Uptake of 18F-Fluorocholine, 18F-FET, and 18F-FDG in C6 gliomas and correlation with 131I-SIP(L19), a marker of angiogenesis.
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.
Wyss
Matthias T
MT
PET Center, Division of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland.
Spaeth
Nicolas
N
Biollaz
Gregoire
G
Pahnke
Jens
J
Alessi
Patrizia
P
Trachsel
Eveline
E
Treyer
Valerie
V
Weber
Bruno
B
Neri
Dario
D
Buck
Alfred
A
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
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