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.