A POLYCHROMATIC METHOD TO ENHANCE THE SOFT TISSUE CONTRAST OF COMPUTERIZED TOMOGRAPHIC IMAGES USING A SADDLE POINT APPROXIMATION

A new method is introduced for the reconstruction of CT images that takes advantage of the polychromatic character of the incident X-ray beam. This is made possible using a saddle point integration approximation. The data needed for reconstructing the image are simulated using the Shepp and Logan head phantom. Projections are calculated by both the monochromatic and polychromatic methods using the simulated data. The two images so reconstructed, along with their contrasts, are compared. We find that inclusion of the polychromatic composition of the beam greatly increases the contrast between different soft tissue types and therefore the ability to resolve tissues of slightly different densities