Monte Carlo Simulation of Siemens ONCOR Linear Accelerator with BEAMnrc and DOSXYZnrc Code

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Dosimetry

Background:

• Linear accelerators (linacs) are essential in radiation therapy.
• Accurate simulation of linac output is critical for patient safety and effective treatment.
• Monte Carlo methods offer high precision for simulating radiation therapy equipment.

Purpose of the Study:

• To perform Monte Carlo modeling of the Siemens ONCOR linear accelerator.
• To validate simulation results with experimental measurements.
• To assess the accuracy of Monte Carlo simulations for clinical applications.

Main Methods:

• Utilized BEAMnrc for head simulation and DOSXYZnrc for dose calculation.
• Validated simulations using ionization chamber and EDR2 film measurements in solid water.
• Analyzed simulation data with a custom MATLAB program.

Main Results:

• Monte Carlo modeling achieved high agreement with measurements (within 1-2%) for 6 MV and 18 MV beams.
• Excellent agreement was observed, even in the build-up region, for the 6 MV beam.
• Small mean differences indicate the accuracy of the simulation for both energies.

Conclusions:

• Monte Carlo simulations provide highly accurate data for the Siemens ONCOR linac.
• Validated simulations can be reliably used for patient dose calculations.
• The methodology is suitable for modeling small field sizes used in techniques like intensity-modulated radiation therapy.