Microwave imaging and spectroscopy of tissues

本文主要讨论了低功率微波成像在医学诊断中的两个应用问题。第一种是乳房筛查，目的是发现早期癌症。第二是人体皮肤的特征，旨在区分黑色素瘤和良性病变。这两种生物医学应用都源于相同的基本假设，即在微波频率范围内，恶性病变的电特性与健康组织不同，我们可以利用这种差异进行诊断。在最近的2017年统计数据中，加拿大癌症协会（CCS）表示，平均每天有72名加拿大女性被诊断患有乳腺癌，14名加拿大女性死于乳腺癌。在这里，我建议开发一种低成本、安全的微波系统，可以早期发现乳腺癌，提高生存机会。目标是设计一种可穿戴系统，具有负担得起的组件，从而使小型诊所可以使用它进行大规模筛查。该系统符合加拿大健康安全法规6的规定。由于没有电离辐射（在推荐的年度乳房x光检查中），基于微波的诊断工具将使用频繁的、每月的扫描来提供早期的异常预警。第一个研究途径的结果是一个可穿戴系统，它将补充当前的诊断模式，及时提醒医生偏离正常，需要进一步的检查和成像。此外，CCS在2017年宣布，估计有7200名加拿大人被诊断患有皮肤癌黑色素瘤，1270人死于皮肤癌黑色素瘤。可疑病变表面可见，但需要活检来确定可疑组织是否为恶性组织。活检本质上是侵入性的，是在有经验的皮肤科医生认为必要的要求下进行的。专家们很少有工具来决定病变类型和是否需要活检。我最近的兴趣是研究一种安全，低功耗的宽带微波诊断传感器，它将根据皮肤损伤的电学特性对其进行分类。为了初步验证，我们建议开发皮肤组织幻影，用于控制实验室实验。第二种研究途径的结果是一种诊断微波传感器，它将帮助皮肤科医生在要求活检分析之前更有信心地识别黑色素瘤。以上提出的两种研究途径将对生物组织的介电特性及其变化如何影响成功的微波成像和光谱学应用产生新的见解。所培养的人员将在理论和应用电磁学方面具有很高的素质，熟练使用数值模拟工具和微波仪器，并为加拿大工业界和学术界做出卓越的贡献。

This proposal focuses on low-power microwave imaging applied to two diagnostic problems in medicine. The first is breast screening, with the goal to detect early-stage cancers. The second is the characterization of the human skin, aiming to differentiate between melanoma and the benign lesions. Both biomedical applications stem from the same underlying hypothesis that the electric properties of the malign lesions differ from the healthy tissue in the microwave frequency range and that we can exploit this difference for diagnostic purposes. In the recent 2017 statistics, the Canadian Cancer Society (CCS) stated that, on average, 72 Canadian women are daily diagnosed with breast cancer and 14 Canadian women die from it. Here, I propose development of a low-cost, safe, microwave system that can detect breast cancer early, improving the chances of survival. The objective is to design a wearable system, with affordable components, thus making it accessible to small clinics for mass-screenings. The system complies Health Canada Safety Code 6 regulations. With no ionizing radiation (present in the recommended annual mammograms), the microwave-based diagnostic tool will used frequent, monthly scans to provide early warning about a developing abnormality. The result of the first research avenue is a wearable system that will complement the current diagnostic modalities, timely alerting the physician of a departure from the normal and the need for further tests and imaging. Further, CCS announced in 2017 that an estimated 7200 Canadians were diagnosed with and 1270 died from skin cancer melanoma. The suspicious lesions are visible on the surface, however, biopsy is required to determine whether the suspect tissue is malign. The biopsy is intrinsically invasive and is done at the request of an experienced dermatologist who deems it necessary. The specialists have very few tools at their disposal for making a decision on the lesion type and whether the biopsy is required. My recent interest is research on a safe, low-power broadband microwave diagnostic sensor, which will categorize the skin lesions based on their electric properties. For initial validation, we propose development of skin tissue phantoms, for controlled laboratory experiments. The result of the second research avenue is a diagnostic microwave sensor that will help the dermatologists identify the melanoma with increased confidence prior to requesting a biopsy analysis. The two research avenues proposed above will result in novel insights into dielectric properties of biological tissues and how their variation can affect successful microwave imaging and spectroscopy applications. The resulting personnel will be highly qualified in theoretical and applied electromagnetics, skilled in using numerical simulation tools as well as microwave instrumentation, and excellently positioned to contribute to the Canadian industry and academia.