Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, UK.
Department of Electrical Engineering, Graduate School of Engineering, Tokyo Metropolitan University, Japan.
Environ Int. 2017 Apr;101:59-69. doi: 10.1016/j.envint.2017.01.005. Epub 2017 Jan 24.
This paper describes measurements and computational modelling carried out in the MOBI-Kids case-control study to assess the extremely low frequency (ELF) exposure of the brain from use of mobile and cordless phones. Four different communication systems were investigated: Global System for Mobile (GSM), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT) and Wi-Fi Voice over Internet Protocol (VoIP). The magnetic fields produced by the phones during transmission were measured under controlled laboratory conditions, and an equivalent loop was fitted to the data to produce three-dimensional extrapolations of the field. Computational modelling was then used to calculate the induced current density and electric field strength in the brain resulting from exposure to these magnetic fields. Human voxel phantoms of four different ages were used: 8, 11, 14 and adult. The results indicate that the current densities induced in the brain during DECT calls are likely to be an order of magnitude lower than those generated during GSM calls but over twice that during UMTS calls. The average current density during Wi-Fi VoIP calls was found to be lower than for UMTS by 30%, but the variability across the samples investigated was high. Spectral contributions were important to consider in relation to current density, particularly for DECT phones. This study suggests that the spatial distribution of the ELF induced current densities in brain tissues is determined by the physical characteristics of the phone (in particular battery position) while the amplitude is mainly dependent on communication system, thus providing a feasible basis for assessing ELF exposure in the epidemiological study. The number of phantoms was not large enough to provide definitive evidence of an increase of induced current density with age, but the data that are available suggest that, if present, the effect is likely to be very small.
本论文描述了在 MOBI-Kids 病例对照研究中进行的测量和计算建模工作，以评估使用移动电话和无绳电话对大脑的极低频（ELF）暴露。研究了四种不同的通信系统：全球移动通信系统（GSM）、通用移动通信系统（UMTS）、数字增强型无绳通信（DECT）和 Wi-Fi 网络电话（VoIP）。在受控实验室条件下测量了手机在传输过程中产生的磁场，并对数据进行拟合，得出了磁场的三维外推。然后，使用计算建模来计算由于暴露于这些磁场而在大脑中产生的感应电流密度和电场强度。使用了四个不同年龄的人体体素模型：8 岁、11 岁、14 岁和成人。结果表明，在 DECT 通话过程中诱导的大脑电流密度可能比在 GSM 通话过程中低一个数量级，但比在 UMTS 通话过程中高两倍。Wi-Fi VoIP 通话期间的平均电流密度比 UMTS 低 30%，但研究中样本的变异性很高。在考虑电流密度时，频谱贡献很重要，特别是对于 DECT 手机。本研究表明，ELF 诱导电流密度在脑组织中的空间分布取决于手机的物理特性（特别是电池位置），而幅度主要取决于通信系统，从而为评估流行病学研究中的 ELF 暴露提供了可行的基础。体素的数量不足以提供年龄增加引起的感应电流密度增加的明确证据，但现有的数据表明，如果存在，这种影响可能非常小。
