基于碳纳米管X射线源的静态扫描系统设计

摘要

Compared with conventional hot-cathode X-ray source, carbon nanotube X-ray source has multiple advantages, such as compact structure, high time-resolution and programmable emission. Therefore, the electronic scanning strategy can be used to replace traditional scanning method for improving the time resolution of image acquisition, and reducing motion artifacts and radiation dose. This paper aims at designing the software and hardware platforms for this new-type stationary scanning system with X-ray source. Among them, the hardware platform integrates multi-beam X-ray source and its corresponding drive circuit, a high voltage generator, a compound vacuum gauge and digital flat-panel detector; the lower computer software implements the generation of multi-channel pulse and trigger signal using Quartus II development platform and Verilog hardware description language; the upper computer software platform implements the integrated control of multiple instruments and completes the stationary scanning, high voltage control, vacuum degree monitoring and image acquisition of multi-beam X-ray source adopting LabVIEW graphical programming tools. The design of this system was veriifed by our experiments, which reveals that it can realize the imaging of pulse-type stationary scanning of multi-beam carbon nanotube X-ray source, and thereby provide the experimental and testing platforms for the development of carbon nanotube stationary CT.%相比传统热阴极 X射线源而言，碳纳米管 X射线源具有结构紧凑、高时间分辨率、可编程式发射等优势，因此可以采用电子式的扫描方式取代传统扫描方式，提高采集图像的时间分辨率，减少运动伪影，降低辐射剂量。文章针对该新型 X射线源静态扫描系统进行软硬件平台设计。其中，硬件平台集成了多光束 X射线源及其驱动电路、高压发生器、复合真空计和数字平板探测器；下位机软件采用 Quartus II开发平台，Verilog硬件描述语言，实现多路脉冲及触发信号的产生；上位机软件平台采用 LabVIEW图形化编程工具，实现多台仪器的集成控制，完成多光束 X射线源静态扫描、高压控制、真空度监测和图像采集功能。本系统设计通过实验验证，可实现多光束碳纳米管 X射线源脉冲式静态扫描成像，为碳纳米管静态 CT的研制提供了实验和测试平台。