68Ga-Labeled 3PRGD2 for Dual PET and Cerenkov Luminescence Imaging of Orthotopic Human Glioblastoma

β-Emitters can produce Cerenkov radiation that is detectable by Cerenkov luminescence imaging (CLI), allowing the combination of PET and CLI with one radiotracer for both tumor diagnosis and visual guidance during surgery. Recently, the clinical feasibility of CLI with the established therapeutic reagent Na131I and the PET tracer 18F-FDG was demonstrated. 68Ga possesses a higher Cerenkov light output than 18F and 131I, which would result in higher sensitivity for CLI and improve the outcome of CLI in clinical applications. However, the research on 68Ga-based tumor-specific tracers for CLI is limited. In this study, we examined the use of 68Ga-radiolabeled DOTA-3PRGD2 (68Ga-3PRGD2) for dual PET and CLI of orthotopic U87MG human glioblastoma. For this purpose, the Cerenkov efficiencies of 68Ga and 18F were measured with the IVIS Spectrum system (PerkinElmer, USA). The CLI signal intensity of 68Ga was 15 times stronger than that of 18F. PET and CLI of 68Ga-3PRGD2 were performed in U87MG human glioblastoma xe...