Moving a neodymium magnet promotes the migration of a magnetic tracer and increases the monitoring counts on the skin surface of sentinel lymph nodes in breast cancer

Abstract

Background: We suspected that moving a small neodymium magnet would promote migration of the magnetic tracer to the sentinel lymph node (SLN). Higher monitoring counts on the skin surface before making an incision help us detect SLNs easily and successfully. The present study evaluated the enhancement of the monitoring count on the skin surface in SLN detection based on the magnet movement in a sentinel lymph node biopsy (SNB) using superparamagnetic iron oxide (SPIO) nanoparticles. Methods: After induction of general anesthesia, superparamagnetic iron oxide nanoparticles were injected subdermally into the subareolar area or peritumorally. The neodymium magnet was moved over the skin from the injection site to the axilla to promote migration of the magnetic tracer without massage. A total of 62 patients were enrolled from February 2018 to November 2018: 13 cases were subjected to magnet movement 20 times (Group A), 8 were subjected to 1-min magnet movement (Group B), 26 were given a short (about 5 min) interval from injection to 1-min magnet movement (Group C), and 15 were given a long (about 25 min) interval before 1min magnet movement using the magnetometer's head (Group D). In all cases, an SNB was conducted using both the radioisotope (RI) and SPIO methods. The monitoring counts on the skin surface were measured by a handheld magnetometer and compared among the four groups. Changes in the monitoring count by the interval and magnet movement were evaluated.

Understanding MNPs Behaviour in Response to AMF in Biological Milieus and the Effects at the Cellular Level: Implications for a Rational Design That Drives Magnetic Hyperthermia Therapy toward Clinical Implementation

“…Both the possibilities for diagnosis and treatment make these nanomaterials, and specifically MNPs, very powerful candidates in the fight against cancer, know referred to as theranostic agents [ 16 , 26 ]. The success of NPs can be largely explained by the possibility of using them as more specific guided medicines and from the growing number of clinical trials, the use of NPs in cancer is becoming a reality [ 27 , 28 , 29 ].…”

The Application of Magnetic Nanoparticles for Sentinel Lymph Node Detection in Clinically Node-Negative Breast Cancer Patients: A Systemic Review and Meta-Analysis

“…The generally administered doses of SPIO were 0.5 mL [ 24 , 32 ], 1.0 mL [ 31 , 34 ], 1.5 mL [ 34 ], and 2.0 mL [ 7 , 12 , 14 , 21 , 23 , 25 , 26 , 27 , 28 , 29 , 30 , 33 , 35 , 36 ] for clinical usage, usually diluted with saline and administered through subcutaneous injection into the peritumoral [ 32 ], intratumoral [ 24 ], or periareolar or subareolar zones [ 7 , 12 , 14 , 21 , 23 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. The optimal time for administration of this agent was at least 20 min ahead of the axillary surgery [ 7 , 12 , 14 , 21 , 23 , 25 , 27 , 29 , 30 , 32 , 33 , 34 ,…”

“…During surgery, the surgeon used the handheld magnetometer for skin localization of the sentinel lymph node, which was followed by a gamma probe to confirm the position. Among them, thirteen studies used the magnetometer with a combination of standard techniques for in vivo confirmation [ 14 , 21 , 25 , 27 , 28 , 29 , 30 , 32 , 33 , 34 , 35 , 36 ]. Six studies used the standard technique only after SLNB was performed with the magnetometer, as well as for ex vivo verification.…”

“…Six studies had performed lymphoscintigraphy before SLNB [ 14 , 21 , 23 , 28 , 29 , 33 ]. Eleven studies did not report whether lymphoscintigraphy had been taken [ 7 , 12 , 21 , 24 , 25 , 30 , 31 , 32 , 34 , 35 , 36 ], while the remaining studies did not take lymphoscintigraphy routinely [ 26 , 27 ]. Of note, two studies which blinded the surgeons when executing the lymphoscintigraphy were later resolved by the introduction of the magnetic technique [ 23 , 28 ].…”

A Propensity Score Matched Analysis of Superparamagnetic Iron Oxide versus Radioisotope Sentinel Node Biopsy in Breast Cancer Patients after Neoadjuvant Chemotherapy

“…Moreover, since the magnetometer must seek out a small tracer collection point, the detection of SLNs by SPIO may be limited. In contrast, the RI probe can detect the radiation beam directly from SLNs [39]. Peek et al investigated injection characteristics of the magnetic tracer on the rat model, proving that iron uptake appears to be proportional to the injection dose before reaching a plateau level [40].…”