X-rays - What Are They And Different Types - Healthdirect

Key facts

• An x-ray uses a small amount of radiation to create an image of body structures.
• X-rays are used to diagnose disease and injury.
• A contrast dye, such as iodine or gadolinium, can be used during an x-ray to help to improve images.
• Before an x-ray you should tell the doctor if you are pregnant or may be pregnant.

On this page

• What is an x-ray?
• What are the types of x-rays?
• When is an x-ray needed?
• How do I prepare for an x-ray?
• What happens during an x-ray?
• Possible risks with x-rays
• What is contrast dye?
• Alternatives to x-rays
• Resources and support
• Related information on Australian websites

What is an x-ray?

An x-ray is a type of radiation used to create a picture of the inside of your body. As x-ray beams pass through your body they are absorbed differently by various structures in the body, such as your bones and soft tissues. This is used to create an image. X-ray imaging is also known as radiography.

What are the types of x-rays?

There are several different types of x-ray:

• plain radiography (plain x-ray)
• computed tomography, known as CT scanning
• fluoroscopy — which produces moving images of an organ
• mammography — an x-ray of your breasts
• angiography — an x-ray of your blood vessels
• bone density scan — helps identify low bone density and diagnose osteoporosis

When is an x-ray needed?

X-rays are used to diagnose disease and injuries, including:

• bone conditions — such as breaks, dislocations, bone infections, arthritis and osteoporosis
• lung conditions — such as pneumonia and collapsed lung
• congestive heart failure
• blood vessel problems — such as an aortic aneurysm (a bulge in the aorta)
• cancer — such as lung cancer, bone cancer and breast cancer
• blockages in your bowel
• tooth decay
• detection of foreign objects — such as when a child accidentally swallows an object
• to check the position of wires, leads and tubes after a surgical procedure

How do I prepare for an x-ray?

Preparing for an x-ray is simple:

• bring the referral from your doctor
• tell the radiographer if you might be pregnant
• tell the radiographer if you have kidney problems or have allergies to contrast dye
• be prepared to remove any jewellery
• change into a hospital gown if needed
• follow any instructions given to you by your doctor or radiographer

What should I tell my doctor before the x-ray?

You should tell the doctor if you are or may be pregnant. In most cases x-rays should be avoided in pregnancy as radiation can be harmful to your baby.

Some types of x-ray use injected or swallowed contrast dye (contrast media) to improve the images. It's important to tell your doctor if you have:

• kidney disease
• previously had an allergic reaction to contrast media
• difficulty taking a deep breath and holding it

What happens during an x-ray?

A plain x-ray is painless and usually takes less than 15 minutes. It can be done in a hospital or a private radiology practice. X-rays are done by a radiographer or medical imaging technologist.

A radiologist (doctor trained to interpret x-rays) will review your images. Your doctor will be sent a report.

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. You may be asked to take a deep breath and hold it while the images are taken.

A protective shield or apron may be used to protect parts of your body that are not being x-rayed.

If you use a wheelchair, you may need to move or be moved onto a different chair. This prevents the metal parts of your wheelchair affecting the image.

For children, a parent or carer can usually stay with a child during the x-ray. This will help reassure them and keep them still.

Possible risks with x-rays

An x-ray uses a small amount of radiation to create an image. Some types of x-rays, such as CT scanning and angiography, use higher doses of radiation than plain x-rays. The amount of radiation used is unlikely to cause any serious problems. Talk to your doctor if you are concerned.

Generally, the benefit of the x-ray in diagnosing a health condition is greater than the risk of the radiation.

What is contrast dye?

Contrast dye (contrast medium) is a substance that can be used during x-rays, CT scans, angiography and other tests. It helps to improve the contrast in the x-ray images. This makes it easier to see diseased or damaged areas.

The contrast dye may be given to you orally (by mouth) or by injection. Commonly used contrast dyes contain iodine or gadolinium.

It's normal to have a warm feeling that spreads through your body after an injection of iodine-containing contrast medium. This may last for around 20 seconds. You may even feel like you have wet yourself, but you won't have.

Gadolinium contrast medium is generally very safe and reactions are uncommon. You may be aware of a cold feeling in your arm during the injection.

Possible risks from contrast dyes

People with kidney problems have greater risks from contrast medium than other people. If you have kidney problems and need an x-ray using contrast medium, talk to your doctor first.

Some people have an allergic reaction to iodine-containing contrast dye. Reactions can be mild, moderate or severe. Anyone can have an allergic reaction, even if you have not had problems before.

Alternatives to x-rays

X-rays and children

For children, there may be alternatives to having x-ray, such as having an ultrasound or magnetic resonance imaging (MRI). These imaging methods do not use x-ray beams.

If a diagnosis is not urgent, your child's doctor may consider a 'wait and see' approach.

X-rays and pregnancy

During pregnancy, x-rays expose your baby to radiation. Any harm to your baby will depend on:

• the radiation dose — smaller doses (amounts) are safer
• the stage of your pregnancy — the further along you are in your pregnancy, the better
• the part of your body being imaged

It's best to avoid exposing your abdomen (tummy) to radiation if possible.

In some circumstances, different tests, such as ultrasound or MRI, may be used. These imaging methods do not use x-ray beams.

Resources and support

Use these 5 questions to ask your doctor on the Choosing Wisely Australia website, to make sure you end up with the right amount of care.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.