An Aubert Ring Aggregate Magnet Helmet for 3D Head Imaging in a Low-field Portable MRI

A permanent magnet helmet based on an Aubert ring aggregate is proposed to have a linear gradient along the axial direction for 3D head imaging in a low-field portable MRI system. It is a magnet array that consists of a series of asymmetric Aubert ring pairs, forming a Helmet shape. The inner radii of each ring are successfully optimized for a linear gradient along the axial direction, a comparably strong field strength (67.06mT), and a controlled homogeneity. Genetic Algorithm (GA) was used for the optimization. This design can be used to supply B₀ in a miniaturized low-field portable MRI system.