CAT refers to computerized axial tomography.
CAT scans are used detect diseases such as cancer. They also help doctors determine how effective a treatment is by letting them see if a tumor is shrinking. Initially, the CAT scan was used to generate images of only the head, but now it is used for the rest of the body. To begin imaging, the patient is placed in a tube like scanner. An X-ray source then revolves around the patients body, taking pictures.