China International Youth Conference on Electrical Engineeing (CIYCEE 2025)

Compact gantry systems are critical for minimizing the footprint and cost of proton therapy facilities. This study presents the design and evaluation of a compact proton therapy gantry that utilizes a short source-to-axis distance (SAD) downstream scanning configuration along with high-field magnets made of FeCo alloy. Multi-objective beam optics optimization, which was carried out with COSY-INFINITY code and NSGA-III algorithm, enabled achromatic transport and sub-5.5 mm (2σ) beam spots at the isocenter. Dipole magnets are designed using FeCo alloy with a high saturation flux density. This allows the bending radius to be reduced to 1.35 m while lowering magnet and gantry weight, with field uniformity maintained below 0.0281%. These results demonstrate the feasibility of a lightweight and compact gantry scenario, offering a practical solution for miniaturized proton therapy facilities.

Compact gantry,FeCo alloy Magnet,Beam optics,Proton therapy