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X-Rays
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Diagnostic Tests

X-Rays

X-rays are a painless medical imaging test that use a small amount of radiation to create images of bones and organs to help providers diagnose health issues.

What is an x-ray?

X-rays are a painless medical imaging test. They send a small amount of radiation through your body to create pictures of bones and organs.

X-rays are a type of electromagnetic radiation. They create images in shades of black, white, and gray because different tissues absorb radiation differently:

  • Bones absorb the most radiation and appear white.
  • Fat and other soft tissues absorb less and appear gray.
  • Air absorbs the least radiation, so areas like the lungs appear black.

The image is recorded on film or sent to a computer. Health care providers use x-rays to find health problems and to check how well certain treatments are working.

Who needs an x-ray?

X-rays are commonly used to check for fractures (broken bones). They are also used for other purposes:

  • Chest x-rays can detect pneumonia.
  • Mammograms use x-rays to look for breast cancer.
  • X-rays are also used as part of other imaging tests, such as CT scans.

How do you prepare for an x-ray?

In most cases, little or no preparation is needed. You may be asked to wear a lead apron to protect certain parts of your body. You may also be asked to remove jewelry or other items that could affect the image.

The amount of radiation from an x-ray is small. For example, the radiation from a chest x-ray is about the same as the natural radiation you are exposed to from the environment over about 10 days.

Always tell your provider if you are pregnant or think you may be pregnant.

How is an x-ray done?

Depending on the part of your body being examined, you may be asked to stand, sit, or lie down. You will need to stay still for a short time while the image is taken.

What should you expect after an x-ray?

After an x-ray, you can return to normal activities right away. A specialist called a radiologist reviews the images and shares the results with your provider.

Frequently Asked Questions

Tell the technologist or ordering clinician immediately. In most cases, a chest X‑ray can be performed with a lead apron shielding the abdomen, and the radiation dose is too low to harm a fetus. However, for abdominal or pelvic X‑rays, the exam is usually postponed until after pregnancy or replaced with an ultrasound if urgent imaging is needed.
Each X‑ray delivers a very low dose of radiation—often comparable to a few days of natural background exposure. While a single exam is safe, cumulative exposure can become a concern if you undergo many high‑dose studies (e.g., CT scans) in a short period. Your provider will track total exposure and choose the lowest‑dose technique or alternative imaging (like ultrasound or MRI) when appropriate.
Generally, no special preparation is required for a standard chest X‑ray. You can eat, drink, and take routine medications as usual. The only exception is if you are scheduled for a contrast‑enhanced study (rare for plain X‑rays), where you might be asked to fast for a few hours.
If the technologist notices poor positioning, motion blur, or inadequate exposure, they will usually repeat the image right away to ensure diagnostic quality. You won’t need a separate appointment; the repeat is done during the same visit, and the extra radiation dose is minimal.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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