The Application of Transition Radiation to Non-invasive Angiography (Physics)

本研究的目的是证明过渡辐射在血管造影中的价值。在诊断放射学的这一领域，具体的兴趣集中在开发一种非侵入性的冠状动脉造影方法，该方法基于使用能量接近碘的k吸收边缘的单能x射线。在过去，传统光源和同步加速器光源都被使用过。不幸的是，传统光源缺乏足够强度的单色x射线束，而同步加速器源的成本令人望而却步。提出这项研究的具体动机是迫切需要降低冠状动脉造影的风险和成本。所提出的方法包括获取x射线能量略高于和低于碘在33.16 keV的k边缘的x射线照片，然后对这两张图像进行数字相减，以实现动脉内碘可视化的最大对比度。过渡辐射的高亮度和类似激光的准直使其成为医疗应用的理想x射线源。作为高亮度的x射线发生器，这种光源受到的关注相对较少。然而，每个电子的辐射比同步加速器辐射大几个数量级，并且，正如该计划第一阶段所证明的那样，可以使用100至500 MeV的中等电子束，而同步加速器源需要3 GeV或更高的电子能量才能获得30 keV的光子。过渡辐射是一种成本有效的硬x射线源，用于无创血管造影检测冠心病；用于生产集成电路的光刻；生物材料的x射线分析；以及肾脏和心脏等器官的高分辨率医用x光片。

The purpose of this research is to demonstrate the value of transition radiation in angiography. Within this area of diagnostic radiology, the specific interest is centered on the development of a non-invasive method of coronary angiography based on the use of monoenergetic x-rays at energies close to the K-absorption edge of iodine. In the past, both conventional and synchrotron sources have been used. Unfortunately, the conventional sources lack monochromatic x- ray beams of adequate intensity, while the cost of a synchrotron source is prohibitive. The specific motivation for the proposed studies is an urgent need to reduce both the risk and cost of coronary arteriography. The proposed method involves the acquisition of radiographs at x-ray energies slightly above and below the k-edge in iodine at 33.16 keV and the subsequent digital subtract of these two images to achieve maximum contrast in the visualization of the intra-arterial iodine. The high brightness and laser-like collimation of transition radiation make it an ideal source of x-rays for medical applications. This source has received a relatively small amount of attention as a x-ray generator of high brightness. Yet the radiation per electron is several orders of magnitude greater than synchrotron radiation, and, as demonstrated in Phase I of this program, a moderate electron beam of 100 to 500 MeV can be used, whereas a synchrotron source requires electron energies of 3 GeV or greater to obtain 30 keV photons. Transition radiation is a cost effective source of hard x- rays for non-invasive angiography for the detection of coronary disease; lithography for the production of integrated circuits; x-ray analysis of biological material; and high resolution medical x-ray of organs such as kidneys and heart.