论文标题
宠物成像系统中使用的TDC体系结构的VLSI实现
VLSI Implementation of TDC Architectures Used in PET Imaging Systems
论文作者
论文摘要
正电子发射断层扫描（PET）是一种基于生物体内发射正电子放射性核素浓度的浓度的医学成像方法。在PET成像系统中，葡萄糖用发射正电子核素标记并静脉注射。然后，正电子通过组织移动，并与它们相互作用的细胞的电子碰撞。由于这种相互作用，两个伽马射线朝相反的方向发射。通过环形检测器检测到从癌组织中发出的GAMA射线。并将检测到的信号转换为电响应。随后，将这些响应用电子电路采样，并将其记录为直方图矩阵以生成图像集。伽马射线可能在相等的时间内无法到达位于相对位置的检测器。在具有TOF特征的宠物中，它的目的是根据测量两个光子到达检测器之间差异的原理来获得更好的定位信息。使用TDC结构进行飞行时间的测量。在PS水平上的此时间差的测量与PET系统的空间分辨率直接相关。在这项研究中，对具有各种体系结构方法的TDC结构进行了45 nm CMOS VLSI模拟，以用于PET系统。使用设计的TDC架构，已经模拟了两个伽马光子的时间到达检测器，并且时间差已成功数字化。此外，已经确定了TDC体系结构的各种性能指标，例如输入和输出电压，时间分辨率，测量范围和功率分析。拟议的基于Vernier振荡器的TDC架构已达到25 ps的时间分辨率，低功耗在1V电源电压下为1.62681兆瓦。
Positron emission tomography (PET) is a medical imaging method based on the measurement of concentrations of positron-emitting radionuclides in a living body. In the PET imaging system, glucose is labeled with a positron-emitting radionuclide and injected intravenously. Then, the positrons move through the tissue and collide with the electrons of the cells in which they interact. As a result of this interaction, two gamma rays are emitted in the opposite direction. Gama rays emitted from cancerous tissue that has retained radioactive glucose are detected through ring-shaped detectors. And the detected signals are converted into an electrical response. Subsequently, these responses are sampled with electronic circuits and recorded as histogram matrix to generate the image set. The gamma rays may not reach the detectors located in the opposite position in equal time. In PETs having TOF characteristics, it is aimed to obtain better positioning information by a method based on the principle of measuring the difference between the reach time of the two photons to detectors. The measurement of the flight time is carried out with TDC structures. The measurement of this time difference at the ps level is directly related to the spatial resolution of the PET system. In this study, 45 nm CMOS VLSI simulations of TDC structures that have various architectural approaches were performed for use in PET systems. With the designed TDC architectures, two gamma photons time reach to detectors have been simulated and the time difference has been successfully digitized. In addition, various performance metrics such as input and output voltages, time resolutions, measurement ranges, and power analysis of TDC architectures have been determined. Proposed Vernier oscillator-based TDC architecture has been reached 25 ps time resolution with a low power consumption of 1.62681 mW at 1V supply voltage.
