (16 male, 11 females; age 42-77) with newly diagnosed renal cell carcinoma suitable for resection were prospectively enrolled. All patients had preoperative FLT and FDG PET scans. Visual identification of tumour using FLT PET compared to normal kidney was facilitated by the use of a pre-operative contrast enhanced CT scan. After surgery tumour was taken for histologic analysis and immunohistochemical staining by Ki-67.
  
  
  RESULTS
  The SUVmax (maximum standardized uptake value) mean±SD for FLT in tumour was 2.59±1.27, compared to normal kidney (2.47±0.34). The mean SUVmax for FDG in tumour was similar to FLT (2.60±1.08). There was a significant correlation between FLT uptake and the immunohistochemical marker Ki-67 (r=0.72, P<0.0001) in RCC. Ki-67 proliferative index was mean ± SD of 13.3%±9.2 (range 2.2% - 36.3%).
  
  
  CONCLUSIONS
  There is detectable uptake of FLT in primary renal cell carcinoma, which correlates with cellular proliferation as assessed by Ki-67 labelling index. This finding has relevance to the use of FLT PET in molecular imaging studies of renal cell carcinoma biology.
authors.affiliation: Department of Surgery and Urology, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia; Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Wong
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia; Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, Victoria, Australia; Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Sze Ting
authors.initials: ST
authors.lastname: Lee
authors.affiliation: Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Carmel
authors.initials: C
authors.lastname: Murone
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Eng
authors.affiliation: Department of Surgery and Urology, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia; Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Nathan
authors.initials: N
authors.lastname: Lawrentschuk
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Salvatore U
authors.initials: SU
authors.lastname: Berlangieri
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Kunthi
authors.initials: K
authors.lastname: Pathmaraj
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: O'Keefe
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Sachinidis
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Byrne
authors.affiliation: Department of Surgery and Urology, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Damien M
authors.initials: DM
authors.lastname: Bolton
authors.affiliation: Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, Victoria, Australia; Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Davis
authors.affiliation: Centre for PET, Austin Hospital, Heidelberg, Victoria, Australia; Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, Victoria, Australia; Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Scott
keywords: FDG PET; FLT PET; Renal cell carcinoma