High-resolution deep-tissue microwave thermometry

人体内部的温度可能与皮肤的温度有很大的不同。运动员、士兵、消防员和宇航员在繁重的训练或具有挑战性的环境条件下可能会出现异常的核心温度，导致体温过高和中暑，因此内部体温监测很重要。对于一个健康的人来说，内部温度（例如，心脏）和皮肤之间的差异在24小时的昼夜周期内变化高达2摄氏度。昼夜节律紊乱会导致季节性情感障碍、2型糖尿病和心脏病。内部组织温度与癌症热疗（加热）治疗和新生儿低温（冷却）脑抢救有关。目前，还没有一种无创、可穿戴和廉价的测量体内温度的方法。提出的研究目标是研究和开发一种具有一次性和廉价潜力的内部体温监测装置。激励应用在以下领域：(1)医疗诊断和监测；（二）医疗；(3)法医学、器官运输和人工组织生长。该设备适用于医院、家庭和救护车环境中的物联网（IoT）集成。此外，该方法适用于工业应用，如监测食品温度，混合废物等。PI积极开展外展活动，并通过Timmerhaus大使计划与当地学校联系，并通过通知运动员并与科罗拉多大学睡眠和时间生物学实验室合作，提出了与该工作计划相关的工作计划。这项计划的国际组成部分包括与马德里卡洛斯三世大学的合作，以拟议的学生交换和免费参与组织移植应用为证据。研究和开发一种集成设计、实现和校准的外部被动辐射计的新方法，该方法通过在较短的频率范围内测量黑体总功率来监测体内温度，且集成时间较长。操作频率选择为低干扰（安静波段）和高皮肤深度的组织。拟议的基础研究建立在一个成功的概念验证的基础上，该概念验证揭示了在该方法应用之前需要解决的挑战。本提案主要围绕以下主题展开：比较辐射计架构并确定最佳架构，以在具有低射频干扰的频率下，在芯片上的小（几摄氏度）温度范围内实现更高的温度分辨率，例如1.4 GHz安静频段。2. 研究空间分辨率的基本限制，并设计能够实现高分辨率的探针和探针阵列。近场相控阵探头被提出用于提高横向空间分辨率，而多频探头有望提高深度分辨率，目标是在所有三个维度上达到1cm。3. 组织层的厚度和电特性在身体的不同部位和人与人之间是不同的。为了估计内部温度，提出了一种确定组织层特征的一次性时域反射探针阵列测量方法，以提高温度估计的分辨率。综上所述，其智力优势包括在高频电路和系统设计、复杂层状介质上的近场相控阵探测和时域层表征方面的贡献。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The internal temperature of the human body can be considerably different from that of the skin. Athletes, soldiers, firefighters, and astronauts under heavy training or challenging ambient conditions can have abnormal core temperatures, resulting in hyperthermia, and heatstroke, making internal body temperature monitoring important. The difference between internal temperature (e.g., heart) and skin varies up to 2 degrees Celsius over the 24-hour circadian cycle for a healthy person. A disrupted circadian rhythm can result in seasonal affective disorder, type-2 diabetes, and heart disease. Internal tissue temperature is relevant in cancer hyperthermia (heating) treatment, and hypothermic (cooling) neo-natal brain rescue. Currently, a noninvasive, wearable and inexpensive method of measuring internal body temperature (IBT) does not exist. The goal of the proposed research is to study and develop an internal body temperature monitoring device that has the potential of being disposable and inexpensive. The motivating applications are in areas of: (1) medical diagnostics and monitoring; (2) medical treatment; and (3) forensics, organ transportation and artificial tissue growth. The proposed device lends itself to internet of things (IoT) integration in hospital, home and ambulance settings. Additionally, the method applies to industrial applications such as monitoring temperature of food, mixed waste, etc. The PI is active in outreach, and related to this proposed work plans to engage with local schools through the Timmerhaus Ambassador program, and by informing athletes and working with the University of Colorado Sleep and Chronobiology Laboratory. The international component of the proposed effort includes a collaboration with Carlos III Univ. in Madrid, evidenced by proposed student exchanges and no-cost participation in tissue grafting applications.A new method of integrated design, implementation and calibration of an external passive radiometer will be studied and developed for monitoring internal body temperature by measuring total black-body power in a narrow frequency range with relatively long integration time. The frequency of operation is chosen for low interference (quiet bands) and high skin depth in tissues. The proposed basic research builds on a successful proof-of-concept that unveiled challenges that need to be solved before the method can be applied. This proposal focuses on the following topics: 1. Comparing radiometer architectures and determining the best architecture to achieve improved temperature resolution over a small (few degrees C) temperature range on a chip, at frequencies that have low RF interference, e.g. the 1.4 GHz quiet band. 2. Investigating the fundamental limits on spatial resolution, and designing probes and probe arrays that enable high resolution. Near-field phased array probes are proposed for improving transversal spatial resolution, while multi-frequency probes show promise for improved depth resolution, with a goal of 1cm in all three dimensions. 3. Tissue layer thicknesses and electrical properties vary on different parts of the body and between humans. In order to estimate internal temperature, a one-time time-domain reflectometry probe array measurement that determines tissue layer characteristics is proposed, for improved temperature resolution estimation. In summary, the intellectual merits include contributions in high-frequency circuit and system design, near-field phased array probes over complex layered media and time-domain layer characterization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.