Information about your CT scan

Patient Experience

  • Reference Number: HEY-444/2019
  • Departments: Radiology
  • Last Updated: 29 July 2019


This leaflet has been produced to give you general information. Most of your questions should be answered by this leaflet. It is not intended to replace the discussion between you and the healthcare team, but may act as a starting point for discussion. If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

What is a CT scan?

CT (computed tomography) is also known as a CAT scan.  The scanner uses X-rays to take a series of very detailed pictures of sections of the body. The scanner is shaped like a very large ‘polo mint’.  The hole is almost 3 feet (0.91 metres) wide and only about 10 inches (25.4cms) deep. You will lie on a movable table and pass through the scanner whilst the X-rays are being taken.    The X-rays pass through the body and are detected by sensors on the other side of the machine.  This information then goes to a computer which produces a picture of the structures of the inside of your body.

Who will be involved with the CT examination?

A healthcare professional called a Radiographer, trained in producing the best images with minimum radiation, will perform the examination.  During your visit you may also meet a Clinical Imaging Support Worker who may help prepare you for your examination.

The resulting pictures (tomographs) are seen and interpreted by a Radiologist, who is a doctor trained in reading your X-ray images.

What is a CT scan used for?

A CT scan can be performed on any area of the head or body.  It can give clear pictures of soft tissues such as muscles, organs, large blood vessels, the brain and nerves.  It can also give clear pictures of bones.  CT examinations are performed for a number of reasons, for example:

  • To detect abnormalities in the body, such as tumours, abscesses, abnormal blood vessels
  • To give a surgeon a clear picture of an area of your body before surgery
  • To identify the exact site of tumours prior to radiotherapy
  • To help doctors find the correct place to take biopsies (tissue samples)

How should I prepare for the CT scan?

Please read the information leaflet.  Share the information it contains with your partner and family (if you wish) so that they can be of help and support.  There may be information they need to know, especially if they are taking care of you following this examination.

You should wear comfortable, loose-fitting clothing for your CT examination. Metal objects can affect the image, so avoid clothing with zippers and poppers. Depending on the part of the body that is being scanned, you may also be asked to remove hairpins, jewellery, glasses, hearing aids, body piercing and any removable dental work. In some cases if you are wearing an under-wired bra or corset you may be asked to remove this. Gowns are available as required.

You may be asked not to eat or drink anything for one or more hours before the examination.  Please read the appointment letter you have received with this leaflet.

If your scan is being taken of your abdomen or pelvis, you may be given a drink containing contrast (a liquid to highlight organs and blood vessels).  The contrast is called Omnipaque which is not barium based. You will be asked to drink this over a period of 30 minutes to 1 hour before your scan, so a book or newspaper may help you to pass the time.

Please do not bring any unnecessary valuables with you as we have very limited secure storage.

How long will the CT examination take?

This depends on the area of the body to be examined.

For those patients who are given drink containing the Omnipaque contrast, you will be asked to drink this over 30 minutes prior to the actual scan.  If you require an injection during the scan, a small plastic tube (cannula) will be placed in your arm before you go into the scanning room.

Once you are in the scanning room, the scan/X-ray time is approximately 20 seconds.  However, the Radiographer will wait for the X-ray images to be processed in order that their quality can be checked.  You will be asked to stay on the table during this time.  This can often take another 5 -10 minutes.

Sometimes your appointment may be delayed because an emergency arises in the department.  Your patience during this time will be appreciated.

Will I need an injection?

This depends on the area to be scanned.  Most body scans involve an injection of a contrast agent (a clear liquid used to highlight organs and blood vessels) into a vein in the arm.  Some head scans also require this.

It is extremely important that you notify the department immediately upon receipt of this appointment if you suffer any severe allergies.  If you use inhalers please bring them with you.

This procedure does not require a special diet beforehand – you may eat and drink as normal.

What are the possible risks?

Unborn babies are more susceptible to radiation than adults so please telephone the department before your appointment if there is any possibility that you are pregnant.

CT scanning uses X-rays to produce the images.  Patients are often worried about being exposed to radiation. However, it is important to put any risks into perspective.  The risk to your health from not having the required examination is likely to be much greater than any risk from the radiation itself.

The contrast liquid we inject may cause a brief allergic reaction such as itching, nausea, or rapid breathing, which is easily treated. Severe reactions including difficulty breathing are quite rare but do occur. The Radiographers and Radiologists are well equipped and trained to deal with these.

What are the benefits of CT?

CT examinations are fast and simple. For example, in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.

CT scanning is accurate. There is no pain from CT. Apart from an intravenous injection if needed, the procedure is non-invasive (not penetrating the body). Unlike other imaging methods, CT scanning offers detailed views of many types of tissue, including the lungs, bones, soft tissues and blood vessels.

Diagnosis made with the assistance of CT can eliminate the need for surgery.

CT scanning can identify both normal and abnormal structures, making it a useful tool to guide radiotherapy, needle biopsies and other minimally invasive procedures.

What happens after the CT examination?

If you have had an injection during your CT examination you will need to remain in the department for approximately 20 minutes.  We will tell you when you are able to leave. Following this you can return to your normal activities.

The scans will be reviewed by a radiologist within a few days of your examination. The results are sent to the consultant who referred you for your scan.   You will then receive an outpatient appointment through the post advising you of when your consultant wants to see you to discuss your results.

If your General Practitioner has referred you for your CT examination your results will be sent to him/her.

If you already have your next out-patient appointment date and this is within one week of your CT scan, please inform the Radiographer before the scan begins.

After the scan you may eat and drink as normal. You will also be allowed to drive.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the CT Department on tel no: (01482) 622043

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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