Multi-Contrast X-ray Breast Imaging

 描述（由申请人提供）：乳腺癌是当今女性中最常见的癌症。目前最好的策略是在癌症有机会转移之前早期发现和治疗乳腺癌。传统的X射线乳腺摄影术仍然是早期乳腺癌检测最常用的成像方法。然而，在X射线乳腺摄影中的灵敏度和特异性受到限制，主要是由于其二维（2D）性质和随之而来的结构重叠。这种局限性在放射学上致密的乳房中加剧，其中正常组织可能掩盖癌症。尽管通过引入数字乳腺断层合成摄影和专用乳腺锥形束CT已经取得了巨大的进步来改善对癌症肿块和微钙化的检测，但是在所有当前的X射线方法中仍然存在一个共同的限制：两种乳腺癌检测任务都依赖于单个X射线吸收对比机制。这两个探测任务的最佳探测性能往往有空间分辨率和辐射剂量的竞争要求。因此，这两个检测任务的性能在一定程度上受到损害。该提案的总体目标是开发一种多对比度X射线数字乳腺X射线摄影和数字乳腺断层合成成像系统，以提高乳腺致密女性的乳腺癌检测。在这种新的成像系统中，将通过增加两种补充对比机制来保持当前基于吸收的数字乳腺X射线摄影和DBT成像能力：第一种利用基于软组织中X射线折射特性的对比机制，并允许改善低对比度肿块的可视化。微钙化的检测可以通过另一种伴随的新的X射线暗场对比机制来完成。注意，所有三种类型的图像，即，吸收图像、相衬图像和暗场图像从单次数据采集产生。鉴于目前的临床DBT成像系统能够同时采集数字乳腺X线摄影和DBT图像的事实，将通过将X射线Talbot-Lau光栅干涉仪纳入这些系统之一来构建所提出的多对比度乳腺成像系统。将开发新的图像重建、处理和显示方法，以帮助医生从多对比度乳腺X射线摄影和DBT图像中提取最有价值的信息。本研究的主要目的有四个：（1）优化和制作用于多对比度乳腺成像系统的光栅干涉仪;（2）将光栅集成到现有的临床DBT系统中并进行物理性能的实验表征;（3）进行定量成像性能评估并优化成像协议;（4）对多对比成像系统进行初步临床性能评价。该项目完成后，将构建第一个临床原型多对比系统用于临床研究。将了解所获取的多对比度DBT图像中的疾病特征，并且该系统将在项目的下一阶段准备进行临床试验研究。

 DESCRIPTION (provided by applicant): Breast cancer is the most common cancer among women today. The best current strategy is to detect and treat breast cancer early, before the cancer has a chance to metastasize. Conventional x-ray mammography remains the most commonly used imaging method for early breast cancer detection. However, the sensitivity and specificity are limited in x-ray mammography largely due to its two-dimensional (2D) nature and the consequent structural overlapping. This limitation is exacerbated for radiologically dense breasts in which normal tissue may obscure a cancer. Despite the fact that tremendous progress has been made to improve the detection of cancer masses and of microcalcifications by the introduction of digital breast tomosynthesis and dedicated breast cone- beam CT, one common limitation remains in all current x-ray methods: both breast cancer detection tasks depend on a single x-ray absorption contrast mechanism. The optimal detection performances of these two detection tasks often have competing requirements on spatial resolution and radiation dose. As a result, the performance of both detection tasks is somewhat compromised. The overall objective of this proposal is to develop a multi-contrast x-ray digital mammography and digital breast tomosynthesis imaging system to improve breast cancer detection for women with dense breasts. In this new imaging system, the current absorption-based digital mammography and DBT imaging capability will be maintained with the addition of two supplemental contrast mechanisms: the first utilizes a contrast mechanism based on the x-ray refraction property in soft tissue and permits improved visualization of low contrast masses. The detection of microcalcifications can be accomplished by another concomitant novel x-ray dark field contrast mechanism. Note that all three types of images, viz., absorption image, phase contrast image, and dark field image, are generated from a single data acquisition. Given the fact that the current clinical DBT imaging system enables one to acquire both digital mammography and DBT images, the proposed multi-contrast breast imaging system will be constructed by incorporating an x-ray Talbot-Lau grating interferometer into one of these systems. Novel image reconstruction, processing, and display methods will be developed to help physicians extract the most valuable information from the multi-contrast mammography and DBT images. There are four primary specific aims in this proposal: (1) Optimize and fabricate grating interferometer for the multi-contrast breast imaging system; (2) Integrate gratings into the current clinical DBT systems and perform an experimental characterization of physical performance; (3) Perform quantitative imaging performance assessment and optimize imaging protocols; (4) Perform initial clinical performance evaluation of the multi-contrast imaging system. Upon the completion of this project, the first clinical prototype multi-contrast system will have been constructed for clinical studies. The disease signatures in the acquired multi-contrast DBT images will be understood, and the system will be ready for clinical trial studies in the next stage of the project.