The purpose of this study is to help researchers investigate if a new imaging agent named 18F-FMISO can predict if patients with lung cancer will respond to standard therapy, as well as whether disease will reoccur in the future. The study will also investigate whether a 18F-FDG PET scan in the middle of radiation treatment can predict if lung cancer will respond to standard therapy. Information obtained from this study may help doctors design future studies in which they may target tumor areas that do not respond to therapy or may likely reoccur in the future.