Proton therapy

Proton therapy, also known as proton beam therapy, is a form of radiation therapy used to treat cancer. It selectively targets tumors while preserving healthy tissues and allows for the administration of higher radiation doses, thereby increasing the likelihood of treatment success. Unlike conventional radiotherapy, which uses X-rays or electrons, proton therapy utilizes protons, which are heavier atomic particles with greater energy than electrons, making them more precise and effective. In proton therapy, energy is released at a specific depth within the tissue, corresponding to the so-called Bragg peak.

The use of protons for cancer treatment was first proposed in the 1940s and was experimented with in the 1950s. However, it wasn’t until the 1990s that the first hospital dedicated to this therapy was built in America, at Loma Linda, which remains a global reference point to this day. Since then, more than 60 facilities have been established worldwide, with many others under construction or planned. The number of patients treated worldwide exceeds 130,000.

The Bragg peak is the curve obtained by plotting the energy lost by a particle penetrating matter against the depth it reaches as it progresses. The “peak” shape of protons shows that these particles release most of their energy at the end of their path, and this important characteristic is exploited in medicine to treat tumors without surgery, using the particles as “depth charges.”

Healthcare professionals, by adjusting the energy of the protons, gain control of the proton beam, which thus releases the tumoricidal dose only in the last millimeters of its path, precisely on target.