Explanation

Ultrasound is a way of using sound waves to look inside the human body.

Why do I need it?

Ultrasound is a fast and easy way for doctors to find problems that they can't see from the outside.

Your mum may also have had an ultrasound scan to look at you when you were still a baby in her tummy.

How does it work?

Ultrasound sends sound waves, which are too high for human ears to hear, into your body.

The sound waves bounce off things inside your body, just like an echo in a cave! Different types of tissue (eg fluid or bone or muscle) have different sounding echoes. The machine listens to the echoes and uses them to make pictures of your insides.

It is similar to the echoes and clicking noises that bats and dolphins send out so that they can see when they fly or swim in the dark.

What does it show?

The pictures from an ultrasound are 'live', which means that doctors can see the pictures right away as they are scanning - they can see your heart beating, your blood vessels pulsing, and even your tummy squishing around!

The pictures are in black and white, but the doctor or ultrasonographer can add colour if needed to see things that are moving in greater detail.

What happens?

Usually you don't need to prepare before you go for an ultrasound scan. It usually helps to have a full bladder, so if you can, you should drink plenty of water or other liquid before the scan, and avoid having a wee!

The person who does the scan may be a doctor called a radiologist, or an ultrasonographer. He or she will ask you to lie down on a table, will put a little bit of jelly on the part of your body that the doctors want to know about, and will then use a small hand-held ultrasound scanner to see inside you.

All the scanner does is slide around on the jelly on your skin, sending sound waves into your body and listening for the 'ECHO!' Most scans only take about 15 minutes.

Will it hurt?

Ultrasoun will not hurt at all. The jelly on your skin may feel cold and cool you down, but they'll wipe it off afterwards. It is a different type of jelly from the one you eat though!

The lights will be turned down a little to be able to see the pictures better, but the room will not be totally dark. There will always be some light inside. Your family or a friend can be in the room with you if you want, but there's nothing to be scared of.

What happens next?

Once the ultrasonographer finishes looking at your body, they show the pictures to a doctor who will then use them to decide what is wrong with you.

Your doctors will then give you the treatment you need, depending on what they find. It is the same process as when doctors look at you when you are still inside your mum's tummy to make sure you are OK before you are born.