Choong W-S, Abu-Nimeh F, Moses W W, Peng Q, Vu C Q, Wu J-Y
Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S.A.
Fermi National Accelerator Laboratory, Batavia, IL 60510, U.S.A.
J Instrum. 2015 Aug;10. doi: 10.1088/1748-0221/10/08/T08002. Epub 2015 Aug 12.
We present a 16-channel front-end readout board for the OpenPET electronics system. A major task in developing a nuclear medical imaging system, such as a positron emission computed tomograph (PET) or a single-photon emission computed tomograph (SPECT), is the electronics system. While there are a wide variety of detector and camera design concepts, the relatively simple nature of the acquired data allows for a common set of electronics requirements that can be met by a flexible, scalable, and high-performance OpenPET electronics system. The analog signals from the different types of detectors used in medical imaging share similar characteristics, which allows for a common analog signal processing. The OpenPET electronics processes the analog signals with Detector Boards. Here we report on the development of a 16-channel Detector Board. Each signal is digitized by a continuously sampled analog-to-digital converter (ADC), which is processed by a field programmable gate array (FPGA) to extract pulse height information. A leading edge discriminator creates a timing edge that is "time stamped" by a time-to-digital converter (TDC) implemented inside the FPGA. This digital information from each channel is sent to an FPGA that services 16 analog channels, and then information from multiple channels is processed by this FPGA to perform logic for crystal lookup, DOI calculation, calibration, etc.
我们展示了一款用于OpenPET电子系统的16通道前端读出板。开发核医学成像系统（如正电子发射计算机断层扫描仪（PET）或单光子发射计算机断层扫描仪（SPECT））的一项主要任务是电子系统。虽然有各种各样的探测器和相机设计概念，但采集数据的相对简单性质使得可以通过灵活、可扩展且高性能的OpenPET电子系统满足一组通用的电子要求。医学成像中使用的不同类型探测器的模拟信号具有相似的特性，这使得可以进行通用的模拟信号处理。OpenPET电子系统通过探测器板处理模拟信号。在此，我们报告一款16通道探测器板的开发情况。每个信号由连续采样的模数转换器（ADC）数字化，该转换器由现场可编程门阵列（FPGA）处理以提取脉冲高度信息。前沿鉴别器创建一个定时边沿，该边沿由FPGA内部实现的时间数字转换器（TDC）进行“时间标记”。来自每个通道的此数字信息被发送到服务16个模拟通道的FPGA，然后来自多个通道的信息由该FPGA处理以执行晶体查找、DOI计算、校准等逻辑操作。
