An X-ray is a quick, painless test that produces images of the structures inside your body — particularly your bones.
X-ray beams can pass through your body, but 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 look like varying shades of gray.
For some types of X-ray tests, contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the X-ray images. Some people experience side effects from contrast material. X-ray beams also expose you to small doses of radiation, but the benefits from these tests far outweigh the risks.
X-ray technology is used to examine many parts of the body.
Different types of X-rays require different preparations. Ask your doctor or nurse to provide you with specific instructions.
In general, you undress whatever part of your body needs examination. You may wear a gown to cover yourself during the exam, depending on which area is being X-rayed. You may also be asked to remove jewelry, eyeglasses and any metal objects that may obscure the X-ray image, because these objects can show up on an X-ray.
Before 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 as an enema.
Radiation exposure. You may worry that X-rays aren't safe because high levels of radiation exposure can cause cell mutations that may lead to cancer. But the amount of radiation you're exposed to during an X-ray is so small that the risk of any damage to cells in your body is extremely low.
However, if you're pregnant or suspect that you may be pregnant, inform your doctor before having an X-ray. Though the risk of most diagnostic X-rays to an unborn baby is small, your doctor may consider whether it's better to wait or to use another imaging test, such as ultrasound.