X-rays are a form of energy—radiation. X-rays exist in nature, radiating from outer space, rocks and even the soil. You can't see or feel X-rays. Because they're higher energy than visible light, X-rays can penetrate objects, including your body.

X-rays are one of the oldest forms of medical imaging. An X-ray is an electromagnetic beam that is aimed through your body to a piece of film behind it. This allows doctors to make pictures of the inside of your body.

Different parts of the body absorb the X-rays differently. The calcium in bone blocks X-rays completely. This creates a white shadow on the film. Because soft tissues such as organs, muscles, fat and nerves block part or none of the beam, they appear in shades of gray.

While X-rays are particularly useful in examining bony structures such as the spine, they are not helpful in showing nerve damage or herniated discs between the bones of the spine (the vertebrae).

X-rays, however, can be used to:

  • See whether a bone is chipped, dislocated or broken
  • Evaluate joint or spine injuries
  • Detect bone infections
  • Diagnose and monitor conditions such as arthritis or osteoporosis that grow worse over time
  • Identify scoliosis (an abnormal curvature of the spine) and other spinal defects

The film used to capture the X-ray is usually developed quickly. A radiologist, a doctor who is specially trained to read X-rays, will examine the film and send a report to your doctor or surgeon.

X-rays are generally safe and effective for children as well as adults. The radiation is well controlled and kept at low levels. In some cases, parts of your body may be covered with a lead apron to minimize your exposure to unnecessary X-rays.

If you are pregnant or think you might be, please let your doctor and the radiology technician know before you have an X-ray. Sometimes the benefits outweigh the risks. Your doctor may decide to use a different type of testing or postpone the X-ray to avoid any possibility of complications.

While X-ray technology hasn't changed much since it was developed by a German physicist about 100 years ago, it is the base for a number of other imaging techniques including:

  • Computerized tomography scanning, which uses X-ray images and a computer to create cross-section pictures of your body
  • Fluoroscopy, which creates real-time, moving images of your body

More information on preparing for your X-ray.