In proton/ion therapy, a proton/ ion beam is used for treatment. Unlike photons, proton/ ion beams deposit their maximum dose at a certain depth in the body, which reduces the dose to healthy tissues around the tumor / cancerous tissue. The position where the proton /ion beam deposits its maximum dose is known as the Bragg peak. How depth the Bragg peak occurs in the patient’s body depends on the energy of the proton / ion beam. The higher the energy of the proton / ion, the more proton / ion penetrates the body and the Bragg peak places in more penetration depth. Magnetic dipoles are used to superficially irradiation to the tumor/ cancerous tissue so that they can irradiate the entire tumor surface with proton/ ion beams. As a result, in order to achieve a homogenous dose to the tumor / cancerous tissue of a certain volume, a rapid sequence of large amounts of proton / ion beams is combined with different amounts of energy and position. In addition to the ability to reposition the Bragg peak, the intensity of the proton/ion beams can also be adjusted that the more ability of adjusting the dose distribution be feasible according to the shape of the tumor / cancerous tissue.
In order to create an optimal dose-volume compromise in tumor tissue and to minimize the dose reached to healthy tissue, therapeutic beams are applied to the tumor at several different angles.