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CT (computerised tomography) scan under oral sedation

Patient information A-Z

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 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 and any abnormality.

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, 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 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. Another sensation that can be felt as a result of the injection is the feeling that you’re going to the toilet. This is not the case but the sensation can feel a bit strange.

X-ray risks

CT scans use x-rays radiation to obtain the images; your child will receive a small dose of radiation when having a scan. The dose received would depend on what was 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, they must make sure the potential benefits to the patient, outweighs 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.

Why sedate and what is oral sedation?

During the scan, your child will have to lie quite flat and remain very still. If your child is distressed, in pain or frightened, this can be difficult for them. In some cases, a gentle form of sedation is required to be able to complete the scan successfully. This decision is made by the doctor looking after your child. It will be discussed fully with you.

The oral sedation used is called chloral hydrate. It has to be given one hour before the scan. It comes in both oral liquid and suppository form (medicated material for insertion into a bodily passage or cavity). The nurses will discuss with you on the day of your child’s admission the best form of administration of this drug. In some cases a different oral sedation, called midazolam, may need to be used.

It is also recommended that you try to sleep deprive your child to help the oral sedation to be more effective. Please try to keep your child awake for two hours longer the night before. Wake them up two hours earlier than normal. Do not let them have a nap, on long car journeys. If possible, have another person sitting in the back with your child to distract them from falling asleep in the car before the scan.

Can my child eat and drink?

For your child’s safety, it is essential they are nil by mouth in preparation for the sedation. They will be able to have their last food and milk (cow and formula) seven hours before the scan time. Your child can continue to drink water or diluted squash up until four hours before the scan. For breastfed babies the last feed will need to be five hours before the scan.

When will my child be able to go home?

After your child’s scan they will need to eat and drink before going home. They may still be wobbly on their feet. This will pass over the course of the day. Children usually go home an hour or two after completion of the scan but this depends on how quickly your child recovers.

The nurses will be responsible for allowing your child to be discharged home under the nurse led discharge policy. You will not routinely see the doctor before discharge.

If your child is unwell

If your child is unwell in the days leading up to the scan please call the ward to discuss if it is advisable for the scan to go ahead.

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

It takes a long time to look at all the pictures the scan produces so the report will not be available for several days. You will be sent an outpatient appointment to discuss the findings and any further treatment that might be necessary.

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