The ultra wideband capsule endoscope

One of the most innovative applications of wireless technology in medicine is the capsule endoscope (CE). This electronic device helps to examine hard-to-reach parts of the gastrointestinal (GI) tract with significantly less discomfort for the patient than traditional endoscopic methods based on the insertion of flexible tubes. A CE has the size and shape of a pill, and after being swallowed it transmits wirelessly images of the GI tract to an external receiver worn by the patient. The images are captured with the aid of an integrated tiny camera and a light source. Through the use of sophisticated software, a video is created offline with the received images for analysis and inspection by the medical staff. In most cases, real-time video transmission is not possible. A number of commercial CE systems operating with narrowband radio interfaces are already available. Nevertheless, the quality of the CE video is generally poorer than conventional endoscopy´s. The use of an ultra wideband (UWB) radio interface, which can enable high data rate transmission, would significantly enhance the video quality and reduce power consumption. The low power consumption feature could be exploited to add functional tools for purposes like biopsy or targeted drug delivery to current CE systems. Nevertheless, the high attenuation of radio signals propagating through living tissues in frequencies above 1 GHz make the use of UWB radio links for this application a major challenge. In addition, the design of an appropriate high data rate transmitter and a tiny antenna for efficient transmission over a large bandwidth are complicate tasks that require an accurate characterization of the channel. This paper presents the most important research results that we have obtained towards the implementation of a UWB-CE. Challenges and research problems in this area are outlined.