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CT scan

  • Computed Tomography (CT), and is also sometimes called a CAT scan. The CT scanner uses X-rays to create cross-sectional images of all or a part of the body. A CT scan can be performed on any area of the body.

    Why does my child need a CT scan?

    Your child may need a CT scan for many different reasons, for example to:

    • look at the shape or structure of parts of the body
    • check for any signs of disease
    • help plan follow-up treatment after a procedure
    • help with planning before an operation

    Preparing your child for their appointment  

    For some ideas on how to prepare your child for the procedure, and tips on distracting them and helping them stay calm during the procedure, see our fact sheet Reducing your child's discomfort during procedures

    It may be helpful to your child if the procedure is explained to them before they come in for their important. Explain that: 

    • the scans do not take long
    • the scans are painless
    • a parent or carer can stay with the child during the scan

    Specialist staff from Child Life Therapy may also be of benefit for your child. The Child Life Therapist engages families in imaging-specific education and medical play, as well as providing distraction and support during procedures. Appointments for Child Life Therapist support can be made in advance via Medical Imaging or your referring doctor.

    What to expect with a CT scan

    Before a CT scan

    Preparation for a CT scan depends on the body area that is being scanned and your child’s individual needs. If your child is having an abdominal scan, they may need to drink oral contrast one hour before the scan. This is a drink that helps to see the stomach and intestines more clearly. The oral contrast is almost tasteless. Sometimes your child may need to have a contrast injection, which helps see blood vessels and organs of the body. The contrast fluid is given through a small IV (intravenous, or a drip) line, which is a small tube inserted into a vein. If your child requires contrast through an intravenous line they will need to fast (have nothing to eat or drink) before the CT scan. You will be given instructions about fasting requirements in your appointment letter. In some cases, it may not be known that contrast is required until the first image is taken. In very rare cases, contrast may case reactions in some children. Staff will safely manage any side effects or reactions that may occur.

    If your child needs to have an IV line inserted, topical anaesthesia will be applied to the injection site to make it numb – this can be in the form of a cream or via Coolsense® – a hand-held device that uses cryotherapy to numb the area. Cream usually takes over 45 minutes to work, so you will be asked to attend the department earlier than your scheduled appointment time. You will be advised if you need to do this when you are given your appointment.

    During the CT scan

    A CT scan is not painful. The CT scanner is a big open doughnut-shaped machine. Your child will lie down on a table, which moves through the middle of the machine at least twice during the scan. The CT scanner takes all of its pictures as the table is moving.

    Your child will need to remain very still for the pictures and sometimes hold their breath; usually this is for less than 10 seconds. Generally, the CT scan study takes about 10–15 minutes in total.

    After the CT scan

    If your child has not had IV contrast, sedation or general anaesthetic, you will be able to leave straight after the CT scan. If IV contrast was needed, your child will be observed for 10 minutes after the CT scan.

    A report will be prepared by the Radiologist and sent to the referring doctor. The report is usually available within a few days but can be received earlier if required. If you have any questions about why your child needs a CT scan, or questions about the results of your scan, please speak to your doctor.

    CT scan with sedation

    Whether or not your child needs sedation depends on the type of scan they are having and their individual circumstances. In cases where a child is unable to remain still enough or they are very anxious or distressed, sedation may be required. Your child will be assessed to ensure sedation is suitable for them. 

    See our fact sheet Sedation for procedures

    CT scan with general anaesthetic

    Some CT scans need to be performed while your child is asleep under a general anaesthetic. This is rare, but may be required if sedation will not be effective for your child and their scan. If your child does need a general anaesthetic for their scan, you will be given specific instructions for what to do before the scan, including fasting requirements.

    Key points to remember  

    • CT scans use X-rays to create cross-sectional images of the body
    • Some children need to take a contrast drink or have IV contrast to make parts of the body show up more clearly
    • It is very rare for contrast to cause reactions in children. Staff can safely manage any side effects or reactions that may occur
    • Sometimes, CT scans need to be performed while your child is under sedation or general anaesthetic

    For more information

    Common questions our doctors are asked

    My child is anxious about medical procedures and I am worried they won't remain still for the CT scan. How can I help?

    To get some ideas of how to talk to your child about the scan before you come to hospital, see our fact sheet. Also consider showing your child our ‘Be Positive’ videos of children having procedures at The Royal Children's Hospital (RCH). Seeing the videos may help them by knowing what to expect. You can also download our Okee in Medical Imaging app, which includes games and information especially designed to help children feel more comfortable about having medical imaging at RCH.

    Specialist staff from Child Life Therapy may also be of benefit for your child. The Child Life Therapist engages families in imaging-specific education and medical play, as well as providing distraction and support during procedures. Appointments for Child Life Therapist support can be made in advance via Medical Imaging or your referring doctor. 

    Are CT scans safe for children?

    All medical imaging procedures at RCH have been justified by a Radiologist or Specialist before the exam is performed. All imaging procedures are optimised – each study is performed with the aim to provide the highest quality imaging with the lowest radiation dose to each child.

    For more information on radiation, please see the Australian Government fact sheet: Ionising Radiation and Health, or speak to your CT technologist.

    Are there any side effects of contrast?

    In rare cases, contrast (usually swallowed or injected into a vein) can cause reactions in children. About one child in 1000 might get a rash, hives, or an irritated mouth or throat. If this happens, your child might need to stay in the hospital a few hours longer and may need some extra medicine (e.g. antihistamines). Very rarely, your child may have a serious and life-threatening reaction and will need to be admitted to hospital for treatment. These are allergic reactions that cannot be predicted unless a previous reaction has been experienced. Staff can safely manage any side effects or reactions that may occur.


    Developed by The Royal Children's Hospital Medical Imaging and Day Surgery departments. We acknowledge the input of RCH consumers and carers.

    Reviewed November 2018.

    Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit www.rchfoundation.org.au.

Disclaimer  

This information is intended to support, not replace, discussion with your doctor or healthcare professionals. The authors of these consumer health information handouts have made a considerable effort to ensure the information is accurate, up to date and easy to understand. The Royal Children's Hospital Melbourne accepts no responsibility for any inaccuracies, information perceived as misleading, or the success of any treatment regimen detailed in these handouts. Information contained in the handouts is updated regularly and therefore you should always check you are referring to the most recent version of the handout. The onus is on you, the user, to ensure that you have downloaded the most up-to-date version of a consumer health information handout.