STMO-5 Utilization of intraoperative multimodal technologies [PET and 5-ALA] for treating glioblastoma

Background: We can improve prognosis of glioblastoma by using positron emission tomography (PET) scans to guide them in removing tumors, and intraoperative magnetic resonance imaging (IoMRI) and 5-aminolevulinic acid (5-ALA) for identifying residual tumors. Tau proteins are reported to accumulate in glioblastomas, so we compared the efficacy of their PET tracer, THK5351, against that of (11)C-MET, (18)F-FLT, and (18)F-FMISO. Methods: Patients (n = 11) underwent scans between February 2020 and July 2021 for glioblastoma resection. Tumor-to-normal tissue accumulation ratio (TNR) and accumulation volumes of 4 PET tracers were evaluated. Following excisions, 5-ALA fluorescent evaluation was classified as strong, vague, or none. Residual tumor volumes and removal rates were determined using T1Gd assessments and PET tracers. IoMRI confirmed presence of residual tumors.Results: THK5351 had a TNR of 5.20, and its accumulated volume was greater than that of other tracers: 1.80 for (11)C-MET, 1.72 for (18)F-FLT, and 2.82 for (18)F-FMISO. 5-ALA fluorescent evaluation was vague (n = 7) or none (n = 4); respective residual tumor volumes (mL) were 2.3 and 0.2 (T1Gd), 5.7 and 0.9 ((11)C-MET), 5.6 and 0.6 ((18)F-FLT), 1.3 and 0.4 ((18)F-FMISO), and 7 and 1.4 (THK5351); respective tumor removal rates (%) were 90.4 and 99.6 (T1Gd), 79.2 and 86.4 ((11)C-MET), 84.4 and 89.2 ((18)F-FLT), 94.3 and 94.4 ((18)F-FMISO), and 72.3 and 83.4 (THK5351). The excised tumor tissue was found in the area where only THK5351 was accumulated.Conclusions: THK5351 accumulated in glioblastomas to a greater degree than that of other tracers, making it useful for discriminating between healthy and malignant tissues.