X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones and organs on film or digital media. Standard X-rays are performed for many reasons, including diagnosing tumors or bone injuries. X-ray technology is used in many types of diagnostic procedures, such as arteriograms, computed tomography (CT) scans and fluoroscopy.

During an X-ray, different parts of the body allow varying amounts of X-ray beams to pass through:

• Soft tissues in the body (such as blood, skin, fat and muscle) allow most of the X-ray to pass through and appear dark gray on the film or digital media.
• A bone or a tumor, which is denser than soft tissue, allows only a few of the X-rays to pass through and appears white on the X-ray. At a break in a bone, the X-ray beam passes through the broken area and appears as a dark line in the white bone.