[68Ga]Ga-FAPI PET/CT in brain tumors: comparison with [18F]F-FDG PET/CT

Purpose To investigate the feasibility of [Ga-68]Ga-FAPI PET/CT in brain tumor imaging and to compare it with [F-18]F-FDG PET/CT. Methods 25 patients with MRI-suspected brain tumors were included in the study. They underwent whole body [F-18]F-FDG PET/CT and [Ga-68]Ga-FAPI PET/CT and brain scans. The target-to-background ratio (TBR) of brain tumors was calculated with the background of surrounding normal brain tissues uptake. The SUVmax and TBR of [F-18]F-FDG PET/CT and [Ga-68]Ga-FAPI PET/CT were compared. Additionally, the correlation between the uptake of the tracer by lesions with the greatest diameter of the lesion, the breadth of the oedema band, and the enhancement scores of the MRI enhancement scans was analyzed. Result [Ga-68]Ga-FAPI PET/CT was superior to [F-18]F-FDG PET/CT for lesion detection, especially for brain metastases. Among gliomas, only high-grade gliomas uptake [Ga-68]Ga-FAPI. Compared with [F-18]F-FDG PET/CT, [Ga-68]Ga-FAPI PET/CT had a lower SUVmax but a significantly better TBR. On [Ga-68]Ga-FAPI PET/CT, the TBR may be associated with brain tumor blood-brain barrier disruption. Conclusions [Ga-68]Ga-FAPI PET/CT is a promising imaging tool for the assessment of brain tumors. Lack of physiological uptake of [Ga-68]Ga-FAPI in normal brain parenchyma results in high TBR values, leading to better visualization of lesions and contributing to subsequent targeted therapy studies. Advances in knowledge Clinical utility of [Ga-68]Ga-FAPI PET/CT in brain tumors remains unclear, and there aren't many similar studies in the literature. We evaluated the role of [Ga-68]Ga-FAPI PET/CT in diagnosing brain tumors.