Can pancreatic cancer or cancer in pancreas be detected with CT scan?

Often. Ct scan is a very good way to detect pancreatic cancer, but there are a few caveats. One, no test is 100% accurate. Two, some cancers may not be detected on ct scan because of the way the study was performed. Three, some may not be detectable due to small size or location. There may need to be other tests such as ERCP or endoscopic ultrasound.
Yes, but. A high resolution ct scan done in a certain way (pancreas protocol) has a very good chance of detecting a tumor in the pancreas, if evaluated by a radiologist with specialist level experience in pancreatic cases.
Often. Very small tumors may be missed. Generally suspicious masses can be seen. Sometimes special versions can be helpful.