Fludeoxyglucose F-18-PET in Planning Lung Cancer Radiation Therapy

Inclusion Criteria: * Patients who are offered radiotherapy using a 5-fraction stereotactic body radiation therapy course, at the recommendation of the treating radiation oncologist * Patients with early non-small cell lung carcinoma, or clinically-diagnosed early stage lung cancer, or pulmonary metastases * Patients with a limited (1-5) number of metastatic foci outside of the thorax who are candidates for consolidative treatment with SBRT * Patient with either a single focus or multiple foci (multi-isocentric planning) of disease in the thorax amenable to SBRT with at least one focus with at least 1.5 cm or larger in its largest diameter * Patients who are planned to receive either chemotherapy, targeted therapy, immunotherapy, or no additional cancer-directed drug therapy Exclusion Criteria: * Prior radiation therapy which would provide significant dose overlap with the planned target volume(s) delivered within 30 days of enrollment or registration * Major invasive surgical procedure occurring between the first treatment-eligible PET/CT examination and end of radiotherapy that would affect the treatment target region * Patients with minimal FDG-avidity localized to the planned treatment target (e.g. maximum standardized uptake value \[SUV\] \< 4.0) * Pregnancy