It is obvious that FDG-PET has added value to CT, but there is still insufficient data to define the role of FDG-PET/CT in clinical practice. Usually data are gathered from multiple sources and in consequence the information obtained is heterogeneous and not always comparable between patients. To alleviate this lack of data, we attempted to investigate the differences in staging and therapeutic intent as compared with conventional staging in non small cell lung cancer (NSCLC) patients scheduled for RT after adding FDG-PET/CT to conventional staging in 104 included subjects. In contrary to the multicentric studies relying on patients medical records from outside institutions, these data were generated entirely with the institution's PET/CT unit. Significant modifications of both, M-stage and clinical stage were detected after inclusion of FDG-PET/CT data (p< 0.001), while there was no statistically significant T- and N-stage modification. Overall implenting FDG-PET/CT revised RT intention decision in 34% of patients. FDG-PET/CT provides enhanced staging capabilities compared to conventional CT in staging of non small cell lung carcinoma and allows improved selection of patients suitable for curative intention, while avoiding unnecessary irradiation and costs in patients eligible to palliative intention.