Backed by two new studies published in the January issue of the International Journal of Radiation Oncology•Biology•Physics (Red Journal), the American Society for Radiation Oncology's (ASTRO) official scientific journal, researchers are looking at this beam radiation therapy as safe and effective.
During treatment, a particle accelerator is used to target the tumor with a beam of protons. These charged particles damage the DNA of the targeted cancer cells which either destroys it or negates its proliferation. Cancerous cells are particularly vulnerable to attacks on the cell's DNA because of its high rate of division and its reduced abilities to repair the damage to its DNA.
Protons have little lateral side scatter in the tissue, Because of this the beam does not broaden much and stays focused on the target shape and delivers only low-dose side-effects to the surrounding tissue. All protons of a given energy have a certain range that very few protons penetrate beyond that distance. The dose delivered to tissue is maximum just over the last few millimeters of the particle’s range which is called the Bragg peak.
To treat cancerous tumors at deeper levels, the proton particle accelerator must produce a proton beam with higher energy. Cancer tumors closer to the surface of the body are treated using protons with lower energy. The accelerators used for proton therapy typically produce protons with energies in the range of 70 to 250 MeV (Mega electron Volts or million electron Volts). By adjusting the energy of the protons during application of treatment, the cell damage due to the proton beam is maximized within the tumor itself. Tissues closer to the surface of the body than the tumor receive reduced radiation, and therefore reduced damage. Tissues deeper within the body receive very few protons so that the dosage becomes immeasurably small.
