Optimized Digital Mammography with an a-Se FP Imager

描述（由申请人提供）： 乳腺癌被认为是对妇女健康和寿命的主要威胁，特别是在北美。在美国，每9名妇女中就有1名可能在其一生中被诊断出患有乳腺癌。尽管超声、磁共振和光学成像技术取得了进步，但X射线乳腺摄影仍然是早期发现乳腺癌和随后诊断检查的主要工具。因此，提高乳腺X线摄影技术，优化乳腺癌的检测和诊断具有重要意义。随着对改善图像质量和图像管理的期望，存在从传统的屏幕/胶片技术转移到数字图像获取技术的强烈动机。几种数字乳腺摄影技术已经开发和商业化。这些技术中的每一种在某些方面可能具有优点，而在其它方面可能具有缺点。本研究的目标是优化和研究数字乳腺X射线摄影技术，以提高数字乳腺X射线摄影的质量和利用率。 为了实现这些目标，我们将设计，构建和研究扫描均衡数字乳腺X射线摄影（SEDM）系统使用非晶硒和非晶硅薄膜晶体管（aSe/aSi TFT）阵列为基础的平板成像器作为X射线探测器。具有区域调制光束宽度的狭缝扫描将用于实现散射抑制和曝光均衡。一种新的图像读出技术将被实施和研究，以允许电子后准直。将实施并测试重新缩放技术，以生成数字乳腺X射线摄影图像，其外观与常规乳腺X射线摄影图像相似，但具有改善的对比度噪声比（CNR）、均衡的信噪比（SNR），并能够进行准确的透射测量。我们将评估和研究拟议的SEDM系统与物理测量和观察员的性能研究的基础上，设计模仿临床乳房X线照片的体模图像。 所提出的系统预计将导致改进的检测和可视化的微钙化和群众和更好地利用图像数据在筛查和诊断乳腺X射线摄影。这是通过以下方式实现的：（1）利用基于aSe/aSi TFT的FP检测器改进的调制传递函数（MTF）和检测量子效率（DQE），（2）与防散射栅格技术相比，检测器曝光增加约两倍，具有类似或甚至更好的散射抑制，（3）X射线能量密度从高透射区域到致密组织区域的重新分布（曝光均衡）以实现更均匀的图像SNR，以及（4）提供具有均衡SNR的几乎无散射的图像数据，用于更好的图像处理、分析和定量研究。

DESCRIPTION (provided by applicant): Breast cancer has been recognized as a major threat to women's health and longevity particularly in North America. one of 9 women in the United States may be diagnosed to have breast cancer in her lifetime. Despite advances of ultrasound, magnetic resonance and optical imaging techniques, x-ray mammography remains the main tool for early detection of breast cancer and subsequent diagnostic workup. It is therefore of great importance to improve the x-ray mammography techniques to optimize the detection and diagnosis of breast cancer. With a desire to improve image quality and image management, there has been a strong motivation to shift from the conventional screen/film techniques to digital image acquisition techniques. Several digital mamrnography techniques have been developed and commercialized. Each of these techniques may have advantages in some aspects and drawbacks in others. The goals of this research are to optimize and investigate a digital mammography technique to improve the quality and utilization of the resulting digital mammograms. To achieve these goals, we will design, construct and investigate a Scanning Equalization Digital Mammography (SEDM) system using an amorphous selenium and amorphous silicon thin film transistor (aSe/aSi TFT) array based flat-panel imager as the x-ray detector. Slot scanning with regionally modulated beam width will be used to achieve both scatter rejection and exposure equalization. A novel image readout technique will be implemented and investigated to allow for electronic aft-collimation. A re-scaling technique will be implemented and tested to generate digital mammography images with appearance similar to that of a regular mammogram but with improved contrast-tonoise ratios (CNRs), equalized signal-to-noise ratios (SNRs) and enabling accurate transmission measurement. We will evaluate and investigate the proposed SEDM system with physical measurements and observers' performance studies based on phantom images designed to mimic clinical mammograms. The proposed system is expected to result in improved detection and visualization of microcalcifications and masses and better utilization of image data in both screening and diagnostic mammography. This is achieved through: (1) improved modulation transfer function (MTF) and detective quantum efficiency (DQE) with an aSe/aSi TFT based FP detector, (2) an approximately twofold increase of the detector exposure with similar or even better scatter rejection as compared to the anti-scatter grid technique, (3) a redistribution of x-ray fluence from highly transmitted areas to dense tissue regions (exposure equalization) to achieve more uniform image SNRs, and (4) provision of nearly scatterfree image data with equalized SNRs for better image processing, analysis and quantitative studies.