This study compared the performance of 18F-fibroblast activation protein inhibitor (FAPI)-04 PET/CT with 18F-FDG PET/CT in the evaluation of pancreatic ductal adenocarcinoma (PDAC). Sixty-two PDAC patients underwent both imaging techniques. The results showed that 18F-FAPI-04 PET/CT identified all primary tumors, while 18F-FDG PET/CT missed one case. 18F-FAPI-04 PET/CT demonstrated higher tracer uptake in primary tumors, lymph node metastases, and distant metastases (liver and peritoneal) compared to 18F-FDG PET/CT. The methods showed no significant difference in T staging but had higher N and M values for 18F-FAPI-04 PET/CT. 18F-FAPI-04 PET/CT upgraded the TNM staging in 14 patients and downgraded it in one patient. A high SUVmax of the primary tumor did not correlate with treatment response for either tracer. The study concluded that 18F-FAPI-04 PET/CT outperformed 18F-FDG PET/CT in identifying primary tumors, lymph node metastases, and distant metastases, and in TNM staging of PDAC.This study compared the performance of 18F-fibroblast activation protein inhibitor (FAPI)-04 PET/CT with 18F-FDG PET/CT in the evaluation of pancreatic ductal adenocarcinoma (PDAC). Sixty-two PDAC patients underwent both imaging techniques. The results showed that 18F-FAPI-04 PET/CT identified all primary tumors, while 18F-FDG PET/CT missed one case. 18F-FAPI-04 PET/CT demonstrated higher tracer uptake in primary tumors, lymph node metastases, and distant metastases (liver and peritoneal) compared to 18F-FDG PET/CT. The methods showed no significant difference in T staging but had higher N and M values for 18F-FAPI-04 PET/CT. 18F-FAPI-04 PET/CT upgraded the TNM staging in 14 patients and downgraded it in one patient. A high SUVmax of the primary tumor did not correlate with treatment response for either tracer. The study concluded that 18F-FAPI-04 PET/CT outperformed 18F-FDG PET/CT in identifying primary tumors, lymph node metastases, and distant metastases, and in TNM staging of PDAC.