CT scan

Computerised Tomography (CT) scans are a series of x-rays that are put together to give a 3D picture of the inside of the body. The images that are produced are very detailed and can help doctors at Great Ormond Street Hospital (GOSH) to distinguish between different types of tissue.

CT scans are used to help doctors to understand what is happening inside your body, either so that they can find out what's wrong with you or so that they can monitor your progress when you're being treated. 

CT scans are particularly good for producing images of:

  • internal organs 
  • bones 
  • the brain 
  • blood flow 

What happens 

Sometimes when you go for a CT scan you'll have to have a drink or be injected with a dye so that the pictures become clearer.

You'll most likely have to wear a gown (over your underwear) and remove any jewellery that you might be wearing.

You will then have to lie on a motorised bed which slides into the middle of the scanner (which looks a bit like a giant doughnut). The radiographer will explain everything to you.

Before the scanning starts the radiographer will have to leave the room, though you'll still be able to talk to them through a microphone. You will have to lie as still as you can to stop the images from blurring. You may be asked to hold your breath for a few seconds during the scan. Usually CT scans take around half an hour.

Many of the studies we perform involve the use of x-rays. All girls aged 12 years or older are tested to make sure they are not pregnant on the day of their scan. If they are found to be pregnant the Radiography team will decide if the scan should be delayed or cancelled.

Does it hurt?

No, CT scans do not hurt at all, though sometimes the bed is a little uncomfortable.

Compiled by:
Great Ormond Street Hospital
Last review date:
March 2012