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Electromagnetic Fields in Biological Systems
EMF. This chapter emphasizes the conceptual understanding of the development of the
human body model and the coupling between the exposure to ELF EMF and the developed human body model rather than the validation of proposed numerical dosimetry
techniques. There are many review publications on the experiments, and numerical
dosimetries and interactions of ELF EMF with matter (Kaune 1993; Kavet et al. 2001;
Martens 2007; Stuchly and Dawson 2000).
Dosimetry is very important for the design and interpretation of all types of exposure
experiment studies and for the establishment of human protection guidelines. Apart
from experimental dosimetry, numerical dosimetry provides fundamental information
about the external electric and magnetic fields and the internal electrical quantities in
living tissues. Earlier, a very simple homogeneous human model was used to estimate
the induced electric fields and current densities produced by exposure to ELF EMF. The
recent progress in computer technology allowed the development of a more heterogeneous human model with very fine resolution and with CAD mesh. These models have
been mainly produced by using MRI scan data of the body. The anatomically realistic
human body model consists of various volumes of different conductivities with over
30 organs and tissues of 1- to 10-mm 3 voxels. Two-dimensional simple human body
models can be used for the calculation of internal electric fields and current densities
in the international standards of IEC in which a simple loop model is proposed for the
human body (IEC 2004a, 2007). Three-dimensional models have been developed as an
MRI-based human body model.
After publishing EHC 238 in 2007 (WHO 2007a), WHO opened the research recommendations of ELF EMF (WHO 2007b). The research needs are as follows: (1) computational dosimetry relating external electric and magnetic fields to internal electric fields,
particularly concerning exposure to combined electric and magnetic fields in different
orientations; (2) calculation of induced electric fields in pregnant women and in the
fetus; and (3) refinement of microdosimetric models taking into account cellular architecture of neural networks and other complex suborgan systems. The reasons for this
research are that (1) for a better understanding of biological effects and for the development of exposure guidelines, more data on internal electric fields for different exposure
conditions are needed, (2) it is important to assess possible enhanced induction of electric fields during fetal life in relation to childhood leukemia, and (3) there is a need to
further refine microdosimetric models to take into account the cellular architecture of
neural networks and other complex suborgan systems identified as being sensitive to
induced electric field effects compared with other tissues. In addition to the above issues,
the study of electrical properties of tissues is still very important for the qualification of
the ELF EMF effect and for the evaluation of possible mechanisms. As suggested in the
research agenda, it is necessary to study further the specification of the electrical qualities induced in finer-resolution human body models.
Our scientific understanding of the coupling between ELF EMF and the human body
has been gradually improved from the development of experimental and numerical
dosimetries. Accurate modeling of a very heterogeneous human body and a human body
of complex shape will have a major role in understanding the interactions between the
EMF including IF and higher frequency and biological systems. In the future, numerical
dosimetry will continue to support research in bioelectromagnetics.
Electromagnetic Fields in Biological Systems
EMF. This chapter emphasizes the conceptual understanding of the development of the
human body model and the coupling between the exposure to ELF EMF and the developed human body model rather than the validation of proposed numerical dosimetry
techniques. There are many review publications on the experiments, and numerical
dosimetries and interactions of ELF EMF with matter (Kaune 1993; Kavet et al. 2001;
Martens 2007; Stuchly and Dawson 2000).
Dosimetry is very important for the design and interpretation of all types of exposure
experiment studies and for the establishment of human protection guidelines. Apart
from experimental dosimetry, numerical dosimetry provides fundamental information
about the external electric and magnetic fields and the internal electrical quantities in
living tissues. Earlier, a very simple homogeneous human model was used to estimate
the induced electric fields and current densities produced by exposure to ELF EMF. The
recent progress in computer technology allowed the development of a more heterogeneous human model with very fine resolution and with CAD mesh. These models have
been mainly produced by using MRI scan data of the body. The anatomically realistic
human body model consists of various volumes of different conductivities with over
30 organs and tissues of 1- to 10-mm 3 voxels. Two-dimensional simple human body
models can be used for the calculation of internal electric fields and current densities
in the international standards of IEC in which a simple loop model is proposed for the
human body (IEC 2004a, 2007). Three-dimensional models have been developed as an
MRI-based human body model.
After publishing EHC 238 in 2007 (WHO 2007a), WHO opened the research recommendations of ELF EMF (WHO 2007b). The research needs are as follows: (1) computational dosimetry relating external electric and magnetic fields to internal electric fields,
particularly concerning exposure to combined electric and magnetic fields in different
orientations; (2) calculation of induced electric fields in pregnant women and in the
fetus; and (3) refinement of microdosimetric models taking into account cellular architecture of neural networks and other complex suborgan systems. The reasons for this
research are that (1) for a better understanding of biological effects and for the development of exposure guidelines, more data on internal electric fields for different exposure
conditions are needed, (2) it is important to assess possible enhanced induction of electric fields during fetal life in relation to childhood leukemia, and (3) there is a need to
further refine microdosimetric models to take into account the cellular architecture of
neural networks and other complex suborgan systems identified as being sensitive to
induced electric field effects compared with other tissues. In addition to the above issues,
the study of electrical properties of tissues is still very important for the qualification of
the ELF EMF effect and for the evaluation of possible mechanisms. As suggested in the
research agenda, it is necessary to study further the specification of the electrical qualities induced in finer-resolution human body models.
Our scientific understanding of the coupling between ELF EMF and the human body
has been gradually improved from the development of experimental and numerical
dosimetries. Accurate modeling of a very heterogeneous human body and a human body
of complex shape will have a major role in understanding the interactions between the
EMF including IF and higher frequency and biological systems. In the future, numerical
dosimetry will continue to support research in bioelectromagnetics.