What is the main advantage of proton therapy over conventional photon therapy?

Proton therapy offers a significant advantage over conventional photon therapy in terms of better conformity to tumor shape. This is primarily due to the unique physical properties of protons. Unlike photons, which generally deposit energy along their entire path and can continue to affect surrounding healthy tissue even after passing through the tumor, protons are charged particles that have a well-defined range.

When protons enter the body, they deposit minimal energy until they reach a specific depth, known as the Bragg peak, where they release the majority of their energy. This allows clinicians to precisely tailor the radiation dose to match the three-dimensional shape of the tumor, thereby sparing more surrounding healthy tissue from unnecessary radiation exposure. This increased conformity helps to minimize side effects and complications associated with radiation therapy.

In contrast, while factors such as treatment duration, patient discomfort, and radiation dose are relevant to both types of therapy, they do not capture the unique benefit of dose distribution that proton therapy provides, making better conformity to tumor shape the key advantage in this context.