Feedback controlled geometry registration system for radiographs

Abstract

A system for reproducibly aiming an X-ray source array to provide substantial registration of exposure geometry through an organ or a portion of tissue from one examination to the next. The system derives functions or signals based on computer controlled X-ray source point geometries to create multiple images produced from known positions via a detector array which feeds this information to a computer image storage system and which provides for comparison of the detected signals with reference signals originally stored in a memory; the comparison yields correction signals which act to shift the X-ray raster toward restoration of the original effective geometry. Thus, the X-ray sources are coupled to the detector array through a feedback loop circuit including a computer which, by sequentially activating each X-ray point source and noting the resulting functions generated by the detector array, can compare the results with the stored functions and revise the working geometry to simulate that of the original geometry from which the stored reference functions were obtained. The computer also activates a visual display device providing a crude X-ray scan through the tissue of interest, which can be used to create low resolution tomograms of the irradiated structures.