Dr. Ohtsuka is a physician and endoscopist. He is a professor at Tokyo Medical and Dental University and Chairman of Endoscopy at University Hospital of Tokyo Medical and Dental University in Tokyo, Japan. Dr. Ohtsuka graduated from Niigata University School of Medicine in 1988. He completed residency in Internal Medicine at Akita Red Cross Hospital, and he completed the Niigata University Graduate School in 1995. After obtaining a doctor's degree, he advanced research at University of Southern California and received the 18th Annual American College of Rheumatology Senior Rheumatology Scholar Awards. After returning to Japan, he worked as the faculty at Showa University Northern Yokohama Hospital for 11 years. During this time, he participated in the development of capsule endoscopy and single-balloon endoscopy (SBE). He developed single operator method of SBE. In 2012, he has moved to Tokyo Medical and Dental University, and focused on endoscopic diagnosis and treatment of inflammatory bowel disease. He recently reported the importance of balloon assisted endoscopy for detecting small bowel stenosis in Crohn’s disease (CD), and the relation of endoscopic findings and prognosis of CD.