The X-ray appts. includes an open ring X-ray tube (5) with a ring anode (6). The housing includes an opening on one side (2) which matches the opening of the ring X-ray tube. The X-ray detector (9) is positioned synchronously with the focal point of the X-ray bundle within the ring X-ray tube. The detector is composed of several parallel detector lines. A guide ring is provided in the X-ray tube, and the detector is positioned on the guide ring. The detector can be extended in the direction of the system axis. The ring X-ray tube emits electrons and images are obtained by diverting the electrons on the ring anode. The focus lens shifts from the start position to its end position in clockwise fashion.
