Dosimetric Characterization and Workflow Optimization of the FLASH-SARRP for Reliable Preclinical Radiobiological...

Area of Science:

• Medical Physics
• Radiation Oncology
• Preclinical Research

Background:

• The FLASH-SARRP preclinical irradiator is vital for advancing photon-FLASH radiotherapy towards clinical application.
• Robust quality assurance (QA) is essential for accurate and reproducible preclinical experiments in FLASH radiotherapy.

Purpose of the Study:

• To characterize the FLASH-SARRP system.
• To establish a comprehensive QA workflow for reproducible preclinical FLASH irradiations.

Main Methods:

• Utilized custom 3D-printed spacers for precise alignment of X-ray tubes and sample positioning.
• Employed Gafchromic films for high-resolution dose distribution mapping.
• Used a plastic scintillating fiber for real-time monitoring of temporal pulse structure and synchronization.
• Evaluated day-to-day delivery variability over multiple sessions.

Main Results:

• Achieved dose rates of approximately 80 Gy/s with simultaneous dual-tube operation, creating a homogeneous field for small animals.
• Identified a 10 ms desynchronization between X-ray tubes, causing temporal dose-rate heterogeneity.
• Observed substantial inter-session variability (~11%) compared to low intra-session variability (~4%).
• Reduced inter-session variability to 5% by integrating a QA workflow with Gafchromic films and scintillators.

Conclusions:

• Temporal dosimetry is critical for preclinical FLASH studies.
• A practical QA framework combining real-time monitoring and reference dosimetry enhances irradiation reproducibility.
• The proposed framework supports adaptive dose delivery, essential for reliable preclinical investigation of the FLASH effect.