The purpose of this study is to compare conventional PET/CT scan performed 1 hour after injection of the radioactive tracer FDG (PET/CT[1]) with PET/CT performed after 3 hours (PET/CT[3]) in a group of patients with biopsy verified lung cancer or high suspicion of lung cancer after initial work-up (chest x-ray and CT of thorax/upper abdomen), who are potentially operable.