Combined Application of Technetium-99m Sulfur Colloid and Blue Dye for Sentinel Lymph Node Detection in Early-stage Breast Cancer

Sentinel lymph node biopsy (SLNB) is the standard procedure for axillary lymph node staging in breast cancer patients, and its application has prevented unnecessary axillary lymph node dissection (ALND) in early-stage breast cancer in the past decades. Accurate sentinel lymph nodes (SLNs) localization helps improve the success rate of SLNB. The dual-tracer technique (radiocolloid plus blue dye) for SLN mapping significantly improves the identification rate compared to single tracer methods. The most widely adopted radiocolloid is 99m Tc-SC, and methylene blue is widely used in visual mapping. However, previous studies have found that the identification rate of SLN imaging varies significantly, which may be closely related to the preparation process and the operator's experience.Standardization of the SLN mapping protocol is crucial for maximizing the identification rate and minimizing false-negative results. This article provides a detailed process using 99m Tc - SC combined with methylene blue for SLN mapping in early-stage breast cancer, including procedures for the preparation of 99m Tc-SC, injection, SLN image acquisition, methylene blue mapping and intraoperative localization.