What would a pet scan show that a ct scan may not for a person with pancreatic cancer?

PET in cancer: PET scans are used to detect areas of abnormally increased metabolism, while CT scans only detect areas of differing density or lucency to radiation. So an abnormality like an area of scarred old tumor might look abnormal on CT scan but not have increased metabolism indicating active cancer on PET scan. False positives still occur with both, but they tend to commplement each other.