Comparative analysis of eMC algorithm dose calculations using GATE validation: impact of tissue heterogeneity on...

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Dosimetry

Background:

• Electron beam radiotherapy is vital for superficial tumors.
• Accurate dose calculation is critical for treatment efficacy and safety.
• Full Monte Carlo (MC) simulations offer high accuracy but are computationally intensive.

Purpose of the Study:

• To compare the accuracy of the electron Monte Carlo (eMC) algorithm with full MC simulations for electron beam dose calculations.
• To evaluate eMC performance in homogeneous and heterogeneous phantom environments.

Main Methods:

• Dose distributions from eMC in a treatment planning system (TPS) were compared to full MC simulations (GATE).
• Evaluations were performed using various electron energies (6-12 MeV) and field sizes.
• Both homogeneous water and heterogeneous phantoms (lung, bone) were used.

Main Results:

• eMC showed good agreement with GATE in homogeneous phantoms, with minor discrepancies.
• Significant deviations were observed in heterogeneous phantoms, especially near density interfaces and at higher energies.
• Accuracy decreased considerably in complex, heterogeneous environments.

Conclusions:

• The eMC algorithm has limitations in accurately modeling complex tissue heterogeneities.
• eMC is acceptable for simple scenarios but less reliable in clinically realistic heterogeneous environments.
• Caution is advised for eMC in treatment planning; improved algorithms are needed.