Page 54 - Fluorescence-guided cancer surgery

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Chapter 3
tumor-speci c “800 nm” contrast agents will become widely available during the next few years, although MB could ll the gap in the meantime. Improved laser or LED light sources and cameras are under constant development to overcome the imaging system associated factors.
Another important consideration is extraneous NIR uorescence generated from other drugs in the surgical eld. During this study we found that Patent Blue, used for sentinel lymph node mapping, exhibited a weak NIR uorescence at 700 nm that could confound the MB results (data not shown). Because we have previously demonstrated that blue dye can be omitted from sentinel lymph node mapping when indocyanine green (ICG) is used29, and the FLARE imaging system is capable of imaging 2 independent channels of NIR uorescence, e.g., NIR Channel 1 for MB-guided breast cancer resection and NIR Channel 2 for ICG-guided sentinel lymph node mapping, it should be possible to eliminate Patent Blue from future protocols and thus eliminate this potential confounder.
The primary endpoint of this study was the identi cation ratio of breast cancer using NIR uorescence and MB and optimization of injection timing. As it was the rst feasibility study with MB in breast cancer, no outcomes data were collected to correlate with intraoperative NIR uorescence ndings. Therefore, it is not possible to draw conclusions on the prognostic relevance of the technology, although one might ponder that true negative MB uptake selected for tumors of low perfusion and relatively low metastatic potential. Thereby only one patient directly bene tted from this technique with respect to direct resection of residual tumor tissue due to the reasons mentioned above. Future studies will need to address this and other remaining questions.
In conclusion, this is the rst study to demonstrate the use of low dose MB for the real-time identi cation of breast cancer using NIR uorescence and MB. No di erence was seen between di erent administration groups in TBR and background signal, suggesting that the more convenient early imaging protocol could be used in future studies. Although larger studies are necessary to determine patient bene t, results with MB are promising and improved contrast agents will likely become available in the future.
ACKNOWLEDGEMENTS
We thank David Burrington jr. for editing.