In electron radiation therapy, conforming the radiation dose to the tumor is important, yet challenging due to electron scatter by air molecules. The conventional approach involves placing a fixed metal collimator near the patient’s skin to block scattered radiation, providing a static treatment. This study explores the dosimetric impact of magnetic fields on therapeutic electron beams and the potential application of magnetic fields in modulated electron radiation therapy (MERT). Employing Monte Carlo methods, we developed experimentally validated source models with electron beams shaped by the multileaf collimator. Additionally, we calculated magnetic field maps for specific coil configurations and devised a method to implement non-uniform magnetic fields into PENELOPE, a Monte Carlo code system for radiation transport. Our approach facilitates easy evaluation of different coil-generated magnetic fields. Our framework was used to study the impact of magnetic fields generated by solenoids on realistic electron beams. This showed that while simplistic simulations using uniform magnetic fields and mono-directional electron sources show promising results, simulations with realistic electron beams and the magnetic field generated by a solenoid reveal the complexities involved in maintaining electron fluence within realistic magnetic fields. Overall, this work lays the foundation for potential advancements in the application of magnetic fields in electron radiation therapy, underscoring the importance of accurate simulations when exploring innovative treatment modalities.