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异常的核心温度，导致体温过高和中暑，因此内部体温监测非常重要。内部温度（例如，心脏）和皮肤在24小时的昼夜节律周期内变化高达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高温（加热）治疗和低温（冷却）新生儿脑抢救有关。目前，不存在测量内部体温（IBT）的非侵入性、可穿戴且廉价的方法。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内部体温监测设备。激励应用领域包括：（1）医疗诊断和监测;（2）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，如监测温度的食物，混合废物等PI是积极的外展，并与此有关的拟议工作计划，通过蒂默豪斯大使计划，并通过通知运动员和工作与科罗拉多大学睡眠和时间生物学实验室与当地学校。拟议努力的国际部分包括与马德里的卡洛斯三世大学的合作，拟议的学生交流和组织移植应用的免费参与证明了这一点。将研究和开发一种外部被动辐射计的实施和校准，通过测量总黑在较窄的频率范围内具有相对较长的积分时间的体功率。选择低干扰（安静频带）和组织中高趋肤深度的工作频率。拟议的基础研究建立在成功的概念验证的基础上，该概念验证揭示了在应用该方法之前需要解决的挑战。本提案侧重于以下主题：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安静频带）下在芯片上的小温度范围（几度C）内实现改进的温度分辨率。 2.研究空间分辨率的基本限制，并设计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，而多频探头显示出提高深度分辨率的希望，目标是在所有三个维度上都达到1 cm。3.组织层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，提出了确定组织层特性的一次性时域反射计探针阵列测量，用于改进温度分辨率估计。 总之，智力价值包括在高频电路和系统设计，近场相控阵探头在复杂分层介质和时域层表征的贡献。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.