A proton beam energy modulator for rapid proton therapy

Area of Science:

• Medical Physics
• Accelerator Physics

Background:

• Proton therapy requires precise control of proton beam energy for targeted radiation delivery.
• Traditional mechanical energy degraders are slow and limit treatment speed.
• Advancements in accelerator technology can potentially overcome these limitations.

Purpose of the Study:

• To design a rapid proton energy modulator utilizing radiofrequency accelerator cavities.
• To achieve faster proton dose delivery to varied depths in human tissues.
• To provide a viable alternative to mechanical beam energy degraders.

Main Methods:

• Design of a multi-cell, 1-m long accelerator operating at 2.856 GHz.
• Utilizing compact klystrons to power individual cavities, achieving a 30 MV/m gradient.
• Conducting beam dynamics simulations for energy modulation and spread analysis.

Main Results:

• The modulator demonstrated a ±30 MeV beam energy change capability for a 150 MeV proton bunch.
• A total energy spread of 3 MeV was achieved, meeting clinical requirements.
• Prototype single-cell experiments validated simulation results with low-power microwave measurements.

Conclusions:

• The designed radiofrequency accelerator cavity system offers a rapid proton energy modulation solution.
• This technology promises significantly faster proton radiation therapy delivery.
• The approach is adaptable for various beam energies, including optimized performance for 150 MeV cyclotron beams.