Prenosil George A, Sari Hasan, Fürstner Markus, Afshar-Oromieh Ali, Shi Kuangyu, Rominger Axel, Hentschel Michael
Department of Nuclear Medicine, Bern University Hospital, University of Bern, Bern, Switzerland; and
Department of Nuclear Medicine, Bern University Hospital, University of Bern, Bern, Switzerland; and.
J Nucl Med. 2022 Mar;63(3):476-484. doi: 10.2967/jnumed.121.261972. Epub 2021 Jul 22.
Our purpose was to evaluate the performance of the Biograph Vision Quadra PET/CT system. This new system is based on the Biograph Vision 600, using the same silicon photomultiplier-based detectors with 3.2 × 3.2 × 20 mm lutetium-oxoorthosilicate crystals. The 32 detector rings of the Quadra provide a 4-fold larger axial field of view (AFOV) of 106 cm, enabling imaging of major organs in 1 bed position. The physical performance of the scanner was evaluated according to the National Electrical Manufacturers Association NU 2-2018 standard, with additional experiments to characterize energy resolution. Image quality was assessed with foreground-to-background ratios of 4:1 and 8:1. Additionally, a clinical F-FDG PET study was reconstructed with varying frame durations. In all experiments, data were acquired using the maximum ring distance of 322 crystals (MRD 322), whereas image reconstructions could be performed with a maximum ring distance of only 85 crystals (MRD 85). The spatial resolution at full width at half maximum in the radial, tangential, and axial directions was 3.3, 3.4, and 3.8 mm, respectively. The sensitivity was 83 cps/kBq for MRD 85 and 176 cps/kBq for MRD 322. The noise-equivalent count rates (NECRs) at peak were 1,613 kcps for MRD 85 and 2,956 kcps for MRD 322, both at 27.49 kBq/mL. The respective scatter fractions at peak NECR equaled 36% and 37%. The time-of-flight resolution at peak NECR was 228 ps for MRD 85 and 230 ps for MRD 322. Image contrast recovery ranged from 69.6% to 86.9% for 4:1 contrast ratios and from 77.7% to 92.6% for 8:1 contrast ratios reconstructed using point-spread function time of flight with 8 iterations and 5 subsets. Thirty-second frames provided readable lesion detectability and acceptable noise levels in clinical images. The Biograph Vision Quadra PET/CT device has spatial and time resolution similar to those of the Biograph Vision 600 but exhibits improved sensitivity and NECR because of its extended AFOV. The reported spatial resolution, time resolution, and sensitivity make it a competitive new device in the class of PET scanners with an extended AFOV.
我们的目的是评估Biograph Vision Quadra PET/CT系统的性能。这个新系统基于Biograph Vision 600，使用相同的基于硅光电倍增管的探测器，配有3.2×3.2×20毫米的硅酸镥氧晶体。Quadra的32个探测器环提供了106厘米的4倍大轴向视野（AFOV），能够在一个床位位置对主要器官进行成像。根据美国国家电气制造商协会NU 2-2018标准对扫描仪的物理性能进行了评估，并进行了额外的实验以表征能量分辨率。使用4:1和8:1的前景与背景比评估图像质量。此外，对一项临床F-FDG PET研究进行了不同帧持续时间的重建。在所有实验中，数据采集使用的是322晶体的最大环距离（MRD 322），而图像重建仅能使用85晶体的最大环距离（MRD 85）进行。在径向、切向和轴向方向上，半高宽处的空间分辨率分别为3.3毫米、3.4毫米和3.8毫米。对于MRD 85，灵敏度为83 cps/kBq，对于MRD 322，灵敏度为176 cps/kBq。在27.49 kBq/mL时，MRD 85和MRD 322在峰值处的噪声等效计数率（NECR）分别为1613 kcps和2956 kcps。在峰值NECR处各自的散射分数分别为36%和37%。在峰值NECR处，MRD 85的飞行时间分辨率为228 ps，MRD 322为230 ps。对于4:1的对比度，使用点扩散函数飞行时间并进行8次迭代和5个子集重建时，图像对比度恢复范围为69.6%至86.9%；对于8:1的对比度，范围为77.7%至92.6%。30秒的帧在临床图像中提供了可读的病变可检测性和可接受的噪声水平。Biograph Vision Quadra PET/CT设备的空间和时间分辨率与Biograph Vision 600相似，但由于其扩展的AFOV，灵敏度和NECR有所提高。所报告的空间分辨率、时间分辨率和灵敏度使其在具有扩展AFOV的PET扫描仪类别中成为一种有竞争力的新设备。
