Adrian Harrison - Respiratory Physician
Computer Tomography (CT) Scan
With CT scans you can see much more detail than with a normal X-ray. During a CT scan, X-ray beams are sent from different angles through part of the body. The strength of the X-ray signals is altered as they pass through the body. The signals are picked up by X-ray detectors. They are then manipulated by a computer, using a complicated mathematical process, and an image is produced. This allows detailed cross-sectional images of the body without cutting it open. CT scans can be used to view all body structures but especially soft tissue, such as body organs (the heart, lungs, liver etc.).
What to expect?
You will have all metal objects removed from your body. You will lie down on a narrow, padded, moveable table that will be slid into the scanner, through a circular opening.
You will feel nothing while the scan is in progress. Some people can feel slightly claustrophobic or closed in, whilst inside the scanner. You will be asked to remain still and hold your breath on command. There are staff present, but they will not remain in the room. They will speak with you via an intercom system and will be viewing the procedure constantly through a windowed control room.
Some procedures require contrast medium. Contrast medium is a substance that makes the image of the CT clearer and it outlines blood vessels. Contrast medium can be given by mouth, or by injection into the bloodstream. Please advise the radiologist if you are allergic to iodine.
The scan time will vary depending on the type of examination required, but as a rule it will take up to 30 minutes. Scanning times are gradually reducing as the technology is improved.