Benchmarking of the dose planning method (DPM) Monte Carlo code using electron beams from a racetrack microtron

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Dosimetry

Background:

• Accurate dose calculation is critical for effective radiation therapy.
• Monte Carlo methods offer high precision in simulating radiation transport.
• The Dose Planning Method (DPM) is a Monte Carlo code used for treatment planning.

Purpose of the Study:

• To investigate the accuracy of the DPM Monte Carlo code for dose calculations.
• To evaluate DPM's performance with scanned electron beams from a racetrack microtron.
• To compare DPM calculations with experimental measurements in a water phantom.

Main Methods:

• Measurements of central axis depth dose and beam profiles were performed using an ion chamber in a water phantom.
• Source spatial distributions were reconstructed from in-air ion chamber measurements.
• Energy spectra were determined by simulating the microtron treatment head using MCNP4B.
• DPM calculations were compared against experimental data.

Main Results:

• In-air spatial distributions (FWHM) were 4.7 cm for 10 MeV and 1.3 cm for 50 MeV beams at 100 cm.
• DPM calculations demonstrated an average agreement within +/- 2% with measurements.
• This agreement was consistent across all depth dose and profile comparisons.

Conclusions:

• The DPM Monte Carlo code accurately calculates doses for scanned electron beams.
• DPM's validated accuracy supports its use as a reliable tool in treatment planning.
• This study confirms DPM's potential for precise electron beam dosimetry.