Fast reconstruction for unconstrained cone beam tomosynthesis

Traditional tomosynthesis requires the X-ray, source to be parallel beams or cone beams constrained to the same plane above the object of interest. Commonly, the X-ray sources are placed uniformly around a circle or along a line in the same plane, which demands fixed and high-precision equipment. To eliminate the constraints to the X-ray sources and obtain fast and efficient reconstruction with adequate quality, an unconstrained cone beam tomosynthesis reconstruction and the corresponding deblurring methods are presented in this paper. In this method, two reference balls, whose connecting line is parallel to the detector, are placed above the detector. According to the information provided by these two balls, the X-ray source position and its relative motion are readily calculated for the reconstruction and deblurring processes. A layer-by-layer instead of voxel-by-voxel reconstruction is also utilized to speed up the calculation. This unconstrained cone beam tomosynthesis has a large commercial value, allowing unconstrained projection acquisition and making portable and relatively cheap tomosynthesis equipment possible.