While making conversation with a neighbor, I asked " What do you do for work"? Paul Meaney started to tell me about the projects that he and his team are working on. As he was telling me, I thought this would make for an interesting story. See group photo below:
L to R, Alex Hartov, professor at the Thayer school, Paul Meaney, and Sherri Geimer , research engineer
Since graduate school, Paul has been very interested in what you can do with microwaves in the medical arena. You can see that these signals were immensely useful for different radars – starting with WWII and continuing till now. Once you get past the ubiquitous notion that microwaves can heat you up, you realize there are immense opportunities. In fact, when you turn the power up, conventional and “harmless” technologies can also heat you up (focused ultrasound). The neat thing with microwaves is you can use them at really low levels but still measure them after they’ve passed through the body. As the signals pass through the body, they are altered depending on what they pass through. For example, very often, the properties of tumors are different enough from those of normal tissue such that you can distinguish between the two since the microwave signals interact with each differently. Likewise, the properties of normal bones are different from those of osteoporotic bone.
Paul sent me a few photos for you to look at. These are only meant to give you a taste of a few things. None is especially high quality. I think at a later stage, it might be useful to show photos of the group members near the equipment being developed.
Similar property differences also occur for other imaging modalities such as ultrasound, near infrared light, MR properties and others. The challenge for all these modalities is always to figure out how to get enough signal into the region of interest and measure the resulting signal. This is easier for some than others. The microwaves are quite good at penetrating to tissue, but they also like to go all over the place – for instance, you see this when you hold onto your radio antenna and notice the reception change. Coping with these multi-path signals has proven to be terribly challenging – there are over 150 microwave imaging research groups worldwide, with only a handful getting anything into the clinic.
Lab where we build and test our products
Most of these groups have evolved primarily from numerical modeling teams at different universities. The last 30 years has seen the advent of microwave simulations which have sped up the rapid development of new technologies – think cell phones. But in funny ways, these simulations tend to obscure the challenges of translating microwave imaging concepts into the clinic. In working with Keith Paulsen, Paul says we’ve brought to the table first rate numerical modeling skills along with exhaustive experience in building hardware. Paul's experience in microwave engineering is broad and deep – He has built a lot of stuff. The solutions on how to approach problems are unique compared with numerical modelers and the end results are often quite counter intuitive as viewed by a classically trained microwave engineer. But they work. It’s kind of sad to watch the myriad of attempts by other researchers that inevitably fail.
Breast imaging system during assembly phase
The team has done exhaustive research in breast imaging and performed over 500 patient exams – first ever microwave breast images. They are about to start a clinical trial monitoring breast tumors during chemotherapy. This project is sponsored by NIH and is in collaboration with GE. They plan to do the trials at DHMC and at UVM. Their imaging approach is getting simpler, faster and more sophisticated. But they are also branching out. Paul and his team also did some pilot bone imaging and found that the microwave properties correlate with bone density. In a somewhat circuitous route, this has led them to develop a probe for strength testing of vertebrae at the point of surgery to help doctors determine whether the bones are strong enough to withstand the strain from the screws implanted to hold the spinal column in place. This work is continuing in collaboration with colleagues in Sweden. They have also explored related probes for sensing what is inside of a closed bottle. It turns out this is a remarkably hard problem. This could have application in food safety tests and possibly be a means to distinguish between normal and explosive liquids.
Getting closer to the finish product
Research in this field is really quite international with huge synergism between fields. Paul spent a year at the Royal Marsden Hospital in London, UK studying ultrasound – both imaging and heat treatment. He stated it is remarkable the similarities between microwaves and ultrasound and the common issues that have to be dealt with. He also said his international interest and collaborations have expanded over the years. The company actually licensed the breast imaging technology to a research institute in South Korea. Paul is also a professor at Chalmers University of Technology in Gothenburg, Sweden and is actively collaborating with colleagues at Uppsala University. These interactions inevitably spur new ideas and innovations.
Bone dielectric probes inserted into a 3D printed model of a vertebrae
A sensor developed to examine the internal contents of bottles
Sensor and bottle
You can reach Paul at email@example.com or call him at 603-646-3939
Thanks, for reading
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