FET-PET and Multiparametric MRI for High-grade Glioma Patients Undergoing Radiotherapy (IMAGG)

Glioblastoma is the most common malignant brain tumor in adults. The primary treatment consists of maximal tumor removal followed by radiotherapy (RT) with concomitant and adjuvant temozolomide. Tumor recurrence after chemoradiotherapy has previously been shown to be predominantly within or at the margin of the irradiated volume, but distant failure are not rare, especially in patients with MGMT methylation.Traditionally, RT has been planned based on on planning CT with co-registered postoperative MRI, with the addition of a clinical target volume margin of 2-3 cm to account for infiltrative odema.

To better characterize the disease, more specific physiological and/or metabolical markers of tumor cells, vascularization and hypoxia measured on multiparametric MRI as perfusion, diffusion and spectroscopy alongside with PET tracer like Fluoroéthyl-L-tyrosine ([18F]-FET) are now available and suggest that aggressive areas, like uptake of PET tracer and vascularity are present outside areas of contrast enhancement usually irradiated. These informations could be incorporated to optimize the treatment of radiotherapy.