Computed tomography (CT scan)

An overview of computed tomography scans, what to expect during the procedure and resources for further information.


A computerized tomography scan (CT scan) is a diagnostic imaging procedure. It uses X-rays and technology to produce detailed high resolution images. These images are often called slices. As the scan progresses, slices are captured to get a detailed map of the body, including bones, organs and blood vessels.

Picture cutting an orange into slices. Each slice of orange shows a different cell form and amount of seeds. If you look at each piece, it will show you what is inside that part of the orange. When enough "slices" are captured, they are arranged into a three-dimensional map of what has been scanned.

A doctor will be able to pinpoint issues in almost any part of the body like:

  • Blood clots
  • Fractures
  • Broken bones
  • Tumours
  • Internal Injuries
  • Internal bleeding
  • Vascular problems
  • Heart disease
  • Muscle disorders
  • Aneurysms

Preparing for the scan

Before the scan, you are asked to change into a hospital gown. A technician will review the procedure with you. 

With contrast dye

If intravenous contrast dye is needed, it will be administered at the start of the exam. Patients may experience a warm sensation throughout the body and a metallic taste in the mouth after the contrast injection. These sensations usually disappear in a few minutes. The dye allows your organs and bones to appear clearly within the images.

Before the scan

  • Try not to eat or drink for an hour before your exam
  • If CT oral contrast dye is ordered, drink it according to directions and time

Please tell your provider before the appointment if you have:

  • Allergies to medications or contrast dye
  • Diabetes
  • Asthma
  • Heart disease
  • Kidney problems
  • A thyroid condition

Please also let your provider know if you are pregnant, or suspect you may be pregnant.

During the scan

You will lie on your back or side during the scan and be brought into the machine. The bed moves into a tunnel-like space where the procedure takes place. Although it's small, the machine leaves plenty of room for you to feel comfortable and calm.

While the scan is in progress, a technician will supervise you and the scans from the next room. You can ask to stop the test if you feel uncomfortable at any point. Your technologist will hear you through the microphone stop the scan.

The procedure takes about 30 minutes, and only 10 minutes are spent within the machine for your test.

After the scan

A radiologist will review your CT scan exam results and create a report. We will send results to your referring doctor, and they will contact you.

If you do not receive results after 14 days, please get in touch with your health care provider’s office.

Possible complications & side effects

There is a very low dose of radiation exposure during a CT scan, but the exposure is minimal. CT scans have not been shown to cause long-term harm in patients.

Side effects are rare. The most common side effects are minimal reactions to the contrast dye, which include:

  • Itchiness
  • Soreness
  • A warm feeling across the body
  • A metallic taste in the mouth
  • A false sense of urination

It is rare, but a patient may not know they are allergic to contrast dye. This reaction may include sneezing, hives or difficulty breathing. WAnyone reacting will be given care before they are sent home.

After the procedure, please drink lots of fluids to flush out any remaining contrast dye in your system. Regular diet and exercise can be resumed with no restrictions.

Support for Indigenous Peoples

The Indigenous Wellness Liaison Team is here to support your health journey. Team members offer cultural support and healthcare advocacy. Learn more below or call them at 604-682-2344,62937 or email

  • Indigenous wellness services

    The Indigenous Wellness Team at Providence is available to support Indigenous patients and their families. We are here to coordinate culturally safe wellness supports and services.

Medical & professional referrals