Numerical and Experimental Evaluation of Magnetic Markers for Localized Tumor Excision with a Handheld Magnetic Probe

For patients with nonpalpable breast lesions, breast-conserving surgery can be performed to remove the primary lesion while leaving as much normal breast tissue as possible. To perform breast-conserving surgery, localization tools are required to indicate such lesions' location. Conventional localization tools such as wire-guided localization (WGL) lead to a high reexcision rate. A magnetic detection system reduces the reexcision rate by providing objective information about the marker's location. In this study, we numerically evaluated the induced magnetic field strength from the magnetic marker from all orientations and found an optimal design achieving 100% detection at 40 mm distance from all orientations. Two marker samples are fabricated, and the experimentally detectable magnetic field strength is compared with the numerical simulation results. Both data show similar trends, thus validating the numerical simulation. The application of premagnetization on the magnetic markers are also evaluated. With the use of premagnetization, magnetic markers with 0.6 mm diameter can be detected in 46 mm distance, exceeding existing commercialized magnetic markers.