A CT Scan is a way of using X-rays to take pictures or images in very fine slices through a part of your body that your doctor has asked to be investigated. Modern CT scanners are fast, and our staff minimise radiation doses as much as possible.
Each scan is created specifically for the part of the body of interest and the condition that needs investigation. These are interpreted by a radiologist who will perform a report that is sent to your doctor.
You will receive instructions from our staff prior to your appointment. These instructions are very important as they may affect the accuracy of the test.
Many types of CT scans require an injection of an iodinated contrast material to show blood vessels and some organs. You will need to fast for two to four hours and drink water over one hour before your appointment time for these scans. It is important that the need to fast does not affect you if you have special dietary requirements (e.g. diabetes).
While the iodinated contrast used for injections is considered very safe, some precautions must be taken when using it, particularly if you have poor kidney function, diabetes or if you have a known allergy to iodinated contrast. If you have any concerns, you should contact North Shore Radiology and Nuclear Medicine on 02 9170 4500.
It is important to follow the instructions you are given to ensure that the scan is completed safely, accurately and efficiently and so that you do not need to have the scan rescheduled or repeated.
Each scan is different, so the time it takes to complete will vary depending on why you are having it. Generally, most CT scans are completed in five to 20 minutes.
The CT scanner is a large square machine, or gantry, with a circular hole that looks like a doughnut. The general process involves you lying on a bed attached to the scanner, and the bed slides in and out of the gantry several times while pictures are being taken. The radiographer performing the scan may ask you to hold your breath for some scans. The length of time for each breath-hold is usually under 10 seconds. If you require an iodinated contrast injection for your scan, a radiographer or a nurse will discuss iodine contrast.
They will then use a needle to insert a cannula (a small plastic tube) into a vein in your arm or the back of your hand. This is so that the iodine contrast can be injected into the cannula during the scan, usually by an automated injector. Once the radiographer has reviewed the images to check that the appropriate areas have been shown, they will come into the room to remove the cannula and help you off the bed.
The radiographer will not give you any results after the scan; this is the responsibility of your doctor and the radiologist who interprets the pictures from the scan. A report will be provided to your doctor.
Most people who have a CT scan have no after-effects. After the scan, you may resume your regular diet and activities. In very uncommon cases, some people may be allergic to the iodinated contrast given into the vein in your arm or the back of your hand. It is important to make the radiographer or nurse aware of any other allergies you may have before the injection.
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