Expert reviewer, Dr Daniel Boxer, Consultant Radiologist
Next review due May 2022

X-ray tests (also called scans) are quick and painless. They use small amounts of radiation to take pictures of the inside of your body — especially your chest or bones.

Doctor looking at an x-ray

About X-ray tests

An X-ray machine sends X-ray beams through the part of your body that your doctor needs to look at. An X-ray-sensitive detector then captures the radiation that has passed through your body and converts it into a black and white image. This is called a radiograph.

X-rays are absorbed differently by different structures, tissues and organs in your body. Dense (very solid) structures such as your bones absorb X-rays and appear light grey on the radiograph. Less dense structures like your air-filled lungs let X-rays pass through them and show up as dark grey or black.

For some types of X-ray tests, a contrast medium such as iodine or barium may be given as a drink or enema. This means a more detailed radiograph (X-ray image) is produced.

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

What are X-ray tests used for?

X-rays are a type of radiation that is used to produce images of many parts of the inside of your body. These images are used to examine your bones and joints, as well as sometimes helping to detect different health conditions. The scans are carried out by radiographers (health professionals trained to perform imaging techniques). Dental X-ray tests are carried out by dentists.

Some of the problems that may be revealed by an X-ray image (radiograph) are listed here.

Chest and breast

  • Heart problems. X-ray scans can occasionally show if there are problems with your heart.
  • Infections and conditions. Doctors can take an X-ray image of your chest to show if you have fluid or an infection in your lungs. Chest X-rays can also reveal evidence of lung cancer.
  • Breast cancer. A type of X-ray test called a mammography is used to examine breast tissue.


  • Fractures and infections. X-ray images are commonly used to look for infections and breaks (fractures) in your bones.
  • Osteoporosis. Some types of X-ray test are used to measure bone density.
  • Arthritis. X-ray images of your joints may show signs of arthritis. If a series of images is taken over a period of time, they can help your doctor to decide if your arthritis is getting worse.
  • Bone cancer. X-ray images may show if you have bone tumours.

Abdomen (belly)

  • Swallowed objects. An X-ray scan can find the location of an object such as a coin that may have been swallowed by a child.
  • Abdominal pain. An X-ray image may help to find the cause of abdominal pain or vomiting. It may detect a blockage in the bowel or an inflamed bowel.

Teeth and jaw

  • Teeth decay. Dentists use X-ray images to help them to find and treat dental problems.

Special X-ray tests that use iodine-based dyes or other contrast materials are sometimes used to get more detailed pictures of the inside of your body. For example, some people may need a test called a ‘contrast swallow’. This is an X-ray examination to show the throat and oesophagus in detail as you swallow a special liquid at the same time as X-ray images are taken.

You may need to make some preparations before your X-ray test is performed. If so, details will be provided in your appointment letter.

Preparing for an X-ray test

You usually have an X-ray test as an out-patient procedure in the radiology or imaging department of a hospital, health clinic or dental practice.

You can eat and drink beforehand, as normal, and continue taking your usual medications. However, if you’re having an X-ray scan that uses a contrast agent, you may need to avoid eating and drinking beforehand and taking certain medications. Your appointment letter will provide you with information on what you need to do to prepare.

For any X-ray test, it’s important to let the hospital know in advance if you’re pregnant.

Depending on which part of your body is being scanned, you may wish to wear appropriate clothing that’s easy to remove.

Your radiographer will discuss with you what will happen before, during and after an X-ray test. If you’re unsure about anything, don’t be afraid to ask. No question is too small. It’s important that you feel fully informed so you’re happy to go ahead with the procedure.

What happens during an X-ray test?

You may be asked to remove your clothing, put on a hospital gown and take off your jewellery before an X-ray. This will depend on the area of your body that’s being exposed to the radiation. You’ll usually be taken to a private cubicle so that you can change.

Your radiographer will help you to get into the right position on the X-ray machine. Or you may be asked to lie down on an X-ray table or sit in a chair beside the table. It may take a few minutes to get you into the right position. During the X-ray you’ll need to keep still. Sometimes, especially if you’re having a chest X-ray, you’ll need to take a deep breath and hold it for a few seconds.

Your radiographer will stand behind a screen to use the X-ray machine. But they’ll be able to see and hear you at all times. They may need to take more than one X-ray, or X-rays at different angles. You may have to get into a number of slightly different positions for this.

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

What to expect after an X-ray test

You’ll usually be able to go home or back to work when you feel ready.

Your doctor normally receives a report from the radiologist. If your doctor is based in the hospital, they 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.

You may be able 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’re seeing a doctor in a different hospital or are likely to be travelling abroad.

X-ray test results are usually ready within two weeks. You will usually be given them at a follow-up appointment with your specialist, who will be able to view the images. If you haven’t heard anything after a couple of weeks, contact the doctor who arranged the test.

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Are X-ray tests safe?

As with every medical test, X-ray scans have some possible risks. Having several X-rays may slightly increase your chance of getting cancer many years later. If you’ve had any X-ray or other scans recently, let your doctor know – you may not need more tests.

The benefits of having an X-ray test usually far outweigh the risks. We're exposed to natural background radiation in the atmosphere all the time. When you have an X-ray test, you’ll be exposed to some radiation. But the amount of radiation you receive is generally low and is not considered to be harmful.

Different radiology tests expose you to different doses of radiation. The amount of radiation you're exposed to during a chest X-ray is the same as around three days of natural radiation from the atmosphere. And the amount of radiation you receive from a plain X-ray test is lower than other types of radiological test such as a CT scan.

Research shows that risk from the low level of radiation from X-ray tests is very small compared to lifestyle risks such as air pollution, smoking and obesity.

Children and X-rays

The radiation from an X-ray test is generally thought to be safe for adults, but children are more sensitive to its damaging effects. Your doctor will only refer your child for an X-ray test if it’s absolutely necessary. If your child has an X-ray scan, it’s likely that you’ll be able to be with them. You’ll be given a lead apron to wear to protect your body from unnecessary radiation.

Pregnancy and X-rays

Unborn babies are more sensitive to the effects of X-rays. So, if you are pregnant, you won’t be given an X-ray test unless there’s 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 you should go ahead with the test. If you can’t delay, the radiographer may be able to shield your baby with a lead block or apron.

What are the alternatives to an X-ray test?

Sometimes a different type of imaging test may be more appropriate for you. This usually depends on which part of your body needs to be looked at. Alternative tests include an ultrasound scan, a magnetic resonance imaging (MRI) scan or a computerised tomography (CT) scan.

Your doctor will discuss with you which test is most suitable.

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  • Reviewed by Marcella McEvoy, Specialist Health Editor, Bupa Health Content Team, April 2019
    Expert reviewer, Dr Daniel Boxer, Consultant Radiologist
    Next review due May 2022