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

PRIMARY OBJECTIVE: To determine the maximum inter-fraction variability of fludeoxyglucose F-18 (18-F FDG)-PET activity of thoracic tumor treatment volumes through a 5-fraction stereotactic body radiation therapy (SBRT) course as it relates to the planning feasibility of emission-guided radiation therapy, or biologically-guided radiation therapy (BgRT). SECONDARY OBJECTIVES: I. To compare similar inter-fraction variability of FDG-PET activity for non-thoracic SBRT target volumes for the purpose of determining the feasibility of BgRT. II. To compare dosimetric endpoints for primary tumor coverage and dose to organs at risk between conventional SBRT planning and simulated BgRT, or emission-guided radiation therapy planning for thoracic and non-thoracic targets. III. To compare dosimetry for primary tumor coverage and dose to organs at risk between adaptive cone beam computed tomography (CT) planning, and simulated adaptive emission-guided radiation therapy (BgRT) planning for thoracic and non-thoracic targets. IV. To compare variability of 18-F FDG-PET in patients undergoing immunotherapy simultaneously during SBRT, or within 4 weeks of SBRT treatment with patients undergoing SBRT but not receiving immunotherapy. OUTLINE: Participants receive fludeoxyglucose F-18 intravenously (IV) and after 60 minutes undergo PET within 4 weeks of the first planned SBRT fraction, prior to the second planned fraction, and prior to the fifth planned fraction.