NEW FIBEROPTIC SCREENS AND FILTRATION FOR X-RAY IMAGING

该建议旨在提高诊断图像质量 在减少辐射剂量的情况下进行射线照相和透视检查。这个 目前可获得的X射线量子效率的状态- ART稀土增感屏的比例从40%到70%不等。增加 量子效率在空间上造成不可接受的损失 决议。捕获剩余部分而不进行解析 损失将导致图像对比度的提高和图像质量的降低 辐射剂量。将尝试达到100%的量子 通过优化和使用新型荧光剂来提高效率 增强屏。这块新屏幕是用闪光材料制成的 (掺Tb)光学透明玻璃，也可提供 作为一个光纤板。这些闪烁的光纤板提供了 远超常规增强的空间分辨率 屏幕，在诊断x射线时具有近100%的量子效率 能量。在这项研究中，我们建议研究量子和 平面和光纤闪烁的转换效率 玻璃，预期在放射成像方面的潜在应用。 这些材料的适用性将被测试为 放射学或治疗治疗验证中的强化筛查 带胶片，或作为荧光透视图像的输入荧光屏 增强剂。目前投入的潜在替代 传统增强器的窗口和荧光粉 我们将探索光纤板。为此，我们还计划 量化来自输入窗口的x射线散射的影响 传统的像增强器，并找到减少它的方法。这 将导致透视对比度的提高 图像，从而增加了使用 主体对比度低。图像对比度的潜在劣化 也将对x射线滤光片进行调查，首先由一个 计算方法，然后是实验。这一部分是 研究将使我们能够量化来自x射线的散射通量 过滤器。然后，我们将能够识别产生 最小的散射和改善的对比度。散布 还将研究其特性和透射谱 一些重要的k边滤光片(Er、Gd、La和 Sm)。将对这些过滤器的适用性进行测试 一些放射检查程序，如乳房X光照相和儿科 成像。

This proposal is aimed at improving the diagnostic image quality in radiography and fluoroscopy at a reduced radiation dose. The currently attainable x-ray quantum efficiency of the state-of-the- art rare earth intensifying screens varies from 40-70%. Increase in the quantum efficiency results in unacceptable loss in spatial resolution. Capture of the remaining fraction without resolution loss will lead to improvement in image contrast and reduction in radiation dose. Attempts will be made to attain 100% quantum efficiency by optimization and use of a new type of fluorscent intensifying screen. This new screen is made of scintillating (terbium-doped) optically transparent glass which is also available as a fiberoptic plate. These scintillating fiberoptic plates provide spatial resolution far exceeding that of conventional intensifying screens, with nearly 100% quantum efficiency at diagnostic x-ray energies. In this study we propose to investigate the quantum and conversion efficiency of both plain and fiberoptic scintillating glass, anticipating potential applications in radiologic imaging. The applicability of these materials will be tested for use as intensifying screens in radiology or therapy treatment verification with film, or as input phosphor screens for fluoroscopic image intensifiers. The potential replacement of the present input window and phosphor of conventional intensifiers with a single fiberoptic plate will be explored. For this reason, we also plan to quantify the effect of x-ray scatter from the input window of conventional image intensifiers and find means to reduce it. This will result in an improvement of the contrast of fluoroscopic images, thus increasing the probability of detecting lesions with low subject contrast. The potential degradation in image contrast from the x-ray filters will also be investigated, first by a computational approach and then experimentally. This part of the study will enable us to quantify the scatter fluence from the x-ray filters. We will then be able to identify the filters which produce minimal scattering and improved contrast. The scattering properties and transmission spectra will also be investigated for some important k-edge filters (erbium, gadolinium, lanthanum and samarium). The applicability of these filters will be tested for some radiographic procedures such as mammography and pediatric imaging.