Your child is having a CT scan

CT scanner

A CT scan (Computed Tomography) uses x-rays and computers to take pictures of the internal structures of your child’s body. This information sheet from Great Ormond Street Hospital (GOSH) explains about having a CT scan at, how to prepare for it and what care your child will need afterwards.

The CT scanner is a large doughnut-shaped machine with a hole in the centre through which a special bed can move. The scan can last anywhere from five minutes to 20 minutes, depending on the area and complexity of the scan. Although the bed will move through the scanner, it will not come into contact with your child.

Some children need to have injection of ‘contrast’ a liquid that shows up as a different colour on the scan. If your child is likely to need contrast, we will put local anaesthetic cream on their skin to make it numb before the injection.

If your child is apprehensive or scared of needles or injections or the scan itself, please telephone the Radiology play specialist before the appointment.

Are there any alternatives?

Your child may need this scan to show the doctors detailed pictures of part of their body. Various types of scan such as ultrasound and x-rays can show the size and shape of parts of your child’s body but not in as much detail as a CT scan. The information from the scan is then used to help with diagnosis and plan their treatment.

When you receive your appointment letter

If you are unable to keep this appointment, please inform the department as soon as possible beforehand. Sometimes, we can offer the appointment to another child on the waiting list.

As so many children and young people need to use our services, we have had to introduce a policy where if a child cancels or does not attend two appointments in a row, we will close their referral and inform their GOSH consultant.

Before the appointment

If you are pregnant or think you could be pregnant, please let us know. The x-rays used in the CT scan could harm your unborn baby, so we would advise bringing another adult to come into the scanning room with your child.

If your daughter is 12 years old or older, we will ask her about her periods and any possibility that she could be pregnant.

Children and young people who are having the scan awake, that is, without sedation or general anaesthetic do not need to ‘fast’ or stop eating and drinking before the scan. However, as they will be lying down for the scan, it may be better to avoid a big or heavy meal.


The person bringing your child to the scan should have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the scan.

The day of the scan

When you arrive at the hospital, you should go to the Turtle Imaging department.

You are welcome to stay with your child during the scan, but you will need to wear a lead apron to protect you from the x-rays. We will give your child a hospital gown to wear – wearing clothes containing metal such as zips or buttons can interfere with the scan.

Your child will need to lie on the scanner bed, either head towards the scanner or feet first, depending on the part of their body being scanned.

Once your child is in the correct position, the radiographer will go into the control room to operate the scanner. They will be able to talk to you and your child using the in-built microphone. They will move the bed into the scanner – it will not touch your child – and the scan will start.

The scanner makes some quiet whirring noises as it takes the pictures. Your child may be asked to hold their breath for a few seconds but can then breathe normally.

A radiologist (doctor who specialises in imaging) may come into the room to check the pictures and confirm they are good enough. When the scan has finished, the radiographer will move the bed out of the scanner so your child can get off it and get changed.

Radiation and risk

It is our legal duty to tell you about the potential risk of having a CT scan.

CT scans are only ever requested if the benefits outweigh the risks involved. CT does use radiation, but the dose is kept as low as possible. This is because the radiographers are specially trained to obtain the best quality pictures while using the lowest amount of radiation possible.

Anyone staying in the scanner room with your child will need to wear a lead apron – this works as a barrier to radiation. We advise that anyone who is pregnant or thinks they might be pregnant should not go into the scanner room.

After the scan

If your child is not having any further scans or tests, you will be free to go home. A radiologist will send a report about the scan to your child’s doctor in time for your next appointment. If you have not been given a follow up appointment to see your consultant, please contact their secretary after two weeks.

Compiled by:
The Radiology department in collaboration with the Child and Family Information Group.
Last review date:
March 2019