A CT scan can see much more detail than with a normal X-ray. Using an X-ray beam, which is sent through the body from different angles, the CT scanner creates an image by using a complicated mathematical process. This allows cross-sectional images of the body without cutting it open. The CT is used to view all body structures but especially soft tissue such as body organs (heart, lungs, liver etc.).
What to expect?
You will lie down on a narrow padded moveable table that will be slid into the scanner, which looks like a large doughnut in shape. You will be asked to remain still and hold your breath on command. There are staff present, but they will not necessarily be in the room; they will speak with you via an intercom system and will be viewing the procedure constantly through a windowed control room.
You will not feel anything while the scan is in progress. Some people can feel slightly claustrophobic while inside the scanner, although modern scanners are not as closed in as they used to be. Some procedures will need contrast medium to be injected into a vein in your arm, to show up clearly the blood vessels in the chest and lungs. Injection of contrast often makes you feel hot briefly. Some people can be allergic to the medium used. If you have had allergy to x-ray contrast or to iodine, YOU MUST TELL the radiographer at the beginning.
The scan time will vary depending on the type of examination required, but as a rule it will take around 30 minutes.