o-(2-fluoroethyl)tyrosine and fluorocholine

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.. 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.. 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).. 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.

Topics: Animals; Antibodies; Brain Neoplasms; Cell Line, Tumor; Choline; Fibronectins; Glioma; Male; Neovascularization, Pathologic; Radiopharmaceuticals; Rats; Rats, Wistar; Recombinant Fusion Proteins; Tyrosine

The positron emission tomography (PET) tracers (18)F-fluoro-ethyl-L: -tyrosine (FET), (18)F-fluorocholine (N,N-dimethyl-N-[(18)F]fluoromethyl-2-hydroxyethylammonium (FCH]) and (18)F-fluoro-2-deoxyglucose (FDG) are used in the diagnosis of brain tumours. The aim of this study was threefold: (a) to assess the uptake of the different tracers in the F98 rat glioma, (b) to evaluate the impact of blood-brain barrier (BBB) disruption and microvessel density (MVD) on tracer uptake and (c) to compare the uptake in the tumours to that in the radiation injuries (induced by proton irradiation of healthy rats) of our previous study.. F98 gliomas were induced in 26 rats. The uptake of FET, FCH and FDG was measured using autoradiography and correlated with histology, disruption of the BBB and MVD.. The mean FET, FCH and FDG standardised uptake values (SUVs) in the tumour and the contralateral normal cortex (in parentheses) were 4.19+/-0.86 (1.32+/-0.26), 2.98+/-0.58 (0.51+/-0.11) and 11.02+/-3.84 (4.76+/-1.77) respectively. MVD was significantly correlated only with FCH uptake. There was a trend towards a negative correlation between the degree of BBB disruption and FCH uptake and a trend towards a positive correlation with FET uptake. The ratio of the uptake in tumours to that in the radiation injuries was 1.97 (FCH), 2.71 (FET) and 2.37 (FDG).. MVD displayed a significant effect only on FCH uptake. The degree of BBB disruption seems to affect the accumulation of FET and FCH, but not FDG. Mean tumour uptake for all tracers was significantly higher than the accumulation in radiation injuries.

Topics: Animals; Blood-Brain Barrier; Brain Injuries; Brain Neoplasms; Cell Line, Tumor; Choline; Fluorodeoxyglucose F18; Glioma; Male; Metabolic Clearance Rate; Radiation Injuries; Radionuclide Imaging; Radiopharmaceuticals; Rats; Rats, Inbred F344; Tyrosine