at 16 feet in diameter this particle accelerator the synchrotron uses a ring of small magnets to spin protons that come from hydrogen atoms up to 2/3 the speed of light the protons are injected into the ring accelerated to energies between 70 and 230 MeV and then extracted to the synchrotron and transported to each of the treatment rooms the 80,000 square-foot proton Center contains the synchrotron a space for research and three treatment rooms used for adult and pediatric patients proton beams travel down a beam line nearly 50 yards long and enter one of four rooms an organized assembly of electromagnets focuses the proton beam toward the gantry nearly three stories high a large mechanical arm called a gantry can move the beam 360 degrees around the patient treating the tumor from several angles as it destroys tumor cells layer by layer 3d imaging built into the gantry with cone beam CT capability allows pinpoint precision in locating the tumor a 5 millimeter wide proton beam guided by a 21,000 pound magnet is directed to the resting patient you