X射线荧光CT和能谱CT双模态同时成像关键技术研究

Different from the traditional X-ray CT, X-ray fluorescence CT (XFCT) can realize high-sensitivity molecular imaging by using high-Z molecular probes and their characteristic fluorescence photons stimulated by an excitation X-ray beam. XFCT has showed a great potential in biomedical research field. However, current XFCT usually uses high-cost synchrotron radiation source or a pencil beam collimated from an X-ray tube scanning in a rotation-and-translation mode in a very long time, which limits the use of XFCT for clinical applications. This project proposes a new simultaneous XFCT and spectral CT dual-modality imaging technique which uses a conventional X-ray tube, a pin-hole collimator and two photon-counting detector arrays placed vertically. Fast and high-sensitivity XFCT imaging can be completed in a large field-of-view, as well as fusion imaging with spectral CT. This project will study the physical mechanism and mathematical model, image reconstruction and fusion algorithms of this simultaneous XFCT and spectral CT. Upgrade and build the experimental platform. Complete experimental research and achieve the gold nanoparticle distribution in a mouse. Once the key techniques of this project are verified, it will be an important innovation in the X-ray imaging field. It will greatly promote the international XFCT research and have a significant impact on both the biomedical molecular imaging and specific material identification in security inspection.

不同于传统X射线CT，X射线荧光CT（XFCT）利用原子受X射线照射激发产生的特征荧光光子，借助高Z元素分子探针能够实现高灵敏度和特异性的分子功能成像，在生物医学研究领域展现出了巨大潜力。然而，当前的XFCT研究主要使用昂贵的同步辐射光源，或将X光机准直成笔形束“旋转+平移”长时间扫描完成，难以用于临床应用。本项目创新性地提出一种XFCT和能谱CT双模态同时成像技术，使用普通X光机、针孔准直器和两台近似垂直布置的阵列光子计数探测器，实现大视野、快速、高灵敏度的XFCT成像，及与能谱CT的融合成像。本项目将研究XFCT和能谱CT同时成像的物理机制和数学模型、图像重建算法及融合算法，升级、搭建实验平台，进行实验验证，开展小老鼠纳米金颗粒成像实验研究。本项目关键技术的突破将是X射线成像领域的重要创新，有力推动国内外XFCT研究的发展，将会对生物分子功能成像、安检特异物质识别等领域产生重要影响。

不同于传统X射线CT，X射线荧光CT（X-ray fluorescence CT, XFCT）利用原子受X射线照射激发产生的特征荧光光子，借助高Z元素分子探针能够实现高灵敏度和特异性的分子功能成像，在生物医学研究领域展现出了巨大潜力。然而，当前的XFCT研究主要使用昂贵的同步辐射光源，或将X光机准直成笔形束“旋转+平移”长时间扫描完成，难以用于临床应用。本项目创新性地提出一种X射线能谱和荧光CT双模态同时成像技术，使用普通X光机、针孔准直器和两台近似垂直布置的阵列光子计数探测器，实现大视野、快速、高灵敏度的XFCT成像，及与能谱CT的融合成像。本项目解决了X射线能谱和荧光CT双模态同时成像的关键理论和算法问题，建立了统一的双模态成像物理模型，获得了该双模态图像重建算法和融合算法，优化设计、搭建了目前已知的首套基于普通X光机的扇束/锥束X射线和荧光CT双模态同时成像实验平台，完成了相关实验研究，获得了基于纳米颗粒药物的小鼠双模态CT图像，并初步尝试了针对大动物成像的可行性。为研制可以用于医疗等领域的新型高灵敏度和特异性的X射线和荧光双模态CT同时成像系统奠定理论和实验基础。本项目关键技术的突破是X射线成像领域的重要创新，推动了国内外XFCT研究的发展。