9 WORLD GASTROENTEROLOGY NEWS NOVEMBER 2016 Editorial | Expert Point of View | Gastro 2016: EGHS-WGO | WDHD News | WGO & WGOF News | WGO Global Guidelines | Calendar of Events external magnetic field coupled with a permanent magnet within the capsule to propel the device. 4 Perhaps a hy-brid locomotion system that combines internal and external actuators may eventually prevail. 5 Currently research focuses on the development of a safe, low power consuming system that will offer proper endoscope velocity and ability to move backward - forwards and to stop under real time control. 4 Exact localization of the capsule endoscope in the digestive tract is of imperative importance for the accurate localization of the detected lesions and potential therapy ap-plication in real-time. The existing capsule route 2-D tracking softwares are inaccurate and their use is limited in clinical practice. Magnetic field strength-based and electromagnetic wave-based methods are currently un-der investigation to resolve the issue of device localization; the former giving promising results. However, none of these methods can provide informa-tion regarding the distance that the robot has traveled from a landmark (e.g. pylorus) to the detected lesion. 6 A device like OdoCapsule that incorporates a micro-motor system, consisting of three miniature legs, torsion springs, and wheels, promises accurate measurement of the distance from the duodenal bulb to areas with pathological findings. 7 Another challenge for active capsule endoscopes is to incorporate mecha-nisms that allow tissue sampling. Several prototypes have been tested ex vivo, but their clinical utility is limited by unprecise targeting, difficulty navigating to the target, and obtain-ing single sample capacity. Recently, the combination of a magnetically actuated soft capsule robot that has abilities for advanced functions (e.g. localized drug delivery) with self-folding microgrippers –which have already been used in vivo to obtain bi-opsy in pig’s bile duct- offers the next “sweet dream” option for accurate active biopsy capsule operation –albeit with many limitations. 8 The ultimate challenge for the future endoscopy robot is active drug delivery. The major problem to over-come is limited capsule space, where two principal mechanisms should be incorporated: an anchoring system to guide capsule positioning and a drug release mechanism to control the dose and the frequency of the released drug by remote actuation. Researchers have suggested mechanical systems using micro motors embedded in the capsule and a specific “legged” mechanism to attach the wall of the gastrointestinal tract. Magnetically actuated mechanisms have been tested to control the active drug release; however, a lot of work has to be done yet. 9 Part of this work has been in-corporated in two European projects: the NEMO (Nano-based capsule Endoscopy with Molecular imaging and Optical biopsy) and the VEC-TOR (Versatile Endoscopic Capsule for gastrointestinal TumOr Recogni-tion and therapy) design intending to create new capsules with therapeutic and diagnostic capabilities. 10 Regarding higher image resolu-tion, the closest to our expectations prototype is a low energy ASCI model that supports light and autofluores-cence imaging at 24 frames/sec, 400 x 400 (almost double the existing) image resolution, and an efficient im-age compressing module. The device has successfully been tested in pigs, however attenuation of the signal transmitted through biological tissues has still to be addressed. 3 In 1966 the original “Fantastic Voyage” movie was released. Today, Guillermo del Toro is in talks to remake the film where the miniatur-ized scientist will reach and treat the trauma of the scientist’s brain. Is the ideal future micro-robot still faraway 11 and how long is far? During the last five years major technological achieve-ments have been accomplished in the field of endoscopic micro-robots, promising that the future of endos-copy is wireless, indeed! References 1. Basar R, Ahmad MY, Cho J, Ibrahim F Application of wireless power transmission in wireless capsule endoscopy: an overview. Sensors 2014; 14:10929-10951. 2. Shi Y, Yan G, Zhu B, Liu G. A portable wireless power transmis-sion system for video capsule endoscopes. Bio-Medical Materials and Engineering 2015; 26: S1721– S1730. 3. Liu G, Yan G, Zhu B, Lu L. De-sign of a video capsule endoscopy system with low power ASIC for monitoring gastrointestinal tract. Med Biol Eng Comput 2016, doi: 10.1007/s11517-016-1472-2. 4. Liu L, Towfighian S, Hila A. a review of locomotion systems for capsule endoscopy. IEEE Rev Biomed Eng 2015, doi: 10.1109/ RBME.2015.2451031 . 5. Simi M, Valdastri P, Quaglia C, Menciassi A, Dario P. Design, fabrication and testing of a capsule with hybrid locomotion for gastro-intestinal tract exploration. IEEe/ ASME Transactions on Mechatron-ics 2010; 15:170-180. 6. Than TD, Alici G, Zhou H, Li W. a review of localization systems for robotic endoscopic capsules. IEEE Trans Biomed Eng 2012; 59:2387- 2399 . 7. Karargyris A, Koulouazis A. Odo- Capsule: next-generation wireless capsule endoscopy with accurate lesion localization and video sta-bilization capabilities. IEEE Trans Biomed Eng 2015; 62:352-360.
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