High-frequency microwave ablation for targeted, minimally invasive cancer therapy

该项目的主要研究目标是开发一种新的微创技术，用于使用高频微波消融热治疗癌性肿瘤。据美国癌症协会估计，2013年预计将有超过160万例新的癌症病例被诊断出来。死亡率最高的前十种癌症都是微波消融的候选者。这项技术避免了手术带来的高成本、侵入性、长时间使用全身麻醉等风险，以及较长的恢复时间，而手术是目前治疗癌症最常用的方法。该项目的目的是研究使用高频微波摧毁癌细胞的基本机制，并开发适合于微创向肿瘤输送微波能量的微型天线。此外，还将探讨利用纳米颗粒提高加热效率。总的来说，这些技术将使几乎位于身体任何部位的肿瘤的微创、靶向治疗成为可能。这个项目是整合研究和教育，并促进工程多样性的一个主要例子。将为中学女生开设以癌症微创治疗为重点的“拓展你的视野”讲习班。每年，一个暑期研究机会将提供给一个高中学生从麦迪逊大都会学区科学研究实习计划。机构计划将使少数民族和本科生参与研究活动。该项目将特别有效地招收和留住电气工程本科和研究生级别的女学生，因为它强调具有世界意义的保健问题。所有参与该项目的学生将在电磁学和医学的界面上接受宝贵的跨学科培训。微波消融采用间质天线将微波能量直接输送到肿瘤中，并将其加热到细胞毒性温度。之前的绝大多数研究都使用低于2.5 GHz的频率，部分原因是担心电磁波在较高频率下穿透深度较小，会妨碍形成足够大的烧蚀区。然而，最近获得了与此相反的实验证据。高频微波消融提供了许多尚未被探索的优点。首先，高频微波天线，特别是本项目中提出的新型天线类型和馈电技术，比低频天线要小得多。其次，在体内使用更高的频率可以更快地达到所需的消融区域。第三，高频微波的使用使紧凑和微型天线阵列的发展具有可定制的加热模式，这是传统的单元件低频天线所不能提供的。总的来说，这些特性有望克服现有热烧蚀技术的缺点，并扩大微波烧蚀系统的能力领域，以实现对几乎位于身体任何部位的肿瘤的微创、靶向治疗。利用电磁/热混合模拟的计算试验台和离体组织实验的物理试验台来完成以下研究目标：1)阐明高频MWA的基本机制，研究新的间隙天线设计概念；2)研究纳米颗粒介导的MWA提高加热选择性和降低功率要求；3)建立使用柔性高频MWA天线通过导管或内窥镜进入消融部位的可行性；4)研究用于定制烧蚀区大小和形状的高频微波间隙天线阵列。

The main research goal of this project is to develop a new minimally-invasive technology for thermal treatment of cancerous tumors using high-frequency microwave ablation. According to American Cancer Society estimates, over 1.6 million new cancer cases are expected to be diagnosed in 2013. The top ten cancers with the highest mortality rates are all candidates for microwave ablation. This technology avoids the high costs, invasiveness, prolonged use of general anesthesia and other risks, and long recovery times associated with surgery, which is currently the most common method of treatment of cancer.The objective of this project is to investigate the fundamental mechanisms of destroying cancerous cells using high-frequency microwaves as well as to develop miniature antennas suitable for minimally invasive delivery of microwave energy to the tumor. The use of nanoparticles to enhance heating efficiency will also be explored. Collectively, these technologies will enable minimally invasive, targeted treatment of tumors that are located nearly anywhere in the body. This project is a prime example of integrating research and education, and fostering diversity in engineering. An 'Expanding Your Horizons' workshop focused on minimally invasive treatment of cancer will be developed for middle-school girls. Each year, a summer research opportunity will be offered to a high school student from the Madison Metropolitan School District Science Research Internship Program. Institutional programs will be leveraged to involve minorities and undergraduates in the research activities. The project will be particularly effective in recruiting and retaining female students in electrical engineering at both the undergraduate and graduate levels due to its emphasis on a health care issue of worldwide significance. All students involved in the project will receive invaluable interdisciplinary training at the interface of electromagnetics and medicine.Microwave ablation employs an interstitial antenna to deliver microwave energy directly into the tumor and heat it to cytotoxic temperatures. The vast majority of prior studies have made use of frequencies below 2.5 GHz, in part due to concerns that smaller penetration depths of electromagnetic waves at higher frequencies would preclude the creation of sufficiently large ablation zones. However, experimental evidence to the contrary has been recently obtained. High-frequency microwave ablation offers a number of advantages that have not yet been explored. First, high-frequency microwave antennas, particularly the novel antenna types and feeding techniques proposed in this project, are radically smaller than their low-frequency counterparts. Second, the desired ablation zone can be achieved much faster in vivo using higher frequencies. Third, the use of high-frequency microwaves enables the development of compact and miniature antenna arrays with customizable heating patterns that are not available from conventional single-element low-frequency antennas. Collectively, these attributes are expected to overcome the shortcomings of existing thermoablative technologies and expand the realm of capabilities of microwave ablation systems to enable minimally invasive, targeted treatment of tumors located nearly anywhere in the body. Computational test beds involving hybrid electromagnetic/thermal simulations and physical test beds involving experiments with ex vivo tissue will be employed to accomplish the following research objectives: 1) elucidate fundamental mechanisms of HF MWA and investigate novel interstitial antenna design concepts; 2) investigate nanoparticle-mediated MWA for improving heating selectivity and reducing power requirements; 3) establish the feasibility of using flexible HF MWA antennas for gaining access to the ablation site via a catheter or endoscope; and 4) investigate arrays of HF microwave interstitial antennas for customizing the size and shape of the ablation zone.