Positron emission tomography (PET) using radiolabeled amino acids has shown great potential for a more accurate diagnosis of cerebral gliomas. Magnetic resonance imaging (MRI) is the investigation of choice for diagnosing cerebral glioma, but its capacity to differentiate tumor tissue from non-specific tissue changes is limited. ([ 18 F] Fluoroethyl)-L-tyrosine (FET) is a new tracer for PET that can be produced with high efficiency and distributed on a wide clinical scale like [ 18 F]-Fluorodeoxyglucose (FDG). The use of FET PET allows better delineation of tumor margins and improves targeting of biopsy and radiotherapy, and planning surgery. In addition, amino acid imaging appears useful in distinguishing tumor recurrence from non-specific post-therapeutic scar tissue, predicting prognosis in low grade gliomas, and monitoring metabolic response during treatment.