Iterative shimming for low-field head-optimized MRI

A method, comprising:

• generating a first field map of a magnetic field Bo from a magnetic resonance imaging (MRI) system, wherein the MRI system comprises:
• an array of permanent magnets in a modified Halbach dome arrangement, wherein the array comprises one open end sized to receive a head of a patient, and wherein the array is configured to generate the magnetic field B0;
• and
• a shim tray comprising slots configured to receive shim magnets;
• wherein the first field map corresponds to a magnetic field based on each of the slots being empty;
• applying the first field map to a genetic algorithm to determine a first set of slots to receive a first set of shim magnets;
• installing the first set of shim magnets in the first set of slots;
• generating a second field map of the magnetic field B0, wherein the second field map corresponds to a magnetic field based on the first set of shim magnets being installed in the first set of slots;
• applying the second field map to the genetic algorithm to determine a second set of slots to receive a second set of shim magnets, wherein the second set of slots is different than the first set of slots;
• and
• installing the second set of shim magnets in the second set of slots.