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Why can proton beam therapy reduce long-term radiation effects in children?

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linear accelerator; external beam radiation therapy — radiation therapy External beam radiation therapy (also known as external beam teletherapy, or long-distance therapy) being delivered using a machine known as a linear accelerator.

Proton beam therapy reduces long-term radiation effects in children primarily because of its unique physical properties, which allow for more precise targeting of tumors while sparing surrounding healthy tissue.1

Unlike traditional photon radiation, which passes through the body and delivers an "exit dose" to healthy tissues beyond the tumor, proton beams deposit the majority of their energy at a specific depth known as the Bragg peak. Beyond this peak, the radiation dose drops rapidly to zero.1

This absence of an exit dose is particularly beneficial for pediatric patients, as it minimizes exposure to normal, developing tissues. By avoiding unnecessary irradiation of healthy organs and structures, clinicians can significantly decrease the risk of long-term side effects, such as impaired bone growth, hormonal deficiencies, and secondary malignancies, which are critical concerns when treating children.12