Overview

Proton therapy is a type of radiation therapy — a treatment that uses high-powered energy to treat cancer and some noncancerous tumors. Radiation therapy using X-rays has long been used to treat these conditions. Proton therapy is a newer type of radiation therapy that uses energy from positively charged particles (protons).

Proton therapy has shown promise in treating several kinds of cancer. Studies have suggested that proton therapy may cause fewer side effects than traditional radiation, since doctors can better control where the proton beams deliver their energy. But few studies have compared proton radiation and X-ray radiation, so it's not clear whether proton therapy is more effective at prolonging lives.

Proton therapy isn't widely available, although new proton therapy centers are being built in the United States and in other countries.