FAP and neoplasm: In this study, we evaluated the potential of gallium-68 (68Ga)-labeled DOTAGA-Glu(FAPi)2 ([68Ga]Ga-DOTAGA-Glu(FAPi)2) for the in vivo PET imaging of mice xenografted with an endogenously FAP-expressing human glioblastoma cell line, aiming to demonstrate enhanced tumor uptake and retention, thereby supporting its use as an effective theranostic agent.