Your health expert: Julia Ross, Head of MSK & Radiology at Bupa
Content editor review by Pippa Coulter, October 2021
Next review due October 2024

An X-ray is a quick and painless test. It uses radiation to take pictures of the inside of your body. X-rays can be used to help diagnose and treat medical conditions and injuries such as broken bones.

About X-rays

In an X-ray, a machine sends beams of radiation (called X-rays) through the part of your body to be tested. The beams are picked up by a detector, which converts them into a black and white image.

X-rays are absorbed differently by different parts of your body. Dense (very solid) structures, such as your bones, absorb X-rays and appear light grey on the image. X-rays pass straight through less dense structures, like your air-filled lungs. This means they show up as dark grey or black on the image. Some types of X-ray tests use a special dye called a contrast medium to show up certain organs, tissues or blood vessels.

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

What are X-rays used for?

X-rays can be used to take images of almost any part of your body. Doctors will use the images to find out what’s wrong or help to diagnose a condition.

X-rays are often one of the first tests you’ll have to investigate problems, such as breathing difficulties or sudden pain in your chest or abdomen (tummy). They’re also the main type of test for broken bones. X-rays can help in the diagnosis of the following problems and conditions.

  • Heart problems, including heart failure.
  • Lung conditions, such as pneumonia, fluid on your lungs and lung cancer.
  • Problems affecting your bones and joints. These can include broken bones (fractures), joint dislocation, infection and arthritis.
  • Blockages in your intestines, or tearing of your stomach or intestines.
  • Teeth decay and infections. Dentists use X-ray images to help them to find and treat dental problems.

Doctors can also use X-rays to locate objects that you may have swallowed, and to check the position of medical devices such as a catheter or needle. They can also use X-rays to provide ‘real-time’ images to help guide medical procedures.

Special X-ray techniques

There are also certain specialised tests that use X-ray. These include the following.

  • DEXA (dual-energy X-rays absorptiometry) scans. These use a low dose of X-ray to measure bone density. They can check for a condition called osteoporosis, which is when your bones start to become weaker.
  • Mammogram. This is a special type of X-ray to examine your breasts, and check for signs of breast cancer.
  • CT scans. These take a series of X-ray images at different angles around the part of your body being tested. A computer puts all the images together to form a more detailed picture.
  • Contrast studies. These use a dye to show up certain structures and create more detailed pictures of the inside of your body. Sometimes these can be used to create moving, real-time images. For example, an angiogram can show up your blood vessels, and a urogram can show your urinary tract.

Your doctor will explain why you need an X-ray and the benefits and any risks involved. If you have any questions, ask your doctor.


Sometimes a different type of imaging test may be more appropriate. This usually depends on which part of your body needs to be looked at. Alternative tests to plain X-rays include ultrasound scans, MRI scans and CT scans. These can often provide an image with more detail.

Your doctor will explain which test is most suitable for you.

Preparing for an X-ray

You usually have an X-ray as an out-patient procedure in the radiology or imaging department of a hospital or health clinic. A health professional called a radiographer will usually carry out the X-ray. A dentist can carry out a dental X-ray at a dental practice.

You don’t usually need any special preparation before an X-ray. You can eat and drink normally beforehand, and continue taking your usual medications. It’s important to let the hospital staff know before your test if there’s any chance you could be pregnant.

Depending on which part of your body is being tested, you may need to change into a hospital gown before your X-ray. You may be asked to remove any jewellery too. You may want to consider wearing clothes that will be easy to remove and leaving jewellery at home.

What happens during an X-ray?

X-rays can be carried out in different ways, depending on the part of your body being X-rayed. If you’re having a chest X-ray, you may need to stand against an X-ray machine. For other types of X-ray, you may need to lie on an X-ray table or couch. Your radiographer will help you to get into the right position.

When they’re ready to take the X-ray, your radiographer will need to stand behind a screen. They’ll still 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. During the X-ray you’ll need to keep still. Sometimes you’ll be asked to take a deep breath and hold it for a few seconds. You won’t feel anything while you’re having the X-ray. You’ll usually be able to go home or back to work straight after your X-ray.

Getting your X-ray results

Your X-ray images will usually be sent off to be examined and the results sent to the doctor who requested your X-ray. Your doctor will discuss the results with you at a follow-up appointment.

You may be able to ask for a copy of your images to be transferred to you, or sent to another hospital electronically. This can be useful if you’re seeing a doctor in a different hospital or are likely to be travelling abroad for treatment.

The time it takes for your results to be available can vary. Ask your radiographer when you can expect to get your results before you go home.

Are X-rays safe?

There is always some level of risk with any medical test or procedure. But X-rays are generally considered to be very safe and the potential risks very low.

Having an X-ray involves being exposed to radiation. Any exposure to radiation carries a risk of developing cancer. Simple X-rays use a very low dose. It’s about the same as you’d receive from natural radiation in the atmosphere over a few days. Your doctor will only recommend an X-ray when it’s really necessary, so you can be sure that the benefits outweigh the risks.

Children and X-rays

Children can be more sensitive to the damaging effects of X-rays, and are more likely to be affected during their lifetime. Your doctor will only refer your child for an X-ray test if it’s absolutely needed. If your child has an X-ray, it’s likely that you’ll be able to stay 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 at greater risk from the effects of X-rays than adults. So if you’re pregnant, you won’t be given an X-ray unless there’s an urgent medical reason and there’s no safe alternative. 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.

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X-rays can be used to help diagnose health conditions and problems affecting various parts of your body. They can also be used for cancer screening, to locate foreign objects in your body and to help guide medical procedures. See our section on Uses for more information.

X-rays are considered to be very low risk. High doses of radiation can be harmful to your body. But X-rays use a very low dose of radiation, similar to that you’d get from natural radiation over a few days. See section on Risks for more information.

Your doctor will tell you if they recommend an X-ray. It might be that you’ve had pain in your chest or abdomen (tummy) that they want to investigate, or they may want to check for broken bones. Your doctor will only advise you have one if they think it will help. See our section on Uses for more information.

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