Kiriki Masato, Muraoka Rina, Maeda Katsuhiko, Ikeuchi Yoko, Aoyama Shuhei, Nakano Shinya, Kotoura Noriko
Department of Radiological Technology, Hyogo College of Medicine College Hospital.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2020;76(10):1035-1043. doi: 10.6009/jjrt.2020_JSRT_76.10.1035.
This study evaluated the effects of three types of hybrid iterative reconstruction (IR) on image quality of pediatric body computed tomography images. The image quality components evaluated were noise power spectrum (NPS), task-based modulation transfer function (TTF), and system performance function (SPF). As the IR strength was increased while reducing the radiation dose, the NPS increased in a low-frequency range and the TTF decreased in low-contrast regions. In the low-contrast regions, the calculated SPF decreased over the entire frequency range. Alternatively, in the high-contrast regions, the SPF decreased in the low-frequency regions and increased in the high-frequency regions. The radiation dose reduction using the hybrid IR resulted in the deterioration of the image quality in the low-contrast regions and changes in the spatial frequency characteristics in the high-contrast regions.
本研究评估了三种类型的混合迭代重建（IR）对儿童体部计算机断层扫描图像质量的影响。所评估的图像质量组成部分包括噪声功率谱（NPS）、基于任务的调制传递函数（TTF）和系统性能函数（SPF）。随着在降低辐射剂量的同时增加IR强度，NPS在低频范围内增加，而TTF在低对比度区域降低。在低对比度区域，计算得出的SPF在整个频率范围内均降低。另外，在高对比度区域，SPF在低频区域降低，而在高频区域增加。使用混合IR降低辐射剂量导致低对比度区域的图像质量下降以及高对比度区域的空间频率特征发生变化。
