Use of Electron Beam under Effect of Magnetic Field to Optimize the Pattern of Prescribed Dose in Patients under Radiation Therapy

Document Type : Original Article


1 Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

2 Department of Medical Physics, School of Allied Medical Sciences, Arak University of Medical Sciences, Arak, Iran.

3 Department of Radiotherapy and Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical sciences, Ahvaz, Iran.


Background and Objective:In radiation therapy,depending on the depth and type of the tumor, photon or electron irradiation is often applied to treat malignant tumors. Normal tissues are inevitably damaged, due to dose absorption. Since the electron beam is deviated by the magnetic field, it could be applied to detour the dose deposition from normal tissues to tumor mass. 
Subjects and Methods: 15MeV electron beam, produced with Varian clinac 2100C/D, was used in this research. Relative dosimetry process was done by use of 3D water phantom and CC13 cylindrical chamber. This process was accomplished with and without magnetic field. 
Results: After use of magnetic field the surface dose was  increased. In addition the dose in buildup region had incremented.the depth of maximum dose in presence of magnetic field had a shift rather than without magnetic field. The penumbra had increment in some directions and decrease in some other directions.
Conclusion: By applying the magnetic field one can produce a region with increased and adjacent to a lower dose. It seems that arrangement of this region over normal and tumoral region can lead to increase in the efficiency of radiation therapy.


1-Lazarakis P, Bug MU, Gargioni E, Guatelli S, Incerti S, Rabus H, et al. Effect of a static magnetic field on nanodosimetric quantities in a DNA volume. Int J Radiat Biol 2012;88(1-2):183-8.
2-Oborn BM, Metcalfe PE, Butson MJ, Rosenfeld AB. Monte Carlo characterization of skin doses in 6 MV transverse field MRI-linac systems: effect of field size, surface orientation, magnetic field strength, and exit bolus. Med Phys 2010;37(10):5208-17.
3-Bostick WH. Possible techniques in direct-electron beam tumor therapy. Phys Rev 1950;77(4):564–5.
4-Shih CC. High energy electron radiotherapy in a magnetic field. Med Phys 1975;2(1):9-13.
5-Nardi E, Barnea G. Electron beam therapy with transverse magnetic fields. Med Phys 1999;26(6):967-73.
6-Lee MC, Ma CM. Monte Carlo characterization ofclinical electron beams in transverse magnetic fields. Phys Med Biol 2000;45(10):2947-67.
7-Jette D. Magnetic fields with photon beams: Monte Carlo calculations for a model magnetic field. Med Phys 2000;27(12):2726-38.
8-Li XA, Reiffel L, Chu J, Naqvi S. Conformal photon-beam therapy with transverse magnetic fields: a Monte Carlo study. Med Phys 2001;28(2):127-33.
9-Bielajew AF. The effect of strong longitudinal magnetic fields on dose deposition from electron and photon beams. Med Phys 1993;20(4):1171-9.
10-Litzenberg DW, Benedick A, McShan DL. Experimental apparatus to measure the effects of strong longitudinal magnetic fields on photon and electron radiotherapy beams. Phys Med Biol 2000.
11-Litzenberg DW, Fraass BA, McShan DL, O'Donnell TW, Roberts DA, Becchetti FD, et al. An apparatus for applying strong longitudinal magnetic fields to clinical photon and electron beams. Phys Med Biol 2001;46(5):N105-15.
12-Butson MJ, Wong TP, Law A, Law M, Mathur JN, Metcalfe PE. Magnetic repulsion of linear accelerator contaminates. Med Phys 1996;23(6):953-5.
13-Chen Y, Bielajew AF, Litzenberg DW, Moran JM, Becchetti FD. Magnetic confinement of electron and photon radiotherapy dose: a Monte Carlo simulation with a nonuniform longitudinal magnetic field. Med Phys 2005;32(12):3810-8.
14-Nettelbeck H, Takacs GJ, Rosenfeld AB. Effect of transverse magnetic fields on dose distribution and RBE of photon beams: comparing PENELOPE and EGS4 Monte Carlo codes. Phys Med Biol 2008;53(18):5123-37.
15-Belousov A, Chernyaev AP, Varzar SM. Simulation of the conditions of photon and electron beam irradiation in magnetic fields for increasing conformity of radiation therapy II. B Russ Acad Sci: Phys 2007;71(6):841-3.
16-Belousov AV, Namestnikov AS, Chernyaev AP. Model for the calculation of the trajectories of electron movements in an aqueous environment placed in a magnetic field. Moscow Univ Phys Bull 2011;66(5):458-61.
17-Ma L. Dosimetric properties of magnetically collimated electron beams for radiation therapy. Med Phys 2004;31(11):2973-7.
18-Belousov AV, Plotnikov AB, Chernyaev AP, Shvedunov VI. Increasing the efficiency of target irradiation with photon and electron beams in radiation therapy. Instrum Exp Tech 2003;46(6):828-31.
19-Jette D. Magnetic fields with photon beams: dose calculation using electron multiple-scattering theory. Med Phys 2000;27(8):1705-16.
20-Phaisangittisakul N, D'Souza WD, Ma L. Magnetic collimation and metal foil filtering for electron range and fluence modulation. Med Phys 2004;31(1):17-23.