  The use of wireless implanted medical devices (IMDs) is growing because they
facilitate continuous monitoring of patients during normal activities, simplify
medical procedures required for data retrieval and reduce the likelihood of
infection associated with trailing wires. However, most of the state-of-the-art
IMDs are passive and offline devices. One of the key obstacles to an active and
online IMD is the infeasibility of real-time, high-quality video broadcast from
the IMD. Such broadcast would help develop innovative devices such as a
video-streaming capsule endoscopy (CE) pill with therapeutic intervention
capabilities. State-of-the-art IMDs employ radio-frequency electromagnetic
waves for information transmission. However, high attenuation of RF-EM waves in
tissues and federal restrictions on the transmit power and operable bandwidth
lead to fundamental performance constraints for IMDs employing RF links, and
prevent achieving high data rates that could accomodate video broadcast. In
this work, ultrasonic waves were used for video transmission and broadcast
through biological tissues. The proposed proof-of-concept system was tested on
a porcine intestine ex vivo and a rabbit in vivo. It was demonstrated that
using a millimeter-sized, implanted biocompatible transducer operating at
1.1-1.2 MHz, it was possible to transmit endoscopic video with high resolution
(1280 pixels by 720 pixels) through porcine intestine wrapped with bacon, and
to broadcast standard definition (640 pixels by 480 pixels) video near
real-time through rabbit abdomen in vivo. A media repository that includes
experimental demonstrations and media files accompanies this paper. The
accompanying media repository can be found at this link:
https://bit.ly/3wuc7tk.
