In the field of lung cancer, 18F-fluorodeoxyglucose positron emission tomography (FDG- PET) currently has utility in characterization of the solitary pulmonary nodule, diagnosis of primary lung cancer, mediastinal staging, extrathoracic staging, radiotherapy programming, planning and monitoring of therapy and detection of recurrence. PET may help in determining the ideal site for possible tissue diagnosis as well as predicting prognosis. Combined PET and computed tomography (PET/CT) offers the best of metabolic and anatomic imaging and may provide optimal disease assessment. It is particularly useful for the planning of radiation therapy or surgical biopsy. Pneumon 2007; 20(1):43-48.