1. In an X-ray diagnostic apparatus for producing a transverse-layer image; including a first X-ray measuring arrangement having an X-ray source generating an X-ray of a transverse diffusion perpendicular to the layer being equal to the layer thickness and parallel to the layer being equal to or lesser than the layer thickness, a first radiation receiver means in said arrangement for measuring the radiation intensity behind an object at successive equidistant points, and drive means for said measuring arrangement for effecting a linear scanning movement across the entire object expanse perpendicular to the direction of the central X-ray in alternating sequence at small equidistant angular increments over a range of 180.degree., said angular increments being measured about a rotational point on said central X-ray approximately centrally of said layer plane, the improvement comprising; a second measuring arrangement being disposed in parallel offset relationship with respect to the linear direction of movement of said first measuring arrangement including an X-ray source generating X-rays of different radiation energy value in comparison with the x-rays of the X-ray source of said first measuring arrangement, a second radiation receiver means in said arrangement for measuring the radiation intensity behind the object at successive equidistant points for receiving the X-rays of different radiation value; a calculator for formulating two absorption coefficients or their proportional magnitudes for each image point in dependence upon the measured signals of said first and second measuring arrangements for the two different values of the radiation energy, said calculator being adapted to form respective quotients and through stored calibrating tables provide the median ordinate value or corresponding parameter for each image point.