Preliminary Study on Capsule Endoscopes Propelled by Variable Threads

Y.-S. Hong, J.-Y. Kim, Y.-C. Kwon, and S.Y. Song (Korea)


Variable screw propeller, capsule endoscope, and rotatingpermanent magnet.


In order to enable the capsule endoscopes to move actively in human digestive organs, a variable screw propeller mechanism is proposed in this study. The screw propeller consists of variable threads whose direction is linked with the rotating direction of the capsule endoscopes. When the capsule body equipped with disk type permanent magnets is rotated by an external magnetic field, the threads are then swung by the friction force between intestine wall and their tips. According to the rotating direction, the variable threads will be right- or left-handed. Therefore, the capsule endoscope moves always in forward direction, regardless of its rotating direction and its operator can select either left- or right handed threads considering locomotive conditions. As the thread angle is variable, the capsule endoscopes can be put in the spiral motion or in the axial translation arbitrarily. In order to evaluate the performance of the new screw propellers, their moving speed is tested in an artificial tract, changing the parameters such as rotational speed of the external magnetic field, distance between the external magnet and the capsule, and viscosity of lubrication oil in artificial GI tract. In addition to it, in vivo tests were carried out. In a pig’s colon and esophagus they recorded up to 200mm/min, rotating at 18rpm.

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