DEVELOPING A MORE FOCAL MAGNETIC STIMULATOR .1. SOME BASIC PRINCIPLES
DEVELOPING A MORE FOCAL MAGNETIC STIMULATOR .1. SOME BASIC PRINCIPLES
复制标题
DOI：
10.1097/00004691-199101000-00013
复制
发表时间：
1991-01-01
影响因子：
2.4
通讯作者：
CUFFIN, BN
中科院分区：
文献类型：
--
作者：
COHEN, D;CUFFIN, BN
首先回顾了磁刺激器在任何形状的体积导体中感应的电流的一些一般特性。 然后，讨论由于不同方向和配置的线圈而在头部球形模型中感应的电流的焦点特性（集中在某个内部点）。 结果表明，无论使用何种线圈，焦点的一个重要特性是完全不存在电流的径向分量。 图中显示了理论上计算出的由三个不同线圈产生的球体中的电流分布。 它们是 (1) 平行于头部的圆形线圈（非常非焦点），(2) 直立在头部的圆形线圈（更焦点），以及 (3) 平行于头部的 8 字形线圈（最焦点）。 对更多聚焦线圈配置的计算搜索表明，8 字形焦度只能稍微改变，但基本上无法改善。 八字形线圈的焦度与其线圈直径的关系图显示，随着直径减小至一厘米，焦度有所改善。 在此直径下，线圈下方 2 cm 处的感应电流集中在 1.5 cm 宽的带内（半最大值点）。 最后，值得注意的是，随着八字形线圈的直径减小，线圈中刺激所需的电流迅速增加，工程问题也随之增加。
Some general properties of currents induced by magnetic stimulators in volume conductors of any shape are first reviewed. Then, the property of focality (concentration at some internal point) of the current induced in a spherical model of the head is discussed, due to coils of various orientations and configurations. It is shown that one important property for focality is the complete absence of the radial component of current, regardless of the coil used. The theoretically computed current distributions in the sphere produced by three different coils are illustrated. These are (1) a circular coil parallel to the head (very nonfocal), (2) a circular coil erect on the head (more focal), and (3) a figure-eight coil parallel to the head (most focal). A computational search for yet more focal coil configurations shows that the figure-eight focality can only be altered somewhat, but basically not improved. A plot of focality of the figure-eight coil versus the diameter of its coils shows an improvement in focality with decreasing diameter down to one cm. At this diameter, the induced current at a level 2 cm below the coil is concentrated in a band 1.5 cm wide (half-maximum points). Finally, it is noted that as the diameter of the figure-eight coil is decreased, the current in the coil necessary for stimulation increases rapidly, with increasing engineering problems.