Patent ID: 6574500
Filing Date: 2003-06-03
Classification: A61B

Abstract:
A method of imaging a body, comprising the steps:(a) exposing the body from one angular position with respect to the body, to radiation transmitted through the body from a radiation source on one side of the body to a radiation detector in alignment with the radiation source on the opposite side of the body; said radiation detector including a two-dimensional array of detector elements producing electrical outputs corresponding to magnitudes of the radiation received by each detector element; said radiation source producing a conical beam sufficiently large to cover all the detector elements in said two-dimensional array after traversing said body; (b) successively changing the angular position in a plurality of angular increments over a predetermined angular sector, and repeating said exposing step at each of said angular positions; (c) storing the electrical outputs of each of said detector elements in each of said angular positions; (d) and utilizing said stored outputs for reconstructing and storing an image of the body in three dimensions; said method further comprising the steps of injecting contrast material into the examined body; producing a masking image of the examined body before the injection of said contrast material; producing a contrast image of the examined body after injection of said contrast material; and producing a difference image by subtracting the masking image from the contrast image; said method further comprising enhancing the contrast-to-noise-ratio (CNR) of said difference image by the following stepsâ€”therefore; before an injection of contrast material, producing a sequence of said masking images, and determining the masking image in said sequence having a minimum change over its immediately preceding masking image in said sequence; and after injecting the contrast material, producing a corresponding sequence of said contrast images, and subtracting from each contrast image the corresponding masking image in the sequence starting with said minimum change masking image.