[en] An apparatus and techniques for obtaining cross sectional images of patients by computerized tomography are described. A source of radiation, such as gamma or x-ray, revolves concentrically within or without a stationary circular array of detectors. The source emits a fan beam which passes through the patient and illuminates a number of detectors simultaneously to provide a number of signals, each representative of the energy transmissivity between the source and the detector. Signal processing means combine the detected signals to provide a cross sectional image of the scanned region