Fig. 2.

Graphs showing ¹¹C-methionine (MET) (A), ¹¹C-choline (CHO) (C), and ¹⁸F-fluorodeoxyglucose (FDG) (E) lesion/normal brain uptake ratios (L/N ratios) of radiation necrosis (RN), recurrent grade 3- glioma (Gr.3), and recurrent glioblastoma (Gr.4), and MET (B), CHO (D), and FDG (F) L/N ratios of RN, anaplastic astrocytoma (AA), and anaplastic oligodendroglioma (AO). The significant differences of tracer uptake intensity between Gr.4 glioma recurrence and RN were shown in MET (P < 0.001), CHO (P < 0.001), and FDG (P < 0.001)-PETs. Gr. 3 glioma recurrence, especially for AO, could be distinguished from RN only in MET-PET (P < 0.005). Graph (G) shows receiver operating characteristic (ROC) curves for the three PET tracers for distinguishing glioma recurrence from RN. The areas under the curve of MET, CHO, and FDG are 0.926, 0.822, and 0.755, respectively. *P < 0.05, **P < 0.005, ***P < 0.001.