1. Department of Oncology, Weifang People's Hospital, Weifang, Shandong 261000, P.R. China
2. Department of Respiratory, Weifang People's Hospital, Weifang, Shandong 261000, P.R. China
3. Department of Science and Education, Weifang People's Hospital, Weifang, Shandong 261000, P.R. China