1. Division of Radiation Oncology, NHO Okinawa Hospital, Okinawa 901-2214, Japan
2. Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Okinawa 903-0213, Japan
3. Division of Palliative Care, NHO Okinawa Hospital, Okinawa 901-2214, Japan
4. Division of Pulmonary Medicine, NHO Okinawa Hospital, Okinawa 901-2214, Japan
5. Health Information Management Center, University of the Ryukyus Hospital, Okinawa 903-0213, Japan