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What are X-rays?

X-rays are a type of radiation used to take images of the inside of a person’s body to help doctors diagnose and monitor conditions such as chest infections or bone fractures. Common uses of X-rays include chest x-rays to diagnose chest infections, dental X-rays to diagnose cavities and bone X-rays to diagnose fractures.

xray of wrist

How do X-rays work?

X-rays work by sending a focused high frequency radiation beam through the body that is absorbed and captured by the X-ray images. Depending on the density of the part of the body examined, there will be variation in the colour of the X-ray images taken. For example, an X-ray of your bones will show white areas while an X-ray of your lungs will show darker areas.

Types of imaging using X-rays

X-rays are used in different imaging methods, from plain X-rays that produce a still image, to X-rays used in fluoroscopy which produce moving images of parts of your body (for example, barium meal) and CT scans.

What to expect during an X-ray?

X-rays are usually carried out by radiographers who are healthcare professionals trained to use imaging technology, or by radiologists who are specialist doctors who can also interpret the images taken and either discuss the results with you or send a report to your GP.

Depending on the body part that needs an X-ray, you will be asked to either lie on a table or stand against a flat surface. This will allow the positioning of the X-ray machine and the photographic plate in close proximity to the part of your body that requires the X-ray. You will be required to keep still during the X-ray. It will only take a fraction of a second. Sometimes, you will have more than one X-ray taken in order to determine the diagnosis. The photographic plate will catch the image that will then be looked at on a computer or printed.

The procedure is safe and painless. You should inform your doctor of any other recent X-rays or scans you have had so they can decide on the benefits and risks of the current X-ray.

Who should avoid having an X-ray?

While X-rays are safe for the majority of people, for some - for example, pregnant women or young children - the benefits of X-rays versus their overall health will be assessed. Pregnant women should avoid having an X-ray due to potential harm to the unborn baby. However, an X-ray of the arm or the chest might be performed if the benefits outweigh the risks. You should discuss your options with your doctor. If you believe you might be pregnant, you should inform the radiographer or the radiologist before the X-ray procedure.

What are the risks of having an X-ray?

All people are exposed to radiation, whether it is naturally-occurring radiation - also known as background radiation (cosmic rays, the earth, food and water, radon gas) - or radiation from ultraviolet light. X-rays use a small amount of radiation, for example, the radiation dose of a single chest X-ray is 0.02 milllisieverts (mSv) which is the same radiation dose as a 4-hour flight.

Although the possible dangers from X-rays are outweighed by the benefits of occasional diagnostic X-rays when medically necessary, doctors and dentists always want to limit the number of X-rays a person has over their lifetime.

The possible dangers of exposure to X-rays are more likely to affect children and babies in the womb than older people. Always let the radiographer or dentist know about other recent scans you've had involving X-rays.

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on June 28, 2017

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