Abstract：
Objective.Time-of-flight (TOF) capability and high sensitivity are essential for brain-dedicated positron emission tomography (PET) imaging, as they improve the contrast and the signal-to-noise ratio (SNR) enabling a precise localization of functional mechanisms in the different brain regions.Approach.We present a new brain PET system with transverse and axial field-of-view (FOV) of 320 mm and 255 mm, respectively. The system head is an array of 6 × 6 detection elements, each consisting of a 3.9 × 3.9 × 20 mm3lutetium-yttrium oxyorthosilicate crystal coupled with a 3.93 × 3.93 mm2SiPM. The SiPMs analog signals are individually digitized using the multi-voltage threshold (MVT) technology, employing a 1:1:1 coupling configuration.Main results.The brain PET system exhibits a TOF resolution of 249 ps at 5.3 kBq ml-1, an average sensitivity of 22.1 cps kBq-1, and a noise equivalent count rate (NECR) peak of 150.9 kcps at 8.36 kBq ml-1. Furthermore, the mini-Derenzo phantom study demonstrated the system\'s ability to distinguish rods with a diameter of 2.0 mm. Moreover, incorporating the TOF reconstruction algorithm in an image quality phantom study optimizes the background variability, resulting in reductions ranging from 44% (37 mm) to 75% (10 mm) with comparable contrast. In the human brain imaging study, the SNR improved by a factor of 1.7 with the inclusion of TOF, increasing from 27.07 to 46.05. Time-dynamic human brain imaging was performed, showing the distinctive traits of cortex and thalamus uptake, as well as of the arterial and venous flow with 2 s per time frame.Significance.The system exhibited a good TOF capability, which is coupled with the high sensitivity and count rate performance based on the MVT digital sampling technique. The developed TOF-enabled brain PET system opens the possibility of precise kinetic brain PET imaging, towards new quantitative predictive brain diagnostics.
摘要：
目标：飞行时间（TOF）能力和高灵敏度对于大脑专用正电子发射断层扫描（PET）成像至关重要，因为它们提高了对比度和信噪比（SNR），从而可以精确定位不同大脑区域的功能机制。＆＃xD;方法：我们提出了一种新的大脑PET系统，其横向和轴向视场（FOV）分别为320毫米和255毫米，分别。系统头是一个由6x6个检测元件组成的阵列，每个由3.9x3.9x20mm3的LYSO晶体和3.93x3.93mm2的SiPM组成。SiPM模拟信号使用多电压阈值(MVT)技术单独数字化，采用1:1:1耦合配置。＆＃xD;主要结果：大脑PET系统在5.3kBq/mL时的TOF分辨率为249ps，平均灵敏度为22.1cps/kBq，以及在8.36kBq/mL时150.9kcps的噪声等效计数率(NECR)峰值。此外，迷你Derenzo幻影研究证明了该系统能够区分直径为2.0毫米的杆。此外，将TOF重建算法结合到图像质量体模研究中，优化了背景变异性，导致从44％（37毫米）到75％（10毫米）与可比的对比度范围内的减少。在人脑成像研究中，在包含TOF的情况下，信噪比(SNR)提高了1.7倍，从27.07增加到46.05。进行了时间动态人脑成像，显示皮质和丘脑摄取的独特特征，以及每时2s的动脉和静脉流量。＆＃xD;意义：该系统表现出良好的TOF能力，再加上基于MVT数字采样技术的高灵敏度和计数率性能。开发的具有TOF功能的脑PET系统为精确的动态脑PET成像提供了可能性，迈向新的定量预测大脑诊断。
