An X-ray is a quick, painless test that produces images of the structures inside your body — particularly your bones.
X-ray beams pass through your body, and they are absorbed in different amounts depending on the density of the material they pass through. Dense materials, such as bone and metal, show up as white on X-rays. The air in your lungs shows up as black. Fat and muscle appear as shades of gray.
For some types of X-ray tests, a contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the images.
Why it's done
X-ray technology is used to examine many parts of the body.
Bones and teeth
- Fractures and infections. In most cases, fractures and infections in bones and teeth show up clearly on X-rays.
- Arthritis. X-rays of your joints can reveal evidence of arthritis. X-rays taken over the years can help your doctor determine if your arthritis is worsening.
- Dental decay. Dentists use X-rays to check for cavities in your teeth.
- Osteoporosis. Special types of X-ray tests can measure your bone density.
- Bone cancer. X-rays can reveal bone tumors.
Chest
- Lung infections or conditions. Evidence of pneumonia, tuberculosis or lung cancer can show up on chest X-rays.
Chest X-rays may be used to diagnose, stage and treat lung cancer. In low doses, X-rays may be used to construct images of structures inside the body to detect and stage a tumor. Chest X-rays help doctors determine how well treatments are working and are often performed before surgery so doctors are able to see the structures in the chest in advance.
- Enlarged heart. This sign of congestive heart failure shows up clearly on X-rays.
- Blocked blood vessels. Injecting a contrast material that contains iodine can help highlight sections of your circulatory system to make them visible on X-rays.
- Breast cancer. Mammography is a special type of X-ray test used to examine breast tissue.
Abdomen
- Digestive tract problems. Barium, a contrast medium delivered in a drink or an enema, can help reveal problems in your digestive system.
- Swallowed items. If your child has swallowed something such as a key or a coin, an X-ray can show the location of that object.
Risks
Radiation exposure
- Generally, however, radiation exposure from an X-ray is low, and the benefits from these tests far outweigh the risks.
- However, if you are pregnant or suspect that you may be pregnant, tell your doctor before having an X-ray.
Contrast medium
In some people, the injection of a contrast medium can cause side effects such as:
- feeling of warmth or flushing
- metallic taste
- Lightheadedness
- Nausea
- Itching
- Hives