In a prospective study using 68Ga-PSMA-617 in a small sample of patients with recurrent glioma, 68Ga-PSMA-617 accumulated in large parts of the tumor that extended beyond the 18F-FET-avid margins, suggesting that PSMA ligands target a complementary biological process and might be a useful diagnostic marker to delineate parts of the recurrent tumor that are neoangiogenic but not extremely metabolically active yet. Here, FOLH1 is linked to central nervous system cancer.