TAC1 and glioblastoma: In phase 1 and 2 studies, this new form of targeted radiotherapy was successfully developed to treat recurrent glioblastomas [28,29,30,32] using radiopharmaceutical [213Bi]Bi/[225Ac]Ac-DOTA-substance P, which is a linear, small-peptide vector that is repeatedly injected locally into the tumor compartment in GBM.