Endoluminal Motion Recognition of a Magnetically-Guided Capsule Endoscope Based on Capsule-Tissue Interaction Force

A magnetically-guided capsule endoscope, embedding flexible force sensors, is designed to measure the capsule-tissue interaction force. The flexible force sensor is composed of eight force-sensitive elements surrounding the internal permanent magnet (IPM). The control of interaction force acting on the intestinal wall can reduce patient’s discomfort and maintain the magnetic coupling between the external permanent magnet (EPM) and the IPM during capsule navigation. A flexible force sensor can achieve this control. In particular, by analyzing the signals of the force sensitive elements, we propose a method to recognize the status of the motion of the magnetic capsule, and provide corresponding formulas to evaluate whether the magnetic capsule follows the motion of the external driving magnet. Accuracy of the motion recognition in Ex Vivo tests reached 94% when the EPM was translated along the longitudinal axis. In addition, a method is proposed to realign the EPM and the IPM before the loss of their magnetic coupling. Its translational error, rotational error, and runtime are 7.04 ± 0.71 mm, 3.13 ± 0.47∘, and 11.4 ± 0.39 s, respectively. Finally, a control strategy is proposed to prevent the magnetic capsule endoscope from losing control during the magnetically-guided capsule colonoscopy.

An overview of 1998 versus 2020 edition of Guidelines for Limiting Exposure to electromagnetic fields

One of the most important documents defining recommendations for limiting exposure to almost inevitable electromagnetic radiation was released in 1998 by International Commission on Non-Ionizing Radiation Protection (ICNIRP). This document is "Guidelines for Limiting Exposure to Time-varying Electric, Magnetic and Electromagnetic Fields (up to 300 GHz)". However, the growing knowledge about the electromagnetic field (EMF)-tissue interaction and appearance of innovative telecommunication technologies, raised the need for the improvement of these Guidelines. Thus, the ICNIRP published the latest version of its recommendations in 2020. The purpose of this paper is to briefly present some important differences between the ICNIRP 1998 and 2020 Guidelines and to enlighten their reflection on national EMF legislation.