Development of In situ Dosimetry for FLASH Proton Radiotherapy via Organic Scintillating Fibers

Area of Science:

• Medical Physics
• Radiotherapy Technology

Background:

• FLASH radiotherapy offers potential advantages over conventional radiation therapy.
• Accurate real-time dosimetry is critical for ensuring patient safety and optimizing treatment delivery in advanced radiotherapy techniques.

Purpose of the Study:

• To design, develop, and test a proof-of-concept dosimetry device for FLASH radiotherapy.
• To evaluate the device's capability for real-time dose monitoring and beam pulse resolution.

Main Methods:

• The dosimetry system utilizes organic scintillating fibers coupled to silicon photomultipliers (SiPMs).
• An FPGA-based readout system was implemented, with optimized fiber geometry to minimize proton beam perturbation.
• Device performance was evaluated using X-ray units and proton irradiations at the Huntsman Cancer Institute (HCI).

Main Results:

• The device demonstrated a strong correlation between integrated charge and delivered dose (up to ~35 mrem/s).
• The detector exhibited nanosecond response times, suitable for rapid safety interlock triggering.
• Preliminary irradiations confirmed the ability to resolve individual proton beam pulses.

Conclusions:

• The developed dosimetry device shows promise for real-time dose and pulse monitoring in FLASH radiotherapy.
• Further refinement of the experimental setup and electronics is needed for full implementation.
• The device's capabilities are valuable for both FLASH and conventional radiotherapy research.