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

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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.