Technical challenges for FLASH proton therapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Accelerator Technology

Background:

• FLASH radiotherapy, delivering radiation doses in less than one second, is gaining attention for potentially sparing healthy tissues.
• Pre-clinical studies suggest FLASH radiotherapy preserves its tumor-damaging effects while reducing damage to healthy cells compared to conventional methods.
• The FLASH effect has also been observed in proton therapy, indicating its potential applicability in this field.

Purpose of the Study:

• To explore the technical challenges and potential solutions for implementing FLASH proton therapy.
• To identify key areas for technological advancement required for clinical translation of FLASH proton therapy.

Main Methods:

• Review of existing accelerator technology and beam delivery systems for proton therapy.
• Analysis of technical requirements for achieving high dose rates and rapid beam scanning.
• Consideration of hybrid systems incorporating 3D-printed components for dose modulation.

Main Results:

• Increasing average beam current to over 100 nA is feasible with current technology.
• Rapid energy adjustments (milliseconds) and significantly faster pencil beam scanning (two orders of magnitude) present major challenges.
• Hybrid systems with patient-specific range modulators are a likely path to clinical implementation.

Conclusions:

• Significant advancements in accelerator technology, particularly in beam scanning speeds and dosimetry, are necessary for FLASH proton therapy.
• Further pre-clinical research is crucial to define the optimal beam parameters for eliciting the FLASH effect.
• Hybrid systems and continued technological development are key to realizing clinical FLASH proton therapy.