Volumetric FLASH dosimetryin vivousing real-time radiacoustic imaging

Area of Science:

• Medical Physics
• Radiation Oncology
• Biomedical Imaging

Background:

• Ultra-high dose rate FLASH radiotherapy (FLASH-RT) shows promise for reducing normal tissue toxicity.
• Clinical adoption of FLASH-RT is hindered by the lack of real-time, in vivo dosimetry systems.
• Current dosimetry methods cannot resolve dose deposition at the microsecond timescales required for FLASH-RT.

Purpose of the Study:

• To verify the spatial fidelity of Radiacoustic Imaging (RAI) as a quantitative dosimetric tool for FLASH-RT.
• To demonstrate the capability of RAI for in vivo dose monitoring during FLASH-RT.
• To establish RAI as a viable technology for real-time dosimetry in FLASH radiotherapy.

Main Methods:

• Development of an RAI platform for volumetric, single-pulse radiation dose mapping.
• Utilizing a 16x16 ultrasound transducer matrix array and a model-based reconstruction algorithm.
• Generating quantitative 3D dose maps with single-pulse temporal resolution for in vivo FLASH-RT.

Main Results:

• RAI demonstrated high concordance with film dosimetry and TOPAS Monte Carlo simulations.
• Achieved >90% pass rates for 3%/3mm gamma index in water phantoms and murine models.
• Validated the spatial fidelity and quantitative accuracy of RAI for FLASH-RT dosimetry.

Conclusions:

• RAI is established as a viable technology for real-time, quantitative electron FLASH dosimetry in vivo.
• RAI has the potential to support adaptive FLASH-RT delivery and improve treatment safety.
• This work facilitates the clinical translation of FLASH-RT by providing a critical dosimetry solution.