Optimization and fabrication of a novel 3D-printed variable density range modulation device for proton FLASH beams

Area of Science:

• Medical Physics
• Radiation Oncology
• 3D Printing Technology

Background:

• Proton FLASH therapy utilizes range-modulating devices to create spread-out-Bragg-peaks (SOBPs) for ultrafast radiation delivery.
• Current range modulators have limited structural stability and modulation flexibility due to uniform density designs.

Purpose of the Study:

• To introduce a new class of 3D-printed range-modulating devices for particle therapy featuring spatially modulated density.
• To enable greater flexibility and stability in creating SOBPs for advanced radiation treatments.

Main Methods:

• Utilized PixelPrint technology for 3D printing variable density range modulators by controlling filament-to-air ratios.
• Developed an inverse optimization algorithm to generate density maps for SOBP creation.
• Verified device performance using Monte Carlo simulations (MCsquare) and measured range modulation with a multi-layer ionization chamber (MLIC).

Main Results:

• Successfully generated density distributions for multiple SOBP widths using the optimization framework.
• Monte Carlo simulations confirmed the accuracy of SOBP width and flatness.
• MLIC measurements validated the accuracy of the produced SOBPs across various proton beam energies.

Conclusions:

• A novel variable density range-modulating device for proton therapy was successfully developed and validated.
• These 3D-printed devices offer potential for easier handling and significantly faster proton therapy treatment delivery.