This pilot clinical trial studies computed tomography (CT) perfusion imaging in predicting treatment response in patients with non-small cell lung cancer or tumors that have spread from the primary site (place where it started) to the lungs (metastases) treated with stereotactic ablative radiation therapy. CT perfusion imaging is a special type of CT that uses an injected dye in order to see how blood flow through tissues, including lung tissue. CT perfusion imaging of the lungs may help doctors learn whether perfusion characteristics of lung tumors may be predictive of response to treatment and whether lung perfusion characteristics can be used to follow response to treatment.