一种基于双平面扫描方式的双能静态CT系统

A Dual-energy Stationary CT System Based on Dual-plane Scanning Mode

静态CT技术相较于传统的螺旋CT,在扫描速度上有着革命性的优势,这使得其在行李安检等领域有着巨大的应用前景。目前,要实现静态CT系统的实际应用,需要解决几何尺寸误差标定、有限角重建、双能投影数据匹配等一系列实际问题。本文提出了一种基于分布式X射线源和双平面扫描方式的双能静态CT系统。该系统采用碳纳米管冷阴极射线管,实现X射线源的高速启停;并采用双平面扫描方式,提高投影数据的覆盖角度以减小伪影,并通过采集双能投影数据实现物质识别。本文详细介绍该静态CT系统的系统设计、几何校正及成像方法等内容。实际实验结果显示该系统可对箱包及其内部物体进行三维成像,获得较为理想的形状及材料信息,在行李安检领域具有较高的实际应用价值。

Stationary CT technique is a promising approach for baggage inspection due to its high scanning speed compared with traditional spiral-CT.The main challenges which current stationary CT system meets are the geometric calibration,image reconstruction from limited angle data and matching of dual-energy projection.In this paper,we presented a dual-energy stationary CT system based on dual-plane scanning mode.The multi-bean X-ray source of the system is made of carbon nanotube cathode,which enables fast switching of exposure sequence.The dual-plane scanning mode is applied in order to increase the cover angle of projection data and reduce artifacts.The attenuation information is collected by the dual-energy detector which enables materials decomposition and recognition.According to the experimental results of luggage,the stationary CT system presented in this paper enables three-dimensional imaging of luggage with high resolution and detailed material information,which indicates its potential in applications of baggage inspection.