Computerized tomographic scanner with shaped radiation filter

An apparatus for reconstructing an image of at least a region of an object positioned in a scan circle comprising:

• a source of radiation having a polychromatic spectrum for irradiating the scan circle from a plurality of directions with a generally fan-shaped array of radiation having an apex generally at the source of radiation;
• at least one radiation detector positioned to receive radiation from said source of radiation which has traversed the scan circle;
• a radiation filter for altering the polychromatic spectrum of the radiation, comprising a body of filter material, said body having a generally parabolic recess therein, said parabolic recess having a central axis, said body being disposed between said source and said scan circle with said central axis in line with the apex of the fan-shaped array and the center of the scan circle;
• data collection means for collecting data indicative of the intensity of radiation received by said at least one detector and organizing the collected data into data lines, said data collection means operatively connected with said at least one detector;
• filter correction means for adjusting said data line for nonlinearities introduced by alterations to the polychromatic spectrum of the radiation caused by said radiation filter, said filter correction means being operatively connected with the data collection means;
• and
• reconstruction means for reconstructing the adjusted data lines into a representation of an image of said region, said reconstruction means being operatively connected with said filter correction means.