Hundred patients will be recruited by means of informed consent. In a narrow logistic scheme the study subjects will undergo a diagnostic work up to a maximum of 3 patients per study day (p. 32). Patients will be admitted at the pulmonary ward for the study day and will be accompanied by nurses. All patients will get PET-CT scanning in the morning of the study day. Depending on the location of lesions seen on PET-CT, further invasive diagnostic procedures will be planned for the afternoon, according to a scheme outlined on page 33. In the meanwhile, routine blood tests, EKG and pulmonary function tests are done. The invasive diagnostic procedure to be chosen, has to provide ideally a diagnosis and stage at one time.