CT Scan (Computerised Tomography Scan)
Introduction to CT Scan (Computerised Tomography Scan)
A computerised tomography (CT) scan is a specialist X-ray test that gives pictures of bones and soft tissue of the body.
What is a CT Scan?
A computerised tomography (CT) scan is a specialist X-ray test that gives pictures of bones and soft tissue of the body. It can be done for any section of the body or head. A CT scan is different from an X-ray as it can show muscles, blood vessels and organs, which an X-ray can’t.
How is a CT Scan performed?
The CT scanner is a large machine with a hole in the middle, which looks like a ring like structure. Within the scanner there is an X-ray source and on the other side there is an X-ray detector. You lie on the bed that goes through the centre of the ring and the part of the body needed to be scanned is put into the centre of the ring. The machine then rotates around your body, emitting X-rays as it does so. The detectors determine the strength of the beam of X-rays that passes through your body. The higher the density of tissue, the lower the strength of X-ray beams that passes through. The computer makes up a cross-sectional image as different tissue has different densities. When you move through the scanner, several cross-sectional images are taken from the part of the body being investigated. The CT scan is painless and usually takes between 5-30 minutes, depending on the area being scanned.
How to prepare for a CT Scan?
It usually depends on the part of the body being scanned. Usually you will be asked to remove any metal objects from your body. You will also not be allowed to wear clothes with metal parts on them such as zips etc. You may also not be able to eat or drink a few hours before your scan, depending on the body part being scanned. If a contrast is going to be injected during your scan you will need to consult your General Practitioner or hospital doctor about what medication you can and cant take before the procedure.
What happens after a CT Scan?
Once the scan is over you can resume normal activity. The images from the scan are reported on by a radiologist and sent to your doctor. The complications of a CT scan are very rare. Pregnant women should not have a CT scan as the radiation from the X-ray can cause harm to an unborn child. There are risks from the radiation of using X-rays. CT scans generally give a relatively small dose of radiation and usually cause little harm.