Since the introduction of sentinel lymph node biopsy (SLNB) for breast cancer in the late 20th century, there has been a significant de-escalation of axillary surgery [1]. This procedure has obviated the need for axillary lymph node dissection in patients with histopathologically negative sentinel lymph nodes (SLNs), thereby reducing the risk of comorbidities such as lymphedema and paresthesia. Consequently, SLNB has been established as the standard of care for axillary staging in breast cancer. Current clinical guidelines recommend the dual-tracer technique, combining a radioisotope and blue dye, as the gold standard for SLN mapping [2]. However, a notable disadvantage of radioisotopes is the unavoidable, albeit minimal, radiation exposure to clinical staff [3]. To advance SLNB techniques, eliminate ionizing radiation exposure, and increase the availability of SLNB in regional hospitals, alternative methods have been developed. This has led to the emergence of indocyanine green (ICG) and magnetic tracer technology [4]. The use of magnetic tracers with superparamagnetic iron oxide (SPIO) nanoparticles protects both patients and staff from ionizing radiation. The introduction of the magnetic technique necessitated a comparison with established methods, particularly the dual-tracer approach, to validate its efficacy. To date, multiple studies have confirmed the non-inferiority of the magnetic method.

At our institution, SLNB has been the standard of care for a decade, following an early validation study [5]. Traditionally, radioisotopes and blue dye have been used either in combination or as single tracers, depending on agent availability. However, reliance on nuclear medicine departments often poses significant logistical challenges, particularly in regional oncological centers where the supply chain for radioisotopes can be inconsistent. The recent acquisition of specialized magnetic equipment has enabled the implementation of a more flexible workflow. The primary aim of this study is to evaluate the practical feasibility and SLN identification rate of SPIO nanoparticles as a single tracer within our regional clinical setting. By focusing on this context, we aim to contribute to the literature regarding the utility of magnetic tracers in environments where access to nuclear medicine is limited. Additionally, we explored the impact of the injection site and timing on the identification rate to further assess the technique's adaptability in routine practice.