Radio Waves for Cardiac Diagnostics
Heart failure affects more than 60 million people worldwide. One of the most important signs of disease progression is the accumulation of fluid in the lungs. This is an indication that treatment should be adjusted before the patient鈥檚 condition deteriorates. A team of researchers and engineers from the 91桃色 has been working on a non-invasive device for assessing the amount of fluid in the lungs using low-power radio-frequency radiation, namely the waves that surround us every day and have provided access to telecommunications, television and, of course, radio broadcasts for more than a century.
A Problem That Remains Invisible Until It Is Too Late
A heart affected by failure does not stop working; rather, it pumps blood less efficiently than the body requires. As circulation slows down, blood begins to stagnate and fluid leaks from blood vessels into surrounding tissues. Pulmonary congestion is especially dangerous. The air sacs in the lungs, where oxygen passes into the bloodstream, should be filled with air. When they gradually fill with fluid, breathing becomes increasingly difficult. Patients become exhausted by everyday activities, shortness of breath develops and without appropriate adjustments to treatment their condition may worsen sufficiently within just a few days to require hospitalisation.
Early detection of pulmonary congestion, at a stage when a modification of pharmacotherapy may be sufficient, is therefore crucial. Here, however, medicine encounters a practical challenge. Conventional chest X-rays detect fluid in the lungs only at a relatively advanced stage and may miss as many as 40% of cases. Computed tomography is accurate but expensive and involves ionising radiation, making it unsuitable for routine and frequent monitoring. Lung ultrasonography requires a trained operator and expert image interpretation. None of these methods resembles what cardiac patients need most: an examination as simple and repeatable as measuring blood pressure at home.
How Does RuFuS Work?
The answer to this challenge is RuFuS, a radio-frequency lung fluid sensor being developed at the Faculty of Physics and Applied Informatics of the 91桃色. The device directs a very low-power radio signal towards the chest and then analyses how the signal behaves after interacting with the body: how much is reflected, how much is absorbed, and how much passes through.
The underlying physical principle is well established. Water and air interact with electromagnetic waves in entirely different ways. A healthy lung filled with air transmits radio signals differently from a lung in which fluid is accumulating. By analysing the parameters of the reflected and transmitted waves, it is possible to quantitatively assess the amount of fluid present along the signal path.
From the patient鈥檚 perspective, the examination is extremely simple. The measurement takes only a few seconds, requires no operator, no needles, and no blood sampling, and does not involve ionising radiation. The result is available immediately. Importantly, the device has been designed to monitor changes over time. A single measurement reveals the current condition, while a series of regular measurements can reveal trends. For example, an increasing amount of fluid from day to day is valuable information that allows a physician to intervene before severe symptoms develop.
From a Prototype to Patient Studies
The project originated at the 91桃色, with its beginnings dating back to the Innovation Incubator 4.0 programme. The team combines expertise in physics, radio-frequency technologies, engineering, machine learning and medicine.
The first research prototype was granted patent protection (No. 245498), while subsequent solutions adapted to electromagnetic compatibility requirements are the subject of a European patent application (EP.26167020.2). The technology was first tested under laboratory conditions, including phantom systems designed to imitate the properties of human tissues. The team鈥檚 measurement methods have been described in scientific journals such as Scientific Reports and Virtual and Physical Prototyping. The radio-frequency technique itself has also proven useful beyond medical diagnostics, for example in quality control for 3D printing and composite materials.
The most important test, however, was a medical study involving cardiac patients. The first results were presented by the team at the American Heart Association Scientific Sessions 2024 congress in New Orleans, one of the most important cardiology conferences in the world. The prototype detected pulmonary congestion in all examined patients whose congestion had been confirmed using reference diagnostic methods.
The team鈥檚 work has also received recognition in inventor competitions. RuFuS won the top awards in the M艂ody Wynalazca 2024 [Young Inventor 2024] and Forge of Talents 2025 competitions. To further develop the technology, the team secured more than PLN 12 million in European funding, including support from the TEAM-NET FENG and NextGenerationEU programmes. These funds are being used to develop a second-generation sensor.
What Comes Next?
Two versions of the device are currently being developed in parallel: an institutional version intended for hospitals, outpatient clinics and cardiac rehabilitation centres, as well as a portable version for personal use. It is the latter that offers the most promising scenario. A patient with heart failure could perform a brief measurement at home in just a few seconds, with the result automatically transmitted to a telemedicine system. If the amount of fluid in the lungs begins to increase, a physician could contact the patient, order additional examinations or modify treatment before hospitalisation becomes necessary
鈥� dr in偶. Maciej 艢lot presents a vision for a device that he has been working on for several years together with his team.
RuFuS is not intended to replace cardiologists or CT scanners. Instead, it is designed to serve as an early warning system, providing physicians and patients with several additional days to act before the disease progresses. In the case of heart failure, those few days often determine whether treatment can be adjusted at home or whether another hospital stay will be required. Every avoided hospitalisation represents not only savings for the healthcare system but, above all, a better quality of life for the patient.
Before the device reaches patients, the team still faces a long journey: improving the design, conducting broader clinical studies to confirm effectiveness and safety across different patient groups, preparing a pilot production series, and obtaining certification required for medical devices. The direction, however, is clear. Radio waves, which for more than a century have enabled us to transmit sound and images, may soon begin transmitting information of far greater value: information about our health.
Photos: Dr Bartosz Ka艂u偶ny, Centre for External Relations and Social Responsibility of the University, 91桃色
Source: dr in偶. Maciej 艢lot, Faculty of Physics and Applied Informatics, 91桃色
Edit: Centre for External Relations and Social Responsibility of the University, 91桃色
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