Abstract：
Objective.Multi-energy CT conducted by photon-counting detector has a wide range of applications, especially in multiple contrast agents imaging. However, static multi-energy (SME) CT imaging suffers from higher statistical noise because of increased energy bins with static energy thresholds. Our team has proposed a dynamic dual-energy (DDE) CT detector model and the corresponding iterative reconstruction algorithm to solve this problem. However, rigorous and detailed analysis of the statistical noise characterization in this DDE CT was lacked.Approach.Starting from the properties of the Poisson random variable, this paper analyzes the noise characterization of the DDE CT and compares it with the SME CT. It is proved that the multi-energy CT projections and reconstruction images calculated from the proposed DDE CT algorithm have less statistical noise than that of the SME CT.Main results.Simulations and experiments verify that the expectations of the multi-energy CT projections calculated from DDE CT are the same as those of the SME projections. Still, the variance of the former is smaller. We further analyze the convergence of the iterative DDE CT algorithm through simulations and prove that the derived noise characterization can be realized under different CT imaging configurations.Significance.The low statistical noise characteristics demonstrate the value of DDE CT imaging technology.
摘要：
目的：由光子计数探测器进行的多能量CT具有广泛的应用，尤其是在多种造影剂成像中。然而,静态多能量(SME)CT成像由于具有静态能量阈值的增加的能量箱而遭受较高的统计噪声。我们的团队提出了一种动态双能（DDE）CT探测器模型以及相应的迭代重建算法来解决此问题。然而,缺乏对该DDECT中统计噪声表征的严格和详细的分析。
方法：从泊松随机变量的性质出发，本文分析了DDECT的噪声特性，并将其与SMECT进行了比较。证明了根据所提出的DDECT算法计算的多能量CT投影和重建图像比SMECT具有更少的统计噪声。
结果：模拟和实验验证了从DDECT计算的多能量CT投影的期望与SME投影的期望相同。尽管如此，前者的方差较小。我们通过仿真进一步分析了迭代DDECT算法的收敛性，并证明了在不同的CT成像配置下可以实现推导的噪声表征。
结论：低统计噪声特征证明了DDECT成像技术的价值。
方法：从泊松随机变量的性质出发，本文分析了DDECT的噪声特性，并将其与SMECT进行了比较。证明了根据所提出的DDECT算法计算的多能量CT投影和重建图像比SMECT具有更少的统计噪声。
结果：模拟和实验验证了从DDECT计算的多能量CT投影的期望与SME投影的期望相同。尽管如此，前者的方差较小。我们通过仿真进一步分析了迭代DDECT算法的收敛性，并证明了在不同的CT成像配置下可以实现推导的噪声表征。
结论：低统计噪声特征证明了DDECT成像技术的价值。
