Tsuda Keisuke, Suzuki Takayuki, Toya Kazuhito, Sato Eisuke, Fujii Hirofumi
Department of Radiological Technology, Faculty of Health Science, Juntendo University, Tokyo, Japan.
Division of Functional Imaging, Exploratory Oncology Research and Clinical Trial Center (EPOC), National Cancer Center, Japan.
World J Nucl Med. 2023 Sep 13;22(3):234-243. doi: 10.1055/s-0043-1774418. eCollection 2023 Sep.
In this study, we investigated the optimal reconstruction algorithm in fluorodeoxyglucose (FDG) positron emission tomography (PET) with a short acquisition time. In the phantom study, six spheres filled with FDG solution (sphere size: 6.23-37 mm; radioactivity ratio of spheres to background = 8:1) and placed in a National Electrical Manufacturers Association phantom were evaluated. Image acquisition time was 15 to 180 seconds, and the obtained image data were reconstructed using each of the Fourier rebinning (FORE) + ordered subsets expectation-maximization (OSEM) and 3D-OSEM algorithms. In the clinical study, mid-abdominal images of 19 patients were evaluated using regions of interest placed on areas of low, intermediate, and high radioactivity. All obtained images were investigated visually, and quantitatively using maximum standardized uptake value (SUV) and coefficient of variation (CV). In the phantom study, FORE + OSEM images with a short acquisition time had large CVs (poor image quality) but comparatively constant maximum SUVs. 3D-OSEM images showed comparatively constant CVs (good image quality) but significantly low maximum SUVs. The results of visual evaluation were well correlated with those of quantitative evaluation. Small spheres were obscured on 3D-OSEM images with short acquisition time, but image quality was not greatly deteriorated. The clinical and phantom studies yielded similar results. FDG PET images with a short acquisition time reconstructed by FORE + OSEM showed poorer image quality than by 3D-OSEM. However, images obtained with a short acquisition time and reconstructed with FORE + OSEM showed clearer FDG uptake and more useful than 3D-OSEM in the light of the detection of lesions.
在本研究中，我们调查了在短采集时间的氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）中的最佳重建算法。
在体模研究中，评估了六个填充有FDG溶液的球体（球体尺寸：6.23 - 37毫米；球体与背景的放射性比 = 8:1），这些球体放置在一个美国国家电气制造商协会体模中。图像采集时间为15至180秒，所获得的图像数据使用傅里叶重排（FORE）+ 有序子集期望最大化（OSEM）和3D - OSEM算法分别进行重建。在临床研究中，使用放置在低、中、高放射性区域的感兴趣区对19例患者的中腹部图像进行评估。所有获得的图像均进行视觉检查，并使用最大标准化摄取值（SUV）和变异系数（CV）进行定量分析。
在体模研究中，采集时间短的FORE + OSEM图像具有较大的CV（图像质量差），但最大SUV相对恒定。3D - OSEM图像显示CV相对恒定（图像质量好），但最大SUV显著较低。视觉评估结果与定量评估结果高度相关。在采集时间短的3D - OSEM图像上，小球体模糊不清，但图像质量并未大幅下降。临床研究和体模研究得出了相似的结果。
FORE + OSEM重建的采集时间短的FDG PET图像的质量比3D - OSEM重建的图像质量差。然而，采集时间短且用FORE + OSEM重建的图像在病变检测方面显示出比3D - OSEM更清晰的FDG摄取且更有用。
