title: Uptake of 18F-Fluorocholine, 18F-FET, and 18F-FDG in C6 gliomas and correlation with 131I-SIP(L19), a marker of angiogenesis.
abstract: Targeting extracellular structures that are involved in angiogenic processes, such as the extra domain B of fibronectin, is a promising approach for the diagnosis of solid tumors. The aim of this study was to determine uptake of the (18)F-labeled PET tracers (18)F-fluorocholine (N,N-dimethyl-N-(18)F-fluoromethyl-2-hydroxyethylammonium), (18)F-fluoro-ethyl-l-tyrosine (FET), and (18)F-FDG in C6 gliomas of the rat and to correlate it with uptake of the anti-extra domain B antibody (131)I-SIP(L19) as a marker of neoangiogenesis.
  
  
  METHODS
  C6 gliomas were orthotopically induced in 17 rats. Uptake of all tracers was measured using quantitative autoradiography, and uptake of (18)F-fluorocholine, (18)F-FET, and (18)F-FDG was correlated with uptake of (131)I-SIP(L19) on a pixelwise basis.
  
  
  RESULTS
  The mean (131)I-SIP(L19), (18)F-fluorocholine, (18)F-FET, and (18)F-FDG standardized uptake values in the tumor and the contralateral normal cortex (in parentheses) were 0.31 +/- 0.22 (not detectable), 2.00 +/- 0.53 (0.49 +/- 0.07), 3.67 +/- 0.36 (1.42 +/- 0.22), and 7.23 +/- 1.22 (3.64 +/- 0.51), respectively. The (131)I-SIP(L19) uptake pattern correlated best with (18)F-fluorocholine uptake (z = 0.80, averaged z-transformed Pearson correlation coefficient) and (18)F-FET uptake (z = 0.79) and least with (18)F-FDG (z = 0.37).
  
  
  CONCLUSIONS
  One day after intravenous injection, (131)I-SIP(L19) displayed a very high tumor-to-cortex ratio, which may be used in the diagnostic work-up of brain tumor patients. Of the 3 investigated (18)F tracers, (18)F-fluorocholine and (18)F-FET correlated better with the pattern of (131)I-SIP(L19) uptake than did (18)F-FDG. Whether this means that (18)F-fluorocholine and (18)F-FET are better suited than (18)F-FDG to monitor antiangiogenic therapy should be investigated in future studies.
authors.affiliation: PET Center, Division of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Matthias T
authors.initials: MT
authors.lastname: Wyss
authors.forename: Nicolas
authors.initials: N
authors.lastname: Spaeth
authors.forename: Gregoire
authors.initials: G
authors.lastname: Biollaz
authors.forename: Jens
authors.initials: J
authors.lastname: Pahnke
authors.forename: Patrizia
authors.initials: P
authors.lastname: Alessi
authors.forename: Eveline
authors.initials: E
authors.lastname: Trachsel
authors.forename: Valerie
authors.initials: V
authors.lastname: Treyer
authors.forename: Bruno
authors.initials: B
authors.lastname: Weber
authors.forename: Dario
authors.initials: D
authors.lastname: Neri
authors.forename: Alfred
authors.initials: A
authors.lastname: Buck
mesh_terms: D000818:Animals; D000906:Antibodies; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology; D045744:Cell Line, Tumor; D002794:Choline / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005353:Fibronectins / Q000737:chemistry; D005910:Glioma / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D009389:Neovascularization, Pathologic; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000493:pharmacokinetics*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
chemical_list: D000906:Antibodies; D005353:Fibronectins; C117289:O-(2-fluoroethyl)tyrosine; D019275:Radiopharmaceuticals; D011993:Recombinant Fusion Proteins; C513931:SIP(L19) fusion protein; D014443:Tyrosine; C514960:fluorocholine; D002794:Choline