Image-guided near-infrared fluorescent sentinel lymph node mapping in human breast cancer

Abstract

e11591 Background: Breast cancer surgery is presently performed without real-time image-guidance. We have developed a novel optical imaging system for image-guided surgery that uses invisible near-infrared (NIR) fluorescent light to highlight structures on the surgical field with high sensitivity, specificity, and contrast. We have also performed the first human clinical trial of the imaging system in women undergoing SLN mapping for breast cancer. Methods: We used a portable imaging system with an articulating arm that has 6 degrees of freedom, high power LED light source, custom optics, custom software, and sterile drape. The imaging system provided simultaneous and real-time imaging of color video and NIR fluorescence at up to 15 frames per second. N = 6 women with biopsy- confirmed breast cancer undergoing SLN mapping gave informed consent. All subjects received conventional mapping with Tc-99m sulfur colloid using a handheld gamma probe as well as NIR fluorescence-guided SLN mapping using a mixture of indocyanine green (ICG) diluted to a final concentration of 10 μM in human serum albumin (ICG:HSA). Results: The imaging system was easy to position in the operating room, with the articulating arm providing 50” horizontal reach and 70” vertical reach. Working distance to the patient was 18”. NIR fluorescence excitation was 20 mW/cm2 at 760 nm. NIR-depleted white light was 40,000 lux. A total of 1.6 ml of ICG:HSA was injected intra-tumorally and peri-tumorally and the site massaged for 5 min. 8 of 9 SLNs identified by Tc- 99m sulfur colloid were also identified by NIR fluorescence. However, NIR fluorescence identified an SLN, confirmed to have cancer in it, that was not identified by Tc-99m sulfur colloid. These differences were consistent with asynchrony in the injection techniques. Unlike the gamma-ray probe, NIR fluorescence provided high-resolution, large area optical imaging of the surgical field, and helped guide surgical resection. Conclusions: In this 6-patient pilot study, a novel NIR fluorescence optical imaging system was used for the first time, and provided real-time image-guided surgery for SLN mapping of breast cancer. No significant financial relationships to disclose.