EFFECT OF INTENSE MAGNETIC FIELDS ON THE TRAJECTORY OF ELECTRONS PROPAGATING IN LOW DENSITY MEDIA OF INTEREST FOR MRI-LINAC RADIOTHERAPY

Abstract

Ionizing radiation transport mechanisms in presence of magnetic fields can be described in terms of formalisms based
on the Boltzmann radiation transport equation. However, when the transport occurs not in vacuum but in scattering
media the difficulty of its analytical calculation considerably increases because of the random character of the radiation
interaction processes with the scattering medium. In this context, the present work proposes and describe a methodology
to characterize effects due to strong magnetic fields on electron trajectories by means of numerical techniques, such as
Monte Carlo simulation, to be applied to scattering media, typically present in MRI-LINAC devices in radiotherapy
situations. The obtained results for air as the scattering material show that variations of the electrons’ trajectories
depend jointly on the magnetic field and the interactions with the scattering medium. Increasing the magnetic field
intensity enhances the curvature of the trajectories while decreasing the displacement in the radial direction.