An X-ray is a quick, painless test that captures images of the structures inside the body — particularly the bones.
X-ray beams pass through the body. These beams 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 the 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 put into the body to get greater detail on the images.
X-ray technology is used to examine many parts of the body.
Some people worry that X-rays aren't safe. This is because radiation exposure can cause cell changes that may lead to cancer. The amount of radiation you're exposed to during an X-ray depends on the tissue or organ being examined. Sensitivity to the radiation depends on your age, with children being more sensitive than adults.
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 healthcare team before having an X-ray. Though most diagnostic X-rays pose only small risk to an unborn baby, your care team may decide to use another imaging test, such as ultrasound.
In some people, the injection of a contrast medium can cause side effects such as:
Rarely, severe reactions to a contrast medium occur, including:
Different types of X-rays require different preparations. Ask your healthcare team to provide you with specific instructions.
In general, you undress whatever part of your body needs examination. You may wear a gown during the exam depending on which area is being X-rayed. You also may be asked to remove jewelry, eyeglasses and any metal objects because they can show up on an X-ray.
Before having some types of X-rays, you're given a liquid called contrast medium. Contrast mediums, such as barium and iodine, help outline a specific area of your body on the X-ray image. You may swallow the contrast medium or receive it as an injection or an enema.
X-rays are performed at medical offices, dentists' offices, emergency rooms and hospitals — wherever an X-ray machine is available. The machine produces a safe level of radiation that passes through the body and records an image on a specialized plate. You can't feel an X-ray.
A technologist positions your body to get the necessary views. Pillows or sandbags may be used to help you hold the position. During the X-ray exposure, you remain still and sometimes hold your breath to avoid moving so that the image doesn't blur.
An X-ray procedure may take just a few minutes for a simple X-ray or longer for more-involved procedures, such as those using a contrast medium.
If a young child is having an X-ray, restraints or other tools may be used to keep the child still. These won't harm the child and they prevent the need for a repeat procedure, which may be necessary if the child moves during the X-ray exposure.
You may be allowed to remain with your child during the test. If you remain in the room during the X-ray exposure, you'll likely be asked to wear a lead apron to shield you from unnecessary X-ray exposure.
After an X-ray, you generally can resume usual activities. Routine X-rays usually have no side effects. However, if you're given contrast medium before your X-ray, drink plenty of fluids to help rid your body of the contrast. Call your healthcare team if you have pain, swelling or redness at the injection site. Ask your team about other symptoms to watch for.
X-rays are saved digitally on computers and can be viewed on-screen within minutes. A radiologist typically views and interprets the results and sends a report to a member of your healthcare team, who then explains the results to you. In an emergency, your X-ray results can be made available in minutes.
