Hisashi Saji1,2, Takahiko Ueno3, Hiroshige Nakamura4. 1. Department of Chest Surgery, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, Kanagawa, 216-8511, Japan. saji-q@ya2.so-net.ne.jp. 2. Department of Thoracic Surgery, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan. saji-q@ya2.so-net.ne.jp. 3. Department of Medical Informatics, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, 216-8511, Kanagawa, Japan. 4. Division of General Thoracic Surgery, Tottori University Hospital, 36-1, Nishimachi, Yonago, 683-8504, Tottori, Japan.