To evaluate the role of 18 FDG-PET in the differential diagnosis of recurrence and radionecrosis in glioma. FDG-PET scans in 15 glioma patients were performed after initial surgery and radiation therapy. Results of the 12 tumor recurrence

11 FDG-PET scans showed hypermetabolism

3 patients with hypometabolic abnormalities on FDG-PET scan had no evidence of recurrence. In recurrence

the primary site showed platelike

ringform and tocal FDG uptake and also increased uptake in remote area. In tumor recurrent patients

the lesion’s highest radioactivity/average white matter radioactivity ratio was 2.85±1.0

while the ratio of radionecrosis was 1.32±0.07

the differences were significant. Conclusions show that FDG-PET scans are helpful in the differentiation between tumor recurrences and radionecrosis in glioma.