Dual energy CT with photon counting and dual source systems: comparative evaluation
Dual energy CT with photon counting and dual source systems: comparative evaluation
复制标题
DOI：
10.1088/0031-9155/60/23/8949
复制
发表时间：
2015-12-07
影响因子：
3.5
通讯作者：
Shikhaliev, Polad M.
中科院分区：
文献类型：
--
作者：
Atak, Haluk;Shikhaliev, Polad M.
最近，新的双能量（DE）计算机断层扫描（CT）系统-双源CT（DSCT）和光子计数CT（PCCT）已被引入。尽管这些系统具有相同的临床目标，但它们具有重大差异，因为它们使用双kVp和单kVp采集以及不同的X射线检测和能量分辨率概念。本研究的目的是理论和实验比较DSCT和PCCT。对DSCT Siemens Somatom Flash进行建模，进行仿真研究。PCCT的配置与DSCT相同，但使用了光子计数探测器。直径为20、30和38 cm的软组织模型包括碘、CaCO 3、脂肪和水样品。所有研究的剂量（空气比释动能）均为14 mGy。对于DSCT，低能量和高能量CT数据分别在80 kVp和140 kVp下模拟，对于PCCT，低能量和高能量CT数据分别在20-58 keV和59-120 keV能量范围内模拟。实验使用Somatom Flash DSCT系统和基于光子计数CdZnTe探测器的PCCT系统，具有2 x 256像素配置和1 x 1 mm（2）像素大小。在模拟的一般CT图像中，PCCT提供了比使用0.4/0.8 mm Sn滤波器的DSCT更高的对比度噪声比（CNR）。具有K边缘滤波器的PCCT提供比具有Cu滤波器的PCCT更高的CNR，并且具有0.4mm Sn滤波器的DSCT提供比具有0.8mm Sn滤波器的DSCT更高的CNR。在模拟DE减影图像中，DSCT的CNR与使用Cu滤波器的PCCT相当。然而，使用Ho a K边缘滤波器的DE PCCT提供的CNR比使用0.4/0.8 mm Sn滤波器的DE DSCT高30-40%。与DSCT相比，实验性PCCT在一般成像中提供了更高的CNR。在实验DE减影图像中，DSCT提供的CNR高于使用Cu滤波器的PCCT。然而，采用K边缘滤波器的DE PCCT的实验CNR比DE DSCT高15%，低于模拟研究预测的30-40%的增加。可以得出结论，在CT成像（包括DE减影CT）中，理想的PCCT可以提供比理想的DSCT更大的优势。然而，PCCT检测器的局限性不允许其充分发挥其潜力，因此需要进一步努力来改进PCCT检测器。
Recently, new dual energy (DE) computed tomography (CT) systems-dual source CT (DSCT) and photon counting CT (PCCT) have been introduced. Although these systems have the same clinical targets, they have major differences as they use dual and single kVp acquisitions and different x-ray detection and energy resolution concepts. The purpose of this study was theoretical and experimental comparisons of DSCT and PCCT. The DSCT Siemens Somatom Flash was modeled for simulation study. The PCCT had the same configuration as DSCT except it used a photon counting detector. The soft tissue phantoms with 20, 30, and 38 cm diameters included iodine, CaCO3, adipose, and water samples. The dose (air kerma) was 14 mGy for all studies. The low and high energy CT data were simulated at 80 kVp and 140 kVp for DSCT, and in 20-58 keV and 59-120 keV energy ranges for PCCT, respectively. The experiments used Somatom Flash DSCT system and PCCT system based on photon counting CdZnTe detector with 2 x 256 pixel configuration and 1 x 1 mm(2) pixels size. In simulated general CT images, PCCT provided higher contrast-to-noise ratio (CNR) than DSCT with 0.4/0.8 mm Sn filters. The PCCT with K-edge filter provided higher CNR than the PCCT with a Cu filter, and DSCT with 0.4 mm Sn filter provided higher CNR than the DSCT with a 0.8 mm Sn filter. In simulated DE subtracted images, CNR of the DSCT was comparable to the PCCT with a Cu filter. However, DE PCCT with Ho a K-edge filter provided 30-40% higher CNR than the DE DSCT with 0.4/0.8 mm Sn filters. The experimental PCCT provided higher CNR in general imaging compared to the DSCT. In experimental DE subtracted images, the DSCT provided higher CNR than the PCCT with a Cu filter. However, experimental CNR with DE PCCT with K-edge filter was 15% higher than in DE DSCT, which is less than 30-40% increase predicted by the simulation study. It is concluded that ideal PCCT can provide substantial advantages over ideal DSCT in CT imaging including DE subtracted CT. However, the limitations of the PCCT detector does not allow it to reach its full potential and therefore further efforts are needed to improve PCCT detectors.