RT Journal Article SR Electronic T1 Head-to-head comparison of 68Ga-FAPI-46 and 18F-FDG PET/CT for evaluation of head and neck squamous cell carcinoma: a single-center exploratory study JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP jnumed.121.262831 DO 10.2967/jnumed.121.262831 A1 Chetsadaporn Promteangtrong A1 Dheeratama Siripongsatian A1 Attapon Jantarato A1 Anchisa Kunawudhi A1 Peerapon Kiatkittikul A1 Sukanya Yaset A1 Natphimol Boonkawin A1 Chanisa Chotipanich YR 2021 UL http://jnm.snmjournals.org/content/early/2021/12/02/jnumed.121.262831.abstract AB 68Ga-conjugated fibroblast activation protein inhibitor (68Ga-FAPI) has become an attractive agent for positron emission tomography (PET). This study aimed to compare 68Ga-FAPI-46 PET/computed tomography (CT) with 18F-fluorodeoxy-D-glucose (18F-FDG) PET/CT for detecting primary cancer and metastatic lesions in patients with head and neck squamous cell carcinoma (HNSCC). Methods: Twelve patients and twenty-eight patients with HNSCC underwent 68Ga-FAPI-46 and 18F-FDG PET/CT for initial staging and recurrence detection, respectively. Concordance and diagnostic accuracy of both tracers were analyzed. Semiquantitative parameters, including the maximum and mean of standardized uptake value (SUVmax and SUVmean) and tumor-to-background ratio (T/B) were compared. FAP expression tumor volume (FTV) and total lesion FAP expression (TLF) of 68Ga-FAPI-46 were compared with metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of 18F-FDG, respectively. Differences between semiquantitative parameters were analyzed using paired t-tests. Results: 68Ga-FAPI -46 PET/CT was 83.3% and 96.4% concordant with 18F-FDG PET/CT for initial staging and recurrence detection, respectively. Eighteen lesions had histopathological validation and both tracers displayed 100% sensitivity, 50% specificity, and 94.4% accuracy for lesion-based analysis. FTV was greater than MTV (P < 0.05), but no significant differences were observed for the other parameters. Conclusion: 68Ga-FAPI-46 PET/CT showed good concordance and comparable diagnostic performance compared with 18F-FDG PET/CT for initial staging and recurrence detection in patients with HNSCC.