1. Center for Frontier Medical Engineering, Chiba University, Chiba, Japan.
2. Department of Anesthesiology, Asahi General Hospital, Asahi, Japan.
3. Department of Gastroenterological Surgery II, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
4. Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan.
5. Department of Urology, Teikyo University Medical Center, Ichihara City, Japan.