Compact GaToroid – Further Developments in Streamlined Particle Therapy Gantries

By Amedeo Habsburg

As this newsletter has highlighted over the past year, interest in particle therapy is growing rapidly. You may remember our first article concerning the GaToroid gantry and its first demonstrator magnet. Well, the innovative team behind the technology has continued to push their gantry’s limits and have designed a compact toroidal gantry for directing Very High Energy Electrons (200 MeV) and protons (70-90 MeV). Like its bigger brother, the compact GaToroid is a fixed 360-degree magnetic configuration, allowing it to take advantage of stereotaxis beam delivery, opening opportunities for highly effective FLASH treatments.

Traditional gantries, which rotate to direct particle beams, struggle to keep up with the rapid dose delivery required for certain treatments due to their size and complexity. The GaToroid’s fixed 360-degree, axis-symmetric design resolves this issue, enabling simultaneous beam delivery from multiple angles with static magnets, whilst benefiting from a significantly reduced size profile that enhances installation flexibility.

Simultaneous beam delivery will potentially allow clinicians to irradiate a patient in under 200 ms from multiple angles, capitalizing on the FLASH effect. Ultimately, this approach can spare significantly more healthy tissue surrounding cancerous tumors.

The system uses iron-dominated toroidal and superferric magnets, as well as, novel components such as a resonant kicker, which steers beams quickly and efficiently into the desired direction. Furthermore, the gantry is designed with toroidal quadrupoles and sets of bending magnets for precise beam shaping and delivery. This should allow the system to support high-energy electron beams (200 MeV) and proton beams (70-90 MeV), ensuring versatile capabilities for cancer irradiation.

Compact GaToroid’s magnets exhibit key specifications tailored to their function. The toroidal quadrupoles are designed with an aperture diameter of 58 mm and gradients up to 16.4 T/m, ensuring precise beam shaping. The bending magnets provide a dipole strength of 1.47 T and are crafted to minimize flux leakage. This integration of magnetic properties enables the system to maintain homogeneity and stability during operation.

With a conceptual design created, the GaToroid team would like to push their initiative forward. The next steps for the team are both a superferric dipole in the range of 3 T, as well as a possible collaboration with Dutch institutes for a gantry demonstrator. With a push in this field, CERN can contribute to the next generation of cancer treatments and pave the way for better healthcare.