Proton Radiation Therapy for Treatment of Cancer
Proton radiation therapy is a kind of particle therapy which uses a beam of protons in the treatment of cancer to remove diseased tissues. The best advantage of proton therapy is its ability to precisely localize the radiation dosage as compared to other types of external beam radiotherapy.
The proton therapy began to develop in the 1950s. In a typical treatment plan for proton therapy, Spread Out Bragg Peak (SOBP) defines the therapeutic radiation distribution. SOBP is the aggregate of several pristine Bragg peaks at staggered depths.
This is a type of external beam radiotherapy that uses ionizing radiation. During the treatment, a particle accelerator is used. This is used to target the tumor with a beam of protons. These charged particles damage the cancerous cells and stop them from reproducing.
Protons have relatively large mass and little lateral side scatter in the tissue. These beams do not scatter much, stay focused and deliver small dose side effects to surrounding tissues. Protons of a given energy have a defined range. These protons generally do not penetrate beyond that range. The total radiation dosage of the protons is defined as the Spread-Out Bragg Peak (SOBP).
The proton accelerator produces beams with higher energy to treat tumors at great depths. The tumors that are close to the surface of the body can be treated using protons with lower energy. The protons have energies in the range of 70 to 250 Mega electron Volts. The energy of the protons is adjusted during the treatment so that the cell damage due to the proton beam is maximized within the tumor itself. The tissues that are closer to the surface of the body receive radiation dosage based on the SOBP. Tissues that are deeper within the body receive few protons and so the dose becomes small.