University of Wisconsin researchers have proposed a system that may one day bring proton therapy, a state-of-the-art cancer treatment method currently available only at a handful of centers, to radiation treatment centers and cancer patients everywhere.

Compared to the x rays conventionally used in radiation therapy, protons are potentially more effective, as they can deposit more cell-killing energy in their tumor targets and less in surrounding healthy tissue. However, to kill tumors, the protons must be accelerated to sufficiently high energies, which currently must be achieved in large, expensive devices called cyclotrons or synchrocyclotrons that cost hundreds of millions of dollars and occupy a room the size of basketball courts.

The proton-therapy design is based on a much smaller device known as a “dielectric wall accelerator” (DWA). The DWA, currently being built as a prototype at Livermore, can accelerate protons to up to 100 million electron volts in just a meter. A two-meter DWA could potentially supply protons of sufficiently high energy to treat all tumors, including those buried deep in the body, while fitting in a conventional radiation treatment room.