EQUALIZED DUAL ENERGY/DUAL PHOSPHOR CHEST RADIOGRAPHY

该提案解决了两种新技术的结合， 总体目标是开发一种实用的单能和双能数字 X射线摄影系统，专用于胸部成像并进行了优化。 过滤器 车轮均衡系统补偿过度和欠渗透 通过减少或增加入射曝光， 这些地区。 一系列计算机控制的轮子安装在 X射线管，滤光轮具有器官特异性补偿 模式，通过分析大量胸部图像确定，加工成 他们 低剂量预扫描图像仅使用 过滤器存在，并基于预扫描的分析 图像计算机自动旋转最合适的过滤器 轮图案到位，以实现补偿和射线照相 曝光是获得的。 心脏、左肺和右肺是 主要的胸部特征，需要巨大的探测器范围; 这些结构的独立补偿将减少曝光 动态范围，并将在信噪比中产生更好的均匀性 系统的性能。 这将提高肺结核的检出率。 由于可检测性基本上与信号相关， 噪声比。 提出的探测器是一种新型的双磷光体（二元） 荧光屏系统，由两种能量依赖性不同的荧光体组成 X射线吸收（不同的k边缘），但在它们的光学特性上也不同 发射特性 一种磷光体（Gd 2 O2 S：Eu，k-edge = 50 keV）发射 主要在624 nm处发射，另一个（y2 O3：Gd，k边= 17 keV）在 315 nm。 使用光学过滤，双CCD摄像机分别 调谐到每种磷光体的光发射光谱，从而允许 同时采集低能量和高能量图像 在一个X射线脉冲期间。 滤光轮均衡的联姻 系统与二元屏幕检测器将导致协同和 胸部X线摄影的综合方法。 研究方法 包括采集胸部图像（数字化的 从电影），以促进统计方法的赔偿 纸样设计与分析、计算机模拟与设计优化 补偿和检测器子系统，结构和 测试原型系统，包括图像性能 表征（MTF & DQE），并对实验获得的 图像. 提出了数字胸部成像的综合方法 这里应该增加胸部X线摄影的有效性， 提高了对肺结节和其他疾病的敏感性和特异性， 胸部病变。

This proposal addresses the marriage of two novel technologies, with the overall objective to develop a practical single- and dual-energy digital radiography system, dedicated and optimized for chest imaging. A filter wheel equalization system compensates for over- and under-penetrated areas in the image, by reducing or increasing the entrance exposure to those areas. A series of computer controlled wheels are mounted near the x-ray tube, and the filter wheels have organ-specific compensation patterns, determined by analysis of numerous chest images, machined into them. A low-dose prescan image is acquired with only homogeneous-filtration present, and based on analysis of the prescan image the computer automatically rotates the most appropriate filter wheel patterns into position to achieve compensation and the radiographic exposure is acquired. The heart, left lung and right lung are the principle thoracic features which demand enormous detector latitude; independent compensation of these structures will reduce the exposure dynamic range and will yield better uniformity in the signal-to-noise performance of the system. This will improve the detectability of pulmo- nary nodules since detectability is fundamentally related to the signal to noise ratio. The proposed detector is a novel dual phosphor (binary) screen system, composed of two phosphors differing in energy-dependent x-ray absorption (different k-edges), but also differing in their optical emission properties. One phosphor (Gd2O2S:Eu, k-edge = 50 keV) emits principally at 624 nm, and the other (y2O3:Gd, k-edge = 17 keV) emits at 315 nm. Using optical filtration, dual CCD cameras are individually tuned to the optical emission spectrum of each phosphor, thereby allowing the low energy and high energy images to be acquired simultaneously during one x-ray pulse. The marriage of the filter wheel equalization system with the binary screen detector will result in a synergistic and comprehensive approach to chest radiography. The research methodology includes the acquisition of a large data base of chest images (digitized from film) to facilitate a statistical approach to the compensation pattern design and analysis, computer simulation and design optimization of both the compensation and detector subsystems, construction and testing of a prototype system including image performance characterization (MTF & DQE), and ROC analysis of experimentally acquired images. The comprehensive approach to digital chest imaging proposed here should increase the effectiveness of chest radiography, by increasing the sensitivity and specificity to pulmonary nodules and other chest pathologies.