PT - JOURNAL ARTICLE AU - Chetsadaporn Promteangtrong AU - Dheeratama Siripongsatian AU - Attapon Jantarato AU - Anchisa Kunawudhi AU - Peerapon Kiatkittikul AU - Sukanya Yaset AU - Natphimol Boonkawin AU - Chanisa Chotipanich TI - Head-to-Head Comparison of <sup>68</sup>Ga-FAPI-46 and <sup>18</sup>F-FDG PET/CT for Evaluation of Head and Neck Squamous Cell Carcinoma: A Single-Center Exploratory Study AID - 10.2967/jnumed.121.262831 DP - 2022 Aug 01 TA - Journal of Nuclear Medicine PG - 1155--1161 VI - 63 IP - 8 4099 - http://jnm.snmjournals.org/content/63/8/1155.short 4100 - http://jnm.snmjournals.org/content/63/8/1155.full SO - J Nucl Med2022 Aug 01; 63 AB - 68Ga-conjugated fibroblast activation protein inhibitor (68Ga-FAPI) has become an attractive agent for PET. This study aimed to compare 68Ga-FAPI-46 PET/CT with 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 28 patients with HNSCC underwent 68Ga-FAPI-46 and 18F-FDG PET/CT for initial staging and recurrence detection, respectively. The concordance and diagnostic accuracy of both tracers were analyzed. Semiquantitative parameters, including SUVmax, SUVmean, and tumor-to-background ratio, were compared. Fibroblast activation protein (FAP) expression tumor volume and total lesion FAP expression of 68Ga-FAPI-46 were compared with metabolic tumor volume and total lesion glycolysis of 18F-FDG, respectively. Differences between semiquantitative parameters were analyzed using paired t testing. 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 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 &lt; 0.05), but no significant differences were observed for the other parameters. Conclusion: 68Ga-FAPI-46 PET/CT showed good concordance with, and comparable diagnostic performance to, 18F-FDG PET/CT for initial staging and recurrence detection in HNSCC patients.