Abstract: A tomographic image of a X-ray tested tissue of body is reconstructed by calculating X-ray absorption coefficients of picture elements constituting a tomographic plane in reference to measured values produced by the first and second projectional distributions of X-ray produced by projecting X-ray. Accordingly, it becomes possible to reconstruct a clear tomographic image of a moving X-ray tested tissue and to make an X-ray exposure level very low by extremely shortening the time of the reconstruction of computed tomographic image. Moreover, a resolving power of measuring is substantially improved, resulting in that an accuracy of reconstructing the tomographic image may also be improved.

Abstract: A method of reconstructing a computed tomographic image comprising projecting X-rays through material to be tested at a plurality of spaced positions, and measuring the X-ray density values of the X-rays projected through the material along the distribution of projected X-rays. The spaced positions at which the X-ray density values are measured are selected such that the tomographic plane of the material to be reconstructed is represented by a pseudo-tomographic plane comprised of an array of n rows of m columns of picture elements, each having a single piece of X-ray density information, and such that each X-ray beam passes through the lower left corner of a corresponding picture element. The X-ray absorption coefficient for each picture element is calculated from the measured values of X-ray density, and the computed tomographic image is reconstructed by positioning picture elements having the computed X-ray absorption coefficients in an array corresponding to the array in the pseudo-tomographic plane.

Abstract: A diagnostic agent for primary hepatoma which has anti-.alpha.1-fetoglobulin, and a process for the preparation of the diagnostic agent for primary hepatoma which comprises the steps of dissolving the anti-.alpha.1-fetoglobulin together with a support medium and allowing the same to solidify in a diffused condition.