Positron Emission Tomography (PET) enables noninvasive evaluation of brain tumours, most commonly gliomas and metastases. However, the application of PET in distinguishing a tumour from an inflammatory lesion is still uncertain. The principle of this imaging test is based on fundamental differences in the central metabolic pathways in neoplastic and non-neoplastic tissues. 2-deoxy-2-fluoro-D-glucose (FDG) is the most widely used PET marker, whose uptake is closely related to the expression of the glucose transporter (GLUT) in malignant tumours. A limitation of FDG-PET studies is false-positive results, e.g., due to inflammation. This problem may be overcome by the use of different radiotracers targeted at different cellular sites; these include, fluoroethyl-l-tyrosine (FET), C- methionine (c- MET), 13-N ammonia, translocator receptor protein (TSPO) and ligand-11C-PK11195. All markers show variable diagnostic potential, however, more prospective trials are required to prove the efficacy.
Keywords: PET, Inflammation, Tumour, FDG..