Development of a dose verification system for Vero4DRT using Monte Carlo method.

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Computational Dosimetry

Background:

• The Vero4DRT is an advanced image-guided radiotherapy system.
• Accurate modeling of radiotherapy systems is crucial for precise dose delivery.
• Monte Carlo (MC) simulations offer high fidelity in modeling radiation transport.

Purpose of the Study:

• To develop and validate specific MC models for the Vero4DRT linac head and multileaf collimator (MLC).
• To assess the accuracy of these MC models against experimental measurements.
• To ensure reliable dose calculations for clinical applications using the Vero4DRT.

Main Methods:

• EGSnrc-based MC code was used to simulate a 6 MV photon beam from the Vero4DRT.
• Linac head and MLC models were created based on system specifications.
• Simulations included percent depth dose (PDD), beam profiles, and MLC leakage.
• Results were compared with ionization chamber and film (EDR2) measurements.

Main Results:

• Simulated PDD for the linac head agreed within 1.0% of measurements.
• Beam profiles showed agreement within 1.3%.
• MLC models reproduced static test dose measurements within 2.5%.
• Step-and-shoot IMRT dose distributions agreed within 3.3% of film measurements.

Conclusions:

• Specific MC models for the Vero4DRT linac head and MLC were successfully developed.
• The validated MC models demonstrate high accuracy for dose calculations.
• These models are suitable for precise radiotherapy planning and delivery with the Vero4DRT system.