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.