Radiation Therapy and Proton Therapy are both used to treat cancer. They have similar aims of delivering high doses of radiation to the tumour while minimizing dose to the normal tissues.
So what makes them different?
Proton beam has a unique characteristic called the “Bragg peak”, which enables emission of the highest radiation dose at the set depth. Thus, we are able to control the proton beam to deposit a large focused amount of radiation right into a tumour. In proton therapy, the shape and depth of the ‘Bragg peak’ are precisely controlled to conform to the shape and size of a tumour, which enables radiation oncologists to provide a focused treatment on the targeted area.
Unlike proton therapy, conventional radiation therapy uses photons which enter the body and deposit most of its energy in normal tissues near the body surface, and then the energy reduces as it goes towards the center of the body. The photons also continue to pass through the tumor and release some radiation to the healthy tissue behind the tumour. This undesirable pattern of energy placement can result in unnecessary damage to healthy tissue, thus increasing the side effects experienced by the patient.