【摘要】 冷阴极X射线源相比与传统热阴极具有体积小、响应快、能耗低等特点,可用于制备具有高时间分辨率的微型X射线源,推动了传统成像系统的发展。然而,目前基于冷阴极X源的成像系统为了完全覆盖成像物体,依然需要较远的源与探测器的距离。为了进一步缩小成像系统的体积,实现便携式、智能、极低剂量成像方式,我们提出基于新型冷阴极平板源的成像系统。该系统通过在平板上密集集成冷阴极射线源,每个射线源仅覆盖物体的一部分,通过预设的点亮模式完全覆盖成像物体。在这种成像系统设计下,可有效缩短源与探测器之间的距离,避免非感兴趣区域的照射,实现了便携、适形成像。目前,这种平板射线源采用全部点亮发光和分时序列发光等两种发光模式。本文针对在全部点亮的情况下导致投影的混叠问题开展解混叠工作。我们进行了束光与算法设计,设计针对混叠投影的解混叠算法,最终获得成像物体的透视结构。通过仿真实验与实际实验的验证,证明了系统设计与算法的有效性,为研究基于新型平板射线源的成像系统打下基础。更多还原

【Abstract】 The technology of a field-emission X-ray source that is of fast temporal response and compact size promote the development of X-ray imaging. Multiple high temporal and spatial resolution imaging systems have been designed using a field-emission X-ray source. However,the current field-emission X-source based system requires a long distance between source and object in order to fully cover the imaging object. To realize a portable and smart imaging modality delivering extremely low dose,we proposed a design of two-dimensional array field-emission,namely a flat-panel source. The proposed source is compact with thousands of lighting cells. During imaging,each cell covers a small region of the object within a small angle. Hence,the short imaging distance is guaranteed,which makes the system smart and portable. The short distance imaging also avoids exposure to the region of non-interest. Current flat-panel source is capable of sequential lighting and simultaneous lighting. In this paper,we mainly focus on simultaneous lighting mode and aim to solve the overlapping problem caused by this mode. Specifically,we design a beam collimator and an algorithm to deconvolve overlapped measurements. With the proposed method,we can generate a pseudo radiographic image of the imaged object. Results show the potential of the flat-panel source and the efficiency of the proposed method. The results are also valuable for further applications with the flat-panel source.更多还原