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Updated: Apr 13, 2026
Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery
Published on: May 4, 2022
Development of a New Magnetometer for Sentinel Lymph Node Mapping Designed for Video-Assisted Thoracic Surgery in
Kazuhiro Imai1, Yasushi Kawaharada2, Jun-Ichi Ogawa2
1Akita University Graduate School of Medicine, Akita, Japan i-karo@mui.biglobe.ne.jp.
Background:
We previously developed a method for sentinel lymph node (SLN) mapping in non-small cell lung cancer (NSCLC), based on the magnetic force produced by a magnetite tracer already approved for use as a contrast material for magnetic resonance imaging. However, it is difficult to use that technique with video-assisted thoracic surgery (VATS) because the sensing element of the magnetometer is large and thick. The purpose of the present study was to develop a smaller, thinner VATS-compatible magnetometer.
Methods:
The tracer employed was Ferucarbotran, a colloidal solution of superparamagnetic iron oxide coated with carbodextran. Fifteen patients with clinical stage I NSCLC were enrolled, and each received 1.6 mL of Ferucarbotran, injected intraoperatively at 5 points around the tumor. The magnetic force within the sampling lymph nodes was measured using the new VATS-compatible magnetometer.
Results:
SLNs were detected in 11 (73.3%) of the 15 patients using the VATS-compatible magnetometer. The average number of SLNs identified per patient was 1.8 (range 0-4). No complications related to the SLN detection method were observed.
Conclusions:
The new VATS-compatible magnetometer appears to have substantial advantages over techniques using a radioisotope and our earlier magnetometer, as it can be inserted through the small VATS port site.
