Application of Wireless Power Transmission Systems in Wireless Capsule Endoscopy: An Overview

Abstract

Wireless capsule endoscopy (WCE) is a promising technology for direct diagnosis of the entire small bowel to detect lethal diseases, including cancer and obscure gastrointestinal bleeding (OGIB). To improve the quality of diagnosis, some vital specifications of WCE such as image resolution, frame rate and working time need to be improved. Additionally, future multi-functioning robotic capsule endoscopy (RCE) units may utilize advanced features such as active system control over capsule motion, drug delivery systems, semi-surgical tools and biopsy. However, the inclusion of the above advanced features demands additional power that make conventional power source methods impractical. In this regards, wireless power transmission (WPT) system has received attention among researchers to overcome this problem. Systematic reviews on techniques of using WPT for WCE are limited, especially when involving the recent technological advancements. This paper aims to fill that gap by providing a systematic review with emphasis on the aspects related to the amount of transmitted power, the power transmission efficiency, the system stability and patient safety. It is noted that, thus far the development of WPT system for this WCE application is still in initial stage and there is room for improvements, especially involving system efficiency, stability, and the patient safety aspects.

Analysis and Performance Improvement of WPT Systems in the Environment of Single Non-Ferromagnetic Metal Plates

“…The metal plate is parallel to the coils and the distance from the metal plate to the transmitter and that from the plate to the receiver are c and d, respectively. The impact of the metal plate on inductance L, mutual inductance M and resistance R can be calculated according to Equation (8). If there is no metal plate, the mutual inductance between the transmitting coil and the receiving coil can be described by:…”

“…Currently it is widely used in consumer electronics such as mobile phones, tablets, laptops, electric toothbrushes, hutch cables, TVs, electric cars, electric buses and so on for charging devices and supplying power [1][2][3][4][5][6][7][8].…”

A Review on Wireless Power Transfer in Free Space and Conducting Lossy Media

“…The SAR can be calculated using Equation (10); where σ (S/m) and ρ (kg/m 3 ) are the tissue conductivity and mass density, respectively, and |E| is the magnitude of electric near field intensity. Excessive received power may cause overheating of the receiver coil, but according to the Japan Society of Medical Electronics and Biological Engineering (JSMEBE), temperatures below 42.5 °C are safe for the tissues surrounding the RC [31].…”

Inductive-Based Wireless Power Recharging System for an Innovative Endoscopic Capsule

“…Inductive coupling is in general one of the most suitable methodologies for near field wireless powering transfer [10]. In particular, a wireless power transmission system based on inductive coupling using a Helmholtz coil is presented in order to deliver stable and sufficient energy to an endoscopic capsule [11].…”