具有大鼠全身成像能力的MRI兼容小动物PET系统SimPET-L和SimPET-XL的性能评估

Performance evaluation of SimPET-L and SimPET-XL: MRI-compatible small-animal PET systems with rat-body imaging capability.

作者信息

Seo Minjee, Ko Guen Bae, Kim Kyeong Yun, Son Jeong-Whan, Byun Jung Woo, Lee Yun-Sang, Kim Kyeong Min, Park Jang Woo, Kim Kipom, Lee Taekwan, Lee Jae Sung

机构信息

Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea.

Department of Nuclear Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, South Korea.

出版信息

EJNMMI Phys. 2023 Mar 7;10(1):16. doi: 10.1186/s40658-023-00534-x.

DOI:10.1186/s40658-023-00534-x

PMID:36881339

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9992463/

Abstract

BACKGROUND

SimPET-L and SimPET-XL have recently been introduced with increased transaxial fields of view (FOV) compared with their predecessors (SimPET™ and SimPET-X), enabling whole-body positron emission tomography (PET) imaging of rats. We conducted performance evaluations of SimPET-L and SimPET-XL and rat-body imaging with SimPET-XL to demonstrate the benefits of increased axial and transaxial FOVs.

PROCEDURES

The detector blocks in SimPET-L and SimPET-XL consist of two 4 × 4 silicon photomultiplier arrays coupled with 20 × 9 array lutetium oxyorthosilicate crystals. SimPET-L and SimPET-XL have an inner diameter (bore size) of 7.6 cm, and they are composed of 40 and 80 detector blocks yielding axial lengths of 5.5 and 11 cm, respectively. Each system was evaluated according to the National Electrical Manufacturers Association NU4-2008 protocol. Rat imaging studies, such as F-NaF and F-FDG PET, were performed using SimPET-XL.

RESULTS

The radial resolutions at the axial center measured using the filtered back projection, 3D ordered-subset expectation maximization (OSEM), and 3D OSEM with point spread functions correction were 1.7, 0.82, and 0.82 mm FWHM in SimPET-L and 1.7, 0.91, and 0.91 mm FWHM in SimPET-XL, respectively. The peak sensitivities of SimPET-L and SimPET-XL were 6.30% and 10.4% for an energy window of 100-900 keV and 4.44% and 7.25% for a window of 250-750 keV, respectively. The peak noise equivalent count rate with an energy window of 250-750 keV was 249 kcps at 44.9 MBq for SimPET-L and 349 kcps at 31.3 MBq for SimPET-XL. In SimPET-L, the uniformity was 4.43%, and the spill-over ratios in air- and water-filled chambers were 5.54% and 4.10%, respectively. In SimPET-XL, the uniformity was 3.89%, and the spill-over ratio in the air- and water-filled chambers were 3.56% and 3.60%. Moreover, SimPET-XL provided high-quality images of rats.

CONCLUSION

SimPET-L and SimPET-XL show adequate performance compared with other SimPET systems. In addition, their large transaxial and long axial FOVs provide imaging capability for rats with high image quality.

摘要

背景

与前代产品（SimPET™ 和 SimPET-X）相比，SimPET-L 和 SimPET-XL 最近推出时具有更大的轴向视野（FOV），能够对大鼠进行全身正电子发射断层扫描（PET）成像。我们对 SimPET-L 和 SimPET-XL 进行了性能评估，并使用 SimPET-XL 进行大鼠全身成像，以证明轴向和横向视野增加的益处。

程序

SimPET-L 和 SimPET-XL 中的探测器模块由两个 4×4 硅光电倍增管阵列与 20×9 阵列的正硅酸镥晶体耦合而成。SimPET-L 和 SimPET-XL 的内径（孔径）为 7.6 厘米，它们分别由 40 个和 80 个探测器模块组成，轴向长度分别为 5.5 厘米和 11 厘米。每个系统均按照美国国家电气制造商协会 NU4-2008 协议进行评估。使用 SimPET-XL 进行了大鼠成像研究，如 F-NaF 和 F-FDG PET。

结果

在 SimPET-L 中，使用滤波反投影、三维有序子集期望最大化（OSEM）以及带点扩散函数校正的三维 OSEM 测量的轴向中心径向分辨率，半高宽分别为 1.7、0.82 和 0.82 毫米；在 SimPET-XL 中分别为 1.7、0.91 和 0.91 毫米。对于 100 - 900 keV 的能量窗，SimPET-L 和 SimPET-XL 的峰值灵敏度分别为 6.30%和 10.4%；对于 250 - 750 keV 的窗，分别为 4.44%和 7.25%。对于 250 - 750 keV 的能量窗，在 44.9 MBq 时 SimPET-L 的峰值噪声等效计数率为 249 kcps，在 31.3 MBq 时 SimPET-XL 的峰值噪声等效计数率为 349 kcps。在 SimPET-L 中，均匀性为 4.43%，在空气填充室和水填充室中的溢出率分别为 5.54%和 4.10%。在 SimPET-XL 中，均匀性为 3.89%，在空气填充室和水填充室中的溢出率分别为 3.56%和 3.60%。此外，SimPET-XL 提供了高质量的大鼠图像。