Recently, some studies have shown that delayed scanning with 18F-FDG PET may help to differentiate malignant from benign pancreatic lesions. However, no study has evaluated the relationship between temporal changes in 18F-FDG uptake and expression of hexokinase or glucose transporter. Methods: Twenty-one consecutive patients with pancreatic cancer were studied preoperatively by dual-phase 18F-FDG PET, performed 1 and 2 h after injection of 18F-FDG. The standardized uptake value (SUV) of the pancreatic cancer was determined, and the retention index (RI) (%) was calculated by subtracting the SUV at 1 h (SUV1) from the SUV at 2 h (SUV2) and dividing by SUV1. The percentages of cells strongly expressing hexokinase type-II (HK-II) and glucose transporter-1 (GLUT-1) were scored on a 5-point scale (1 = 0%-20%, 2 = 20%-40%, 3 = 40%-60%, 4 = 60%-80%, 5 = 80%-100%) by visual analysis of immunohistochemical staining of paraffin sections from the tumor specimens using anti-HK-II and anti-GLUT-1 antibody (HK-index and G-index, respectively). Results: SUV2 (mean ± SD, 5.7 ± 2.6) was higher than SUV1 (5.1 ± 2.1), with an RI of 8.5 ± 11.0. Four cases of cancer, in which SUV2 showed a decline from SUV1, showed a low HK-index (1.8 ± 1.1), whereas 4 cases with an RI of ≥ 20 and 13 cases with an intermediate RI (0-20) showed significantly higher HK-indices (4.3 ± 0.7 and 3.1 ± 1.5, respectively
P &lt
0.05). RI showed a positive correlation with HK-index, with an R2 of 0.27 (P &lt
0.05), but no significant correlation with the G-index. SUV1 showed no relationship with the HK-index but showed a weak positive correlation with the G-index, with an R2 of 0.05 (P = 0.055). Conclusion: These preliminary findings suggest that the RI obtained from dual-phase 18F-FDG PET can predict HK-II expression and that the SUV (at 1 h) has a positive correlation with GLUT-1 expression but not with HK-II expression.