Architecture of a dual-modality, high-resolution, fully digital positron emission tomography/computed tomography (PET/CT) scanner for small animal imaging
Architecture of a dual-modality, high-resolution, fully digital positron emission tomography/computed tomography (PET/CT) scanner for small animal imaging
复制标题
DOI：
10.1109/tns.2005.850484
复制
发表时间：
2005-06-01
影响因子：
1.8
通讯作者：
Lecomte, R
中科院分区：
文献类型：
--
作者：
Fontaine, R;Bélanger, F;Lecomte, R
当代正电子发射断层摄影（PET）扫描仪通常用非常大规模集成的模拟前端电子器件来实现，以减少功耗、空间、噪声和成本。模拟处理在专用应用中可产生出色的结果，但对于复杂的信号处理或使用更新、快速的闪烁晶体进行更精确的测量，灵活性很小。新型Sherbrooke PET/计算机断层扫描（CT）扫描仪的设计目标是：1）使用相同的探测器通道在发射（PET）和透射（CT）成像中实现1 nm分辨率; 2）能够在CT模式下计数和区分单个X射线光子。通过使用现成的8-B、100 MHz高速模数转换器（ADC）和现场可编程门阵列（FPGA）中的数字处理，尽可能早地从每个检测器通道采样模拟信号，可以更好地满足这些要求。处理单元的核心由Xilinx SpartanIIe组成，最多可容纳16个独立通道。最初的架构是为1024个通道设计的，但模块化允许将系统扩展到10 K通道或更多。这种并行架构支持CT模式下超过100万次/秒/闪烁体的计数率和PET模式下高达100 K次/秒/闪烁体的计数率，符合时间窗口的半峰全宽小于10 ns。
Contemporary positron emission tomography (PET) scanners are commonly implemented with very large scale integration analog front-end electronics to reduce power consumption, space, noise, and cost. Analog processing yields excellent results in dedicated applications, but offers little flexibility for sophisticated signal processing or for more accurate measurements with newer, fast scintillation crystals. Design goals of the new Sherbrooke PET/computed tomography (CT) scanner are: 1) to achieve 1 nun resolution in both emission (PET) and transmission (CT) imaging using the same detector channels; 2) to be able to count and discriminate individual X-ray photons in CT mode. These requirements can be better met by sampling the analog signal from each individual detector channel as early as possible, using off-the-shelf, 8-b, 100-MHz, high-speed analog-to-digital converters (ADC) and digital processing in field programmable gate arrays (FPGAs). The core of the processing units consists of Xilinx SpartanIIe that can hold up to 16 individual channels. The initial architecture is designed for 1024 channels, but modularity allows extending the system up to 10 K channels or more. This parallel architecture supports count rates in excess of a million hits/s/scintillator in CT mode and up to 100 K events/s/scintillator in PET mode, with a coincidence time window of less than 10 ns full-width at half-maximum.