TSPO and glioblastoma: To address this issue, we conducted a longitudinal dual tracer TSPO and amino acid PET study using the TSPO PET tracer [18F]GE-180 [28] in direct comparison to [18F]FET at days 7/8 and 14/15 after the orthotopic inoculation of GL261 murine glioblastoma cells (n = 24) or sham inoculation (n = 6) into the brains of fully immunocompetent C57BL/6 mice.