Clinical implementation of a Monte Carlo based independent TPS dose checking system

Area of Science:

• Medical Physics
• Radiotherapy Physics
• Computational Dosimetry

Background:

• Modern radiotherapy techniques like intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) increase treatment plan complexity.
• Existing secondary dose calculation checking systems often lack the capability to accurately verify these complex plans.
• Monte Carlo (MC) simulation codes, such as EGSnrc, offer high accuracy for complex radiotherapy dose calculations.

Purpose of the Study:

• To demonstrate a fully automated system for performing and analyzing MC dose calculations for conformal, IMRT, and VMAT radiotherapy plans.
• To evaluate the accuracy and clinical workflow integration of this automated MC system for secondary dose verification.
• To compare the accuracy of MC calculations against traditional secondary check systems and the treatment planning system (TPS).

Main Methods:

• Development and implementation of an automated system using BEAMnrc/DOSXYZnrc for MC calculations.
• Integration with a Python-based web interface for DICOM data upload or a monitored network location for automated plan processing.
• Analysis of MC results through automated dose point comparison reports and re-import into the TPS.

Main Results:

• The automated MC system demonstrated improved agreement with the TPS compared to RadCalc, with differences of 0.1-1.7% for MC vs. 1.2-5.5% for RadCalc.
• Dose-volume histogram (DVH) parameters for VMAT plans showed good agreement, with mean planning target volume dose within acceptable clinical margins.
• The system integrated well into existing clinical workflows, proving valuable for secondary plan checking.

Conclusions:

• An automated Monte Carlo system provides a valuable and accurate tool for secondary dose verification of complex radiotherapy plans (IMRT, VMAT).
• This system enhances the safety and reliability of radiotherapy treatment planning by improving the accuracy of dose calculation checks.
• The demonstrated workflow integration suggests practical clinical applicability and potential for widespread adoption in radiotherapy departments.