Enhancing Tissue Equivalence in ⁷Li Heavy Ion Therapy with MC Algorithm Optimized Polymer-Based Bioinks

Area of Science:

• Medical Physics and Radiation Oncology
• Biomaterials Science
• Computational Physics

Background:

• Heavy ion beams are crucial in tumor therapy due to their precise dose distribution.
• Accurate dosimetry requires phantoms mimicking human tissue, with polymers being promising substitutes.
• Understanding beam interactions with biomaterials is essential for safe and effective heavy ion therapy.

Purpose of the Study:

• To investigate the physical and interaction properties of polymeric biomaterials for heavy ion therapy.
• To evaluate tissue-equivalent characteristics of polymers using lithium-ion beams.
• To identify suitable polymer biomaterials for radiological phantom construction in heavy ion treatment planning.

Main Methods:

• Utilized Monte Carlo Transport of Ions in Matter (Moliere) simulation.
• Simulated interactions of 7Li (lithium-ion) beams with polymer biomaterials.
• Analyzed ionization, recoils, phonon release, collision events, and lateral straggle.

Main Results:

• Polymethylmethacrylate (PMMA) demonstrated a Bragg peak position with a 7.3% difference compared to soft tissue.
• Average values for recoils, collision events, and lateral straggle were 10.5%, 33%, and 22.6%, respectively.
• Secondary interactions and linear energy transfer (LET) were analyzed for the 7Li beam.

Conclusions:

• Polymeric biomaterials, particularly PMMA, show potential as tissue-equivalent materials for heavy ion therapy.
• The study provides insights into secondary particle interactions and energy deposition relevant to treatment.
• This research aids in selecting optimal polymer biomaterials for constructing phantoms in heavy ion radiotherapy.