Machine Description File-based Monte Carlo Simulation Modeling and its Validation Using Pencil Beam Scanning Proton...

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Biology

Background:

• Proton pencil beam scanning (PBS) offers precise radiation delivery.
• Accurate dose modeling is crucial for effective proton therapy.
• Independent Monte Carlo (MC) engines require rigorous validation with clinical data.

Purpose of the Study:

• To model and validate an independent MC dose engine using machine description file (MDF) data.
• To assess the operational parameters and clinical applicability of the validated model.
• To compare modeling results with treatment planning system (TPS) outputs.

Main Methods:

• Commissioning of a Proteus Plus PBS machine using calibrated detectors.
• Modeling of beam parameters (energy spread, spot tuning) in RayStation TPS and TOPAS MC.
• Validation using 36 spread-out Bragg peak plans and five patient-specific quality assurance (PSQA) plans.
• Evaluation of range, modulation, dose fall-off, and lateral profiles.

Main Results:

• Strong agreement between modeled and measured data.
• Over 95% of PSQA cases met gamma passing criteria (3%/3 mm).
• Discrepancies in heterogeneous tissues were within 0.5% of range uncertainty.

Conclusions:

• MDF-based MC modeling and validation is robust for clinical proton therapy.
• The validated TOPAS MC model supports research and quality assurance.
• Methodologies enhance patient-specific treatment planning and proton therapy advancements.