Phantom study quantifying the depth performance of a handheld magnetometer for sentinel lymph node biopsy

Development of Magnetic Probe for Sentinel Lymph Node Detection in Laparoscopic Navigation for Gastric Cancer Patients

New laparoscopic sentinel lymph node navigation using a dedicated magnetic probe and magnetic nanoparticle tracer for gastric cancer patients allows minimally invasive surgeries. By identifying the sentinel lymph nodes containing magnetic nanoparticles, patients can avoid excessive lymph node extraction without nuclear facilities and radiation exposure. This paper describes the development of the laparoscopic magnetic probe, ACDC-probe, for laparoscopic sentinel lymph node identification utilizing the nonlinear response of the magnetic nanoparticles magnetized by an alternating magnetic field with a static magnetic field. For highly sensitive detection, the ratio of static to alternating magnetic fields was optimized to approximately 5. The longitudinal detection length was approximately 10 mm for 140 μg of iron, and the detectable amount of iron was approximately 280 ng at a distance of 1 mm. To demonstrate the feasibility of laparoscopic detection using the ACDC-probe and magnetic tracers, an experiment was performed on a wild swine. The gastric sentinel lymph node was clearly identified during laparoscopic navigation. These results suggest that the newly developed ACDC-probe is useful for laparoscopic sentinel lymph node detection and this magnetic technique appears to be a promising method for future sentinel lymph node navigation of gastric cancer patients.

Comparison of Radio-guided Occult Lesion Localization (ROLL) and Magnetic Occult Lesion Localization (MOLL) for Non-palpable Lesions: A Phantom Model Study

BACKGROUND

Localization of nonpalpable breast cancers can be achieved with several techniques. We sought to compare radio-guided localization (ROLL) and magnetic tracer localization (MOLL) techniques by using a phantom model we previously developed, which can provide an accurate simulation for excision of nonpalpable breast lesions.

MATERIALS AND METHODS

We designed 20 phantom models (10 MOLL, 10 ROLL group) for localization. A handheld gamma probe for the ROLL group and a manual magnetometer (SentiMag) for the MOLL group were used to test the ability of the modality to detect olives in turkey breasts. The excision time for each procedure, specimen size, and weight of the specimens removed from the turkey breasts were recorded.

RESULTS

Both techniques resulted in 100% retrieval of the lesions. There was no difference between the groups in the duration of operative excision, specimen weight, or specimen volume.

CONCLUSION

This experimental trial found similar success rates for ROLL and MOLL in localization of occult lesions using the turkey breast phantom model. MOLL can be performed in clinics without the need for a nuclear medicine team and radiation safety procedures.