Optimization-based scatter estimation using semi-transparent beam absorber array

To correct the scatter in cone beam CT, an optimization-based scatter estimation method (OPMSE) is proposed. Like the previous Fourier-based primary modulation method (FPMSE), semi-transparent beam absorber array (SBAA) is placed between the X-ray source and the imaging target, thus projection data behind the absorber can still be obtained, which is meaningful for dose saving and image quality improving. In the proposed algorithm, scatter is estimated by solving an optimization problem, which makes use of the prior information that primary and scatter are both smooth not only in each frame, but also between adjacent frames. Moreover, an edge-preserving weighting is incorporated to prevent the over-smoothing of structures in the primary signal. The new algorithm is robust that various patterns of modulator can be applied. Simulation and physical experiments demonstrated the good performance of OPMSE in scatter removing.