Photo courtesy Department of Defense
CAT scans take the idea of conventional X-ray imaging to a new level. Instead of finding the outline of bones and organs, a CAT scan machine forms a full three-dimensional computer model of a patient's insides. Doctors can even examine the body one narrow slice at a time to pinpoint specific areas.

In this edition of HowStuffWorks, we'll examine the basic idea of CAT scans. While the computer technology involved is fairly advanced, the fundamental concept at work is really very simple.