基于L_(1/2)范数的扇束X射线荧光CT重建

Reconstruction of Fan Beam X-Ray Fluorescence Computed Tomography Based on L_(1/2)-Norm

X射线荧光CT(XFCT)作为一种分子成像模式,存在着扫描时间长、辐射剂量大的问题,通常通过增大投影间隔、减少投影数量的稀疏投影方式来降低扫描时间与辐射剂量.因此,为在较少投影数量和较少迭代次数下提高重建图像质量,提出一种基于L_(1/2)范数的XFCT重建算法.数值模拟实验结果表明:在较少投影数量和较少迭代次数下,所提基于L_(1/2)范数的XFCT重建算法与传统Maximum Likelihood Expectation Maximization算法相比,其重建图像的均方根误差更小,全局图像质量索引更接近1,达到在较少投影数量和较少迭代次数下提高重建图像质量的目的.

As a molecular imaging mode,Xray fluorescence computed tomography(XFCT)has the problems of long scanning times and large radiation doses.In general,the scanning time and radiation dose of XFCT are reduced by increasing the projection interval and reducing the number of projections.Therefore,to improve the quality of reconstructed images with few projections and iterations,an XFCT reconstruction algorithm based on the L_(1/2)-norm is proposed.The numerical simulation results show that compared with the traditional Maximum Likelihood Expectation Maximization algorithm,the proposed XFCT reconstruction algorithm has a smaller root mean square error and a global image quality index closer to 1 with fewer projections and iterations,achieving the goal of improving the quality of reconstructed images with few projections and iterations.