[Usefulness of positron tomography (PET) in lung cancer]. 
Lung carcinoma is one on the leading causes of death from cancer in all parts of the world.  The frequency of this tumor is increasing; at present, accounts for approximately 25% of all cancer deaths.  The majority of lung cancers are initially detected on chest radiographs, but many benign lesions have radiologic characteristics similar to malignant lesions.  Computed tomography (CT) is most frequently used to provide additional anatomic and morphologic information on lesions, but it is limited in distinguishing between benign and malignant abnormalities.  Fluorodeoxyglucose-Positron emission tomography (PET-FDG) imaging provides physiologic and metabolic information that characterizes lesions indeterminate by CT, is used clinically to-differentiate benign from malignant focal pulmonary abnormalities, to stage mediastinal and extrathoracic metastases, and to identify recurrence.  It is the gold standard that define the therapeutic strategy.