Simulation of induced current densities in the human body at industrial induction heating frequencies

Gustrau, Frank; Bahr, A.; Rittweger, M.; Goltz, S.; Eggert, Siegfried

doi:10.1109/15.809851

Cited by 17 publications

(7 citation statements)

References 9 publications

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“…If we scale the results presented in Fig. 4 by dividing them to the scale factor 1087, they will show a good agreement with results presented in [7]. Slight differences between results may be due to differences in weight and height of actual models.…”

Section: Numerical Resultssupporting

confidence: 71%

“…To verify the model, the results are compared with the results presented in [7]. In this work, a pure magnetic field with the vector oriented from front to back of the body is simulated to produce B = 30.7 μT .…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Other studies have explored effects of very low frequency pure electric fields using high resolution models (with cubic voxels of 3.6 mm edges) [6]. Industrial frequencies in the range of kilo hertz have been also studied due to potential risks imposed on workers near induction heating and melting devices and it has also been shown that for low frequency dosimetric applications, using 1 cm resolution model with realistic shape but relatively lower resolution in discrimination of internal tissues may give good results with acceptable accuracy [7]. …”

Section: Introductionmentioning

confidence: 99%

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Investigating the effects of external fields polarization on the coupling of pure magnetic waves in the human body in very low frequencies

2007

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In this paper we studied the effects of external fields' polarization on the coupling of pure magnetic fields into human body. Finite Difference Time Domain (FDTD) method is used to calculate the current densities induced in a 1 cm resolution anatomically based model with proper tissue conductivities. Twenty different tissues have been considered in this investigation and scaled FDTD technique is used to convert the results of computer code run in 15 MHz to low frequencies which are encountered in the vicinity of industrial induction heating and melting devices. It has been found that external magnetic field's orientation due to human body has a pronounced impact on the level of induced currents in different body tissues. This may potentially help developing protecting strategies to mitigate the situations in which workers are exposed to high levels of external magnetic radiation.

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Section: Numerical Resultssupporting

confidence: 71%

Section: Numerical Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigating the effects of external fields polarization on the coupling of pure magnetic waves in the human body in very low frequencies

2007

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“…The current density within a homogeneous sphere exposed to a time‐varying uniform B‐field is given (36): where r is the radial distance (m), f is the frequency (Hz), B is the magnetic flux density (T), and σ is the conductivity (S m −1 ).…”

Section: Methodsmentioning

confidence: 99%

Numerically‐simulated induced electric field and current density within a human model located close to a z‐gradient coil

Li¹,

Hand²,

Wills³

et al. 2007

Magnetic Resonance Imaging

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Purpose: To simulate exposure (e.g., during interventional procedures) of a worker close to an operating MR scanner by calculating electric fields and current density within an anatomically realistic body model due to a z-gradient coil and to compare results with safety guidelines and European Directive 2004/40/EC. Materials and Methods:Electric field and current density in an adult male model located at three positions within the range 0.19 -0.44 m from the end of a generic z-gradient coil were calculated using the time-domain finite integration technique (FIT). Frequency scaling was used in which quasistatic conditions were assumed and results obtained at 1 MHz (assuming tissue conductivity values at 1 kHz) were scaled to 1 kHz.Results: Current density (averaged over 1 cm 2 ) in central nervous system (CNS) tissues up to 20.6 mA m Ϫ2 and electric fields (averaged over 5 mm) up to 4.1 V m Ϫ1 were predicted for a gradient of 10 mT m Ϫ1 and slew rate of 10 T m Ϫ1 second Ϫ1 . Conclusion:Compliance with 2004/40/EC, and with basic restriction values of Institute of Electrical and Electronics Engineers (IEEE) C95.6-2002, was predicted only at impracticably low gradients/slew rates in the ranges 4.9 -9.1 mT m Ϫ1 /4.9 -9.1 T m Ϫ1 second Ϫ1 and 5-21 mT m Ϫ1 / 5-21 T m Ϫ1 second Ϫ1 , respectively.

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“…Even on a supercomputer, the simulation would run for years. To overcome this problem we used the frequency scaling method used in various publications and compared with analytic solutions by several authors (De Moerloose et al 1997, Furse and Gandhi 1998, Gandhi and Chen 1992, Gandhi 1995, Gustrau et al 1999, Potter et al 2000. This method overcomes excessive simulation times and has been successfully applied to low frequency dosimetry simulations.…”

Section: Fdtd Methods For Quasi-static Frequenciesmentioning

confidence: 99%

Calculation of induced current densities and specific absorption rates (SAR) for pregnant women exposed to hand-held metal detectors

Kainz¹,

Chan²,

Casamento³

et al. 2003

Phys. Med. Biol.

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The finite difference time domain (FDTD) method in combination with a well established frequency scaling method was used to calculate the internal fields and current densities induced in a simple model of a pregnant woman and her foetus, when exposed to hand-held metal detectors. The pregnant woman and foetus were modelled using a simple semi-heterogeneous model in 10 mm resolution, consisting of three different types of tissue. The model is based on the scanned shape of a pregnant woman in the 34th gestational week. Nine different representative models of hand-held metal detectors operating in the frequency range from 8 kHz to 2 MHz were evaluated. The metal detectors were placed directly on the abdomen of the computational model with a spacing of 1 cm. Both the induced current density and the specific absorption rate (SAR) are well below the recommended limits for exposure of the general public published in the ICNIRP Guidelines and the IEEE C95.1 Standard. The highest current density is 8.3 mA m(-2) and the highest SAR is 26.5 microW kg(-1). Compared to the limits for the induced current density recommended in the ICNIRP Guidelines, a minimum safety factor of 3 exists. Compared to the IEEE C95. 1 Standard, a safety factor of 60 000 for the specific absorption rate was found. Based on the very low specific absorption rate and an induced current density below the recommended exposure limits, significant temperature rise or nerve stimulation in the pregnant woman or in the foetus can be excluded.

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Simulation of induced current densities in the human body at industrial induction heating frequencies

Cited by 17 publications

References 9 publications

Investigating the effects of external fields polarization on the coupling of pure magnetic waves in the human body in very low frequencies

Investigating the effects of external fields polarization on the coupling of pure magnetic waves in the human body in very low frequencies

Numerically‐simulated induced electric field and current density within a human model located close to a z‐gradient coil

Calculation of induced current densities and specific absorption rates (SAR) for pregnant women exposed to hand-held metal detectors

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