The sensitivity mapping of a handheld magnetic probe with a permanent magnet for sentinel lymph node biopsy

Abstract

The magnetic technique using a magnetic tracer and handheld magnetic probe with permanent magnet can be alternatives to the radioisotope technique as a noninvasive promising method for sentinel lymph node biopsy. To identify one sentinel lymph node, 5 mm spatial resolution of the probe is required because sentinel lymph nodes are often clustered in axillary lymph nodes. The aim of this study is to demonstrate a spatial resolution of the magnetic probe by a sensitivity mapping measurement with high spatial resolutions.The longitudinal sensitivity and lateral resolution of the probe was approximately 8 mm and 4 mm, respectively, for 5 μL of the magnetic tracer (Resovist). The probe discriminated the one phantom from two phantoms separated 4 mm in the lateral direction. These results indicate that the magnetic probe with the permanent magnet has the ability to identify one sentinel lymph node from the node clusters in actual usages.