High-resolution deep-tissue microwave thermometry

人体的内部温度可能与皮肤的温度有很大的不同。运动员、士兵、消防员和宇航员在高强度训练或具有挑战性的环境条件下，可能会出现核心温度异常，导致体温过高和中暑，这使得体内体温监测变得重要。对于健康人来说，在24小时的生理周期中，体内温度(例如心脏)和皮肤之间的差值最高可达2摄氏度。昼夜节律被打乱会导致季节性情感障碍、2型糖尿病和心脏病。体内组织温度与癌症热疗(加热)和低温(降温)新生儿脑抢救有关。目前，还没有一种非侵入性、可穿戴和廉价的测量体内体温(IBT)的方法。这项拟议研究的目标是研究和开发一种具有一次性和廉价潜力的体内体温监测设备。激励性的应用领域包括：(1)医疗诊断和监测；(2)医疗；以及(3)取证、器官运输和人工组织生长。该提议的设备有助于医院、家庭和救护车环境中的物联网(IoT)集成。此外，该方法还适用于工业应用，如监测食物、混合废物等的温度。PI积极参与外联活动，并与此相关的拟议工作计划是通过Timmerhaus大使计划与当地学校接触，并向运动员提供信息并与科罗拉多大学睡眠和时间生物学实验室合作。拟议工作的国际部分包括与卡洛斯三世大学的合作。在马德里，通过拟议的学生交换和免费参与组织移植应用，将研究和开发一种新的集成设计、实施和校准外部被动辐射计的方法，通过在相对较长的积分时间的窄频率范围内测量总黑体功率来监测体内温度。手术频率选择为低干扰(安静带)和高皮肤深度的组织。拟议的基础研究建立在成功的概念验证的基础上，揭示了在该方法可以应用之前需要解决的挑战。该建议主要关注以下主题：1.比较辐射计架构并确定最佳架构，以在具有低RF干扰的频率(例如1.4 GHz安静频段)上，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。2.研究空间分辨率的基本限制，设计能够实现高分辨率的探头和探头阵列。近场相控阵探头是为了提高横向空间分辨率而提出的，而多频探头则显示出提高深度分辨率的前景，目标是在所有三个维度上都达到1厘米。3.组织层厚度和电学特性在身体不同部位和人之间存在差异。为了提高温度分辨率的估计，提出了一种确定组织层特性的一次时域反射仪探头阵列测量方法来估计体内温度。总而言之，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器和时间域层特征方面的贡献。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.