It is important to be still during a computerized tomography scan, according to the National Health Service. A computerized tomography scan, also known as a CT scan or CAT scan, is a noninvasive diagnostic tool used by health-care professionals to create detailed images of the internals of the body.
Moving during a computerized tomography scan sometimes causes blurred images, explains the National Health Service. Regular breathing at designated intervals helps to keep the images clear. During a CAT scan, the individual lies on his back on a flat bed that passes through the scanner. The scan usually takes 10 to 20 minutes.