CT scan, also known as a computed tomography or CAT scan, is a painless imaging procedure that uses X-rays to create cross-sectional pictures of the inside of the body. CT scans provide more detailed images compared to conventional X-ray techniques and hence are mostly used to identify internal damage from vehicle accidents or trauma. They may also be used to guide radiation treatment, biopsies and other surgeries.
CT scans may also be performed to identify
Cancers or tumours
Abnormal blood clots
Inform your doctor if you are on any medications, have any allergies or underlying medical conditions before going for a CT scan. You may not be a good candidate for a CT scan if you are pregnant, since there is a likelihood for the X-rays to harm your baby. Depending on your condition and the area examined, you may be asked not to eat or drink anything for a few hours before your procedure. Avoid wearing any metal objects such as jewellery or cloths with metal zippers or buttons while going for a CT scan. Even though CT scans have not been known to cause long-term damage, be aware that CT scans expose you to a minimum amount of ionizing radiation that can increase your risk of cancer.
In order to better visualize the images, you may receive an injection of a contrast material before your CT scan. The contrast may be given orally or rectally depending on the area examined. Some people can be allergic to the contrast material and may develop rashes or itchiness. Be sure to inform your doctor if you have ever had any allergies to similar substances before your CT scan.
CT Scan Procedure
A CT scanner is a donut-shaped structure with a mechanical X-ray source that moves around the structure. You will be made to lie comfortably on a bed and slowly slid into the scanner. The X-ray source then moves around your body and fires narrow beams of X-rays through your body. As the X-rays leave your body, digital X-ray detectors in the scanner pick these signals and pass them to a computer. Every time the X-ray source completes one cycle, the computer creates an image, and the cycle is repeated to produce further images. A typical CT scan may take about 10-30 minutes and the procedure is deemed complete once sufficient number of images is obtained. Over the next few days, your CT scan images will be analysed by a radiologist and the result will be interpreted. You will need to visit your doctor again once your CT scan results are ready, and your doctor will then explain its meaning and recommend further treatment.
The image quality of a CT scan is dependent on several technical parameters, which can vary from one manufacturer to the other. Some of the common CT scanner manufacturers include GE (LightSpeed & BrightSpeed), Philips (Brilliance), Siemens (Sensation, Definition, Emotion) and Toshiba (CX, Asteion & Aquilion).