MKI67 and glioblastoma: In that study, in GBM patients, the area of 11C-Met uptake at a tumor-to-contralateral normal brain tissue ratio (TNR) of 1.4 on 11C-Met-PET is generally larger than the area of the Gd-enhanced tumor mass on MRI, and areas showing a TNR over 1.4 for 11C-Met uptake included active tumor cells with a relatively high Ki-67 labeling index (LI).