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Key points

  • An X-ray is a test that uses radiation to produce an image of the inside of your body.
  • The image that is produced is called a radiograph.
  • X-rays can be used to diagnose and monitor different conditions.

X-rays use radiation to produce images of the inside of your body.

About X-rays

An X-ray is a quick and painless test that can help to diagnose and monitor a number of different health conditions. X-rays are carried out by radiographers (health professionals trained to perform imaging techniques).

X-rays are commonly used to look for fractures in your bones after a fall or injury. They can also show changes in your organs. For example, an X-ray image of your chest can show whether you have an infection in your lungs.

X-rays are a form of radiation. Unlike light radiation (normal light), which is absorbed or reflected by your skin, X-ray radiation passes through your body. An X-ray machine works by projecting a beam of X-rays through the part of your body that your doctor needs to look at. An X-ray sensitive detector then captures the radiation that comes out on the other side of your body in the form of a black and white image. This is called a radiograph.

A radiograph is created as a result of the X-rays being absorbed differently by different structures or organs in your body. Structures inside your body that are dense, such as your bones, absorb X-rays and show as light grey on the radiograph. Less dense structures, like the air in your lungs, let X-rays pass through them and show up as dark grey on the radiograph.

The images captured by an X-ray machine are usually stored digitally and displayed on a computer screen.

What are the alternatives?

Depending on which part of your body is being looked at, a different type of imaging test may be more appropriate. Alternative tests may include an ultrasound scan, MRI scan or CT scan. Your doctor will discuss with you which test is most suitable.

Preparing for an X-ray

X-rays are usually done as an outpatient procedure in the radiology or imaging department of a hospital or health clinic.

Your radiographer will discuss with you what will happen before, during and after the test. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the test.

What happens during an X-ray

X-rays usually only take about 20 minutes.

Depending on the area of your body that needs to be exposed to the X-rays, you may be asked to remove your clothing, put on a hospital gown and take off your jewellery. There will usually be a private area where you can do this.

You will then go to the X-ray room and your radiographer will help you to get into the right position on the X-ray machine. Alternatively, you may be asked to lie down on an X-ray table or sit in a chair at the side of the table, depending on the part of your body being looked at. You will be asked to stay still and sometimes, particularly if you’re having a chest X-ray, to take a deep breath and hold it for a few seconds.

A radiographer preparing a woman for an X-ray

Having an X-ray

Your radiographer will operate the X-ray machine from behind a screen, but will be able to see and hear you at all times. He or she may need to take more than one X-ray, and so you may have to get into a number of slightly different positions on the machine.

The images will then be sent to a radiologist (a doctor who specialises in using imaging methods to diagnose medical conditions).

What to expect afterwards

You will usually be able to go home when you feel ready.

Your doctor will usually receive a report from the radiologist. He or she may also receive your X-ray images. This can take several days. Before you go home, ask your radiographer when you can expect to get your results.

If you’re seeing a radiologist, he or she may be able to view your images on a computer screen immediately after having your X-ray.

It may be possible to ask for a copy of your images on a disc or have them sent to another hospital electronically. This is particularly useful if you will be seeing a doctor in a different hospital or, for instance, if you will be travelling abroad.

What are the risks?

As with every test there are some risks associated with having an X-ray. However, the benefits of having the test usually outweigh these risks. You will be exposed to some X-ray radiation, but the amount you receive isn't considered to be harmful.

You're exposed to natural background radiation in the atmosphere all the time. For example, the amount of radiation you're exposed to during a chest X-ray is the equivalent of a few days of this background radiation.

Different radiology tests expose you to different doses of radiation. For example, the amount of radiation you receive from a plain X-ray is lower than other types of radiology tests, such as a CT scan. However, radiographers are trained to keep your exposure to a minimum. Ask your radiographer to explain how these risks apply to you.

If you’re pregnant

Although the radiation from an X-ray is generally thought to be safe for adults, it may harm an unborn baby. Therefore, X-rays won’t usually be used on pregnant women unless there is an urgent medical reason.

If you think you could be pregnant, tell your doctor before your appointment. Your doctor will advise you whether or not to go ahead with the test.


Reviewed by Kuljeet Battoo, Bupa Health Information Team, August 2013.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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