Breast screening with microwave pulses

目的：这项发现资助计划提出开发一种用于乳腺组织筛查的低功率脉冲微波设备，包括设计、实施和对患者志愿者的测试。该设备将补充现有的临床测量，而不是取代它们;拟议的系统预期用于定期筛查，作为监测健康基线变化和显著偏离的工具。科学方法：该计划的主要目标是开发和测试一种类似胸罩的检测设备的原型，该设备包含一个网络化的微波传感器阵列，可供妇女在家中或小型家庭诊所定期使用。最近的研究表明，低功率微波可以通过利用微波频率范围（100 MHz-10 GHz）内恶性肿瘤和健康乳腺组织之间的电对比来检测早期小肿瘤。如果存在肿瘤，则发射到组织中的入射电磁波的一部分散射。乳房的脂肪组织中的微波传播损耗足够低，以允许通过皮肤表面上的接收天线来检测该散射。这种天线元件价格便宜，体积小，因此可以编织到胸罩的织物中，这种结构是熟悉的，舒适的，使用简单的。采集的信号将通过复杂的算法进行处理，产生的结果可以提醒医生潜在的异常。方法：将同时审查拟议原型的几个明确确定的组成部分。1.天线设计和布局。天线传感器需要体积小，价格便宜，并印刷在柔性基板上。除了针对单个天线的有利特性之外，传感器的数量以及它们的相对布局将在空间和硬件约束内进行优化。需要根据乳房组织的平均电特性来选择将乳房耦合到天线的基板和介质。这些挑战将通过全面的模拟、制造和测试来解决。2.微波脉冲发生器馈送到发射天线的信号将是定制形状的，以选择感兴趣的频率范围，以及天线能力的最佳使用。3.切换机制。天线元件一次一个地充当发射器，而网络的其余部分以接收模式操作。每次扫描都涉及一组顺序测量，因为天线轮流执行发射和接收角色。这项任务包括仔细考虑电路连接，以最大限度地减少信号损失并保持信号完整性。4.顺序异常检测。将与信号处理领域的专家合作，开发复杂的算法来检测任何异常和重大变化。将定期从医学专家那里收集反馈，以评估与激素周期引起的正常组织变化相对应的变化范围。这些算法将在合成信号（通过电磁模拟获得，使用全面的MRI衍生人类乳房模型）以及使用真实乳房体模和志愿者测量的信号上进行测试。5.整体系统设计确保患者舒适度。这包括研究患者的整体位置（站立或俯卧）、与皮肤接触的材料的柔软度以及最大限度地缩短扫描时间。对培养高素质人才的贡献：我们计划的多学科性质使其成为一个培训平台，为应用于以医疗保健为中心的问题的一系列领域的专家提供培训：电磁仿真分析，天线设计，微波工程和信号处理。

OBJECTIVES: This Discovery Grant program proposes development of a low-power pulsed microwave device for breast tissue screening, including design, implementation and testing on patient volunteers. The device will complement existing clinical measurements rather than replace them; the proposed system is intended for regular screening as a tool for monitoring changes and significant departures from a healthy baseline. SCIENTIFIC APPROACH: The primary goal of the program is to develop and test a prototype of a bra-like detection device that incorporates a networked array of microwave sensors which can be used regularly by women at home or in small family clinics. Recent research suggests that low-power microwaves can detect small, early-stage tumors by exploiting the electrical contrast between malign tumors and healthy breast tissue in the microwave frequency range (100MHz – 10GHz). If a tumor is present, then part of an incident electromagnetic wave, launched into the tissue, scatters. The microwave propagation loss in the fatty tissue of the breast is sufficiently low to allow for this scatter to be detectable by receiving antennas on the skin surface. The antenna elements are inexpensive and small, so they can be woven into the fabric of a bra, a structure that is familiar, comfortable and simple to use. Acquired signals will be processed with sophisticated algorithms, yielding results that can alert the physician to potential abnormalities. METHODOLOGY: Several clearly identified components of the proposed prototype will be examined concurrently. 1. Antenna design and layout. The antenna-sensors need to be small, inexpensive and printed on a flexible substrate. In addition to targeting favorable characteristics of individual antennas, the number of sensors, as well as their relative layout will be optimized within spatial and hardware constraints. The substrate and the medium which couples the breast to the antennas need to be chosen in accordance with average electrical properties of the breast tissue. These challenges will be addressed through thorough simulation, fabrication and testing. 2. Microwave pulse generation. The signals fed to the transmitting antennas will be custom-shaped for selection of the frequency range of interest, as well as optimal usage of antenna capabilities. 3. The switching mechanism. Antenna elements act as transmitters one at a time, while the rest of the network operates in the receiving mode. Each scan involves a set of sequential measurements as the antennas take turns in their transmitting and receiving roles. This task includes careful consideration of circuit connections which will minimize signal loss and maintain signal integrity. 4. Sequential anomaly detection. In collaboration with experts in the signal-processing field, sophisticated algorithms will be developed to detect any abnormalities and significant changes. Regular feedback will be collected from medical experts to assess the range of changes which correspond to normal tissue changes due to hormonal cycles. The algorithms will be tested on synthetic signals (obtained through electromagnetic simulation with comprehensive MRI-derived human breast models) as well as on signals measured with realistic breast phantoms and volunteers. 5. Overall system design for patient comfort. This includes investigations of overall patient position (standing or prone), softness of materials in contact with skin, and minimizing the scan time. CONTRIBUTION TO TRAINING HIGHLY-QUALIFIED PERSONNEL: The multi-disciplinary nature of our program allows it to be a training platform for experts in a range of areas applied to a healthcare-centered problem: electromagnetic simulation analysis, antenna design, microwave engineering and signal processing.