Maeda Yukito, Nagaki Akio, Komi Yoshihiro, Abe Nobukazu, Kashimura Shinya
Department of Clinical Radiology, Kagawa University Hospital.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2015 Nov;71(11):1070-9. doi: 10.6009/jjrt.2015_JSRT_71.11.1070.
The aim of this study was to evaluate the resolution recovery techniques of Flash3D, Astonish, and Evolution in single photon emission computed tomography(SPECT) using a body phantom.
We scanned a National Electrical Manufactures Association body phantom filled with 99mTc. The body of the phantom with radioactive sphere and background was filled with either water or radioactive solution. We investigated image quality using profile curves, recovery coefficient, and image contrast.
The profile curve at the edge of the hot sphere showed artifact due to Gibbs oscillation for all techniques, and also over estimation of recovery coefficient was seen in the hot sphere, as had been previously reported in a simulation study. These phenomena were more remarkable than Evolution in the Flash3D and Astonish techniques. For the contrast between hot sphere and background, the contrast recover was enough for the <17-mm hot spheres. These results showed that the effect of contrast correction was less as the radius of rotation diameter became large.
In the present study using the body phantom, overestimated counts and edge artifacts due to Gibbs oscillation were shown. These phenomena were different by each resolution correction algorithms. Also, there were limitation regarding image quality improvement by resolution correction depending on sphere size and length of radius of rotation.
本研究旨在使用体模评估单光子发射计算机断层扫描（SPECT）中Flash3D、Astonish和Evolution的分辨率恢复技术。
我们扫描了一个填充有99mTc的美国国家电气制造商协会体模。体模中带有放射性球体和背景的部分填充有水或放射性溶液。我们使用轮廓曲线、恢复系数和图像对比度来研究图像质量。
对于所有技术，热球体边缘的轮廓曲线均显示出由于吉布斯振荡导致的伪影，并且在热球体中也观察到恢复系数的高估，这与之前模拟研究中的报道一致。这些现象在Flash3D和Astonish技术中比Evolution更为明显。对于热球体与背景之间的对比度，对于直径小于17mm的热球体，对比度恢复足够。这些结果表明，随着旋转直径半径变大，对比度校正的效果较小。
在本使用体模的研究中，显示出由于吉布斯振荡导致的计数高估和边缘伪影。这些现象因每种分辨率校正算法而异。此外，根据球体大小和旋转半径长度，通过分辨率校正改善图像质量存在局限性。
