Thoracic FDG PET: State of the art

The D-glucose analogue 2-(fluorine-18) fluoro-2-deoxy-D-glucose (FDG) is the most commonly used radionuclide in positron emission tomography (PET) of the thorax. Increased glucose metabolism by malignant cells allows physiologic differentiation between benign and malignant abnormalities. FDG PET is consequently useful in characterizing indeterminate pulmonary nodules and in staging and assessing the response to treatment of lung cancer. FDG PET is accurate in classification of indeterminate pulmonary nodules as benign. Nodules with low FDG uptake are followed up radiographically; nodules with increased FDG uptake should be evaluated with biopsy or resected. In the staging of lung cancer, FDG PET is useful in evaluating local disease and pleural and chest wall involvement. The accuracy of FDG PET in demonstrating intrathoracic metastatic nodal disease is greater than that of computed tomography or magnetic resonance imaging. Whole-body PET is useful in detection of extrathoracic metastases. Conventional imaging often does not allow differentiation of tumor from posttreatment scarring. Increased FDG uptake at the sites of residual radiographic abnormalities is indicative of persistent or recurrent tumor.