The purpose of this study is to characterize tumour uptake of somatostatin analog 68Ga-DOTATOC in patients with either primary or recurrent malignant glioma. The investigators hypothesis is that some primary and recurrent malignant gliomas overexpress SST2 receptor which can be imaged with 68Ga-DOTATOC PET/CT. The investigators also hypothesize that tumor uptake of 68Ga-DOTATOC correlates with immunohistochemically determined SST2 receptor status of the tumor specimen.