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Abstract：
To develop new concepts for minimum electric-field (E-field) gradient design, and to define the extents to which E-field can be reduced in gradient design while maintaining a desired imaging performance.
Efficient calculation of induced electric field in simplified patient models was integrated into gradient design software, allowing constraints to be placed on the peak E-field. Gradient coils confined to various build envelopes were designed with minimum E-fields subject to standard magnetic field constraints. We examined the characteristics of E-field-constrained gradients designed for imaging the head and body and the importance of asymmetry and concomitant fields in achieving these solutions.
For transverse gradients, symmetric solutions create high levels of E-fields in the shoulder region, while fully asymmetric solutions create high E-fields on the top of the head. Partially asymmetric solutions result in the lowest E-fields, balanced between shoulders and head and resulting in factors of 1.8 to 2.8 reduction in E-field for x-gradient and y-gradient coils, respectively, when compared with the symmetric designs of identical gradient distortion.
We introduce a generalized method for minimum E-field gradient design and define the theoretical limits of magnetic energy and peak E-field for gradient coils of arbitrary cylindrical geometry.
Efficient calculation of induced electric field in simplified patient models was integrated into gradient design software, allowing constraints to be placed on the peak E-field. Gradient coils confined to various build envelopes were designed with minimum E-fields subject to standard magnetic field constraints. We examined the characteristics of E-field-constrained gradients designed for imaging the head and body and the importance of asymmetry and concomitant fields in achieving these solutions.
For transverse gradients, symmetric solutions create high levels of E-fields in the shoulder region, while fully asymmetric solutions create high E-fields on the top of the head. Partially asymmetric solutions result in the lowest E-fields, balanced between shoulders and head and resulting in factors of 1.8 to 2.8 reduction in E-field for x-gradient and y-gradient coils, respectively, when compared with the symmetric designs of identical gradient distortion.
We introduce a generalized method for minimum E-field gradient design and define the theoretical limits of magnetic energy and peak E-field for gradient coils of arbitrary cylindrical geometry.
摘要：
为了开发最小电场（E场）梯度设计的新概念，并且定义在梯度设计中可以将E场减小到的范围,同时保持期望的成像性能。
简化患者模型中感应电场的有效计算已集成到梯度设计软件中，允许约束被放置在峰值E场。受限于各种构建包络的梯度线圈被设计为具有受标准磁场约束的最小电场。我们研究了用于对头部和身体进行成像的电场约束梯度的特性，以及不对称和伴随场在实现这些解决方案中的重要性。
对于横向坡度，对称解在肩部区域产生高水平的电场，而完全不对称的解决方案在头顶创建高电场。部分非对称解决方案导致最低的E场，在肩部和头部之间平衡，并导致x梯度和y梯度线圈的电场减少1.8到2.8的系数，分别,与相同梯度失真的对称设计相比。
我们介绍了一种用于最小E场梯度设计的广义方法，并定义了任意圆柱几何形状的梯度线圈的磁能和峰值E场的理论极限。
简化患者模型中感应电场的有效计算已集成到梯度设计软件中，允许约束被放置在峰值E场。受限于各种构建包络的梯度线圈被设计为具有受标准磁场约束的最小电场。我们研究了用于对头部和身体进行成像的电场约束梯度的特性，以及不对称和伴随场在实现这些解决方案中的重要性。
对于横向坡度，对称解在肩部区域产生高水平的电场，而完全不对称的解决方案在头顶创建高电场。部分非对称解决方案导致最低的E场，在肩部和头部之间平衡，并导致x梯度和y梯度线圈的电场减少1.8到2.8的系数，分别,与相同梯度失真的对称设计相比。
我们介绍了一种用于最小E场梯度设计的广义方法，并定义了任意圆柱几何形状的梯度线圈的磁能和峰值E场的理论极限。
