How Does Proton Therapy Work?
Proton therapy is advanced cancer-fighting technology.
Creating Protons: Protons are extracted from hydrogen atoms and accelerated to almost the speed of light using a cyclotron. Electromagnets focus and bend the protons down a beamline to a treatment room.
Precise Targeting: Using images from a patient’s computed tomography (CT) and/or magnetic resonance imaging (MRI), a radiation oncologist and his/her team plan the therapy that directs proton beams at the targeted tumor while minimizing exposure to normal tissues. The gantry rotates around the patient, who is lying on a robotic table, and uses magnets to steer and focus the proton beam to precisely deliver radiation to conform to the shape, size, and depth of the tumor. The protons delivered to the tumor then destroy the cancerous cells, while minimizing damage to the surrounding tissue.
Proton beams can be targeted so that the highest energy of the beam is deposited at the tumor site to kill cancer cells. Less radiation is delivered as the proton beam enters the body and little to no radiation is delivered after it hits the tumor, reducing damage to surrounding healthy tissue and potential acute and late side effects.
Adaptive Treatment Planning: Proton therapy may also utilize ongoing treatment planning based on the most current and accurate “picture” of the tumor possible. Repeat scans during a treatment course assess the changing, shrinking tumor volume. The clinical team may adapt the treatment plan to continue targeting only the tumor to minimize exposure to nearby healthy tissue.
Duration: Treatment sessions typically last for 15-40 minutes with each beam only taking one to three minutes, and the complete course of treatment may be from one to 30 sessions, lasting one day up to nine weeks.
Sources: American Brain Tumor Association, National Association for Proton Therapy, and National Institutes of Health