Promteangtrong_2022_J.Nucl.Med_63_1155

(68)Ga-conjugated fibroblast activation protein inhibitor ((68)Ga-FAPI) has become an attractive agent for PET. This study aimed to compare (68)Ga-FAPI-46 PET/CT with (18)F-FDG PET/CT for detecting primary cancer and metastatic lesions in patients with head and neck squamous cell carcinoma (HNSCC). Methods: Twelve patients and 28 patients with HNSCC underwent (68)Ga-FAPI-46 and (18)F-FDG PET/CT for initial staging and recurrence detection, respectively. The concordance and diagnostic accuracy of both tracers were analyzed. Semiquantitative parameters, including SUV(max), SUV(mean), and tumor-to-background ratio, were compared. Fibroblast activation protein (FAP) expression tumor volume and total lesion FAP expression of (68)Ga-FAPI-46 were compared with metabolic tumor volume and total lesion glycolysis of (18)F-FDG, respectively. Differences between semiquantitative parameters were analyzed using paired t testing. Results:(68)Ga-FAPI-46 PET/CT was 83.3% and 96.4% concordant with (18)F-FDG PET/CT for initial staging and recurrence detection, respectively. Eighteen lesions had histopathologic validation, and both tracers displayed 100% sensitivity, 50% specificity, and 94.4% accuracy for lesion-based analysis. FAP expression tumor volume was greater than metabolic tumor volume (P < 0.05), but no significant differences were observed for the other parameters. Conclusion:(68)Ga-FAPI-46 PET/CT showed good concordance with, and comparable diagnostic performance to, (18)F-FDG PET/CT for initial staging and recurrence detection in HNSCC patients.