Comparison of [68Ga]Ga-DOTA-FAPI-04 PET/CT with [18F]FDG PET/CT for Nodule Characterization and Staging in NSCLC Patients

Abstract Purpose:The aim of this study is to explore the nodule characterization and staging efficacy of [68Ga]Ga-DOTA-FAPI-04 PET/CT in non-small cell lung cancer (NSCLC) patients and to compare with that of [18F]FDG PET/CT lesion-by-lesion.Methods:Sixty-five patients with clinically diagnosed or suspected NSCLC were enrolled in this prospective study (ChiCTR2000038080). All patients received both [18F]FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT, and they were assigned into three groups by different research directions as nodule characterization, node (N) staging and metastatic (M) staging. Imaging characteristics in PET/CT of lung nodules and suspected metastatic lesions were obtained and analyzed.Results:In the nodule characterization group, [18F]FDG and [68Ga]Ga-DOTA-FAPI-04 SUVmax ≥ 2.5 was set as the predictor of NSCLC, and the diagnostic sensitivity of [68Ga]Ga-DOTA-FAPI-04 was higher than [18F]FDG (0.88 vs. 0.67). And for adenocarcinoma with partial-solid density, SUVmax of 68Ga-DOTA-FAPI-04 was higher than [18F]FDG with significant differences (4.8 ± 2.8 vs. 2.1 ± 1.1). In N staging group, lymph nodes SUVmax of [68Ga]Ga-DOTA-FAPI-04 was lower than [18F]FDG in nonmetastatic group (3.1 ± 1.3 vs. 6.1 ± 2.3) and higher than [18F]FDG (10.7 ± 4.7 vs. 6.5 ± 3.3) in metastatic group. Set 6 and 1.1 as the cut-off value for [68Ga]Ga-DOTA-FAPI-04 SUVmax and [68Ga]Ga-DOTA-FAPI-04 SUVmax/FDG SUVmax, diagnostic accuracy of metastatic lymph nodes using each criterion and their combination was 95%, 93% and 97% respectively. In multi-metastatic NSCLC patients, [68Ga]Ga-DOTA-FAPI-04 identified more lesions than [18F]FDG (206 vs. 106 lesions) and the uptake value of [68Ga]Ga-DOTA-FAPI-04 was higher too, but no patients’ staging was changed.Conclusion:Compared with [18F]FDG, [68Ga]Ga-DOTA-FAPI-04 PET/CT imaging has higher sensitivity in primary and metastatic lesion detection of NSCLC patients, it also increases the specificity of metastatic lymph nodes diagnosis.