Stereotactic body radiation therapy (SBRT) is a special form of treatment which pinpoints high doses of radiation directly to cancer. Standard radiation (or photon radiation) is commonly used for SBRT to treat Non-Small Cell Lung Cancer (NSCLC). Proton beam radiation is a special type of radiation only available at a few institutions in the US and has not been previously used in SBRT to treat NSCLC. The use of protons for SBRT may improve the accuracy of the treatment and may help to minimize the dose delivered unnecessarily to healthy tissue.