title: Preliminary clinical assessment of the relationship between tumor alphavbeta3 integrin and perfusion in patients studied with [(18)F]fluciclatide kinetics and [ (15)O]H 2O PET.
abstract: BACKGROUND
  [(18)F]fluciclatide, a peptide ligand with high affinity for αvβ3/αvβ5 integrins, is a proposed biomarker of tumor angiogenesis. The study rationale was to perform a preliminary evaluation of the relationship between tumor [(18)F]fluciclatide uptake and perfusion by [(15)O]H2O PET.
  
  
  METHODS
  Patients with non-small cell lung cancer and melanoma underwent dynamic imaging with arterial sampling following injection of [(15)O]H2O and [(18)F]fluciclatide. Quantification was performed using a one-tissue compartmental model for [(15)O]H2O and a two-tissue model for [(18)F]fluciclatide at volume-of-interest level, and SUV at voxel level.
  
  
  RESULTS
  Tumor binding potential (k 3/k 4 ratio) of [(18)F]fluciclatide tumor was 5.39 ± 1.46, consistent with previous studies in breast cancer metastases. Voxel-by-voxel maps of [(18)F]fluciclatide delivery strongly correlated with [(15)O]H2O-based perfusion (p < 10(-4) tumor, 1,794 ± 1,331 voxels). Interestingly, this correlation was lost when retention of [(18)F]fluciclatide at late time-points was compared with perfusion (p > 0.15).
  
  
  CONCLUSIONS
  Our study suggests tumor [(18)F]fluciclatide retention is unrelated to tumor perfusion, supporting use of late (60-min) imaging protocols in patients.
authors.affiliation: Department of Surgery and Cancer, Hammersmith Campus, Imperial College London, London, UK, l.kenny@imperial.ac.uk.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Kenny
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Tomasi
authors.forename: Federico
authors.initials: F
authors.lastname: Turkheimer
authors.forename: James
authors.initials: J
authors.lastname: Larkin
authors.forename: Martin
authors.initials: M
authors.lastname: Gore
authors.forename: Cathryn S
authors.initials: CS
authors.lastname: Brock
authors.forename: Stephen
authors.initials: S
authors.lastname: Mangar
authors.forename: Eric O
authors.initials: EO
authors.lastname: Aboagye