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Computed tomography (CT) still reigns as the hottest technology in medicine, revolutionizing the diagnostic capabilities of most medical specialties. A number of studies are in progress to further delineate its specific diagnostic potential. At the American College of Chest Physicians meeting in Boston, one panel focused on the use of CT to diagnose heart and lung disease.
The CT whole-body scanner, which is used to visualize the thorax, revolves a roentgenographic beam around a patient, completing a 360-degree revolution in about 4 1/2 s. A 1-cm tissue plane is scanned and then converted into an image that is first depicted by a set of attenuation numbers. These numbers represent the rate at which the beam penetrates the tissues of the thorax, thus reflecting tissue density. Bone has arbitrarily been assigned an attenuation number of +1,000, air —1,000, and water 0. Hence the first image is a set of numbers indicating
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