1. Department of Urology, University of Tsukuba Hospital, Tsukuba, Japan.
2. Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
3. Department of Intelligent Interaction Technologies, Graduate School of System and Information Engineering, University of Tsukuba, Tsukuba, Japan.
4. Department of Urology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.