During a CT scan

What happens during a CT scan?

When you enter the room you will see the CT scanner. You can't miss it. It's big and shaped like a large doughnut standing on its side. When you are ready, you will be asked to lie on a narrow table that slides into the "doughnut hole." This is called a gantry.

The technologist begins by positioning you, usually lying flat on your back or possibly on your side or on your stomach. Straps and pillows may be used, only to help you maintain the correct position and to hold still during the exam. A brace for your head may be used in some instances to keep that part extra still. During the actual scanning, motion will degrade the quality of the final images the same way that it affects photographs so you will need to try and keep as still as you can.

If you have a hard time staying still, are claustrophobic or have chronic pain, you may find a CT exam to be stressful. The technologist or nurse, under the direction of a physician, may offer you a mild sedative to help you tolerate this stress or pain.

For children who cannot hold still for the examination, sedation may be needed and a parent may be allowed in the room but will be required to wear a lead apron to minimize radiation exposure.

If contrast material is used, it will need to be swallowed, injected through an intravenous line (IV) or administered by enema, depending on the type of examination. If you receive an IV, you will feel a slight pin prick when the needle is inserted into your vein. You may have a warm, flushed sensation during the injection from the contrast materials. Some patients say they get a metallic taste in their mouth that lasts for a few minutes. Some patients may experience a sensation like they have to urinate, but this feeling subsides quickly. These sensations are common and should be expected, but should not cause you to worry.

The person administering the test may need to position your arms above your head for certain scans like your abdomin or chest. After you are positioned, they will then slide you and the table into the ‘doughnut’ section of the scanner. This is where the CT scanner sends X-rays through the area of the body being studied. A technologist will be nearby, in a separate room and able to communicate with you via intercom at all times during the entire procedure.

Once inside the CT scanner’s ‘doughnut hole’, special lights may be used to ensure that you are properly positioned. With most CT scanners, you will hear only slight buzzing, clicking and whirring sounds as the actual scanner inside the ‘doughnut hole’ revolves around you.

The table will then move you quickly through the scanner to determine the correct starting position. Then, the table will move slowly through the machine as the actual CT scanning is performed. Again, you may hear clicking and whirring noises. Each rotation of the scanner inside the ‘doughnut’ around you yields several images of your body. These actions are what causes those sounds.

While the table is moving you may be asked to hold your breath for short periods of time to avoid blurring the images. The technician will also let you know when you can release your breath and breath easy again. And you'll need to stay in the position you were put in.

Each rotation of the scanner takes less than a second and provides a picture of a section of your body. All of the pictures are saved as a group on a computer. The actual procedure can take from thirty minutes to an hour and a half. If specific tests, biopsies, or intervention are performed by the radiologist during CT scanning, additional time and monitoring may be required.

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Getting a CT scan:

Find out what the experience is like and what you should expect.

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Before the CT

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During the CT

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After the CT

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