CT Scans

You may be asked to stop taking certain medications before your scan, and you will need to inform your doctor if you have diabetes or think you are pregnant. You may also be asked not to eat or drink anything for 2-4 hours before your procedure, particularly if a contrast dye is being used.

A contrast dye involves drinking a large glass of liquid that contain either barium or iodine. It will take approximately 60-90 minutes for the contrast dye to move through your body. If you are allergic to any of these substances, it is important that you tell your doctor as you may be prescribed an allergy medication or steroid that will counteract any potential side effects you may have.

You will be instructed to remove certain items that include:

• Hearing aids
• Dentures
• Jewellery, including body piercings
• Glasses
• Bras with metal underwire

It is advisable that you wear loose, comfortable clothing, as you will be lying down during the procedure, although you may be given a hospital gown to wear.

A CT scan is a minimally invasive procedure and can be carried out in a short space of time. During the CT scan, you will be required to lie on your back in a large tunnel-like machine, shaped like a doughnut. A radiology technician will perform the scan that involves the table moving through the scanner, taking X-rays around your body from different angles. The machine can be quite loud and you will likely hear a whirring and buzzing noise.

It is important that you remain as still as possible as movement can blur the images. At times, you may be asked to hold your breath to prevent your chest from moving up and down. If a child requires a CT scan, a sedative may be prescribed to stop the child from moving.

The length of the scan depends on the parts of your body that are being scanned, but in general, it is anything from a few minutes to one hour.

CT scans are relatively safe procedures, although there are some risks, particularly for children who are more sensitive to radiation compared to adults. Risks can include:

Slight increased risk of cancer

A CT scan exposes you to more radiation than a typical X-ray, but the risk of cancer caused by radiation is very low, particularly if you only have one scan. However, your risk may increase over time if you have multiple CT scans and X-rays.

Birth Defects

Exposure to radiation during pregnancy does increase the risk of birth defects, so it is important to inform your doctor if you are pregnant or think you might be. Your doctor will likely recommend an alternative method of imaging such as an MRI or ultrasound scan.

Allergic Reaction

Most allergic reactions result from the contrast dye as it contains iodine and barium. If you experience any of the following, you should contact your doctor immediately:

• Nausea and vomiting
• Constipation
• Diarrhoea
• Abdominal pain 
• Excessive itching
• Headache
• Skin rash

If you were given contrast dye and experience any of the below symptoms, you should call the emergency services immediately:

• Rapid heart rate
• Trouble breathing
• Swelling of the throat or other body parts

Once the images have been taken, they are forwarded to a Radiologist for examination. They will be sent to a computer and combined to create images of cross-sections of your body. They may also be combined to produce 3D images of a particular part of the body.

Your results should be available within 48 hours and will be sent to your doctor. If you require a follow-up appointment to review the results, your doctor will inform you to discuss your treatment options.