The magnetic technique for sentinel node biopsy provides a radioisotope-free alternative for staging breast cancer. It requires refinement to reduce "residual iron content" at injection sites by maximising lymphatic uptake to prevent "void artefacts" on magnetic resonance imaging (MRI), which could adversely affect clinical use. The site and timing of injection of magnetic tracer was evaluated in a murine tumour model (right hind limb) in 24 wild type mice. Right-sided intratumoural and left sided subcutaneous injection of magnetic tracer and assessment of nodal iron uptake on MRI, surgical excision and histopathological grading at time frames up to 24 hours were performed. Rapid iron uptake on MRI, smaller "void artefacts"(P <0.001) and a significant increase in iron content with time were identified in the subcutaneous injection group (r = 0.937; P <0.001).Subcutaneous injection and increasing delay between tracer injection and surgery is beneficial for lymphatic iron uptake.
- Magnetic technique
- Magnetic tracer
- Murine tumour model
- Sentinel lymph node biopsy
- Superparamagnetic iron oxide (SPIO)