Peng Zhang1, Yikai Shi1, Wendong Wang1, Yaohui Wang2. 1. School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, China. 2. School of Medicine, Southern China University of Technology, Guangzhou, Guangdong, China.
Abstract
PURPOSE: To design planar gradient coil for MRI applications without discretization of continuous current density and loop-loop connection errors. METHODS: In the new design method, the coil current is represented using a spiral curve function described by just a few control parameters. Using a proper parametric equation set, an ensemble of spiral contours is reshaped to satisfy the coil design requirements, such as gradient linearity, inductance and shielding. RESULTS: In the given case study, by using the spiral coil design, the magnetic field errors in the imaging area were reduced from 5.19% (non-spiral design) to 4.47% (spiral design) for the transverse gradient coils, and for the longitudinal gradient coil design, the magnetic field errors were reduced to 5.02% (spiral design). The numerical evaluation shows that when compared with conventional wire loop, the inductance and resistance of spiral coil was reduced by 11.55% and 8.12% for x gradient coil, respectively. CONCLUSION: A novel spiral gradient coil design for biplanar MRI systems, the new design offers better magnetic field gradients, smooth contours than the conventional connected counterpart, which improves manufacturability.
PURPOSE: To design planar gradient coil for MRI applications without discretization of continuous current density and loop-loop connection errors. METHODS: In the new design method, the coil current is represented using a spiral curve function described by just a few control parameters. Using a proper parametric equation set, an ensemble of spiral contours is reshaped to satisfy the coil design requirements, such as gradient linearity, inductance and shielding. RESULTS: In the given case study, by using the spiral coil design, the magnetic field errors in the imaging area were reduced from 5.19% (non-spiral design) to 4.47% (spiral design) for the transverse gradient coils, and for the longitudinal gradient coil design, the magnetic field errors were reduced to 5.02% (spiral design). The numerical evaluation shows that when compared with conventional wire loop, the inductance and resistance of spiral coil was reduced by 11.55% and 8.12% for x gradient coil, respectively. CONCLUSION: A novel spiral gradient coil design for biplanar MRI systems, the new design offers better magnetic field gradients, smooth contours than the conventional connected counterpart, which improves manufacturability.
Keywords:
Spiral function; discrete wire method; gradient coil; magnetic field; open MRI