A method for extending the dynamic range of flat panel imagers for use in cone beam computed tomography

We propose and experimentally test a method for extending the dynamic range of flat panel imagers (FPI) with a particular emphasis on their use in cone beam computed tomography (CBCT). Although promising results with using FPI's in CBCT have been reported, due to a saturation phenomenon that occurs at higher exposures, as well as their noise properties, their dynamic range is not sufficient for most tomographic tasks where a good low contrast resolution is needed. Our method for extending the dynamic range of FPI's is based on taking, at each angle, two correlated measurements having different exposures, and then combining the two scans appropriately. The method is tested experimentally using a CBCT test bench with a flat panel amorphous silicon (aSi:H) detector with a Lanex screen.