Computational models for contact current dosimetry at frequencies below 1 MHz

Area of Science:

• Biomedical Engineering
• Computational Electromagnetics
• Electrical Safety

Background:

• Electric contact currents (CC) can cause severe health issues, including ventricular fibrillation.
• In vivo and cadaver studies for CC dosimetry are limited, impacting safety standard development.
• Existing safety standards rely on a limited scientific basis for protection against CC.

Purpose of the Study:

• To develop a validated, adaptable numerical body model for computational CC dosimetry.
• To analyze CC dosimetry for frequencies ranging from DC to 1 MHz.
• To evaluate heart current factors (HCF) for various current paths and frequencies.

Main Methods:

• Development of an extendable and adaptable numerical body model named Duke.
• Simulation of contact currents from DC up to 100 kHz using seven contact electrodes.
• Calculation of induced electric fields, current, body impedance, and HCFs for longitudinal and transversal paths.

Main Results:

• Transversal CCs exhibit frequency-dependent HCFs.
• Longitudinal CCs show HCFs largely unaffected by frequency, predicted at 1.0.
• HCFs for chest/back to hand paths may be underestimated by IEC 60479-1, possibly due to blood vessel current flow.

Conclusions:

• The developed numerical model provides a basis for computational CC dosimetry.
• Findings suggest a need to re-evaluate HCFs in existing electrical safety standards.
• Further research is required to confirm the predicted HCFs and their implications for safety standards.