18 F-FET PET for Detection of Recurrent Disease in Gliomas: Tips and Tricks for Interpretation

Gliomas are a heterogeneous group of primary brain tumors that are generally incurable. The current treatment paradigm for these tumors revolves around maximal safe resection and adjuvant chemoradiation; however, posttreatment changes can be difficult to distinguish from residual or recurrent disease. This makes it challenging to know whether treatments are working or the therapy should be escalated. Molecular imaging with amino acid PET has shown promise as a solution to this problem. The authors describe the interpretation considerations for the amino acid radiotracer fluorine 18-fluoroethyltyrosine (FET) in distinguishing posttreatment changes from recurrent glioma. The quantification of FET uptake on PET images and guidelines for interpretation are outlined.