Tadpole endoscope: a wireless micro robot fish for examining the entire gastrointestinal (GI) tract

Abstract

Cancers of the gastrointestinal (GI) tract, including oesophagus cancer, stomach cancer and colon cancer, rank as the second most prevalent among all types of cancers in the world and the first in Hong Kong. The traditional method of diagnosing cancers in the GI tract requires three procedures: oesophagus cancer and stomach cancer can be diagnosed using gastroscopy; intestinal cancer can be diagnosed using capsule endoscopy; and colorectal cancer can be diagnosed using colonoscopy. These separate procedures are not only expensive but also exert a great deal of stress on the human body (both gastroscopy and colonoscopy require anaesthesia). Clearly, a simple, reliable and non-invasive diagnosis procedure for the GI tract would be a major breakthrough. This paper introduces an innovative capsule endoscope, called the Tadpole Endoscope (TE), which it mimics the tadpole in the nature and adopts a thunniform swimming mode. A simplified model is derived to illustrate the propulsion principle. The TE is a type of active locomotion capsule endoscope; it is like a micro-robot fish and can propel itself along the GI tract, especially in the stomach. Through the ex vivo tests, the maximum swimming speed can reach 12.5 mm/s and the minimum turning radius is 25 mm in the stomach.

Keywords:

• GI tract
• capsule endoscope
• active locomotion
• maneuverability

Acknowledgements

This project would not have been possible without the generous support of numerous partner organisations. The Institute of Precision Engineering, the Chinese University of Hong Kong (IPE-CUHK) led this effort and provided significant direct support throughout. The Jockey Club Minimum Invasive Surgery Training Centre, the Chinese University of Hong Kong helped conduct the ex vivo experiments.

Additional information

Dr Yong Zhong received his BEng degree from the Department of Mechanical Science & Engineering at the Huazhong University of Science and Technology, and his master's degree from the University of Chinese Academy of Sciences. Currently, he is a Ph.D. candidate in the Department of Mechanical and Automation Engineering at the Chinese University of Hong Kong (CUHK). His research interests include mechanical design, dynamics and automation, especially in the field of bio-inspired robots and flexible robots.

Ir Prof Ruxu Du received his master's degree from the South China University of Technology, the Mainland China in 1983 and his Ph.D. degree from the University of Michigan, the USA in 1989. He became ASME Fellow in 2009 and SME Fellow in 2012. Currently, he is a Professor in the Department of Mechanical and Automation Engineering at the CUHK. His research interests include design, manufacturing and automation.

Prof Philip W Y Chiu is a Professor in the Department of Surgery at the CUHK. He is also the Director of the CUHK Jockey Club Minimally Invasive Surgical Skills Centre and the Director of the CUHK Chow Yuk Ho Technology Centre for Innovative Medicine.