What a CT scan is
A CT scan is an x-ray taken by a specialised machine. The machine x-rays your head or body as you move slowly through it. This information is used to produce images in slices through your head or body.
Preparing for your appointment
What you should do
We send you instructions with your appointment letter, which explain how you may need to prepare for your scan.
It will tell you:
- the date and time of your appointment
- if you need to stop eating or drinking before your scan, or if you should drink plenty of water
- if you need to drink a flavoured liquid containing a fluid that shows up in the stomach and bowel. Drinking this liquid may take up to 2 hours
- you may be asked to change into a gown. If so, lockers are provided for your belongings
What you should tell us
You should tell us if you are pregnant so we can discuss the risks with you.
How we may need to prepare you for your scan
Different parts of the body need different preparation before being scanned. This is because we need to block a certain amount of x-ray going through tissues. This helps to see organs and tissues on the scan pictures.
For some scans we need to give you an injection into a vein in the arm. This is a special liquid we call contrast, which shows up the blood vessels. You can read more about contrast (dye) injections and CT scans.
What to expect during your CT scan
The scan will be performed by a radiographer. You'll be asked to lie down on a couch. During the scan the couch will move through the doughnut shaped hole in the scanner. This is not a tunnel. The hole is quite large and open to the room on both sides. The scans take a few seconds each. We ask you to lie still and may ask you to hold your breath at times.
You'll be in the CT room for between 5 and 20 minutes, depending on which part of you is being scanned.
Having someone with you during the scan
The scan uses x-rays, so other people shouldn't be in the room with you. The operator controls the scanner from a control room and you can talk to them through an intercom. They can see you at all times.
Some people feel a bit anxious or claustrophobic in the scanner room when they are on their own. If you feel anxious, a mild sedative may help.
There should be no side effects from the scan. You may eat or drink normally as soon as the scan is finished. The examination should not affect your ability to work or drive but you must check your appointment letter for exceptions to this advice.
X-rays are a form of ionising radiation and have enough energy to cause damage to cells. This can increase the risk of cancer later in life. These risks to health are considered very low. Learn more about radiation safety.