Krystyna Maria Adamska MD, PhD, Presenter: Nothing to Disclose

Paulina Cegla, Abstract Co-Author: Nothing to Disclose

Witold Cholewinski, Abstract Co-Author: Nothing to Disclose

Joanna Kazmierska, Abstract Co-Author: Nothing to Disclose

Ewa Wierzchoslawska, Abstract Co-Author: Nothing to Disclose

Michal Smolen, Abstract Co-Author: Nothing to Disclose

Dorota Jezierska, Abstract Co-Author: Nothing to Disclose

Agnieszka Lewandowska, Abstract Co-Author: Nothing to Disclose

18F-FET (tyrosine) is an interesting PET tracer, which have shown promising results in the imaging of brain tumors. 18F-FDG (Deoxyglucose) is a widely used PET tracer however due to physiologic uptake within brain tissue its use in brain tumors is limited. The aim of the study was to evaluate the usefulness of FET-PET and FDG-PET imaging in the detection of glioma recurrence and in the radiotherapy planning.  

13 patients with mean age of 56y±13 and histologically confirmed gliomas were enrolled in the study. The FET scans were performed 20-40 minutes after intravenous injection of 160MBq of 18F-FET. The FDG imaging was performed 60min after injection of 370MBq of 18F-FDG. Scans were acquired on Gemini TF PET/CT scanner using 3D brain imaging protocol over 10min acquisition time. The PET images were evaluated on a dedicated workstation. On reconstructed images, the tumor borders are drawn using semiautomatic dedicated software based on 70% threshold values. Tumor borders and volume were calculated on each nuclear image and compared with the volume calculated on the diagnostic MRI. For each tumor region the tumor-to-background ratio was calculated for both FET and FDG images.  

FET-PET/CT method showed 30 lesions in 11pts with mean SUVmax value of 2.33 (range 1.6-3.5). Based on 70% threshold cutoff value the mean volume of brain foci was calculated on at 40.49±119.27cc. In FET imaging tumor-to-background ratios varied from 1.3 to 1.9. In all but one case in FDG imaging the tumor-to-background ratios showed values below 1.0 (0.5-0.8). There was a mild positive correlation between tyrosine in glucose metabolism in glioma reccurence (r=0.544). In total FET imaging showed more abnormal lesions that MRI, however the difference was not significant (p>0.05).  

18-FET PET/CT seems to be more sensitive than FDG-PET in the detection of the recurrence of glioma brain tumors and may be helpful in radiation therapy planning.

FET-PET/CT and MRI can be used together to improve the diagnostic accuracy of recurrence glioma and planning radiation therapy. Correlation between FDG and FET uptake in brain tumors requires further studies of its potential use as diagnostic and prognostic measure.  

Adamska, K, Cegla, P, Cholewinski, W, Kazmierska, J, Wierzchoslawska, E, Smolen, M, Jezierska, D, Lewandowska, A, Evaluation of Glioma Recurrence Using Dual Tracer 18F-FET and 18F-FDG PET/CT Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006153.html