An iteration algorithm in dual-energy x-ray imaging based on polychromatic physics model

In this paper, we aim at a polychromatic physics model of dual-energy medical x-ray imaging and present a corresponding computation method, which includes two steps: first, bd(s, theta), i.e. the parameter used for expressing the component of Compton scatter, and bp(s, theta), i.e. the parameter used for expressing the component of Photoemission Effect, are decided by solving a nonlinear equation system; then a FBP (Filtered Back Projection) algorithm is used to reconstruct the decomposition images from the sinograms of bp(s, theta) and bp(s, theta). It is noticed that the first step is the most time-consuming, so it is very important to find out a high-speed and effective iteration computation method. In this paper, we propose a Newton iteration method with an effective estimation strategy of initial value for quickly solving the nonlinear equation system. A CT simulation experiment was implemented to validate the effectiveness of the whole procedure.