Abstract: The invention relates to a magnet coil arrangement for generating linear magnetic gradient fields by means of which a three-dimensional spin density distribution of a body can be reconstructed (spin imaging). The magnet coil arrangement inter alia consists of a plurality of groups of single coils which are each time situated on an imaginary cylinder surface and which produce a magnetic field gradient in the interior of the cylinder which is constant over a larger range with respect to known magnetic coil arrangements. The magnetic coil arrangement also comprise four single coils which are situated on an imaginary spherical surface and wherethrough the same current flows for generating a constant field gradient which extends rotation-symmetrically with respect to an axis of examination.

Abstract: The invention relates to a magnet coil arrangement for generating a magnetic field which is homogeneous at least in its center, preferably for magnetic resonance spectroscopy. The arrangement consists of four flat ring coils whose coil planes extend perpendicularly to an axis of examination which extends through the coil centers. The coils are symmetrically arranged with respect to a point situated on this axis. By means of a magnetic coil arrangement of this kind, a magnetic field can be generated which extends in the direction of the axis of examination and rotationally-symmetrically with respect thereto and which, in comparison with the magnetic fields generated by means of known coil arrangements, has an improved homogeneity in the direction perpendicular to the axis of examination over a larger range which extends in the direction perpendicular to the axis of examination in the center of the magnetic coil arrangement.

Abstract: X-ray apparatus for computer tomography. Strip-shaped visible images which correspond to the individual X-ray exposures in one image plane are transferred to the light-sensitive input of an image pick-up tube by means of a lens system. The lens system comprises at least one lens, interposed between the image plane and the light-sensitive input layer of the image pick-up tube, which produces an astigmatic optical path.

Abstract: In tomosynthesis distortions are produced owing to the curvature of the image intensifier input screen and other non-linearities of the transmission system, which in particular affect the synthesis of the laminar image when the individual images should be shifted relative to each other for this purpose. These distortions depend on the angle which the central ray makes with the laminar plane during the individual exposures and therefore they can hardly be compensated for. The invention now proposes that when the individual images are taken the image intensifier is steered so that the optical axis always remains parallel to the central ray. The distortions produced by the curvature of the input screen of the image intensifier etc. are then independent of the angle between the central ray and the laminar plane, and can be compensated for by known commercially available correction devices.

Abstract: In tomosynthesis, as is known, a series of individual images taken in different orientations, are superimposed. By shifting the individual images relative to each other the position of the layer which is sharply reproduced can be changed. However, there may still be unsharpness in said layer, in the case of image distortion during recording of the individual images, for example owing to the curvature of the input screen. This image distortion can hardly be compensated for, because it greatly depends on the projection angle. The invention provides a simple method of compensating for such image distortion. The image intensifier is then arranged and steered so that its optical axis is always parallel to the central ray. The distortion caused by the image intensifier curvature is then independent of the projection angle and can be eliminated in a comparatively simple manner.