Traditional radiation therapy affects everything in its path, so doctors have to limit the dose delivered to the tumor in order to minimize damage to surrounding healthy tissue. With proton therapy, the beam is accelerated to specific energies that determine how deeply in the body protons will deposit their maximum energy.
Protons enter the body with a low dose of radiation, which increases when the beam slows down within the designated target tumor and then protons stop. Compared to an X-ray beam, a proton beam has a low “entrance dose” (the dose delivered from the surface of the skin to the front of the tumor), a high dose designed to cover the entire tumor and no “exit dose” beyond the tumor.The combined effect is greater precision in targeting the tumor with a more potent dose of radiation. The accuracy of proton therapy for treatment delivery is within approximately one millimeter.
Pencil Beam Scanning
Pencil beam scanning, also known as spot scanning, has the ability to treat the most complex of tumors, while leaving healthy tissue and critical structures untouched. Powerful scanning magnets direct thousands of ultra-fine proton beams from multiple directions toward the tumor, creating a “U” shape around healthy tissue and avoiding sensitive areas entirely during treatment. Intricate treatment planning allows the protons to deposit their potent dose of radiation to the exact dimensions of the tumor. Side effects common after radiation therapy are reduced and healthy organs are preserved because the radiation is confined to the tumor.