On the method of investigating human exposure to nonuniform magnetic field

Regarding compliance testing with existing guidelines on human exposure to ELF (extremely low frequency) magnetic fields, the nonuniformity of the fields has been one of the major concerns since guideline-level exposures are generally encountered in the direct vicinity of magnetic field sources such as electric power facilities and electric appliances. According to the guidelines, when the measured maximum magnetic fields exceed the specified field level, induced currents inside human bodies are to be investigated to check their conformity. However, this calculation still needs verification and requires massive computational resources, which are not readily applicable under practical exposure conditions. Therefore, a simple and relevant method of assessing nonuniform magnetic field exposure is highly desirable. In this paper, a method of obtaining an equivalent uniform magnetic field using a coefficient (the normalized induction factor) is investigated by a numerical calculation of induced current in anatomically correct human models. In addition, to assess the obtained coefficient easily, a simple method using a spherical model was proposed. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(3): 1–11, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20691

[1]  John Swanson.  A TRANSMISSION UTILITY’S EXPERIENCE OF APPLYING EMF EXPOSURE STANDARDS , 2002, Health physics.

[2]  P. Dimbylow.  Development of the female voxel phantom, NAOMI, and its application to calculations of induced current densities and electric fields from applied low frequency magnetic and electric fields , 2005, Physics in medicine and biology.

[3]  M A Stuchly,et al.  HUMAN BODY EXPOSURE TO POWER LINES: RELATION OF INDUCED QUANTITIES TO EXTERNAL MAGNETIC FIELDS , 2002, Health physics.

[4]  Tadashi Kawamoto,et al.  Simplified Dosimetry for Human Exposure to Non-uniform ELF Magnetic Field , 2005 .

[5]  P. Dimbylow,et al.  Induced current densities from low-frequency magnetic fields in a 2 mm resolution, anatomically realistic model of the body. , 1998, Physics in medicine and biology.

[6]  Shoji Hamada,et al.  Analysis of Electric Field Induced by ELF Magnetic Field Utilizing Fast-Multipole Surface-Charge-Simulation Method for Voxel Data , 2006 .

[7]  M. Stuchly,et al.  Interaction of low-frequency electric and magnetic fields with the human body , 2000, Proceedings of the IEEE.

[8]  T. Nagaoka,et al.  Development of realistic high-resolution whole-body voxel models of Japanese adult males and females of average height and weight, and application of models to radio-frequency electromagnetic-field dosimetry. , 2004, Physics in medicine and biology.

[9]  M. Taki,et al.  Analysis of induced currents in a rat exposed to 50 Hz linearly and circularly polarized magnetic fields. , 2000, Bioelectromagnetics.

[10]  Masao Taki,et al.  Measurement of Magnetic Field From an Induction Heating Hob and Estimation of Induced Current Density in Human Body , 2005 .

[11]  Reilly Jp.  Comments concerning "Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)". , 1999 .

[12]  C. Gabriel.  Compilation of the Dielectric Properties of Body Tissues at RF and Microwave Frequencies. , 1996 .

[13]  T Dan Bracken,et al.  Evaluation of Nonuniform 60-Hertz Magnetic-Field Exposures for Compliance with Guidelines , 2004, Journal of occupational and environmental hygiene.

[14]  O. Gandhi,et al.  A 3-D impedance method to calculate power deposition in biological bodies subjected to time varying magnetic fields , 1988, IEEE Transactions on Biomedical Engineering.

[15]  Investigation of Relationship between ELF Magnetic Field and Induced Current Inside Human Body , 2000 .

[16]  T Dan Bracken.  ASSESSING COMPLIANCE WITH POWER-FREQUENCY MAGNETIC-FIELD GUIDELINES , 2002, Health physics.

[17]  Osamu Hashimoto,et al.  Numerical study on an equivalent source model for inhomogeneous magnetic field dosimetry in the low-frequency range , 2004, IEEE Transactions on Biomedical Engineering.

[18]  M. Stuchly,et al.  Influence of human model resolution on computed currents induced in organs by 60-Hz magnetic fields. , 1997, Bioelectromagnetics.

[19]  W. H. Bailey,et al.  Evaluation of biological effects, dosimetric models, and exposure assessment related to ELF electric- and magnetic-field guidelines. , 2001, Applied occupational and environmental hygiene.

[20]  W T Kaune,et al.  Comparison of coupling of humans to electric and magnetic fields with frequencies between 100 Hz and 100 kHz. , 1997, Bioelectromagnetics.

[21]  Osamu Hashimoto,et al.  Magnetic Field and Dosimetric Study at Intermediate Frequency Range Using the Coil Source Model , 2006, IEICE Trans. Electron..

[22]  N. Hayashi,et al.  Numerical Analysis of Induced Current in Human Head Exposed to Nonuniform Magnetic Field Including Harmonics , 2003 .