PET Imaging and Glioblastoma

Abstract

INTRODUCTION: Patients who present with Glioblastoma have a median survival of around 15 mo, even when treated with the most aggressive methods available. Imaging of glial cell tumours is faced with multiple challenges, including the accurate delineation of abnormal tissue and the identification of low-grade gliomas. PET imaging depicts aspects of tissue activity in Vivo and thus, helps us improve our understanding of the tumor's size and behavior. While functional imaging is already an established modality in other fields of oncology, the appropriate tracer for the imaging of glial cancers remains under investigation since FDG, the traditional oncological tracer, proves suboptimal due to the high physiological glucose uptake of the cerebral grey matter. METHOD(S): In this literature review, I discuss the physiological characteristics as well as the opportunities for clinical application of the tracers FDG, C-MET, FET, FDOPA and FLT. RESULT(S): Although PET imaging remains expensive and availability of tracers is limited by their mode of production and decaying nature, integration of PET scanning into the treatment pathway offers clear patient benefits. While sensitivity of the PET tracers C-MET and FET exceeds that of traditional imaging modalities, application in screening is limited by associated expenses. Combining amino-acid PET tracers with traditional modalities has shown significant benefits in biopsy and radiotherapy planning. CONCLUSION(S): All amino acid tracers show good results in distinguishing treatment response from early recurrence, a task where MRI, the current gold standard, is lacking in reliability. FET shows especially good results in monitoring residual tumour mass.