3D Printing Integrated Design and Shimming of Sparce Halbach Permanent Magnet Array for Head-Only Portable MRI

Motivation: Traditional MRI devices are hindered by their size and high cost, sparking interest in low-field portable MRI. Permanent magnet arrays are critical for portability, necessitating designs with high field strength and homogeneity. Goal(s): To effectively shim a sparse Halbach permanent magnet array without changing the structure. Approach: Utilize MagTetris, a rapid magnetic field calculator, and genetic algorithm for optimization. Construct and shim the magnet using 3D printing for precise alignment. Results: The final design achieved an average field strength of 38.47 mT with 171 ppm inhomogeneity across an 80 mm FOV post-shimming, an improvement of homogeneity by 11.8%. Impact: This work proposes the applications of 3D printing to shim sparse permanent magnet arrays with construction precision. It enables faster, cost-effective magnet array shimming, advancing MRI capabilities in resource-limited settings and improving global diagnostic access.