TY  - CONF
AU  - Stegmayr, Carina
AU  - Willuweit, Antje
AU  - Schöneck, Michael
AU  - Filss, Christian
AU  - Shah, N. J.
AU  - Coenen, Heinrich Hubert
AU  - Ermert, Johannes
AU  - Langen, Karl-Josef
TI  - Reproducibility of O-(2-[F-18]fluoroethyl)-L-tyrosine kinetics in brain tumors and influence of dexamethasone therapy: A PET study in rat gliomas
M1  - FZJ-2016-07747
PY  - 2015
AB  - Objectives: Previous studies have shown that uptake kinetics of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) in brain tumors correlates with the grade of malignancy. This study investigates the reproducibility of FET kinetics in rat gliomas and the influence of the commonly used dexamethasone (Dex) therapy.Methods: Tumor cells were implanted in the striatum of 31 Fischer rats (15 rats with 9L gliosarcoma; 16 with F98 glioma). Dynamic FET PET (0-60 min post injection, p.i.) was performed after 10 days of tumor growth (baseline) and 48 h later (control) using animal PET (Inveon). Group 1 (n= 8 for 9L; n=10 for F98) received no treatment and group 2 (n= 7 for 9L; n=6 for F98) was injected with 8 mg/kg Dex intraperitoneal after baseline PET plus 4 mg/kg Dex 24 h and 1 h before control PET. Tumor to brain ratios (TBR) (18-60 min p.i.) and the slope of a linear fit of the time activity curve (15 to 60 min p.i.) were determined.Results: The two tumor models showed different FET kinetics (9L slope: +0.17 ± 0.12 SUV/h; F98 slope: +0.76 ± 0.09 SUV/h; p < 0.001) and different TBR (9L: 1.87 ± 0.07; F98: 1.98 ± 0.07; p = 0.005). Both models showed no significant changes of slope in both groups. In all untreated gliomas, TBR slightly increased (9L: 1.87 ± 0.07 vs. 1.95 ± 0.08, p < 0.001; F98: 1.98 ± 0.07 vs. 2.04 ± 0.06, p = 0.002) from baseline to control scan, while the TBR in all Dex treated gliomas decreased (9L: 1.86 ± 0.03 vs. 1.65 ± 0.08, p < 0.001; F98: 1.99 ± 0.10 vs. 1.89 ± 0.15, p = 0.025). This decrease is due to enhanced FET accumulation in normal brain tissue after Dex treatment.Conclusions: FET kinetics in cerebral gliomas show high reproducibility and little interference with Dex therapy. Thus, changes of FET kinetics may be considered reliable indicators of biological reactions occurring in brain tumors during radio/chemotherapy.
T2  - 21st International Symposium on Radiopharmaceutical Sciences
CY  - 26 May 2015 - 31 May 2015, Columbia (USA)
Y2  - 26 May 2015 - 31 May 2015
M2  - Columbia, USA
LB  - PUB:(DE-HGF)24
UR  - https://juser.fz-juelich.de/record/825276
ER  -