Why can breast tumors be imaged using a scanner but colon or pancreatic cancer cannot?

Virtual colonoscopy.: Pancreatic tumors can be visualized using ct scan or MRI with pancreatic protocol and sometimes by ultrasound. Breast tumors can be visualized using mammogram, ultrasound and breast mri. Colon cancers can be visualized colonoscopy or air contrast barium enema. More recently colon cancers have been visualized using ct technology such as virtual colonoscopy although it is not yet considered standard.

See below: This is a difficult question to answer in short format. Mammogram and breast ultrasound can see breast tumors. Tumors of the colon are located inside the organ and are best seen by colonoscopy. Pancreas tumors or colon tumors can be seen by ct scan, but only when they become fairly large.