Directing magnetic nanoparticles to sites within biological tissues requires both strong magnetic field gradients and accurate images of the particles and underlying anatomy. Most modern MR imaging systems require always-on magnetic field sources such as permanent magnets or superconducting coils. These field sources limit the ability to control magnetic particles within the imaging volume. Due to these field sources having a high strength always-on magnetic field, there are additional safety concerns when attempting to integrate these sources into an intraoperative arena. We built a new magnetic field source design that is capable of adjusting its magnetic field strength while retaining a low power usage to improve portability.