Method and apparatus for generating an improved image of natural tissue in reconstructing body images from 3d-measurements

A method of generating images of a human or animal body on the basis of 3D-constructions from 3D-XRAY or 3D-Computer Tomography measurements, which bodies comprise both natural tissue and one or more high-density objects, said method comprising the steps of executing said measurements, distinguishing said one or more high-density objects and executing a separating procedure thereon for generating an improved image of regions of said natural tissue,

• said method being characterized by comprising the steps of:
• applying a ramp filter in the direction of rotation to such various projection measurements and back-projecting the various filtered projections into a 3D-volume reconstruction;
• in said 3D-volume reconstruction segmenting said one or more high-density objects by a thresholding procedure and executing a forward projection of the shadow(s) of the segmented one or more high-density objects onto the ramp-filtered projection, thus marking the borders of said one or more high density objects in the ramp-filtered back-projections;
• suppressing said reconstructed one or more high-density objects from the original projection measurements whilst executing an appropriate substitution of gray values derived from a physical neighbourhood of said one or more high-density objects instead of said one or more high-density objects in question;
• and secondarily executing a back-projection of the various filtered projections with corrected profiles and thereby without said suppressed one or more high-density objects.

A computer readable medium containing instructions for controlling a computer system to perform the steps of a method of generating images of a subject on the basis of 3D-constructions from 3D-XRAY or 3D-Computer Tomography measurements, which subject comprises both natural tissue and one or more high-density objects, said method comprising the steps of executing said measurements, distinguishing said one or more high-density objects and executing a separating procedure thereon for generating an improved image of regions of said natural tissue,

• said method comprising the steps of:
• applying a ramp filter in the direction of rotation to such various projection measurements and back-projecting the various filtered projections into a 3D-volume reconstruction;
• in said 3D-volume reconstruction segmenting said one or more high-density objects by a thresholding procedure and executing a forward projection of the shadow(s) of the segmented one or more high-density objects onto the ramp-filtered projection, thus marking the borders of said one or more high density objects in the ramp-filtered back-projections;
• suppressing said reconstructed one or more high-density objects from the original projection measurements whilst executing an appropriate substitution of gray values derived from a physical neighbourhood of said one or more high-density objects instead of said one or more high-density objects in question;
• and secondarily executing a back-projection of the various filtered projections with corrected profiles and thereby without said suppressed one or more high-density objects.