Abstract

Objective: To develop a multimodal agent based on ^99mTc-nanocoloid and indocyanine green (ICG) for lymph node (LN) mapping and potential application in sentinel node biopsy (SNB).

Materials and methods: The optimal dilutions of ICG and nanocolloid radiolabeled with ^99mTc (direct method) were studied. The nano-radiopharmaceutical characterization of the multimodal agent was performed and the biological behavior was studied in vivo in rats. Early and late radioisotopic images (preoperative) were acquired in dynamic and static mode with a gamma camera, and fluorescent images (intraoperative) with a portable fluorescence detector. The LN were excised and reserved for confirmatory histological analysis.

Results: The co-location of the fluorescent and radioisotopic signals was confirmed biologically and later by histological analysis.

Conclusion: This novel multimodal agent improved the detection of LN by imaging modality, making it a potential effective candidate for SNB.

Key words: Sentinel node, indocyanine green, ^99mTc-radiocolloid, multimodal imaging agent.