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Computerised tomography (CT) scan for children – Advice for parents and carers

Patient information A-Z

Who is the leaflet for? What is its aim?

This leaflet explains your child’s forthcoming CT scan. If you have any questions the leaflet does not answer, or would like any further explanation please contact the CT department and ask a member of staff.

What is a CT scan?

CT is a method of building up a detailed picture of your child’s body and its organs. It uses x-ray radiation to build up the pictures. The scan enables the doctors to see inside the body to examine the tissues.

The CT scanner

The CT scanner is quite a big machine with a circular hole in the centre. It is often described as a ‘giant polo mint’ or ‘doughnut’. Your child will lie down on a bed that moves up and into the scanner. During the scan, the machine makes a quiet humming or whirring sound, but the scan is so quick that most children hardly notice it.

Does it hurt?

No, the scan itself is painless and very quick. For some types of scans, your child may need an injection of x-ray dye to give more information on the images. This is known as contrast media. This is given through a cannula (a small tube which is inserted into a vein in your child’s arm or back of the hand). The dye can make your child feel a little hot and flushed because the dye is kept warm. Another sensation that can be felt as a result of the injection is the feeling that you’re going for a wee. This is not the case but the sensation can feel realistic and a bit strange. It’s caused by the warmed dye moving down through the body.

X-ray risks

CT scans use x-ray radiation to obtain the images, and your child will receive a small dose of radiation when having a scan. The dose received will depend on what is being scanned and the size of your child. The scanner is carefully programmed to give the lowest dose possible for diagnosis. When a doctor requests a scan, it is ensured that the potential benefits to the patient outweigh the tiny risks associated with CT scans.

How long will the scan take?

The scan itself takes seconds to complete. Most patients will be in and out of the scanning room within 5 to 10 minutes. The length of the scan depends on which part of the body is being investigated and whether or not we need to give an injection of x-ray dye. A longer scan does not necessarily mean something is wrong. It simply means that different scanning programmes require different timescales to complete.

Even though the scan is quick it is vitally important your child doesn’t move during the scan as this can blur the images meaning that the anatomy cannot be seen at that point. In some cases this may require a repeat scan.

If your child requires a cannula for their scan, you will remain in the CT scanning department for 15 minutes after the scan. The cannula will then be removed, and you can leave.


Your child may be asked to drink a liquid which prepares their bowel for the scan. This will be given in the few hours before the scan appointment either in the CT department or in the children’s clinic. This is important to allow us to differentiate the bowel from other structures in the abdomen. Squash/ flavouring can be added to the liquid if your child wants. The hospital has a small selection of squashes but you are welcome to bring in your own.

Although most CT scans take only a few minutes your child needs to remain still for the procedure. It is not uncommon for some children not manage this especially when young and so a sedative or general anaesthetic is required to enable the scan images to be obtained safely. The majority of these children will be given a sedative but occasionally a general anaesthetic is required. This is decided by your child’s clinic doctor and communicated with CT.


If your child requires sedation for the scan you will be contacted by and asked to go to the children’s clinic prior to your scan appointment. Your child must be nil by mouth before sedation is given, six hours without food and four hours without fluids. Please DO NOT allow your child to eat or drink the day of the scan appointment unless directed by your clinical team.

Your child will remain in the CT scanning department or children’s clinic until fully awake and recovered before you are allowed home.

General anaesthetic

If your child requires a general anaesthetic for their CT scan your child’s clinic doctor will have informed you and arranged the anaesthetist and anaesthetic team with CT. You will be contacted to bring your child to one of the children’s wards where you and your child will be collected and taken to the CT scanning department.

The general anaesthetic will be performed in the CT scanning room where the scan will take place. Your child will remain in the CT scanning department or children’s ward until fully awake and recovered before you are allowed home.

Can I stay with my child?

Parents/ carers are allowed in the CT scanning room with their child whilst the radiographers set up the scan. If you have a young child you are also encouraged to stay with them whilst the scan takes place unless you are pregnant. You will be required to wear an apron containing lead which is a legal requirement. If your child is older, the radiographer may ask them if they would like you to stay in the scanning room whilst the scan takes place; whatever decision they make is ok.

When will I know the results of my child’s scan?

The radiographer will check that all the images have been obtained but will not be able to give you the result at that time. A radiologist will report on the scan and send a detailed result to the doctor who referred you within two weeks.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151