[18F]FAPI PET/CT in Suspicious Focal Liver Lesions Without FDG Avidity

Inclusion Criteria: * patients with suspected liver malignant lesions based on traditional diagnostic imaging (CT or MRI or ultrasound) and clinical symptoms; * patients underwent \[18F\]FDG PET/CT with negative findings (suspicious primary and/or metastatic lesions were hypo- or isometabolic on \[18F\]FDG PET/CT); * patients who agreed to undergo \[18F\]FAPI PET/CT scans within 1 week. Exclusion Criteria: * pregnancy; * age\<18 years old; * patients with chemo/radio/targeted therapy before scanning; * inability to provide informed consent (signed by participant, parent, or legal representative).