While it is possible to obtain data from medical implants using radio frequencies, data transfer speeds are incredibly slow. Data are typically transferred at a maximum speed of around 50kbs. Unfortunately, while it is possible to increase the speed of data transfer, increasing the bandwidth past around 300 kilohertz could potentially cause patients harm since the body absorbs some of the waves and this can have a localized heating effect. Radio frequencies also have potential to interfere with the functioning of medical devices.
Obtaining data from implanted devices and reprogramming implants can be a long and laborious process. However, researchers have managed to dramatically increase the speed of data transfer by using ultrasonic signals.
The increase in data transfer speed is considerable. Andrew Singer from the University of Illinois at Urbana Champaign and his team managed to achieve record-breaking data transfer speeds of up to 30mbs. Such high speeds would allow doctors to livestream data from patients, including HD video streams from cameras implanted in the body. To put the data transfer speeds into context, HD video streaming typically requires speeds of around 25mbs.
For the test, Singer rigged up two 5-megahertz transducers in a water-filled tank. One transducer converted digital data to ultrasonic signals while the partner device recorded those signals after they had passed through animal tissue. For the test, Singer used a cut of liver and pork loin.
“We were a little bit surprised that the meat really did not provide much in terms of additional dispersion or attenuation,” said Singer. “The signals coupled extremely well and we had almost the entire bandwidth available to us for data transmission.”
While the test showed that high data transfer speeds were possible, the transducers were in close proximity – 5.86 centimeters apart – and the test did not involve passing the signals through bone. While pig knuckles were purchased for the test, they were rejected by the team.
It may not be possible to achieve such high speeds of data transfer from implants deep in the body, or when the signal must pass through bone, but the results are promising. However, there is a considerable drawback to using ultrasonic signals. Radio signals are broadcast omnidirectionally, allowing the signal to be picked up without having to orientate the receiving device too carefully.
Ultrasonic signals are only sent in one direction, so in order to receive the signal it would be necessary to very carefully orientate the receiver – or the patient. The practical applications may therefore be limited. In theory at least, Singer says it may be possible to update the software on implanted devices by using ultrasonic signals. Singer and the team hope to be able to test the system on animals in the near future.