Performance evaluation of the ECAT HRRT: an LSO-LYSO double layer high resolution, high sensitivity scanner
Performance evaluation of the ECAT HRRT: an LSO-LYSO double layer high resolution, high sensitivity scanner
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DOI：
10.1088/0031-9155/52/5/019
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发表时间：
2007-03-07
影响因子：
3.5
通讯作者：
Lammertsma, Adriaan A.
中科院分区：
文献类型：
--
作者：
de Jong, Hugo W. A. M.;van Velden, Floris H. P.;Lammertsma, Adriaan A.
ECAT 高分辨率研究断层扫描仪 (HRRT) 是一款专用的大脑和小动物 PET 扫描仪，其设计特点可实现高图像空间分辨率和高灵敏度。 HRRT 是第一款商用扫描仪，它利用双层 LSO/LYSO 晶体来实现具有交互深度信息的光子检测。在本研究中，以 NEMA 协议为指导，对商用 LSO/LYSO HRRT 的性能进行了表征。除了测量空间分辨率、能量分辨率、灵敏度、散射分数、计数率性能、衰减和散射校正、热点恢复和图像质量外，还通过 HR+/HRRT 人脑比较研究进行临床评估。点源分辨率在整个视场范围内变化，横轴方向上约为 2.3 至 3.2 毫米 (FWHM)，轴向方向上约为 2.5 至 3.4 毫米。绝对线源灵敏度范围为 2.5% 至 3.3%，NEMA-2001 散射分数等于 45%。根据 NEMA-2001 和 1994 协议，最大 NECR 分别为 45 kcps 和 148 kcps。衰减和散射校正使体积均匀度达到 6.3%，系统均匀度达到 3.1%。在高密度和低密度区域中，重建值的偏差分别高达 15% 和 8%，这可能归因于散布估计的不准确。对于直径为 1 至 2.2 厘米的球体，热点回收率为 60% 至 94%。 HR+ 和 HRRT 临床数据之间达到了高度的定量一致性。总之，ECAT HRRT 具有出色的分辨率和灵敏度特性，这在许多研究中是一个至关重要的优势。
The ECAT high resolution research tomograph (HRRT) is a dedicated brain and small animal PET scanner, with design features that enable high image spatial resolution combined with high sensitivity. The HRRT is the first commercially available scanner that utilizes a double layer of LSO/LYSO crystals to achieve photon detection with depth-of-interaction information. In this study, the performance of the commercial LSO/LYSO HRRT was characterized, using the NEMA protocol as a guideline. Besides measurement of spatial resolution, energy resolution, sensitivity, scatter fraction, count rate performance, correction for attenuation and scatter, hot spot recovery and image quality, a clinical evaluation was performed by means of a HR+/HRRT human brain comparison study. Point source resolution varied across the field of view from approximately 2.3 to 3.2 mm (FWHM) in the transaxial direction and from 2.5 to 3.4 mm in the axial direction. Absolute line-source sensitivity ranged from 2.5 to 3.3% and the NEMA-2001 scatter fraction equalled 45%. Maximum NECR was 45 kcps and 148 kcps according to the NEMA-2001 and 1994 protocols, respectively. Attenuation and scatter correction led to a volume uniformity of 6.3% and a system uniformity of 3.1%. Reconstructed values deviated up to 15 and 8% in regions with high and low densities, respectively, which can possibly be assigned to inaccuracies in scatter estimation. Hot spot recovery ranged from 60 to 94% for spheres with diameters of 1 to 2.2 cm. A high quantitative agreement was met between HR+ and HRRT clinical data. In conclusion, the ECAT HRRT has excellent resolution and sensitivity properties, which is a crucial advantage in many research studies.