Simulation study of protoacoustics as a real-time in-line dosimetry tool for FLASH proton therapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Acoustic Physics

Background:

• FLASH radiation therapy offers effective cancer treatment with improved normal tissue sparing.
• A need exists for dosimeters capable of measuring high instantaneous doses in vivo during FLASH therapy.
• Protoacoustics emerges as a promising in vivo range verification method with submillimeter accuracy.

Purpose of the Study:

• To demonstrate the feasibility of protoacoustics for real-time in vivo monitoring during FLASH proton therapy.
• To investigate protoacoustic signal characteristics by varying dose per pulse and pulsewidth.
• To assess the potential of protoacoustics for dosimetry in FLASH proton therapy.

Main Methods:

• Proton beam dose distribution calculated using Monte Carlo TOPAS simulations.
• Protoacoustic simulations performed using k-Wave toolbox in MATLAB to model acoustic propagation.
• Simulations varied dose per pulse and pulsewidth to analyze temporal and spatial resolution of reconstructions.

Main Results:

• Consistent linearity observed between increasing dose per pulse and protoacoustic signal, even at FLASH rates.
• Protoacoustic signal characteristics were analyzed for pulsewidths ranging from 0.1 to 10 μs.
• Successful 3D reconstruction with an 8 cm × 8 cm array demonstrated distinguishable beam spots, indicating potential for in vivo dosimetry.

Conclusions:

• Simulation study verifies protoacoustics as a viable method for FLASH therapy monitoring.
• Protoacoustics provides essential data for varying dose per pulse and pulsewidth, enabling 2D and 3D reconstructions.
• The findings support further exploration of protoacoustics in clinical settings for real-time dosimetry during patient treatment.