Comparison of 18F-FDG and 11C-Methionine for PET-Guided Stereotactic Brain Biopsy of

We compared the contributions of the labeled tracers 11C-methionine (Met) and 18F-FDG for PET-guided stereotactic bi-opsy of brain gliomas. Methods: In 32 patients with glioma, stereotactic Met PET and 18F-FDG PET were integrated in the planning of stereotactic brain biopsy. PET images were ana-lyzed to determine which tracer offered the best information for target definition. The stereotactic coregistration of PET images allowed accurate comparison of the level, distribution, and ex-tent of uptake for both tracers according to tumor location and grade. Results: A histologic diagnosis was obtained for all patients. All gliomas had an area of abnormal Met uptake, and 27 showed abnormal 18F-FDG uptake. 18F-FDG was used for target selection when its uptake was higher in tumor than in gray matter (14 gliomas). Seven were in the basal ganglia or brain stem. Met was used for target selection when there was n