Development and validation of a TOPAS Monte Carlo model for a 0.5 T bi‐planar Linac‐MR

The developed TOPAS MC model of the 0.5 T Linac-MR demonstrates high accuracy for dose verification in magnetic fields. The MLC module, including its coordinate positioning mechanism, is fully validated for open aperture applications. This MC model provides a reliable framework for dose simulations in a magnetic field.