DIGITAL CHEST RADIOGRAPHY WITH A DIGITAL BEAM ATTENUATOR

这项研究的目的是研究新的数字成像算法 与数字波束衰减器设备(DBA)配合使用 改进了胸部的数字摄影技术。具体地说，两种算法 建议：(1)可变补偿模式，根据该模式， 图像补偿是可交互选择的(但图像 信噪比保持优化，以及(2)补偿的双能量 技术，该技术提高了组织消除图像的信噪比，并且 消除由于光束衰减器而产生的图像着色瑕疵。两者都有 算法使用DBA来补偿X射线束，然后添加到 最终补偿的图像是低剂量衰减器形成的一小部分 图像。适当的信噪比是通过模糊 添加前的低分辨率、低剂量衰减器形成图像。 每个算法都将经过幻影验证研究，之后 将为初步的临床研究构建合适的系统。 该系统将由数字光束衰减器、图像处理 硬件和软件，以及一种氟卤化钡光激励数字 探测器。该系统的另一个关键要素将是专用的 用于制作衰减滤光片的低剂量数字探测器。这 低剂量探测器，由×组成的矩阵非常灵敏 光电二极管，是我们实验室最近开发出来的一种应用 到基于胶片和数字DBA的胸部X光检查。 这项建议的具体目标包括： (1)一种新型低剂量机的设计、实现和评估 用于DBA掩模图像采集的探测器。 (2)DBA胸器的制作。 (3)单能源可变补偿算法的研究 使用DBA的数字胸片。 (4)研究了一种改进的补偿双能量算法 组织取消与DBA的数字胸部成像。

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.