Heat and torque minimization for designing brain shim coil translated from Stream Function

Motivation: The safety concerns of heating and torque in ultra-high field MRI easily become a problem in implementing local devices. As our designed brain shim coil with dense wire pattern can improve the B0 homogeneity significantly, it is important to ensure safety before utilization. Goal(s): The study aims to minimize the power dissipation and torque in the designed shim coil. Approach: The study introduced regularization for power dissipation and torque, employs the wire interpolation method to enhance power efficiency, and simulates the impact of varying the number of turns in shim coils. Results: We found the optimal design parameters balancing safety and performance. Impact: We introduced a series of methods to design a safe and efficient shim coil for the brain in ultra-high field. The torque and heat results provide insight into the performance of the local shim coil.