HIGH RESOLUTION CARDIOVASCULAR FLAT-PANEL X-RAY IMAGER

心血管成像的最新进展促进了新的、广泛使用的挽救生命的X射线介入程序的发展。这引发了人们对现有设备和技术的辐射剂量效率的担忧。当设备不能提供出色的图像质量以可视化具有挑战性的诊断或治疗介入操作所需的细微或小血管系统时，医生别无选择，只能延长透视或获得更多电影图像。本研究旨在设计、开发和评价一种用于心脏X光透视和电影成像的新型高分辨率成像设备。这项工作是在我们团队在过去四年中成功地将电荷耦合器件(CCD)技术应用于数字乳房X光成像应用之后进行的。该装置将是一个基于电荷耦合器件的平板探测器，由四个8厘米×8厘米的电荷耦合器件无缝连接在一起，形成16厘米×16厘米(6.3×6.3英寸，8.9英寸对角线)的面积。该设计利用了CCD众所周知的低噪声特性，采用了新的线间电荷传输设计，可用于30帧/S甚至60帧/S透视视频。所提出的检测器和技术避免了与其他类型的平板检测器相关的由于图像滞后(拖尾)引起的问题，并且与任何其他同类检测器完全不同。据我们所知，还没有开发出用于X射线透视或任何其他应用的用于视频帧速率成像的行间传输模式的大科学级CCDs。我们的系统将是X射线量子噪声有限的，不像像增强器系统，它将没有几何失真和面纱眩光效应，这将导致显著的对比度损失。与现有的基于像增强器的系统相比，新系统将能够在荧光和射线照相模式下提供更好的检测量子效率(DQE)和空间分辨率。改进的对比特性将使患者在减少辐射剂量的情况下更好地可视化心血管解剖和功能。这项研究将涉及设计和制造电荷耦合器件，随后将对该设备进行全面调整，以适应透视和射线照相任务。对探测系统成像特性的研究将通过客观和普遍接受的指标进行，如调制传递函数(MTF)和与频率相关的探测量子效率(DQE)。

Recent advances in cardiovascular imaging have contributed to the development of new, widely used lifesaving x-ray interventional procedures. This has prompted concerns about the radiation dose- efficiency of present equipment and techniques. When the equipment is not capable of delivering excellent image quality for visualizing subtle or small vasculature required for challenging diagnostic or therapeutic interventional procedures, physicians have little choice but to prolong fluoroscopy or acquire more cine views. This research is aimed at designing, developing and evaluating a new type of high resolution imaging device for cardiac x-ray fluoroscopy and cine imaging. This effort follows the successful research conducted by our group in the past four years to adapt charge-coupled device (CCD) technology to digital mammographic imaging applications. The device will be a CCD-based flat panel detector consisting of four 8 cm x 8 cm CCDs joined in a seamless design to form an area of 16 cm x 16 cm (6.3 x 6.3 inch, 8.9 inch diagonal). The design takes advantage of the low-noise characteristics for which CCDs are known, with a new interline charge transfer design for 30 frame/s or even 60 frames/s fluoroscopic video. The proposed detector and technique circumvents problems due to image lag (smearing), associated with other types of flat panel detectors and is radically different from any other detector of its kind. As far as we know, large scientific grade CCDs have never been developed to operate in the interline transfer mode for video frame rate imaging for x-ray fluoroscopy or any other application. Our system will be x-ray quantum-noise limited and unlike image intensifier systems, it will be free of geometric distortion and veiling glare effects which cause significant loss of contrast. The new system will be able to deliver better detective quantum efficiency (DQE) and spatial resolution in both fluoroscopic and radiographic modes than existing image intensifier-based systems. The improved contrast characteristics would enable better visualization of cardiovascular anatomy and functionality at a reduced radiation dose to the patient. The research will involve the design and manufacturing of the CCD which will be followed by comprehensive adaptation of the device to the fluoroscopic and radiographic tasks. Investigation of the imaging characteristics of the detection system will be conducted through objective and universally accepted metrics such as modulation transfer function (MTF) and frequency dependent detective quantum efficiency (DQE).