1. Department of Respiratory and Infectious Disease of Geriatrics; The First Hospital of China Medical University; Shenyang 110001 P.R. China
2. Department of Medical Oncology; The First Hospital of China Medical University; No. 155, North Nanjing Street, Heping District Shenyang 110001 P.R. China
3. Department of Pulmonary Medicine; The First Hospital of China Medical University; Shenyang Liaoning 110001 P.R. China