RecruitingDevice studyPatient Position Monitoring System for Beam Gated Radiation Therapy of Malignancies of the Chest and Upper AbdomenThis study will evaluate the feasibility of using this novel patient position monitoring system for patients receiving radiation therapy to targets involving the chest or upper abdomen, as these are the most affected by respiratory motion. This motion monitoring system will be incorporated with standard of care on-board CT imaging to confirm that the respiratory position is tracking the tumor target appropriately.