Head-to-head assessment of [68Ga]Ga-DOTA-FAPI-04 PET/CT vs [18F]FDG PET/CT in fibroblastic tumors

Objectives: We aimed to evaluate [Ga-68]Ga-DOTA-FAPI-04 versus [F-18]FDG PET/CT in the application of fibro-blastic tumors.Methods: Twenty participants with 6 subtypes of fibroblastic tumors prospectively underwent F-18-FDG and [Ga-68] Ga-DOTA-FAPI-04 PET/CT examinations to evaluate the lesions. PET/CT findings were confirmed by surgical pathology of fifteen participants, puncture biopsy of two participants, or imaging follow-up of three participants. Two independent sample t tests were used to compare the uptake of [F-18]FDG vs [Ga-68]Ga-DOTA-FAPI-04 in primary, recurrent and metastatic lesions. One-way ANOVA was used to compare the uptake of [F-18]FDG or [Ga-68]Ga-DOTA-FAPI-04 among primary, recurrent, and metastatic lesions. The uptake of [Ga-68]Ga-DOTA-FAPI-04 vs [F-18]FDG in different histopathological lesions was compared by two independent sample t tests.Results: Twenty participants were confirmed to have 38 lesions. Although there was no significant difference in the detection of lesions between [Ga-68]Ga-DOTA-FAPI-04 and [F-18]FDG PET/CT (38 vs 36, p = 0.493), the uptake of [Ga-68]Ga-DOTA-FAPI-04 in lesions was significantly higher than that of [F-18]FDG (p < 0.001), including primary (p < 0.001), recurrent (p = 0.018) and metastatic (p < 0.001) lesions. The SUVmax of [Ga-68] Ga-DOTA-FAPI-04 in primary and recurrent lesions was higher than that in metastasis (p = 0.034 and p = 0.015, respectively). The SUVmax of [Ga-68]Ga-DOTA-FAPI-04 in primary and recurrent malignant lesions was significantly higher than that of the intermediate (p < 0.001). The SUVmax of [Ga-68]Ga-DOTA-FAPI-04 in one participant of recurrent SFT with 5 lesions was significantly lower after treatment than before treatment (p = 0.016). Conclusions: [Ga-68]Ga-DOTA-FAPI-04 outperformed [F-18]FDG PET/CT in displaying the primary, recurrent and metastatic lesions of fibroblastic tumors.