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

To investigate the feasibility of [⁶⁸Ga]Ga-FAPI PET/CT in brain tumor imaging and to compare it with [¹⁸F]F-FDG PET/CT.

25 patients with MRI-suspected brain tumors were included in the study. They underwent whole body [¹⁸F]F-FDG PET/CT and [⁶⁸Ga]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 [¹⁸F]F-FDG PET/CT and [⁶⁸Ga]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.

[⁶⁸Ga]Ga-FAPI PET/CT was superior to [¹⁸F]F-FDG PET/CT for lesion detection, especially for brain metastases. Among gliomas, only high-grade gliomas uptake [⁶⁸Ga]Ga-FAPI. Compared with [¹⁸F]F-FDG PET/CT, [⁶⁸Ga]Ga-FAPI PET/CT had a lower SUVmax but a significantly better TBR. On [⁶⁸Ga]Ga-FAPI PET/CT, the TBR may be associated with brain tumor blood-brain barrier disruption.

[⁶⁸Ga]Ga-FAPI PET/CT is a promising imaging tool for the assessment of brain tumors. Lack of physiological uptake of [⁶⁸Ga]Ga-FAPI in normal brain parenchyma results in high TBR values, leading to better visualization of lesions and contributing to subsequent targeted therapy studies.

Clinical utility of [⁶⁸Ga]Ga-FAPI PET/CT in brain tumors remains unclear, and there aren't many similar studies in the literature. We evaluated the role of [⁶⁸Ga]Ga-FAPI PET/CT in diagnosing brain tumors.