What specialists try to do is get at least three imaging processes that are totally different from each other. Then you can run these through a computer program and make a composite image. In one scenario you suspect a brain tumor, so you image the brain tumor with PET scans, MRIs, and CT scans and create a 3D model. The doctor opens up the skull to excise the cancer, but they can't see anything. Do you cut out what's supposed to be in that spot or not? The current story is yes, you believe the images over what you see with your eyes.