A modern diagnostic tool for which the inventors have received the Nobel Prize in medicine and physiology. CAT stands for computerized axial tomography. It provides x-ray or gamma ray images of the interior of the body with unprecedented clarity and detail. To make a regular x-ray, one's body is placed between the x-ray source and the x-ray detector which is usually a sheet of x-ray film. The x-ray image is a superimposed set of shadows of everything between the source and detector, which can make finding a minute tumor or a tiny blocked artery quite difficult. A CAT scanner scans the x-ray source and electronic x-ray detector completely around the body in a circle. A computer memorizes and displays a series of three dimensional cross sections of the CAT scanned body. From a diagnostic standpoint, it is the next best thing to actually cutting the person up; indeed, much unnecessary surgery has been prevented by the use of CAT scanners.