Cyclotrons, synchrocyclotrons, and synchrotrons are the most common accelerators used in proton or ion therapy facilities. Cyclotrons are usually used only for protons. Their output energy is usually constant, but there are techniques for obtaining variable energy for these types of accelerators. Synchrotrons are suitable for treatment with protons and other ions. The synchrotron has the ability to accelerate protons and other ions, and it is possible to easily change the energy of the output beam.