In gastric cancer, 18F-FDG PET/CT can non-invasively visualize tumor metabolic activity by measuring glucose uptake, facilitating early detection, accurate staging, and treatment response evaluation (9, 10).Despite its wide application, the relationship between 18F-FDG PET/CT metabolic parameters and HER2 expression in gastric cancer remains unclear. This evidence concerns the gene ERBB2 and gastric cancer.