SpecialtyGastroenterology, Endoscopy


Chief and Director of Endoscopy Center
NTT Medical Center Tokyo, Deapartment of Gastroenterology

Specific Strengths:
Expertise in diagnosis and endoscopic treatment of early stage cancers of all the GI tract with special concentration in ESD. ESD treatment experience since 2000, introductory era of ESD. ESD operator in 30 mid-lower pharyngeal, 300 esophageal, 2000 gastric, 100 duodenum and 1000 colorectal cases.
In recent years introduced the Confocal Laser Endoscopy(CLE), and is dedicated for the establishment of Optical Biopsy as new diagnosis method. In this field, the most experienced center in Japan.
The Director Endoscopist and highly motivated and encouraging mentor/educator of ESD at Endoscopy Center of NTT Medical Center Tokyo, nationally recognized as a prominent and outstanding magnifying diagnostic endoscopy and ESD training center. The Endoscopic Center ranks in No. 1 in Japan for number of ESDs performed (103 esophageal, 287 gastric, 270 colorectal cases; 2016). Especially in colorectal ESD, our center is the highest volume center in Japan.

Education & Professional Activities

Internship at Japan Railway General Hospital, 1998-2000
Post Graduate Course: Department of Social Medicine Hirosaki University School of Medicine, 2014-current

Gastroenterology Career
2000 - 2005 Japan Railway General Hospital, Attending Gastroenterologist
2005 - 2007 Japan Railway General Hospital, Chief of Gastroenterology
2007 - 2009 NTT Medical Center Tokyo, Attending Gastroenterologist
2009 - 2013 NTT Medical Center Tokyo, Chief of Endoscopy Center
2011 - Current NTT Medical Center Tokyo, Chief of Gastroenterology
2013 - Current NTT Medical Center Tokyo, Director of Endoscopy Center
Other Services
Institute of Geriatrics Tokyo Women’s Medical University, Diagnostic Endoscopy Instructor
Teikyo University School of Medicine Mizonokuchi Hospital, ESD/Diagnostic Endoscopy Instructor
Tokyo Medical University Hospital, Department of Endoscopy, ESD Lecturer
Qilu Hospital of Shandong University, Visiting Professor
Dalian Municipal Central Hospital Affiliated of Dalian Medical University, Visiting Professor
Peking University People’s Hospital, Visiting Professor

Doctor of Medicine, Universitiy of Japan, Conferred upon: March 1998

Affiliated Organizations
Editorial Boards
World Journal of Gastroenterology
World Journal of Gastrointestinal Endoscopy
Japan Gastroenterological Endoscopy Society, Specialist Endoscopist
The Japanese Society of Internal Medicine, Certified Physician
The Japanese Gastroenterologial Association, Specialist
Junior Endoscopist Training Seminar, Organizer
Endoscopic Gastric Mucosal Resection Workshop, Organizer
Young Endoscopist Practice Seminar, Superviser
Colonoscopy skill up seminar, Organizer
新都心内視鏡病態機能研究会, 世話人
Laoardcopy Endscopy Cooperative Surgery Workshop, Organaizer

Research & Publications

Main Author
1. Education and imaging: Gastrointestinal: pachydermoperiostosis associated with Crohn's disease.
Ohata K, Niinami C, Ohya T, Inamori M, Nakajima A, Kurose N, Yashiro K.
J Gastroenterol Hepatol. 2009 Sep;24(9):1576.
2. Novel endoscopic technique for the diagnosis of early gastric cancer: endoscopy with crystal violet staining.
Ohata K, Misaka R, Ito T, Chiba H, Tsuji Y, Yamawaki M, Ohya T, Inamori M, Nakajima A, Matsuhashi N.
Digestion. 2011;84(1):60-1. 15.
3. Effective training system in colorectal endoscopic submucosal dissection.
Ohata K, Ito T, Chiba H, Tsuji Y, Matsuhashi N.
Dig Endosc. 2012 May;24 Suppl 1:84-9.
4. A novel traction system for esophageal endoscopic submucosal dissection.
Ohata K, Fu K, Shouzushima M, Hamanaka J, Ono A, Ito T, Tsuji Y, Chiba H, Matsuhashi N.
Endoscopy. 2012;44 Suppl 2 UCTN:E410-1.
5. Endoscopic submucosal dissection for large colorectal tumors in a Japanese general hospital.
Ohata Ken, Nonaka Kouichi, Minato Yohei, Misumi Yoshitsugu, Tashima Tomoaki, Matsuhashi Nobuyuki.
J of Oncology. 2013
Ohata K, Murakami Masahiko, Yamazaki Kimiyasu, Nonaka Kouichi, Misumi Nobutsugu, Tashima Tomoaki, Minato Yohei, Shozushima Meiko, Mitsui Takahiro, Matsuhashi Nobuyuki, Fu Kuangi,
The Scientific World Journal, 2014;
7. Simultaneous practice of narrow band imaging and confocal laser endomicroscopy for a case of early duodenal cancer
Ken Ohata, Kouichi Nonaka, Shinichi Ban, Nobuyuki Matsuhashi
J Gastroenterol Hepatol. 2015 Jun;30(6):966.
8. Usefulness of training using animal models for colorectal endoscopic submucosal dissection: is experience performing gastric ESD really needed?
Ohata K, Nonaka K, Misumi Y, Tsunashima H, Takita M, Minato Y, Tashima T, Sakai E, Muramoto T, Matsuyama Y, Hiejima Y, Matsuhashi N
Endosc Int Open. 2016 Mar;4(3):E333-9.
9. Esophageal Endoscopic Submucosal Dissection Assisted by an Overtube with a Traction Forceps: An Animal Study.
Ohata K, Fu K, Sakai E, Nonaka K, Tashima T, Minato Y, Ohno A, Ito T, Tsuji Y, Chiba H, Yamawaki M, Hemmi H, Nakaya T, Fukushima J, Matsuhashi N.Gastroenterol Res Pract. 2016;2016:3186168.
10. Novel technique of endoscopic full-thickness resection for superficial nonampullary duodenal neoplasms to avoid intraperitoneal tumor dissemination.
Ohata K, Nonaka K, Sakai E, Minato Y, Satodate H, Watanabe K, Matsuhashi N. Endosc Int Open. 2016 Jul;4(7):E784-7.
11. Balloon overtube can improve maneuverability of the endoscope during colorectal endoscopic submucosal dissection.
Ohata K, Sakai E, Richard Ohya T. Dig Endosc. 2017 ;29 Suppl 2:68-69.