Learn about what happens during a CT scan as the Department of Diagnostic Radiology at Singapore General Hospital shares.
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What happens during a CT scan
You will lie still on a table that slides in and out of the CT scan gantry.
The X-ray tube inside the CT scanner will rotate around your body and take X-ray images at various angles. You may be asked to hold your breath for a short while during the scan. At any time, you may communicate with the radiographer through the intercom.
- A CT scan examination is painless and the majority of routine scans take approximately 5-15 minutes to complete, depending on the area being scanned and the complexity of the protocols involved.
- Depending on the type and region of scan requested, many CT scans require an iodinated contrast dye to be administered into your body via a vein in your arm or hand.
- During the course of the injection, you may feel a warm sensation all over the body. This is normal. The dye will increase the visibility of organs and other structures as well as the presence of disease. A diagnostic radiologist will interpret the images and submit a report to your doctor.
How to prepare for a CT scan
- Some scans requiring intravenous injection of iodine containing dye require fasting for four hours before the scan. You can take your usual medications. For a pelvic CT scan, you may be instructed not to empty your bladder at least one hour before the scan.
- You will need to remove any jewellery or metallic objects. Metal may interfere with the X-rays and cause artefacts on the images.
- You will need to lie very still and hold your breath when instructed. This will help to ensure that the images taken are clear and sharp.
For more information on
what is a CT scan, see previous page.