基于投影匹配的双能计算机断层成像投影分解加速算法

The acceleration algorithm for projection decomposition of dual-energy computed tomography image reconstruction based on projection matching

双能计算机断层成像(CT)技术是CT成像领域未来重要的发展方向。双能CT重建算法主流的模型是基物质分解模型,算法的核心关键是求出基物质分解系数投影值。基于投影匹配的双能CT投影分解算法通过建立能谱查找表,使用最小二乘法进行匹配查找得到分解系数投影值。但该方法由于查找表数据庞大,计算时间长,不利于临床的应用。本文在该方法的基础上,提出一种通过直线方程拟合和平面方程拟合查找表数据,快速计算分解系数投影值的改进算法。仿真实验证明,该算法在大幅提高计算速度的同时,也能稳定地收敛到正确的解。

Dual-energy computed tomography（CT） reconstruction imaging technology is an important development direction in the field of CT imaging. The mainstream model of dual-energy CT reconstruction algorithm is the basis material decomposition model, and the projection decomposition is the crucial technique. The projection decomposition algorithm based on projection matching was a general method. With establishing the energy spectrum lookup table, we can obtain the stable solution by the least squares matching method. But the computation cost will increase dramatically when size of lookup table enlarges and it will slow down the computer. In this paper, an acceleration algorithm based on projection matching is proposed. The proposed algorithm makes use of linear equations and plane equations to fit the lookup table data, so that the projection value of the decomposition coefficients can be calculated quickly. As the result of simulation experiment, the acceleration algorithm can greatly shorten the running time of the program to get the stable and correct solution.