Perspectives in linear accelerator for FLASH VHEE: Study of a compact C-band system

Area of Science:

• Medical Physics
• Accelerator Physics
• Radiation Oncology

Background:

• The FLASH effect, characterized by ultra-high dose rate (UHDR) radiation delivery, shows potential for improved cancer treatment with reduced normal tissue toxicity.
• Translating the FLASH effect to clinical practice, particularly for deep-seated tumors, necessitates advanced radiation delivery techniques like Very High Electron Energy (VHEE) irradiations.

Purpose of the Study:

• To address the design challenges of a VHEE FLASH machine for clinical applications.
• To present preliminary design and simulation results for a compact C-band VHEE linear accelerator system.

Main Methods:

• The proposed VHEE linac design incorporates a low-energy, high-current injector followed by a high-gradient accelerating structure.
• RF parameters were defined using CST simulations, and beam dynamics were optimized with TSTEP and ASTRA codes.
• An energy pulse compressor option was considered to achieve the maximum energy range of 60-160 MeV.

Main Results:

• Simulations indicate the VHEE linac design meets criteria for FLASH radiotherapy.
• Preliminary results demonstrate the capability to achieve a maximum energy of 160 MeV.
• The system is projected to deliver a peak current of 200 mA, corresponding to a charge of 600 nC per pulse.

Conclusions:

• A promising preliminary design for a VHEE linac suitable for FLASH radiotherapy has been developed.
• Further studies are underway to fully characterize the machine and to develop and test RF prototypes.