High-resolution lower dose dedicated breast CT

 描述(申请人提供)：专用乳腺CT是一项新兴技术，在全球范围内只有不到10个临床原型。它可以消除乳腺组织的重叠，并以接近各向同性的空间分辨率提供3D图像。早期几代乳腺CT使用的探测器在胸壁附近的非活动区域(胸壁死腔)、有限的分辨率和帧速率以及较高的电子(系统)噪声方面不是最理想的。更新的探测器，如本研究中提出的一种，将电子噪声降低20-30倍，将空间分辨率提高至少2倍，并具有类似于乳房X光摄影的胸壁死区，从而实现良好的后部覆盖。然而，这些探测器体积较小，要覆盖巨大的乳房是一个挑战。因此，在这项研究中，我们建议设计、开发和集成高分辨率、低噪声的探测器，在覆盖最大乳房的侧移成像几何结构中。关于乳腺CT的三个主要问题是，胸壁和腋窝覆盖，显示微钙化团的能力，以及以相当于筛查乳房X光检查的辐射剂量提供诊断质量图像的能力。我们假设，拟议的技术方法将解决所有这些问题。与以前临床研究中使用的34.2 mm相比，由于其胸壁死区为3 mm，因此建议的检测器将改善胸壁覆盖率。利用建议的探测器，较小的像素尺寸(与前几代探测器的0.388 mm像素尺寸相比)和较低的电子噪声(约200个电子与前几代的约6,000个电子)的组合将使低剂量高分辨率成像成为可能。此外，它允许在不到4秒的时间内完成扫描，而前几代产品至少需要10秒，从而减少了患者运动的可能性。这项研究还将整合一个可进一步降低辐射剂量的光束成形滤光片，并将整合散射减少和剩余散射校正方法，以提高定量精度。这将允许更可靠地使用Hounsfield分级(CT数字)，从而能够更好地区分良恶性病变。这项研究大致分为三个阶段。在第一阶段，设计的所有方面都将是 在台式平台上进行验证和验证，以确定最佳参数选择。在第二阶段，这些结果将被用于设计、修改和集成用于临床原型乳腺CT系统的方法。在第三阶段，我们将进行一项临床可行性研究，招募4或5名患有微钙化的BIRADS受试者，以确定所实施的技术进步是否转化为改善微钙化的可视化以及更好地区分基于钙化的良性和恶性病变。因此，拟议的研究将为前所未有的改进提供一个创新的设计概念，使成像能够在不对乳房进行物理压缩的情况下进行，并且辐射剂量与筛查乳房X光检查大致相同。

 DESCRIPTION (provided by applicant): Dedicated breast CT is an emerging technology with less than 10 clinical prototypes worldwide. It can eliminate breast tissue superposition and provides 3D images at near-isotropic spatial resolution. Earlier generations of breast CT used detectors that were suboptimal in terms of inactive region near the chest wall (chest-wall dead space), limited resolution and frame rate, and higher electronic (system) noise. Newer detectors such as the one proposed in this research reduces electronic noise by a factor of 20-30, increases the spatial resolution by a factor of at least 2, and has chest-wall dead space similar to mammography that would enable excellent posterior coverage. However, these detectors are smaller in size and it is a challenge to cover large breasts. Hence, in this research we propose to design, develop and integrate the high-resolution, low-noise detector in a laterally-shifted imaging geometry that would cover the largest breast. The three major concerns regarding breast CT are, chest-wall and axillary coverage, ability to visualize microcalcification clusters, and the ability to provide diagnostic quality images at radiation dose equivalent to screening mammography. We hypothesize that the proposed technological approach will address all of these concerns. Chest-wall coverage will be improved with the proposed detector due to its chest-wall dead space of 3 mm compared to 34.2 mm used in previous clinical studies. With the proposed detector, the combination of smaller pixel size (0.15 mm compared to 0.388 mm detector pixel size in previous generations) and lower electronic noise (~200 electrons compared to ~6,000 electrons in previous generations) will allow low-dose high-resolution imaging. Additionally, it allows for completing the scan in less than 4 seconds compared to at least 10 seconds in previous generations, reducing the possibility of patient motion. The study will also integrate a beam shaping filter that further reduces the radiation dose and will incorporate scatter-reduction and residual scatter-correction methods that will improve the quantitative accuracy. This would allow for more reliable use of the Hounsfield scale (CT numbers) that can allow for better discrimination between benign and malignant findings. The research is broadly organized in three phases. In the first phase, all aspect of the design will be verified and validated on a bench-top platform to determine the best choice of parameters. In the second phase, these results will be used to design, modify and integrate the approach to a clinical prototype breast CT system. In the third phase, we will conduct a clinical feasibility stuy that will recruit BIRADS 4 or 5 subjects with microcalcifications to determine if the implemented technological advancements translate to improved visualization of microcalcifications and better discrimination between benign and malignant calcification-based lesions. Thus, the proposed research will provide an innovative design concept for unprecedented improvements that will enable imaging without physical compression of the breast and at radiation dose approximately similar to screening mammography.