Department of Nuclear Medicine and Molecular Imaging, Singapore General Hospital.
Duke-NUS Graduate Medical School, Singapore, Singapore.
Nucl Med Commun. 2023 Jun 1;44(6):480-487. doi: 10.1097/MNM.0000000000001687. Epub 2023 Mar 15.
The objective of this study is to determine the optimal β value for clinical use in digital 68 Ga-prostate-specific membrane antigen (PSMA-11) PET/computed tomography (CT) imaging.
68 Ga PSMA PET/CT of 21 patients with prostate cancer were reconstructed using block-sequential regularized expectation maximization ( β value of 400-1600) and ordered subsets expectation maximization. Nine independent blinded readers evaluated each reconstruction for overall image quality, noise level and lesion detectability. Maximum standardized uptake value (SUVmax) of the most intense lesion, liver SUVmean and liver SUV SD were recorded. Lesions were then subdivided according to uptake and size; the SUVmax of these lesions were analyzed.
There is a statistically significant correlation between improvement in image quality and β value, with the best being β 1400. This trend was also seen in image noise ( P < 0.001), with the least image noise reported with β 1400. Lesion detectability was not significantly different between the different β values ( P = 0.6452). There was no statistically significant difference in SUVmax of the most intense lesion ( P = 0.9966) and SUVmean of liver background between the different β values ( P = 0.9999); however, the SUV SD of the liver background showed a clear trend, with the lowest with β 1400 ( P = 0.0008). There was a decreasing trend observed in SUVmax when β values increased from 800 to 1400 for all four subgroups, and this decrease was greatest in small and low uptake lesions.
Bayesian penalized likelihood reconstruction algorithms improve image quality without affecting lesion detectability. A β value of 1400 is optimal.
本研究旨在确定数字 68Ga-前列腺特异性膜抗原（PSMA-11）PET/计算机断层扫描（CT）成像中用于临床的最佳β值。
对 21 例前列腺癌患者的 68Ga PSMA PET/CT 分别采用块序正则期望极大化（β值为 400-1600）和有序子集期望极大化进行重建。9 名独立盲法读者评估了每种重建方法的整体图像质量、噪声水平和病变可探测性。记录了最强烈病变的最大标准化摄取值（SUVmax）、肝脏 SUVmean 和肝脏 SUV SD。然后根据摄取量和大小对病变进行细分，分析这些病变的 SUVmax。
图像质量的改善与β值呈统计学显著相关，最佳β值为 1400。图像噪声也呈现出同样的趋势（P < 0.001），β值为 1400 时报告的图像噪声最小。不同β值之间的病变可探测性无显著差异（P = 0.6452）。不同β值之间，最强烈病变的 SUVmax（P = 0.9966）和肝脏背景的 SUVmean 无统计学差异；然而，肝脏背景的 SUV SD 呈现出明显的趋势，β值为 1400 时最低（P = 0.0008）。当β值从 800 增加到 1400 时，所有 4 个亚组的 SUVmax 均呈现出下降趋势，小而低摄取病变的下降幅度最大。
贝叶斯惩罚似然重建算法可改善图像质量而不影响病变可探测性。β值为 1400 时效果最佳。
