In traditional radiation therapy, X-ray beams are typically used to treat cancer. The X-ray beams go through the cancerous tissue (tumor) destroying both healthy and cancerous areas along the path of the beam. Proton beams enter the body and deposit most of their energy at the target – the site of the tumor. Radiation oncology physicians are able to focus the energy of the proton beam within a tumor, minimizing damage to nearby healthy tissues and vital organs.