Susceptibility probes for detecting surgical markers

Abstract

A probe for locating a magnetic marker for use in surgery. The probe comprises at least two first coils () and at least one second coil () which are arranged substantially coaxially on a longitudinal axis of the probe for measuring the proximity of a magnetic marker to the probe, and a baseline voltage taring device () comprising a first elongate conductor which defines a conducting path extending partially around the probe axis. The conducting path is configured and arranged such that in use the balancing magnetic field induces a balancing voltage in a sense coil that at least partially offsets the baseline voltage. Also disclosed is a method of manufacturing such a probe, a method of setting up such a probe for use in sensing a magnetic marker, and detection apparatus for locating a magnetic marker during surgery.