Image-Guided, Intensity-Modulated Photon or Proton Beam Radiation Therapy in Treating Patients With Stage II-IIIB Non-small Cell Lung Cancer

This partially randomized phase I/II trial studies the side effects and best dose of image-guided, intensity-modulated photon or proton beam radiation therapy and to see how well they work in treating patients with stage II-IIIB non-small cell lung cancer. This trial is testing a new way of delivering radiation dose when only the tumor receives dose escalation while the surrounding normal structure is kept at standard level. Photon beam radiation therapy is a type of radiation therapy that uses x-rays or gamma rays that come from a special machine called a linear accelerator (linac). The radiation dose is delivered at the surface of the body and goes into the tumor and through the body. Proton beam radiation therapy is a type of radiation therapy that uses streams of protons (tiny particles with a positive charge) to kill tumor cells. Both methods are designed to give a higher than standard dose of treatment to the tumor and may reduce the amount of radiation damage to healthy tissue near a tumor.