Method of and apparatus for reconstructing shape of interested part of object through irradiation with X-rays

An apparatus for reconstructing the shape of an interested part of an object through irradiation thereof with X-rays and on the basis of data representative of a distribution of absorbances of the X-rays in the object and displaying the reconstructed shape, comprising:

• a set of X-ray generating means and X-ray detecting means disposed opposite to each other with the object interposed therebetween so that said X-ray generating means generates cone-beam like X-rays in a predetermined period from each of first and second transverse directions and said X-ray detecting means detects an intensity of the X-rays transmitted through said object;
• injector means for injecting a contrast medium into said object;
• control circuit means for controlling said X-ray generating means and said injector means, said control circuit means supplying to said injector means a control signal indicative of the injection of the contrast medium into said object, said control circuit means also supplying, to said X-ray generating means, control signals which cause said X-ray generating means to generate first and second cone-beam like X-rays in said first direction in first and second periods before and after the contrast medium reaches the interested part of said object respectively as well as control signals which cause said X-ray generating means to generate third and fourth cone-beam like X-rays in said second direction in third and fourth periods before and after the contrast medium reaches the interested part of said object respectively;
• transformation means connected with an output of said X-ray detecting means for transforming output signals of said X-ray detecting means representative of respective intensities of said first to fourth cone beam like X-rays transmitted through said object into absorbance values to produce first to fourth data groups for said first to fourth cone beam like X-rays, each of said first to fourth data groups including data values indicative of absorbances through said object for respective X-ray beams in the corresponding cone-beam like X-rays;
• an operation processing section connected with an output of said transformation means, said operation processing means including first operation means for subtracting said first data group from said second data group to produce a first projection data image of a distribution of the contrast medium in said interested part in said first direction while subtracting said third data group from said fourth data group to produce a second projection data image of a distribution of the contrast medium in said interested part in said second direction, second operation means for determining respective widths of projection of said first and second projection data images to generate an ellipse defined by said projection widths as a preliminary shape of said interested part, and third operation means for comparing the shape of said ellipse with individual data values of said first and second projection data images to correct the shape of said ellipse in accordance with those data values into a corrected shape;
• and
• display means for displaying the corrected shape produced by said third operation means.