TOF-PET前端电子系统设计与实现

Design and implementation of front-end electronic system for TOF-PET

飞行时间技术(TOF)的应用显著的提高了PET系统输出图像的信噪比,但同时也对电子学系统的测量性能提出了更高的要求。前端电子系统是连接探测器与图像输出的桥梁,较大程度上影响了系统的整体分辨能力。本文从前端电子系统采集的角度出发,以优化现有系统的时间分辨性能与能量分辨性能为目的,分析TOF技术对前端电子系统的设计需求,并对其进行实施与测试。结果表明设计得到的全局时钟抖动小于10ps;基于JESD204B协议的ADC采集方案可以使目前的PET系统能量分辨率低于12%;基于CFD和FPGA-TDC的时间测量技术可以使时间分辨率达到100ps,满足系统预期设计需求。

The application of time of flight(TOF)technology significantly improves the signal-to-noise ratio(SNR)of positron emission tomography(PET)system,but also puts forward higher requirements on the timing performance of measurement system.The front-end circuit is a bridge connecting the detector and the image output,which can greatly affect the time resolving ability of system.In order to improve the time and energy resolving ability of the existing system,the paper analyzes the design requirements of TOF technology on front-end electronics,and the circuit was implemented and tested.The results show that the global clock jitter is less than 10ps and the energy resolution can be less than 12%based on JESD204B standard of ADC to FPGA.Besides,the time resolution can achieve 100ps based on CFD and FPGA-TDC,which meets the design requirements of TOF system.