So Poman P M, Stuchly Maria A, Nyenhuis John A
Department of Electrical and Computer Engineering, University of Victoria, Victoria, BC V8W 3P6, Canada.
IEEE Trans Biomed Eng. 2004 Nov;51(11):1907-14. doi: 10.1109/TBME.2004.834251.
A heterogeneous model of the human body and the scalar potential finite difference method are used to compute electric fields induced in tissue by magnetic field exposures. Two types of coils are considered that simulate exposure to gradient switching fields during magnetic resonance imaging (MRI). These coils producing coronal (y axis) and axial (z axis) magnetic fields have previously been used in experiments with humans. The computed fields can, therefore, be directly compared to human response data. The computed electric fields in subcutaneous fat and skin corresponding to peripheral nerve stimulation (PNS) thresholds in humans in simulated MRI experiments range from 3.8 to 5.8 V/m for the fields exceeded in 0.5% of tissue volume (skin and fat of the torso). The threshold depends on coil type and position along the body, and on the anatomy and resolution of the human body model. The computed values are in agreement with previously established thresholds for neural stimulation.
采用人体异质模型和标量势有限差分法来计算磁场暴露在组织中感应产生的电场。考虑了两种类型的线圈，它们模拟磁共振成像（MRI）期间对梯度切换场的暴露。这些产生冠状面（y轴）和轴向（z轴）磁场的线圈先前已用于人体实验。因此，计算得到的场可以直接与人体反应数据进行比较。在模拟MRI实验中，对应于人体外周神经刺激（PNS）阈值的皮下脂肪和皮肤中的计算电场，对于在0.5%组织体积（躯干的皮肤和脂肪）中超过的场，范围为3.8至5.8 V/m。该阈值取决于线圈类型、沿身体的位置以及人体模型的解剖结构和分辨率。计算值与先前确定的神经刺激阈值一致。
