DIGITAL CHEST RADIOGRAPHY WITH A DIGITAL BEAM ATTENUATOR

本研究的目的是探讨新的数字成像算法 与数字光束衰减器装置（DBA）结合使用， 改进胸部的数字X射线摄影。 具体来说，两种算法 提出了：（1）可变补偿模式， 图像补偿是可交互选择的（但是图像 信噪比保持优化，以及（2）补偿的双能量 技术，该技术改善了组织消除图像中的信噪比， 消除了由于光束衰减器引起的图像阴影伪影。 两 算法使用DBA来补偿X射线束，然后添加到 最终补偿图像低剂量衰减器形成的一部分 形象 适当的信噪比是通过模糊 低分辨率、低剂量衰减剂形成图像。 每种算法都将进行体模验证研究，之后， 将建立适当系统用于初步临床研究。 该系统将包括一个数字光束衰减器，图像处理 硬件和软件，以及钡氟卤化物光激励数字 检测器 该系统的另一个关键要素将是一个专门的 低剂量数字探测器，用于制作衰减滤波器。 这 低剂量探测器，由一个64 x 64矩阵的非常敏感的 光电二极管，最近在我们的实验室开发的应用 基于胶片和数字DBA的胸部X线摄影。 这项建议的具体目标包括： (1)一种新型低剂量数字化放射治疗系统的设计、实现和评价 用于DBA掩模图像采集的探测器。 (2)DBA胸部装置的构建。 (3)一种单能源变量补偿算法的研究 数字化胸部X线摄影 (4)一种改进的补偿双能量算法的研究 DBA的组织消除数字胸部成像。

The purpose of this study is to investigate new digital imaging algorithms to be used in conjunction with a digital beam attenuator device (DBA) for improved digital radiography of the chest. Specifically, two algorithms are proposed: (1) a variable compensation mode, whereby the amount of image compensation is interactively selectable (but the image signal-to-noise remains optimized, and (2) a compensated dual-energy technique, which improves signal-to-noise in the tissue-cancelled image and eliminates image shading artifacts due to the beam attenuator. Both algorithms use the DBA to compensate the x-ray beam, and then add to the final compensated image a fraction of the low-dose attenuator-formation image. Proper signal-to-noise is maintained by blurring the low-resolution, low-dose attenuator-formation image prior to addition. Each algorithm will undergo phantom validation studies, after which a suitable system will be constructed for initial clinical investigation. This system will consist of a digital beam attenuator, image processing hardware and software, and a barium fluorohalide photostimulable digital detector. An additional key element of the system will be a dedicated low-dose digital detector for fabrication of the attenuating filters. This low-dose detector, comprised of a 64 x 64 matrix of very sensitive photodiodes, has recently been developed in our laboratory for application to both film-based and digital DBA chest radiography. The specific aims of this proposal include: (1) Design, implementation and evaluation of a new low-dose digital detector for DBA mask-image acquisition. (2) Construction of a DBA chest apparatus. (3) Investigation of a variable compensation algorithm for single-energy digital chest radiography with the DBA. (4) Investigation of a compensated dual-energy algorithm for improved tissue-cancelled digital chest imaging with the DBA.