Protons, unlike X-rays, advance a certain distance into the body, then abruptly release high energy to the surrounding area and immediately disappear.

By making use of this property (the Bragg peak), characteristics such as the dose level can be adjusted so as to release concentrated high energy to cancer cells while reducing the energy released to surrounding healthy cells.

High therapeutic effectiveness can be anticipated by means of high-dose irradiation pinpointed at cancer cells, and reduced damage to healthy tissue also becomes possible, enabling treatment that keeps risk of growth and developmental disorders, secondary cancers, and other late-onset complications to a minimum.