Scientists test faster, gentler proton beams for cancer treatment

Scientists at Brookhaven National Laboratory have tested a novel permanent magnet array designed to improve proton beam cancer therapy by enabling rapid switching across a wide energy range (50 to 250 MeV), the highest energy achieved for such a beamline. This capability allows proton beams to reach tumors at varying depths quickly, facilitating ultra-fast, high-dose "FLASH" treatments that deliver radiation so rapidly healthy tissues adjacent to tumors are better preserved, potentially reducing side effects compared to conventional methods. Unlike traditional proton therapy machines that use electromagnets requiring time-consuming power adjustments to change beam energy, this new design employs fixed permanent magnets arranged in a curved array. The magnetic field strength varies along the arc, allowing proton beams of different energies to follow stable paths simultaneously without needing to adjust magnet power. This innovation supports both high dose rates and rapid energy scaling, overcoming limitations of current systems. Additionally, the compact racetrack-shaped accelerator (about 30 by 10 feet) is small enough to fit in hospital settings, making advanced proton