System for Detecting the Location of a Magnetized Marker in a Human Subject

In this letter, we describe the design and operation of a magnetic detection system for marking lesions in human breasts that might be cancerous. The system is comprised of a thin cylindrical permanent magnet implanted in the breast to mark the lesion location. A handheld detector, covered by a sterilized sleeve, would be manipulated by the surgeon to detect the location of the magnet. Evenly spaced sensors in the neck of the detector are calibrated to mitigate the effects of external magnetic fields. The nominal signature of the embedded magnet is used to estimate the distance from the detector tip to the magnet. The distance is indicated both by a display panel and the pitch of an audible signal. Details of the design process and initial laboratory operation of this magnetic marker detection system are presented.