Abstract: A filter assembly for a computed tomographic imaging system includes first and second endplates at opposite ends of the filter assembly. Also provided is a first moveable subassembly that includes at least a first x-ray filter and which is configured to move along an axis perpendicular to the first endplate between the first the second endplates. A second moveable subassembly is also provided that includes at least a second x-ray filter. The second moveable subassembly is configured to move along an axis perpendicular to the second endplate between the first and second endplates. The first moveable subassembly and the second moveable subassembly are independently movable to provide at least a small bowtie x-ray filter, a large bowtie x-ray filter, a medium bowtie x-ray filter, a flat filter, and a closed position for a radiation source positioned in a fixed position relative to the filter assembly.