AbstractIn NMR imaging, spatial information of an object is made possible by the gradient fields. Desirable qualities in a gradient field for conventional imaging include linearity, speed, and strength. Recent developments in high resolution or fast imaging or both require strong gradient fields and fast switching capability. Until recently, most conventional gradient coils available were the Golay‐type, together with Helmholtz‐type coil, mounted on a cylindrical support. Some of the drawbacks of the cylindrically shaped coils include the fixed geometry and relatively weak gradient fields due to the limitation imposed on the object size, which necessitate the large coil diameter. In this article, a novel gradient coil, namely the surface gradient coil (SGC), is described and reviewed. The SGC, an unconventional gradient coil that is constructed on a flat surface, is presented as an alternative to the conventional Golay‐type coil. This flat and arbitrarily sized surface gradient coil could satisfy two important requirements. First, it could provide much larger gradient fields while providing substantially improved switching speed due to its small size. Secondly, the planar structure of the surface gradient coil, in conjunction with a surface radio frequency (RF) coil, provides a movable probe for localized imaging of large objects. The latter, i.e., the possibility of integrating the SGC with the surface RF coil suggests a new direction in NMR imaging similar to the movable probe, widely used in ultrasound imaging. The movable probe would then allow us to carry out fastin vivohigh‐resolution imaging of the human body hitherto difficult to carry out with conventional gradient coils. The basic design concepts, together with the improved design, achieved through numerical optimization, and some experimental results obtained with the prototype SGC probes, ar
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