Abstract：
The collaboration of Yale, the University of California, Davis, and United Imaging Healthcare has successfully developed the NeuroEXPLORER, a dedicated human brain PET imager with high spatial resolution, high sensitivity, and a built-in 3-dimensional camera for markerless continuous motion tracking. It has high depth-of-interaction and time-of-flight resolutions, along with a 52.4-cm transverse field of view (FOV) and an extended axial FOV (49.5 cm) to enhance sensitivity. Here, we present the physical characterization, performance evaluation, and first human images of the NeuroEXPLORER. Methods: Measurements of spatial resolution, sensitivity, count rate performance, energy and timing resolution, and image quality were performed adhering to the National Electrical Manufacturers Association (NEMA) NU 2-2018 standard. The system\'s performance was demonstrated through imaging studies of the Hoffman 3-dimensional brain phantom and the mini-Derenzo phantom. Initial 18F-FDG images from a healthy volunteer are presented. Results: With filtered backprojection reconstruction, the radial and tangential spatial resolutions (full width at half maximum) averaged 1.64, 2.06, and 2.51 mm, with axial resolutions of 2.73, 2.89, and 2.93 mm for radial offsets of 1, 10, and 20 cm, respectively. The average time-of-flight resolution was 236 ps, and the energy resolution was 10.5%. NEMA sensitivities were 46.0 and 47.6 kcps/MBq at the center and 10-cm offset, respectively. A sensitivity of 11.8% was achieved at the FOV center. The peak noise-equivalent count rate was 1.31 Mcps at 58.0 kBq/mL, and the scatter fraction at 5.3 kBq/mL was 36.5%. The maximum count rate error at the peak noise-equivalent count rate was less than 5%. At 3 iterations, the NEMA image-quality contrast recovery coefficients varied from 74.5% (10-mm sphere) to 92.6% (37-mm sphere), and background variability ranged from 3.1% to 1.4% at a contrast of 4.0:1. An example human brain 18F-FDG image exhibited very high resolution, capturing intricate details in the cortex and subcortical structures. Conclusion: The NeuroEXPLORER offers high sensitivity and high spatial resolution. With its long axial length, it also enables high-quality spinal cord imaging and image-derived input functions from the carotid arteries. These performance enhancements will substantially broaden the range of human brain PET paradigms, protocols, and thereby clinical research applications.
摘要：
耶鲁大学的合作，加州大学，戴维斯,联合成像医疗公司成功开发了NeuroEXPLORER,具有高空间分辨率的专用人脑PET成像仪，高灵敏度,和一个内置的三维相机无标记连续运动跟踪。它具有很高的交互深度和飞行时间分辨率，以及52.4厘米的横向视野（FOV）和扩展的轴向FOV（49.5厘米）以增强灵敏度。这里,我们展示了物理特征，绩效评估，以及神经EXPLORER的第一张人类图像。方法：空间分辨率的测量，灵敏度,计数率性能，能量和定时分辨率，根据美国国家电气制造商协会（NEMA）NU2-2018标准执行图像质量。通过对Hoffman3维大脑模型和微型Derenzo模型的成像研究证明了该系统的性能。呈现来自健康志愿者的初始18F-FDG图像。结果:采用滤波反投影重建,径向和切向空间分辨率（半峰全宽）平均为1.64、2.06和2.51mm，轴向分辨率为2.73、2.89和2.93mm，径向偏移为1、10和20cm，分别。平均飞行时间分辨率为236ps，能量分辨率为10.5%。NEMA灵敏度为中心的46.0和47.6kcps/MBq，偏移为10厘米，分别。在FOV中心实现了11.8%的灵敏度。在58.0kBq/mL时，峰值噪声等效计数率为1.31Mcps，在5.3kBq/mL时的散射分数为36.5%。峰值噪声等效计数率下的最大计数率误差小于5%。在3次迭代时，NEMA图像质量对比度恢复系数从74.5％（10毫米球体）变化到92.6％（37毫米球体），背景变异性为3.1%至1.4%，对比度为4.0:1。示例人脑18F-FDG图像表现出非常高的分辨率，捕捉皮层和皮层下结构的复杂细节。结论：NeuroEXPLORER具有高灵敏度和高空间分辨率。随着其轴向长度长，它还可以实现高质量的脊髓成像和来自颈动脉的图像输入功能。这些性能增强将大大拓宽人脑PET范例的范围，协议,从而临床研究应用。
