Center of Radiology and Diagnostic Imaging, Aizawa Hospital, Nagano, Japan; and.
Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
J Nucl Med. 2023 Dec 1;64(12):1990-1997. doi: 10.2967/jnumed.123.266140.
The Omni Legend 32 PET/CT system features silicon photomultiplier (SiPM)-based detectors with bismuth germanium oxide crystals and a 32-cm axial field of view (FOV). The present study aimed to determine the performance characteristics of the Omni Legend 32 PET/CT system according to National Electrical Manufacturers Association (NEMA) NU 2-2018 standards. The PET component of this system comprises 22 detector modules; each module contains 24 detector blocks with 72 bismuth germanium oxide crystals with a volume of 4.1 × 4.1 × 30 mm coupled to 18 SiPM devices with a 6 × 6 mm area, resulting in an axial FOV of 32 cm. The spatial resolution, sensitivity, count rate performance, and image quality delivered by PET were evaluated using the NEMA NU 2-2018 standard. PET images of 2 patients were evaluated to get a visual first impression of the Omni Legend 32 PET/CT system together with Precision DL. The average spatial resolution at 1, 10, and 20 cm from the central axis was 4.3, 5.3, and 6.2 mm, respectively, for filtered backprojection and 3.7, 4.3, and 5.1 mm, respectively, for ordered-subset expectation maximization. The NEMA sensitivity was 47.30 and 47.05 cps/kBq at the axial center of the FOV and at a 10-cm radial offset, respectively. The scatter fraction, count rate accuracy, and peak noise-equivalent count rates were 35.4%, 1.7%, and 501.7 kcps, respectively, at 15.7 kBq/mL. Contrast recovery for the NEMA body phantom from the smallest to the largest sphere ranged from 61.3% to 93.0%, with a background variability of 5.4%-11.7% and a lung error of 5.1% for Q.Clear (β-value, 50). Good patient image quality was obtained with the Omni Legend 32. The Omni Legend 32 has class-leading sensitivity and count rates within the category of whole-body PET systems while maintaining spatial resolution broadly comparable to that of other current SiPM-based PET/CT systems. This combination of properties results in a very good image quality.
奥米尼传奇 32 PET/CT 系统采用基于硅光电倍增管（SiPM）的探测器，搭配锗酸铋晶体，以及 32cm 的轴向视野（FOV）。本研究旨在根据美国电器制造商协会（NEMA）NU 2-2018 标准，确定奥米尼传奇 32 PET/CT 系统的性能特点。该系统的 PET 组件由 22 个探测器模块组成；每个模块包含 24 个探测器块，每个块包含 72 个锗酸铋晶体，晶体体积为 4.1×4.1×30mm，与 18 个具有 6×6mm 面积的 SiPM 器件耦合，从而实现 32cm 的轴向 FOV。采用 NEMA NU 2-2018 标准评估 PET 的空间分辨率、灵敏度、计数率性能和图像质量。使用 NEMA NU 2-2018 标准对 2 名患者的 PET 图像进行评估，以获得对奥米尼传奇 32 PET/CT 系统和 Precision DL 的直观第一印象。在距中心轴 1、10 和 20cm 处的平均空间分辨率分别为过滤反投影的 4.3、5.3 和 6.2mm，有序子集期望最大化的分别为 3.7、4.3 和 5.1mm。在 FOV 轴中心和 10cm 半径偏移处的 NEMA 灵敏度分别为 47.30 和 47.05cps/kBq。在 15.7kBq/mL 时，散射分数、计数率精度和峰值噪声等效计数率分别为 35.4%、1.7%和 501.7kcps。NEMA 体模的对比恢复范围从小球到最大球分别为 61.3%到 93.0%，背景变异性为 5.4%-11.7%，Q.Clear（β 值，50）的肺部误差为 5.1%。奥米尼传奇 32 获得了良好的患者图像质量。奥米尼传奇 32 在全身 PET 系统类别中具有领先的灵敏度和计数率，同时保持与其他当前基于 SiPM 的 PET/CT 系统大致相当的空间分辨率。这种特性组合带来了非常好的图像质量。
