Your proton therapy cancer treatment begins when each proton begins its journey at the injector located within an electric field. In the field, hydrogen atoms then separate into negatively charged electrons and positively charged protons. The protons travel through a vacuum tube within a pre-accelerator. This process boosts their energy to two million electron volts. Benefits of Proton Therapy The protons continue in the vacuum tube and begin their high-speed journey in the synchrotron. They travel around the synchrotron about 10 million times per second. Each time they circulate, a radio frequency cavity within the ring delivers a boost of energy. This increases the protons' energy to between 70 and 250 million electron volts. The voltage achieved is enough to place them at any depth within the human body. After leaving the synchrotron, the protons move through a beam transport system, continuing in the vacuum tube through a series of steering and focusing mag...