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Mason Professors gain significant headway in the pursuit of personalized prosthetics by using ultrasound imaging wearables.
BY LIBBY BONDI, STAFF WRITER
At George Mason’s Center for Advancing Systems Science and Bioengineering (CASSBI), recent breakthroughs in wearable bioimaging technology by Drs. Samuel Acuña, Siddartha Sikdar and Parag Chitnis are shaping the future of personalized prosthetics.
Karl Dussik was the first neurologist to use ultrasound for medical imaging in 1942, primarily employing ultrasonic waves to detect brain tumors. By the mid-1950s, English obstetrician Ian Donald developed the ultrasound technology further for OB-GYN practices.
Today, ultrasound—often seen in pregnancy scans—is used to customize prosthetics for individual patients. The imaging technique works by sending sound waves through a transducer to create two-dimensional images.
Traditionally, this process depends on large, stationary machines, limiting its flexibility in clinical settings. In a 2024 study, Acuña, Chitnis, Sikdar and their colleagues developed a wearable alternative to this traditional ultrasound technology.
Dr. Chitnis, an assistant professor in Mason’s Department of Bioengineering, explained how the wearable device functions: “Instead of using full two‑dimensional images, we track a single line of tissue deformation over time.”
This method enables smaller and faster devices by filtering only the information needed to track muscle movement, rather than generating full, detailed images.
“We’re not using the pretty 2D fetal ultrasound image. It’s more like a needle—black, white, black, white—and then you plot that line over time to see the tissue shift,” said Dr. Samuel Acuña, biomechanical engineer and leader at CASSBI.
Patients were asked to open and close their hands or walk on a treadmill, with the goal of detecting distinct movement patterns that an algorithm could recognize.
“If you lose your hand, a lot of the muscles that control your hand are still in your forearm,” said Acuña.
Their patented design uses off‑the‑shelf FM radio-style components, enabling a module just a few centimeters wide. Multiple tiny sensors can be placed around various muscles simultaneously, helping reveal asymmetries between the injured and healthy limb for rehabilitation tracking. The device also captures the signals necessary for assimilated prosthetics.
“You have a device that’s able to transmit ultrasound pulses that are sent into the body and come back with echoes, much like bats are able to sense their surroundings by echolocation, it’s the same kind of approach,” Chitnis explained.
Despite its successes, challenges remain in bringing the device to the medical market. One key issue is that ultrasound imaging is still a complementary technology. Electromyogram (EMG) is the closest counterpart in the push for personalized prostheses.
“EMG provides information about the electrical activation of the muscle, whereas ultrasound provides information about muscle contraction,” Chitnis says.
That’s why their wearable device integrates both EMG and ultrasound imaging, allowing for more precise and detailed tracking of muscle movement.
Another major challenge—often overlooked—is usability. Acuña emphasizes this in his role as CASSBI’s graduate coordinator, urging students to prioritize user experience, patient culture, and real-world workflows in device design.
“When I was a young engineer, I thought everything we did was somehow changing the world – with our new gizmos and toys, but that’s not the reality of what actually happens.”
Biomedical Engineering student Jacob Lockey, 21, agreed with this sentiment, “A lot of people tend to not like change, they like what works for them—even though the innovation is beneficial, there’s generally still pushback.”
Still, the future of wearables remains bright. The devices have already been tested on campus in collaboration with Mason athletics.
“We collaborate with these teams and collect data with them when they are doing warm-ups,” Chitnis explained. “We, [Sikdar & Chitnis,] founded a company [Myokinetics LLC] last October and hope, with small‑business grants secured, maybe in a year and a half to two years we can see our first commercial product to be sold—initially targeting sports rehab and college athletics.”
Both Chitnis and Acuña recognize that securing FDA approval and consistent funding are critical hurdles for commercializing wearable ultrasound technology. Interviews with clinical practitioners will also be essential to ensure the final product meets real-world needs and provides an optimal user experience.
“It’s all about getting faster and smaller. We’re shifting now from these very normative, one size fits all approaches to, very specifically, what a particular person needs.”Acuña says.
Studies are still underway and advancements are being made to prepare the device for clinical use. Lockey expresses optimism, looking toward the future. “The more we understand, the more we can improve, the more we can innovate, and the better things will be.”
