Spectral CT using multiple balanced K-edge filters.
Spectral CT using multiple balanced K-edge filters.
复制标题
使用多个平衡 K 边滤波器的光谱 CT。
DOI：
10.1109/tmi.2014.2358561
复制
发表时间：
2015-03
影响因子：
10.6
通讯作者：
Ouyang J
中科院分区：
文献类型：
--
作者：
Rakvongthai Y;Worstell W;El Fakhri G;Bian J;Lorsakul A;Ouyang J
我们的目标是验证一个光谱CT系统的设计，使用一个传统的X射线源与多个平衡的K边缘过滤器。通过在多个能量箱中同时进行合成重建，我们获得了一个相当复杂的体模的测量和模型预期之间的良好协议。我们使用NeuroLogica CT扫描仪对包含不同材料的多个杆的体模进行模拟和数据采集。在X射线管附近分别使用了五个平衡K边缘滤波器，包括钼、铈、镝、铒和钨。对于每个正弦图仓，测量的滤波向量可以被定义为由滤波器确定并且独立于成像对象的传输矩阵与能量分仓的强度向量的乘积。然后，通过反转传输矩阵，然后乘以滤波器测量向量，获得能量分箱正弦图。对于由两个连续的K边缘定义的每个能量箱，使用滤波反投影重建获得合成的能量箱化的衰减图像。由实验得到的各杆的衰减系数与相应的模拟结果吻合较好。此外，重建的衰减系数为一个给定的能量箱，同意美国国家标准与技术研究所的参考值时，能量箱内的射束硬化是小的。所提出的使用多个平衡K边缘滤波器的具有成本效益的系统设计可用于使用常规探测器和集成电子器件以临床相关通量率执行谱CT成像。
Our goal is to validate a spectral CT system design that uses a conventional X-ray source with multiple balanced K-edge filters. By performing a simultaneously synthetic reconstruction in multiple energy bins, we obtained a good agreement between measurements and model expectations for a reasonably complex phantom. We performed simulation and data acquisition on a phantom containing multiple rods of different materials using a NeuroLogica CT scanner. Five balanced K-edge filters including Molybdenum, Cerium, Dysprosium, Erbium, and Tungsten were used separately proximal to the X-ray tube. For each sinogram bin, measured filtered vector can be defined as a product of a transmission matrix, which is determined by the filters and is independent of the imaging object, and energy-binned intensity vector. The energy-binned sinograms were then obtained by inverting the transmission matrix followed by a multiplication of the filter measurement vector. For each energy bin defined by two consecutive K-edges, a synthesized energy-binned attenuation image was obtained using filtered back-projection reconstruction. The reconstructed attenuation coefficients for each rod obtained from the experiment was in good agreement with the corresponding simulated results. Furthermore, the reconstructed attenuation coefficients for a given energy bin, agreed with National Institute of Standards and Technology reference values when beam hardening within the energy bin is small. The proposed cost-effective system design using multiple balanced K-edge filters can be used to perform spectral CT imaging at clinically relevant flux rates using conventional detectors and integrating electronics.