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Home / Swansea / Preparing for your scan

What is a CT scan?

What is a CT scan?

CT stands for ‘computed tomography’. It uses X-rays to produce a cross-sectional, or

‘slice’, image of the inside of your body.

Who will I see?

A small team of radiography staff will look after you during your visit and one of the

radiographers will carry out the scan.

Is it safe?

The amount of radiation used varies. The radiation related risks are very small and the risk

of missing a serious problem if you don’t have a CT scan may be much higher.

  • If you are or you think you may be pregnant, you should tell us before your scan.

Do I need an injection?

Many CT scans involve injecting a substance (known as a ‘contrast medium’) into a vein to

increase the amount of information we can get from the scan. The injection may give you a

warm feeling around your body and a metal taste in your mouth. As with all injections,

there is a very small risk of an allergic reaction, ranging from minor reactions such as a

skin rash to the more serious such as an asthma attack. Our medical teams are trained to

deal with this if it happens. If you have reacted to any other injection given for a kidney X-

ray (IVP or IVU) or a previous CT scan, please let the radiographer know before the

injection takes place.

Before the scan

We will ask you some safety questions when you book your appointment, and you will

need to fill in a safety questionnaire that we will send you with your appointment letter.

  • Please remember to bring this with you to your appointment.
  • To help show different organs in the body, some preparation may be necessary, and if

necessary, your appointment letter will have information about this.

  • You do not need to prepare specially for brain, neck or chest scans. We may ask you to

drink a certain amount of fluid or a special drink before having an abdomen or pelvis scan.

There are a few instructions that you need to follow before the scan:

  • You should not eat or drink if you have been told not to (this will only apply for some

scans). If we need to, we will give you more details when you book your appointment.

  • You should tell us if you are diabetic and taking metformin.
  • You should tell us if you have any allergies or asthma or if you have reacted to any

other injection given for a kidney X-ray (IVP or IVU) or a previous CT scan

  • You should tell us if you are pregnant or breast feeding.
  • You should wear comfortable, loose clothing.
  • You should let us know about any special needs you have (for example if you need

wheelchair access, you are hard of hearing, you have poor eyesight or you are

claustrophobic).

What happens during my appointment?

When you arrive you should go to the reception desk (please bring your appointment letter

which may have details of who to ask for).

The radiographer or another member of staff will meet you and explain the procedure to

you.

We will check your safety questionnaire (or ask you to fill one in if you haven’t already).

You will have the chance to ask any questions you have.

For some types of CT scans we will ask you to drink a special contrast drink up to an hour

before your scan.

We may ask you to change into a gown.

  • If you need to change, your clothes and personal items will be kept in a secure place.

We may need to give you an injection, depending on the area that needs to be scanned.

We will take you into the scanning room and ask you to lie down on the scanner table.

We will move the table slowly so we can position the part of your body that is going to be

scanned under the scanner camera.

During the scan we may ask you to hold your breath or not swallow.

The radiographer operating the scanner will be able to see and hear you throughout the

procedure.

Will it be uncomfortable?

We will make you as comfortable as possible. The scan will not cause any pain. You may

be given an injection.

How long will it take?

  • If you are given fluid to drink when you arrive, you may have to wait up to an hour before

having your scan. Most scans take around 45 minutes.

After the scan

  • After your scan you can eat and drink normally.
  • If you have had an injection, we will ask you to wait in reception for 30 minutes after your

examination in case you have a reaction to the injection.

  • You can drive home afterwards and return to work if you need to.

Are there any side effects?

There are no known side effects from having a CT scan.

When will I get the results?

A radiologist will check the scan results shortly after your appointment and will send a

report to your doctor or consultant. At the time of your appointment you will be told how

long this should take.

If a follow up appointment is not already arranged, you will need to contact your doctor or

consultant to make an appointment to get your results.

Can I bring a relative or friend with me?

Yes but they will only be allowed to go into the examination room in special circumstances

(for safety reasons).

Children will not be allowed into the room while you are having the scan so you

need to make arrangements for them before you come to your appointment. Staff

are unable to assist.

Contacting us

  • If you need any more information please contact us on the number given in your

appointment letter.

Contacting us

Call the Clinical Imaging Facility on 01792 606420, or use the number on your appointment letter. If you cannot attend, please tell us as soon as you can.

Produced by the Clinical Imaging Facility, Institute of Life Science 2, Swansea University. The Facility joins the Prime Health network from 1 November 2026. All guides.