X-rays are electromagnetic waves which penetrate many materials to varying degrees. An x-ray machine is essentially a camera using x-rays instead of visible light to expose an image. X-rays are often the first tools doctors use to diagnose illness so that treatment can begin.
Since tissue, fat, muscle, tumors, bones, and other masses absorb X-rays at different levels, doctors may quickly determine the condition of the internal organs and skeletal structure in order to make crucial decisions. They may also use modified X-ray procedures to examine softer tissue, such as the lungs, blood vessels, or intestines.