Image processing method and system for radiological diagnostics

Claim 1

An image processing system for radiological diagnostics, comprising: mask image memory means for storing a mask image obtained by irradiating, under a specific irradiation condition, radioactive rays onto a subject in which a contrast medium is not injected; correction means for correcting, under said irradiation condition, density values of pixels of said mask image stored in the mask image memory means, said correction means comprising: an estimating means, including memory means for storing thickness data of a specific uniform material corresponding to the density values of the pixels in the form of a first correction coefficient table, means for receiving the corrected density values of pixels and a value indicative of the irradiation condition, and for indexing said memory means for selecting data elements in the stored data for all pixels of the mask image based upon said received values, and means for estimating the thickness of the subject appearing on the mask image as a value calculated in terms of said specific uniform material; correction coefficient memory means for storing correction coefficients based on radiation attenuation, and for outputting, as correction data, one of said correction coefficients which corresponds to the estimated value of the thickness of the subject; a first arithmetic operation means for performing an arithmetic operation on the basis of said corrected density values stored in the first correction coefficient table and all pixels of the mask image stored in the mask image memory means, thereby obtaining a mask image having a reduced beam hardening effect; contrast image memory means for storing a contrast image obtained by irradiating, under a specific irradiation condition, radioactive rays onto said subject in which the contrast medium was injected; subtracting means for performing a subtraction operation on the basis of the contrast image stored in the contrast image memory means and the mask image stored in the mask image memory means, with respect to all pixels of both images, thereby obtaining a subtraction image; a second correction coefficient table for storing correction coefficients based on irradiation attenuation, one of said correction coefficients being selected in accordance with the estimated value obtained by said estimating means and the subtraction value obtained by the subtracting means, and the selected correction coefficient being output as correction data; second arithmetic operation means for performing an arithmetic operation on the basis of the correction data output from the second correction coefficient table and said subtraction image with respect to all pixels of the contrast image, thereby obtaining a contrast image having a reduced beam hardening effect; and display means for displaying at least one of the mask image and the contrast image having the reduced beam hardening effects, which have been output from said first and second arithmetic operation means.