Digital Fluoroscopy for Cardiac Imaging

描述(由申请人提供)： 实时或动态放射成像(透视)提供有关内部器官结构、造影剂流动和体内仪器定位的重要信息。透视是一种非常重要的心脏和血管成像方法，包括减影血管造影术，用于定位和评估心脏结构、主要血管、主要胸部结节的定位以及冠状动脉或心脏瓣膜中是否存在钙。以碘为基础的有机化合物通常用作心血管荧光成像的造影剂。目前的大多数荧光显微镜都是基于X射线像增强管(XRII)技术的。典型的规格是大视场(14英寸)，中等空间分辨率(2-3 lp/mm)，以及高达30帧/秒的操作速率。然而，管子的体积是它们使用范围的一个缺点，并增加了屏蔽和定位机械组装的显著成本。成像特性包括中等探测量子效率(DQE)(在零Ip/mm时为50%，在2.5Ip/mm时为30%)，对比度限制为接近40：1，并且空间分辨率经常因输出屏幕上的晕眩和面纱眩光而降低。管子边缘的视觉失真是增强器管的另一个常见特征。因此，可以得出结论，虽然XRII技术提供了一个有价值的工具，但它产生的图像质量仍有很大的改进空间。 拟议项目的目标是研究一种紧凑的平板探测器，用于实时X射线成像。所提出的检测系统具有较高的灵敏度、空间分辨率和效率。拟议系统的较高空间分辨率将潜在地提高表征冠状动脉中动脉粥样硬化斑块等小病变的能力，这一直是国家心肺血液研究所近年来的主要目标之一。最后，建议的探测器的较高动态范围将为高对比度物体边缘附近的小病变提供更好的图像质量，这种情况发生在使用静脉造影剂的心脏研究中，或者当血管或病变与覆盖的骨骼或肋骨的边缘重叠时。第一阶段项目的目标将是证明拟议方法的可行性。

DESCRIPTION (provided by applicant): Real-time or dynamic radiographic imaging (fluoroscopy) provides vital information concerning internal organ structure, flow of contrast agents and in-vivo instrument positioning. Fluoroscopy is a very important modality for cardiac and vascular imaging including subtraction angiography where it is used for locating and evaluating cardiac structures, major vessels, localization of major chest nodules, and presence of calcium in coronary arteries or cardiac valves. An iodine based organic compound is generally used as a contrast agent in cardio-vascular fluoroscopic imaging. Most current fluoroscopes are based upon x-ray image intensifier tube (XRII) technology. Typical specifications are a large field of view (14 inches), moderate spatial resolution (2-3 lp/mm), and operation rates up to 30 frames/sec. However, the tube's bulk is a drawback on their range of use, and add significant cost to shielding and positioning mechanical assembly. Imaging characteristics include moderate detective quantum efficiency (DQE) (<50% at zero Ip/mm and 30% at 2.5 Ip/mm), contrast ratio limited to near 40:1, and spatial resolution often degraded by vignetting and veiling glare at the output screen. Visual distortions at the tube edge are another common trait of intensifier tubes. Therefore, it can be concluded that while XRII technology provides a valuable tool, the image quality it produces leaves significant room for improvement. The goal of the proposed project is to investigate a compact, flat panel detector for real-time x-ray imaging. High sensitivity, spatial resolution, and efficiency are expected with the proposed detection system. The higher spatial resolution of the proposed system will potentially improve the ability to characterize small lesions such as athersclerotic plaque in the coronary arteries which has been one of the major goals of the National Heart, Lung & Blood Institute in recent years. Finally, the higher dynamic range of the proposed detector will provide improved image quality for small lesions near the edge of a high contrast object, a situation that occurs in cardiac studies with intravenous contrast media or when a vessel or lesion overlaps the edge of an overlying bone or a rib. The goal of the Phase I project will be demonstrate the feasibility of the proposed approach.