CT scan for acute lymphoblastic leukaemia (ALL)

A CT scan is a test that uses x-rays and a computer to create detailed pictures of the inside of your body. It takes pictures from different angles. The computer puts them together to make a 3 dimensional (3D) image.  

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

Photograph of a CT scanner

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 depending on which part of your body they are scanning. 

Why you might have a CT scan

There are many reasons why you might be sent for a CT scan if you have ALL. Its best to ask your doctor or nurse the reason you have to have one. 

Some of these reasons include: 

  • checking whether the leukaemia has caused any of your lymph nodes (glands), spleen or liver to get bigger (enlarged)
  • checking how well your treatment is working if anything was enlarged at diagnosis
  • to look for infections

What happens?

When you arrive

You complete a questionnaire before you have the CT, you might have been sent this in the post with your appointment letter beforehand.  

The radiographer might ask you to change into a hospital gown. You should remove jewellery and other metal objects, bra, hair clips around the area being scanned. Metal interferes with the images produced by the scanner.

In the scanning room

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

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

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

Tell your radiographer if you feel anxious or claustrophobic about having a scan. 

Having the CT scan

You usually lie down on the machine couch on your back. Once you’re in the right position, your radiographer leaves the room to protect them from the radiation. 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 radiographer if you’re getting stiff and need to move.

During the scan

You’ll hear a whirring noise from the scanner.

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

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

This 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 cannula from your arm before you leave.

You then go back to the ward if you are an inpatient or go home. You can eat and drink normally.  

Getting your results

Ask your doctor when to expect your results and how you will receive them. 

Waiting for test results can be a worrying time. You might have contact details for a specialist nurse and you can ask them for information. It may help to talk to a close friend or relative about how you feel.

For support and information, you can also 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.

Allergic reaction

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.

Bruising and swelling

You might get a small bruise around the area where they put the needle in.

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

Kidney problems

There is a small risk that the contrast medium can affect your kidneys. Your radiographer checks your most recent blood test results before your scan to make sure your kidneys are working well. 

Radiation

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.

Pregnancy

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: 
01 Jun 2021
Next review due: 
01 Jun 2024
  • Iodinated Contrast Media Guideline
    The Royal Australian and New Zealand College of Radiologists, March 2018

  • Acute lymphoblastic leukaemia in adult patients: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow up
    D Hoezler and others
    Annals of Oncology, 2016. Volume 27, Supplement 5, Pages 69 to 82

  • The Royal Marsden Manual of Clinical Nursing Procedures, Professional Edition (10th Edition)
    S Lister, H Hofland and H Grafton
    Wiley-Blackwell, June 2020

  • BMJ Best Practice Acute lymphocytic leukaemia
    BMJ Publishing Group Ltd, last updated March 2021

  • Recommendations for cross-sectional imaging in cancer management (2nd Edition)
    Royal College of Radiologists, July 2014

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in if you need additional references for this information.

Related links