Patent US 4,149,249

An apparatus and method for reconstructing data, a fan beam of radiation is passed through an object, which beam lies in the same quasi-plane as the object slice to be examined. Radiation not absorbed in or scattered by the object slice is recorded on oppositely situated detectors aligned with the source of radiation. Relative rotation is provided between the source-detector configuration and the object. Reconstruction means are coupled to the detector means, and may comprise a general purpose computer, a special purpose computer, and control logic for interfacing between said computers and controlling the respective functioning thereof for performing a convolution and back projection based upon non-absorbed and non-scattered radiation detected by said detector means, whereby the reconstruction means converts values of the non-absorbed and non-scattered radiation into values of absorbed radiation at each of an arbitrarily large number of points selected within the object slice. Display means are coupled to the reconstruction means for providing a visual or other display or representation of the quantities of radiation absorbed at the points considered in the object.