X-ray diagnostics installation for subtraction angiography

An X-ray diagnostics installation comprising:

• a subject support;
• an X-ray source which emits an X-ray beam;
• an X-ray image intensifier for detecting X-rays in said X-ray beam emitted by said X-ray source and attenuated by a subject to produce X-ray images;
• video processing means, including a display, for generating video images from said X-ray image and for displaying said video images on said display;
• drive means for cyclically producing relative movement between said subject support and said X-ray beam for producing a plurality of cycles of identical exposure positions;
• detector means for generating a detector signal identifying when each of said exposure positions is reached;
• control means for controlling said video processing means for producing an X-ray image and a video image of said subject at each of said exposure positions;
• memory means for storing a plurality of video images, as stored video images, respectively produced at a plurality of different exposure positions in a cycle;
• and
• subtraction means, in said video processing means, for forming a series of difference images respectively from said stored video images and a plurality of current video images respectively obtained during a current cycle at the same exposure positions as said stored video images, said difference images being displayed on said display.