Patent Number: 052934160
Section: summary

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to an x-ray apparatus of the type used to produce an x-ray shadowgraph. 2. Description of the Prior Art It is known to prepare x-ray shadowgraphs using a slotted diaphragm by scanning a line-shaped detector array with a fan-shaped x-ray beam, by causing the x-ray beam to move across a predetermined measurement field while also moving the detector array. An x-ray shadowgraph of a subject in the scanned measuring field can then be reconstructed from the electrical output signals of the detector array. A disadvantage of this known technique is that a relatively large number of mechanical parts must be moved in synchronism with each other, including at least the detector array as well as a slotted diaphragm for gating the x-ray beam. In order to retain an optimum anode angle in the image-effective beam path, the x-ray radiator is usually also moved, i.e., rotated. SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiography apparatus with which x-ray shadowgraphs can be produced which permits an x-ray shadowgraph of a subject to be reconstructed in a predetermined measuring field with a minimum of mechanically moved components, while using a detector array. The above object is achieved in a radiography apparatus which includes means for moving the x-ray source in a direction perpendicular to the line direction of the detector array, so that the detector array is irradiated by an x-ray beam which scans the measuring field from different directions. In the radiography apparatus disclosed herein, the only component which must be moved for scanning the x-ray field is the x-ray radiator. The detector array remains at rest. In an embodiment of the invention, a screen or slotted diaphragm having diaphragm shafts aligned to the detector array is disposed preceding the measuring field in the direction of radiation propagation. This screen diaphragm assures that a fan-shaped x-ray beam is incident on the detector array for each measuring position of the x-ray radiator. In a further embodiment of the invention, the radiography apparatus can be combined with or in a computer tomography apparatus, having a measuring unit consisting of an x-ray radiator and a CT detector array curved around the focus of the x-ray radiator. The measuring unit can be rotated around a system axis, and the detector array for generating the x-ray shadowgraphs is oriented perpendicularly to the CT detector array. In a computer tomography apparatus, the x-ray radiator is already capable of being mechanically moved in order to create computer tomograms. This same mechanical motion, and the structure for generating the mechanical motion, are used for preparing x-ray shadowgraphs in accordance with the principles of the present invention.