Evaluation of an electron Monte Carlo dose calculation algorithm for treatment planning

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Dosimetry

Background:

• Accurate dose calculation is crucial for effective radiation therapy.
• Electron Monte Carlo (eMC) algorithms offer potential for improved accuracy over traditional methods.
• Evaluating algorithm performance in diverse clinical scenarios is essential.

Purpose of the Study:

• To assess the accuracy of a commercial electron Monte Carlo (eMC) dose calculation algorithm.
• To compare eMC algorithm performance against an electron pencil beam algorithm.
• To validate eMC calculations in simple and complex clinical geometries.

Main Methods:

• Experimental measurements in homogeneous and inhomogeneous phantoms (water, solid, anthropomorphic).
• Comparison of depth-dose curves, beam profiles, and output factors.
• Evaluation of algorithm parameters (seed, grid size) and calculation time.
• Clinical case study of nose cancer with air cavities.

Main Results:

• eMC calculations demonstrated high accuracy in water phantoms (under 2.5% dose difference, 2 mm distance to agreement).
• Agreed within 2% and 4% for small air cylinder and lung phantoms, respectively.
• Showed positive agreement in chest wall and anthropomorphic phantoms.
• Identified up to 20% dose difference in a clinical case with air cavities compared to pencil beam.

Conclusions:

• The eMC algorithm is highly accurate for dose calculation in various phantom geometries.
• eMC significantly outperforms the pencil beam algorithm in predicting dose perturbations caused by inhomogeneities.
• eMC is a more accurate tool for clinical dose calculations, particularly in complex scenarios.