Diffuse Optical B-scan Imaging (DOBI) for Breast Cancer Monitoring

摘要： 组织代谢活动的变化与包括癌症在内的许多疾病有关，然而 目前还没有方法以非侵入性、廉价和高速的方式对这些变化进行成像。漫反射光学 光谱学(DOS)是一种新兴的成像手段，它能够测量血红蛋白浓度和 使用近红外光计算局部血氧饱和度，作为代谢活动的替代指标。然而， 目前的DOS探测器依靠手动逐点扫描来建立2D图像。漫反射光学层析成像 (点)是DOS的深度分辨率变体，但生成单个图像和设备可能需要几个小时 它们本身既庞大又复杂。迫切需要一种低成本、非侵入性、深度分辨率、高分辨率的 具有实时反馈的快速代谢成像模式，可提供频繁的监测和评估 与新陈代谢变化相关的疾病，如癌症。如果没有这样的模式，患者将受到 更具侵入性的手术和不必要的治疗，会产生令人衰弱的副作用。这个项目的目标是 开发一种临床仪器，产生组织新陈代谢的“类似超声”的图像，用于评估 局部改变代谢的疾病的进展，如癌症和中风。使用最新开发的数字 DOS平台，能够采集率大于100赫兹，我们将设计和建造一个探头，在其中 单个光源和探测器光纤中的每一个都以摆线模式扫描。抛物线是一种形状 由一个小圆圈上的一个点围绕一个较大圆圈的内周滚动而成。当两个 内摆线是平行跟踪的，点之间的距离在很大范围内变化，而中心 连接这两个点的线的位置保持不变。这些独特的功能使DOS测量能够 被解释为一条轴线，其中每个源/探测器间隔对应于 组织表面。这种扫描模式将使组织代谢活动的深度分辨测量成为可能。 目前，DOS数据分析速度很慢，分析一次测量需要几秒钟的时间。增加 数据吞吐速率，我们将训练一个人工神经网络来预测吸收和散射 这将使实时分析成为可能。最后，我们将测试新探测器的监控能力 乳腺癌的血流动力学改变。我们将使用探头对接受新辅助治疗的患者进行成像。 乳腺癌化疗，并测试该探头定位和测量血流动力学的能力 肿瘤。预计这一提议将产生以下预期结果：第一，快速、低成本 原型DOS扫描仪将展示能够提供氧合和脱氧血红蛋白的实时图像 与组织代谢有关的浓度。其次，这种设备将被证明能够定位乳房 不同患者群体中的肿瘤。第三，这种扫描方法将使乳房的深度分辨率图像成为可能 肿瘤为未来研究化疗反应铺平了道路。

Abstract: Changes in a tissue’s metabolic activity are associated with many diseases including cancer, yet there is currently no method to image these changes noninvasively, inexpensively, and at high speed. Diffuse Optical Spectroscopy (DOS) is an emerging imaging modality that is able to measure hemoglobin concentrations and calculate local blood oxygen saturation as a proxy for metabolic activity using near-infrared light. However, current DOS probes rely on manual point-by-point scanning to build up 2D images. Diffuse Optical Tomography (DOT) is a depth resolved variant of DOS, but it can take hours to generate a single image and the devices themselves are bulky and complex. There is a critical need for a low-cost, noninvasive, depth resolved, high- speed metabolic imaging modality with real-time feedback to provide frequent monitoring and assessment of diseases associated with metabolic changes such as cancer. Without such a modality, patients are subjected to more invasive procedures and unnecessary treatments with debilitating side-effects. The goal of this project is to develop a clinical instrument that produces “ultrasound-like” images of tissue metabolism for assessing the progression of diseases that locally alter metabolism such as cancer and stroke. Using recently developed digital DOS platform that is capable of acquisition rates greater than 100 Hz, we will design and build a probe in which a single source and detector fiber are each scanned in a hypotrochoidal pattern. A hypotrochoid is a shape traced by a point on a small circle as it rolls around the inner circumference of a larger circle. When two hypocycloids are traced in parallel, the distance between the points varies over a wide range, while the center of the line connecting the two points remains stationary. These unique features enable DOS measurements to be interpreted as an axial line where each source/detector separation corresponds to a different depth below the tissue surface. This scanning pattern will enable depth-resolved measurements of tissue metabolic activity. Currently, DOS data analysis is slow, requiring several seconds to analyze a single measurement. To increase the data throughput rate, we will train an artificial neural network to predict the absorption and scattering properties of the tissue which will enable real-time analysis. Finally, we will test the new probe’s ability to monitor hemodynamic changes in breast cancer. We will use the probe to image patients undergoing neoadjuvant chemotherapy for breast cancer, and test the ability of the probe to locate and measure the hemodynamics of the tumor. It is anticipated this proposal will yield the following expected outcomes: First, a fast, low-cost prototype DOS scanner will be shown capable of providing real-time images of oxy- and deoxy-hemoglobin concentrations which are linked to tissue metabolism. Second, this device will prove capable of locating breast tumors in a diverse patient population. Third, this scanning method will enable depth resolved images of breast tumors paving the way for future work investigating chemotherapy response.