Computed tomography (CT)

How to prepare for your test

We will give you instructions on how to prepare for your scan. Please tell us if you are or suspect you might be pregnant or are breastfeeding. Preparation requirements will depend upon the type of scan to be performed. Some preparations need to start 24 hours before the procedure. It is important to check any CT preparation forms as soon as you receive them. Your scan can be delayed if you don’t complete all necessary preparation steps.

What happens during the procedure?

It can take between 10 and 20 minutes depending on what part of the body is being scanned.

• You will be asked to lie on a table. The radiographer will not be in the room during the scan, but they will be able to see you and communicate with you at all times.
• During the scan, you will hear a whirring or humming noise (like a noisy washing machine) and you will feel the table move slowly through the CT scanner. You should remain as still as possible, as the slightest movement can blur the pictures.
• For some scans, you will be asked to hold your breath for up to 20 seconds.

Contrast

You will sometimes be given contrast as part of your CT scan.

• Contrast allows your organs to be seen more clearly on x-rays.
• Contrast can be given as a drink (oral contrast) and/or as an injection (Iodinated contrast).
• Oral contrast is used to show the stomach and intestines more clearly.
• Iodinated contrast is used to show the organs and blood vessels of your body more clearly.
• A fine needle (IV cannula) will be put into a vein in your arm, making it possible to inject the contrast. For more information on iodinated contrast and the risks involved in its use, please read the Iodinated Contrast Patient Information Sheet.

What happens after the procedure?

You can eat and drink normally after your CT scan is finished. Your CT scan results will be sent to your doctor.

Are the x-rays harmful?

The amount of radiation you will receive will be dependent upon the specific examination your doctor has requested for you. If you have any concerns regarding this examination, you should discuss it further with your doctor as the benefits should outweigh the risks to you.