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CT scan

Find out what a CT scan is, how you have it and what happens afterwards.

A CT scan uses x-rays to take detailed pictures of your body from different angles. A computer then puts them together to give a series of pictures.  

CT (or CAT) stands for computerised (axial) tomography.

Photo of a CT scanner

How you have it

You usually have a CT scan in the x-ray (radiology) department as an outpatient. A radiographer operates the scanner. The whole appointment can take up to an hour and a half.

Why you might have a CT scan

Your specialist may ask you to have a CT scan to show the ovaries more clearly. But sometimes, it is not possible to diagnose ovarian cancer for certain without an operation.

What happens

When you arrive at the scan department

The radiographer might ask you to change into a hospital gown. You might have to remove jewellery and other metal objects, such as hair clips. Metal interferes with the images produced by the scanner.

In the scanning room

When you’re ready, the radiographer or assistant takes you into the scanning room. A CT scanning machine is large and shaped like a doughnut.

You might have an injection of contrast medium (a type of dye) through a small thin tube (cannula) in your arm. This can:

  • make you feel hot and flushed for a minute or two
  • give you a metallic taste in your mouth
  • make you feel like you’re passing urine but you aren’t – this feeling is common and passes quickly

You can have a medicine to help you relax if you think you will feel claustrophobic during the scan.

Having the CT scan

You usually lie down on the machine couch on your back. Once you’re in the right position, the radiographer leaves the room. They can see you on a TV screen or through a window from the control room. You can talk to each other through an intercom.

The couch slowly slides backwards and forwards through the hole of the scanner. The machine takes pictures as you move through it. 

The scan is painless but can be uncomfortable because you have to stay still. Tell your radiographers if you’re getting stiff and need to move.

During the scan

You’ll hear a whirring noise from the scanner.

The radiographer might ask you to hold your breath at times.

When the scan is over, the radiographer comes back into the room and lowers the couch so you can get up.

The 2-minute video shows what happens when you have a CT scan.

After your CT scan

You stay in the department for about 15 to 30 minutes if you had an injection of the dye. This is in case it makes you feel unwell, which is rare.

The radiographer removes the tube from the vein in your arm before you go home.

You should be able to go home or back to work. You can eat and drink normally.  

You need someone to take you home if you had medicine to help you relax. You won’t be able to drive for the rest of the day as it could make you drowsy.

Getting your results

You should get your results within 1 or 2 weeks. 

Waiting for results can make you anxious. Ask your doctor or nurse how long it will take to get them. Contact the doctor who arranged the test if you haven’t heard anything after a couple of weeks.

You might have contact details for a specialist nurse and you can contact them for information if you need to. It may help to talk to a close friend or relative about how you feel.

For information and support, you can contact the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday.

Possible risks

A CT scan is a safe test for most people but like all medical tests it has some possible risks. Your doctor and radiographer make sure the benefits of having the test outweigh these risks.

Rarely, people have an allergic reaction to the contrast medium. This most often starts with weakness, sweating and difficulty breathing. Tell your radiographer immediately if you feel unwell so they can give you medicine.

There is a risk that the contrast medium will leak outside the vein. This can cause swelling and pain in your arm but it’s rare.

Exposure to radiation during a CT scan can slightly increase your risk of developing cancer in the future. Talk to your doctor if this worries you.

Pregnant women should only have CT scans in emergencies. Contact the department as soon as you can before the scan if you are pregnant or think that you might be.

Last reviewed: 
20 Oct 2016
  • Newly diagnosed and relapsed epithelial ovarian carcinoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

    J Ledermann and others; ESMO Guidelines Working Group

    Annals of Oncology. 2013 Oct;24 Suppl 6:vi24-32.

  • Standards for intravascular contrast administration to adult patients  
    Royal College of Radiologists (RCR) (2015) 3rd edition

     

    The Royal Marsden Manual of Clinical Nursing Procedures, 9th Professional Edition
    L Dougherty and S Lister (Editors)
    Royal Marsden Manual Series, 9th Ed, 2015

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