Gradient coil set with a finite shield current

摘要

A method of designing a shielded gradient coil assemblies (22) for magnetic resonance imaging systems is provided. The method includes generating a first continuous current distribution for a primary coil (60) using an inverse approach. The first continuous current distribution is confined within predetermined finite geometric boundaries of a surface defined by two dimensions and generates a magnetic gradient field across an imaging region (14). The magnetic gradient field constrained to predetermined values at specified spatial locations within the imaging region (14). The current distribution and magnetic field are converted into a stored energy and magnetic field domain where a finite element analysis is performed to generate a second continuous current distribution for a shielding coil (62). The second continuous current distribution is confined within predetermined finite geometric boundaries of a surface surrounding the primary coil (60). The second continuous current distribution generates a magnetic field which substantially cancels in an area outside a region defined by the shielding coil a fringe magnetic field generated by the first continuous current density.