CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma...

Area of Science:

• Medical Physics
• Computational Physics

Background:

• Accurate simulation of medical linear accelerators is crucial for radiation therapy.
• Geant4 is a widely used toolkit for simulating particle transport, but its physics models require careful validation.

Purpose of the Study:

• To validate the GAMOS/Geant4 simulation model for a 6 MV Varian Clinac 2100 C/D linear accelerator.
• To optimize Geant4 physics models and parameters for accurate dose distribution simulation.

Main Methods:

• Adjusting initial beam parameters to match experimental percentage depth dose and cross-profile dose data in a water phantom.
• Utilizing a wide range of field sizes (2x2 cm² to 40x40 cm²) and high statistics for precise parameter determination.
• Comparing Standard, Livermore, and Penelope electromagnetic physics models in Geant4, including various bremsstrahlung and multiple-scattering models.

Main Results:

• Achieved fine precision in determining beam parameters through experimental data fitting.
• Identified optimal Geant4 electromagnetic physics models and parameters for the Varian accelerator.
• Demonstrated the effectiveness of CPU time optimization techniques within GAMOS and Geant4.

Conclusions:

• The validated GAMOS/Geant4 model provides a reliable tool for simulating the Varian Clinac 2100 C/D.
• The study highlights the importance of careful selection and optimization of Geant4 physics models for accurate clinical simulations.
• Optimized simulation parameters contribute to improved efficiency in radiation therapy planning.