What is an X-ray?
An X-ray uses radiation to create a picture of the inside of the body. The X-ray beam is absorbed differently by various structures in the body, such as bones and soft tissues, and this is used to create the image. X-ray is also known as radiography.
Types of X-ray
There are several types of X-ray:
- plain radiography, or plain X-ray
- computed tomography, or CT scanning
- fluoroscopy - which produces moving images
- mammography - an X-ray of the breasts
- angiography - an X-ray of the blood vessels.
When is an X-ray done?
X-rays can be used to diagnose disease and injury, including:
- bone conditions - such as fractures, dislocations, bone infections or arthritis
- chest conditions - such as pneumonia, collapsed lung or heart failure
- blockages of the bowel
- detection of foreign objects.
X-rays should be avoided in pregnancy.
How is an X-ray done?
A plain X-ray is painless and usually takes less than 15 minutes. It can be done in a hospital or private radiology practice.
During the procedure you’ll be asked to lie, sit or stand, depending on the part of the body being X-rayed. It is important not to move during the X-ray. A radiologist will then assess the images and send a report to your doctor.
What is contrast dye?
Contrast dye is a substance that is sometimes used during plain X-ray, CT scanning, angiography or other tests. It helps to enhance the contrast in X-ray images, making them easier to read. It may be given to you orally or by injection.
Commonly used contrast dyes are iodine-containing contrast medium and gadolinium contrast medium.
Patients with kidney problems face greater risks when having contrast medium than other people. If you have kidney problems and need an X-ray with contrast medium, talk to your doctor first.
Some people are allergic to contrast dye. Most people who have allergic reactions have mild ones, although a severe allergic reaction is possible.
Are there risks with X-rays?
Yes. An X-ray uses a small amount of radiation to create an image. Some types of X-ray, such as CT scanning and angiography, use higher doses of radiation than plain X-rays.
That small amount of radiation might give people having X-rays a very slightly increased risk of developing cancer some years later.
But there is also the risk that comes from not diagnosing a health condition.
On the whole, it is wise to have X-rays that are necessary, but not ones that won’t help with treatment. Children should have alternatives to X-ray, such as an ultrasound, when possible.
X-rays and pregnancy
In pregnant women, X-rays expose the foetus to small amounts of radiation. The dose used is so low that it is not usually a concern, however it is best to avoid exposing the mother’s abdomen to any radiation if possible.
A different test may need to be used.
How do I prepare for an X-ray?
Preparing for an x-ray is simple:
- Bring the referral that your doctor gave you.
- Bring along any X-rays you’ve had before of similar areas.
- Tell the radiographer if you might be pregnant.
- Tell the radiographer if you have kidney problems or have allergies to contrast material.
- Be prepared to remove your jewellery and change into a hospital gown if needed.
- Follow any instructions given to you by your doctor or radiographer.
Last reviewed: July 2017