Monte carlo simulation of radiation of the beta emitting sources in a magnetic field

Purpose: Following the assumption of reducing the damage to the normal tissues using magnetic field in the cancer treatment carried out by beta-emitting radioisotopes behaviour of beta particles under the magnetic field was investigated with Greant4 simulation program with Monte Carlo basis.Material and Methods: A water-filled spherical medium in which radiation would be detected was formed in Greant4 program and a particle source, in which beta particles had single energies and would be launched randomly, was placed into its center. After applying a homogenous magnetic field in the x direction, cross-sections were formed in the y axis according to the range of the particle from the center of the sphere. In magnetic fields of different magnitudes (0-3 Tesla), the data obtained for beta particles of different energies (0,5-2 MeV) were analyzed counting the interaction numbers of the particles in each cross section by Matlab program.Results: The range of the beta particle from the source was observed to increase in direct proportion to its energy. Maximum ranges of the beta particles are approximately 1,5, 4, 6 and 8 mm for betas with 0,5, 1, 1,5 and 2 MeV respectively. Interaction number decreased exponentially further away from the center. With the increase of the magnetic field, the interaction number at the center was increased, but the interaction number decreased the center inversely proportional to magnetic field. The change perpendicular to the magnetic field is greater compared to parallel to the magnetic field.Conclusion: Beta particles were observed to go forward with circular moves in the magnetic field and to have their range shortened when magnetic field is increased. It was found that beta particles from the point source scattered to random directions spherically in the medium and the geometry became elliptical in magnetic field. When magnetic field increases, the change towards the center becomes more pronounced in perpendicular directions to magnetic field. The effect of magnetic field was more explicit for beta particles with high energies than these with low energies.Key words: Beta radiation, magnetic field, Monte Carlo Simulation, Geant4