Medical imaging equipment, such as endoscopes, transmits data via cables to monitors and hospital information systems. Working with partners, Fraunhofer researchers in the OWIMED project are working to make data cables in the operating theatre of the future obsolete. The project team has developed a prototype for an endoscope that uses light to transmit images from laparoscopic surgery in the abdominal cavity.
With no cables lying around, operations can be performed more efficiently and medical devices can be cleaned and disinfected more easily. However, the radio systems commonly used today do not meet the reliability, safety and latency requirements of medical technology. "Instead of radio waves, we use modulated LED light for wireless communication. Due to the locally limited propagation of light, wireless transmission via light (LiFi) is ideal for medical technology. We can already meet the requirements for high data rates over short distances," says Anagnostis Paraskevopoulos, researcher at the Fraunhofer Institute for Telekommunikation, Heinrich-Hertz-Institut (HHI), who is leading the project.
Wireless endoscope
In the OWIMED project (Optical Wireless Communication for Medical Imaging Devices, see below), scientists are exploring ways to enable LiFi technology in the operating theatre. Working closely with IT Concepts GmbH and the St. Joseph Krankenhaus in Berlin-Tempelhof, they are developing a wireless endoscope that can be used in laparoscopic procedures. The researchers integrate LiFi technology into operating lamps and use the optimal line-of-sight connection to receive data from the endoscope and transmit it to the monitor, where images from the abdominal cavity are displayed in 4K quality.
Ending the cable tangle
Commercially available endoscopy systems require two cable connections. One, a fibre-optic cable, serves for illumination, while the other provides power and the data connection that allows the camera images or video stream to be displayed on the monitor. These cable connections are not hygienic. They have to be shielded with a cover and are laid over the patient or on the floor. This significantly disrupts work in the operating theatre.
Batteries and LiFi
"Our wireless endoscope solves this problem. We integrate the optical light source in the form of an LED directly into the endoscope, which is battery-powered. We also build a battery-powered LiFi module into the endoscope, which sends the data optically to the OR environment and to the monitor. This requires only a few additional LiFi modules on the operating lamp above the operating table," Paraskevopoulos explains. A modulator switches the LED on and off at a frequency too high to be detectable by the human eye. A photodiode detects these light pulses and converts them into electrical signals. The optical wireless link is bidirectional, which also allows changes to the endoscope camera settings from the monitor.
Robust data connection
The LiFi modules are designed to be compact and provide uniform, hemispherical signal propagation over a 180-degree radius, ensuring a robust, high-speed data connection. The integrated camera chip and associated microprocessor provide low-latency data compression, enabling data transmission with low power consumption.
Surgical team involvement
The surgical team at the St Joseph Krankenhaus in Berlin-Tempelhof played a key role by continuously advising on the technical development throughout the project. In the end, they tested the prototype wireless endoscope and associated LiFi infrastructure in a real OR environment using a surgical simulator in the form of a medical phantom. "The tests allowed us to demonstrate that our LiFi solution performs very well in terms of latency as well as reliability, data rates, light quality and ergonomics. The feedback from the surgical team was completely positive. Once our system is fully developed, doctors would prefer it to the wired variant," says Paraskevopoulos.
Opening photo: Optical wireless communication (LiFi) ensures reliable data transmission from the endoscope to the monitor, even under adverse conditions. (Photo: Fraunhofer HHI)
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