In ten patients (n = 5 high-grade glioma, n = 5 brain metastasis) we showed by means of hybrid PET-MRI: 1) uptake of [68Ga]Ga-PSMA-11 in malignant brain tumours, which stably retained up to (at least) 240 min post-injection, while not engaging healthy brain, and 2) a median fifteen-fold higher uptake of [68Ga]Ga-PSMA-11 captured at the tumour site following ssIA administration, leading to standardised uptake values (SUVs) that well exceeded uptake in off-target dose-limiting organs such as the salivary glands, therewith qualifying more patients for treatment. This evidence concerns the gene FOLH1 and central nervous system cancer.