Method and apparatus for acquiring and processing only a necessary volume of radon data consistent with the overall shape of the object for efficient three dimensional image reconstruction

A method for reconstructing an image of a three dimensional object using an inverse Radon transform comprising the steps of:

• providing a mutually spaced irradiating beam source and a suitable array radiation detector in fixed relationship to one another;
• providing an object therebetween;
• irradiating said object within a field of view of said irradiating beam source;
• scanning said irradiated object along a preselected scanning trajectory to acquire a plurality of beam attenuation data at said array detector for a plurality of select source positions;
• organizing said beam attenuation data in the form of line integrals through said object for each of said plurality of source positions;
• determining from said beam attenuation data values representing planar integrals;
• organizing said planar integrals onto discrete polar grids on a predetermined plurality of planes coaxial with respect to a reference axis in Radon space;
• retaining on each said plane only evaluated planar integral values residing within a corresponding overall projected region of support of said object in Radon space in order to truncate each said polar grid to represent source beams actually penetrating said object;
• reconstructing a two dimensional projected image of said object onto each said plane from said retained integral values using parallel processing;
• organizing said plurality of two dimensional projection image data from said plurality of coaxial planes onto a plurality of planes slicing normally through said reference axis;
• and
• reconstructing two dimensional images on each planar slice using parallel processing to collectively provide a three dimensional reconstructed image of said object.