Optimization of SPIO Injection for Sentinel Lymph Node Dissection in a Rat Model.

Area of Science:

• Biomedical Engineering
• Surgical Innovation
• Medical Imaging

Background:

• Sentinel lymph node dissection (SLND) is crucial for cancer staging.
• The magnetic tracer technique offers a promising, non-inferior alternative to standard SLND.
• Optimizing tracer delivery is key to maximizing the technique's efficacy.

Purpose of the Study:

• To optimize magnetic tracer uptake in sentinel lymph nodes (SLN).
• To evaluate the impact of injection characteristics on SLN iron uptake and residual iron at the injection site.
• To establish optimal parameters for magnetic SLND in a preclinical model.

Main Methods:

• A rat hindleg model was used to evaluate injection dose, dilution, time course, and massaging.
• 202 successful sentinel lymph node dissections (SLNDs) were performed using a magnetic tracer and magnetometer.
• Iron uptake in SLN and residual iron at the injection site were quantified.

Main Results:

• SLN iron uptake was dose-dependent up to 200 μg, plateauing around 80 μg at 1000 μg injection.
• Time significantly impacted SLN iron uptake and residual iron washout, more so than dilution.
• Massaging did not significantly alter iron uptake.

Conclusions:

• Injection dose and time are critical factors for optimizing magnetic tracer uptake in SLN.
• Preoperative injection is advantageous for SLN detection and minimizing injection site iron residue.
• Further optimization could enhance the clinical applicability of magnetic SLND.