Why can proton therapy be useful for tumors near the spinal cord?

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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 therapy is particularly useful for treating tumors located near the spinal cord because of the unique way these particles deposit energy within the body.1

Unlike photon radiation, which passes through the body and continues to deliver a dose to healthy tissue beyond the tumor, proton beams exhibit a phenomenon known as the Bragg peak. This allows the radiation to reach a high, uniform dose at the tumor site followed by a rapid falloff to zero dose beyond it.1

Because there is no exit dose, proton therapy minimizes exposure to critical structures like the spinal cord, which are highly sensitive and cannot tolerate high levels of ionizing radiation. This precision helps protect healthy tissues and significantly reduces the risk of long-term side effects.1