Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
Int J Environ Res Public Health. 2021 Dec 30;19(1):390. doi: 10.3390/ijerph19010390.
The external field strength according to the international guidelines and standards for human protection are derived to prevent peripheral nerve system pain at frequencies from 300-750 Hz to 1 MHz. In this frequency range, the stimulation is attributable to axon electrostimulation. One limitation in the current international guidelines is the lack of respective stimulation thresholds in the brain and peripheral nervous system from in vivo human measurements over a wide frequency range. This study investigates peripheral stimulation thresholds using a multi-scale computation based on a human anatomical model for uniform exposure. The nerve parameters are first adjusted from the measured data to fit the peripheral nerve in the trunk. From the parameters, the external magnetic field strength to stimulate the nerve was estimated. Here, the conservativeness of protection limits of the international guidelines and standards for peripheral stimulation was confirmed. The results showed a margin factor of 4-6 and 10-24 times between internal and external protection limits of Institute of Electrical and Electronics Engineers standard (IEEE C95.1) and International Commission on Non-Ionizing Radiation Protection guidelines, with the computed pain thresholds.
根据国际人体保护指南和标准，导出了外部场强，以防止在 300-750 Hz 至 1 MHz 的频率下外周神经系统疼痛。在此频率范围内，刺激归因于轴突电刺激。目前国际指南的一个局限性是缺乏各自的大脑和外周神经系统的刺激阈值，这些阈值是通过在广泛的频率范围内对人体进行活体测量得出的。本研究使用基于人体解剖模型的多尺度计算来研究外周刺激阈值，该模型用于均匀暴露。首先根据测量数据调整神经参数，以适应躯干中的外周神经。根据这些参数，估计了刺激神经的外部磁场强度。在此，确认了国际指南和标准对周围刺激的保护限制的保守性。结果表明，在计算出的疼痛阈值下，与电气和电子工程师协会标准（IEEE C95.1）和国际非电离辐射防护委员会指南的内部和外部保护限值之间存在 4-6 倍和 10-24 倍的差距。
