Active Locomotive Intestinal Capsule Endoscope (ALICE) System: A Prospective Feasibility Study

Owing to the limitations of the conventional flexible endoscopes used in gastrointestinal diagnostic procedures, which cause discomfort and pain in patients, a wireless capsule endoscope has been developed and commercialized. Despite the many advantages of the wireless capsule endoscope, its restricted mobility has limited its use to diagnosis of the esophagus and small intestine only. Therefore, to extend the diagnostic range of the wireless capsule endoscope into the stomach and colon, additional mobility, such as 3-D locomotion, and steering of the capsule endoscope, is necessary. Previously, several researchers reported on the development of mobility mechanisms for the capsule endoscope, but they were unable to achieve adequate degrees of freedom or sufficiently diverse capsule motions. Therefore, we proposed a novel electromagnetic actuation system that can realize 3-D locomotion and steering within the digestive organs. The proposed active locomotion intestinal capsule endoscope (ALICE) consists of five pairs of solenoid components and a capsule endoscope with a permanent magnet. With the magnetic field generated by the solenoid components, the capsule endoscope can perform various movements necessary to the diagnosis of the gastrointestinal tract, such as propulsion in any direction, steering, and helical motion. From the results of a basic locomotion test, ALICE showed a propulsion angle error of less than 4° and a propulsion force of 70 mN. To further validate the feasibility of ALICE as a diagnostic tool, we executed ex vivo testing using small intestine extracted from a cow. Through the basic mobility test and the ex vivo test, we verified ALICE's usefulness as a medical capsule endoscopic system.