Helical motion and 2D locomotion of magnetic capsule endoscope using precessional and gradient magnetic field

Abstract

Recently, a conventional capsule endoscope was developed and has been used for a diagnosis to make up for the limitations of conventional flexible endoscopy. However, the capsule endoscope has also some limitations and low diagnostic effectiveness because of its passive movement through the peristaltic motion of digestive organs. To overcome these problems, there are several researches about active mobility of capsule endoscope. In this paper, we proposed helical motion and locomotion mechanism for magnetic capsule endoscope using the electromagnetic actuation (EMA) system. Through the combination of the magnetization direction of the capsule endoscope prototype and the precessional magnetic field which can be generated by 3-pairs of Helmholtz coils, the capsule endoscope prototype can show a precessional motion. In addition, the capsule endoscope prototype can move toward an aligned direction by a gradient magnetic field of Maxwell coils. First, we fabricated a capsule endoscope prototype with a desired magnetization direction and verified its scanning function through the helical motion of the capsule endoscope prototype in mock-up of tubular digestive organs. Second, the capsule endoscope prototype also has a propulsion force to the perpendicular direction of axial vector when it track the helical path, and this force make the capsule endoscope prototype to attach the inner wall of tubular environment. Finally, through the planar locomotion test in stomach phantom, we have verified the feasibility of the capsule endoscope using an electromagnetic actuation system.