Minimally invasive microwave antennas for image-guided focal tumor ablation

DESCRIPTION (provided by applicant): Micrablate, LLC plans to commercialize a small-diameter, minimally-invasive microwave system for image- guided tumor ablation that markedly improves the ability of physicians to treat even the most challenging tumors. In 2005, an estimated 1.4 million new patients were diagnosed with cancer, 172,570 for lung cancer alone. There is an urgent need for a technology that can offer hope to the 70-75 percent of these patients not eligible for surgery or those who have not responded to other treatments. Current microwave ablation systems can provide a fast, effective means of treating tumors percutaneously using imaging guidance (CT, ultrasound, MRI). However, these devices may be too large for safe percutaneous use, especially in the lung, and/or create zones of ablation too small to adequately treat most tumors. Many microwave devices are also hampered by unwanted heating of the antenna feed line, which leads to tissue injury outside the target zone. These limitations have prevented microwave ablation from becoming the dominant ablation modality, despite intrinsic advantages over the current clinical standard, radiofrequency (RF) ablation. The goal of this SBIR project will be to test the feasibility of new system designs that will eventually help move small-diameter microwave devices from academia into the clinical marketplace. Micrablate's design will contain several new features, including a system optimized to limit power loss, reduced heating of the feed line, and active cooling strategies that will increase the efficacy of microwave ablation devices without increasing invasiveness, making them safer for percutaneous use. Our collaborators have successfully shown that increasing power increases the size of the ablation zone and that our design strategies may allow small- diameter antennas to operate at powers much higher than their usual maximum power rating. In Phase I of this project, we will determine a primary antenna design and test several plausible solutions to decrease self-heating of the antenna while increasing its power throughput. We will build and study prototype antennas using computer simulations, ex vivo, and in vivo models to mimic the effectiveness of the treatment in patients. The Aims of this proposal are to: 1) choose a lead antenna design between two candidates by comparing zones of ablation, and 2) compare the ability of passive and active cooling methods to minimize self-heating in an in vivo model. Key to our aims is that all of the proposed solutions can be enacted without increasing the diameter of the antenna. Completing these aims will set the stage for future Phase II studies where we will validate a complete microwave ablation system prior to preliminary testing in humans and FDA submission. Here, the final antenna design will be integrated with a commercially-available generator and multiple-antenna support. The optimized microwave ablation system will be marketed to companies at the forefront of medical device and ablation technology, such as Johnson and Johnson, Endocare, Tyco Healthcare and Boston Scientific. Micrablate technologies developed in this proposal will combine the best of engineering and medicine into a tool that clinicians will use to treat cancer with minimal invasiveness, low morbidity and rapid recovery times but with maximum patient benefit. Commercialization of this system will have a substantial impact on the treatment of cancers of the lung, liver, kidney and bone resulting in maximum patient benefit.