The magnetic technique was developed for lesion localisation and sentinel lymph node biopsy in breast cancer. A search for alternative techniques, due to susceptibility artefacts on breast MRI created by residual magnetic tracer led to the development and evaluation of four magnetic markers (with solid, barrel, spring and butterfly shapes). Different characteristics were evaluated: (a) marker detectability and repeatability, (b) marker migration, (c) MRI artefacts at 1.5T, 3.0T and 7.0T MRI and (d) biocompatibility of the marker. Sensitivity experiments demonstrated a lateral and anterior detection of 12.5-16.8 mm and 12.8-16.0 mm, respectively. Marker migration was not detected in a magnetic field up to 7.0T. On MRI, in all three dimensions, the smallest artefacts were seen with the butterfly marker. No leaching was found up to seven days after marker injection. The magnetic markers have promising characteristics for lesion localisation and a feasibility trial is required to determine proof of principle.