Multi-Capsule Endoscopy: An initial study on modeling and phantom experimentation of a magnetic capsule train

Purpose: Capsule endoscopy offers increased patient comfort and improved visibility of the entire gastrointestinal (GI) tract. Besides imaging, numerous literary studies on capsule endoscopy have demonstrated drug delivery, navigation strategies, tactile sensing for tumor diagnosis, and biopsy. Yet, the size limitation hampers the availability of multiple features within a single capsule. In an effort to increase the space and functionality, we propose the use of multiple capsules. Methods: All capsules together form a capsule-train, whose wagons are connected with magnetic push/pull forces. Magnets located on each capsule form the virtual magnetic spring. The presence of a preset gap allows for joint tasks on the targeted tissue. The gap in-between capsules also ensures ease of motion throughout the GI, while negating the risk of clinching of tissue parts in between the capsules. Results: Designed capsule train with two capsules successfully traveled through straight phantom without breaking connection for typical bowel speed. Also, same experiment is repeated with higher (2 × to 16 × of expected) speeds to inspect possible abrupt conditions, where capsules traveled together without any disconnection while maintaining constant distance in-between. Experiment results successfully imitate the developed magnet spring model (10–30% mismatch) even with ignored friction forces and camera pixilation errors. Conclusion: As future work, we will be working on adapting the capsule train for curved trajectories and perform demonstrations on ex-vivo animal bowel models. With further development, magnetically connected multi-capsule train can be adapted to clinic for improved functionality and multitasking through the GI tract.