RESUMO
Positron emission tomography with 2-((18)F)-fluoro- 2-deoxy-D-glucose (FDG-PET) is a metabolic imaging technique. FDG-PET is more accurate than CT for the evaluation of mediastinal involvement in patients with nonsmall- cell lung cancer, offering a high negative predictive value. It can detect occult metastases in 11% of patients, although the etiology of the extrathoracic isolated uptakes needs confirmation. Theoretically, FDG-PET can influence the planning volume for radiotherapy, primarily in patients with atelectasis. Quantification of metabolic activity using FDG-PET is influenced by the size of the lesion, glucose levels and the time elapsed since the isotope injection. More clinical trials are required to standardize the methods for performing PET, assess its use as a prognostic factor and for the evaluation of treatment response.