Inventors:
Charles A. Mistretta - Madison WI
Frederick Kelcz - Madison WI
Assignee:
Wisconsin Alumni Research Foundation - Madison WI
International Classification:
G03B 4116
Abstract:
Differential X-ray images are produced in order to improve the visibility of a contrast medium, such as iodine or xenon, having a K absorption edge at a predetermined X-ray energy. Such differential images are produced by combining first, second and third X-ray images which are individually produced by using first, second and third X-ray spectra at first, second and third X-ray energy levels. The first energy level is below the K edge energy, while the second energy level is above the K edge energy. The third energy level is above the second energy level. The second X-ray image is combined subtractively with the average of the first and third X-ray images to produce a differential X-ray image in which any image elements due to soft tissue and bone are largely cancelled out, while image elements due to the contrast medium are enhanced. In one preferred method, two versions of the second image are combined additively, and the first and third images are combined subtractively therewith. The first, second and third X-ray spectra may be produced by using a single X-ray source with first, second and third X-ray filters.