cysteine rhenium colloid

Cysteine rhenium colloid is a radiopharmaceutical agent developed as a novel radiocolloid for sentinel lymph node identification, particularly in breast cancer surgery. It consists of a colloidal preparation containing the amino acid cysteine and the transition metal rhenium, forming particles suitable for injection and subsequent imaging. The mechanism of action involves localization in lymphatic tissue after peritumoral or subdermal injection, allowing visualization of sentinel lymph nodes via gamma imaging techniques. This enables accurate mapping and biopsy during oncologic surgery[3]. Rhenium-based complexes are also being explored as coordinate covalent inhibitors that selectively target surface-accessible cysteine residues on proteins, but this application is distinct from their use as radiocolloids[1][2][5].