CT Scan

ct scanner

A computed tomography scan, also called a CT scan, is a valuable medical exam that combines x-rays and sophisticated computers to generate detailed 2-D and 3-D images of parts of the body. CT scans have been performed safely and successfully for more than 30 years. Advances in CT equipment allows us to produce images of unprecedented detail, in shorter times and while using lower radiation doses than in past. Markham Stouffville Hospital offers CT scans at both its Markham and Uxbridge sites using the latest generation of CT technology.

You may need a CT scan as a result of illness or injury or when a physician suspects a medical problem that cannot easily be detected with a routine physical examination, or other imaging procedures. CT may also be used for screening some types of cancer (such as lung and colon) and for pre-surgical planning.

What you should know

Before your visit

The preparations for a CT scan can vary and it is important that you follow the instructions necessary for the kind of appointment you will be having. Please be sure to confirm if there are any preparation instructions that apply to the procedure you will be having – different CT scans have different prep instructions. Please click here to contact our scheduling team and confirm these instructions or see below for general outlines.

  • CT with CONTRAST (any body part):

    Do not eat or drink for four hours before the appointment, except only what is needed to swallow necessary medications.

  • Abdominal CT:

    Do not eat or drink for four hours before the appointment, except only what is needed to swallow necessary medications.

  • Renal Colic CT:

    Drink two full 8 oz. glasses of water one hour before the appointment. Do not empty your bladder (pee) before the exam; a full bladder is necessary for imaging.

  • Cardiac CT:

    Patients must avoid caffeine products for a full 12 hours before their test and should also stop taking ED medications such as Viagra and Ciallis. Caffeine products include decaffeinated and caffeinated coffee and tea, chocolate and chocolate beverages, cocoa, pop, energy drinks and any medication or supplements that may have caffeine. As part of the cardiac CT protocol many patients will be given a medicine called a beta blocker when arriving in the CT department. This medicine helps to control the heart rate so that the images taken during the scan will be clear. This kind of CT appointment may take up to 2 hours.

  • Colon CT (CT scan of the large bowel, also called CT colonography):

    Patients will have specific instructions to follow for 2 days before their appointment. This preparation will involve the use of barium and laxatives. For more information on this prep, please see the colonography preparation instructions.

  • CT Enteroclysis (CT scan of the small bowel, also called CT Enterogram):

    Patients will have specific instructions to follow for the day of the appointment. It is important to know we strongly suggest you plan to go directly home after the appointment. Please click here to review the important instructions found on the CT Enteroclysis prepartion sheet.

Click here to view other general Patient Preparations for Diagnostic Services Procedures .

During Your Visit

When it is time for your pictures to be taken, you will be brought inside of the CT scanning room. You will notice the large doughnut-shaped equipment, called the gantry. Our technologist will ask you to lie down on the padded table and make sure you are comfortable. You will be asked to lie very still during the scan and sometimes also be instructed to briefly hold your breath so that the images will be clear.

During the scan you might hear a humming or buzzing noise but you should not feel anything unusual. You might notice the table move while we take several images of your body. Once the pictures start the technologist will be watching you through a window during the entire exam and talking with you over an intercom speaker. Some instructions are pre-recorded in English, and there is also a library of other languages that may be selected from to better support our patients during their scan.

Depending on the CT scan ordered, a solution called contrast (also known as x-ray dye) may be given to help improve visibility, accuracy and clarity of specific areas of the body, such as blood vessels or the digestive tract. It is very important to let your doctor and the CT technologist know beforehand if you have ever had an allergic reaction to contrast.  For most studies involving contrast, the total time spent in the CT department may be from 60 to 90 minutes.

Depending on the body area being imaged patients may be required to change into a hospital gown, and remove jewelry and body jewelry.

Care Providers

Your CT scan will be performed by a Medical Radiation Technologist (aka an MRT) who is specialized in radiology and specifically CT. To learn more about this health professional please see this link for College of Medical Radiation Technologists of Ontario - About MRTs.