Computerized axial tomography (CAT), a new method for obtaining tomographic images, is a major advance in diagnostic radiology. Unlike conventional tomographic systems that use film both for the storage and display of transmitted x-rays, CAT makes use of sensitive scintillation detectors to detect x-rays that pass through a body section, and a digital computer is used to process this information. Tomographic images of selected planes through a subject are mathematically derived from a series of transmitted x-ray scan profiles, recorded from an x-ray tube head/detector assembly rotating about the subject. Alterations in tissue density in individual transverse cross sections are displayed on intensity modulated displays.
Conventional tomography can contribute valuable diagnostic information and is an important radiological method.1 Depending on techniques and the structures to be examined, however, blurring of object elements outside of the focal plane can detract from the overall image quality of a tomogram. The digital