Comparison of detection sensitivity of near infrared (NIR) surgical imaging systems using a connective tissue phantom model.

Many tumors for which fluorescence guided surgery (FGS) has been developed are surface tumors, where direct visualization by the surgeon is straightforward. On the other hand, cancers such as soft-tissue sarcomas, are present at a subsurface level. Resection of these sub-surface tumors is performed using 'wide local excision' where a single, complete mass is removed with an intact zone of normal tissue (~ 1 cm 'margin'). We used a phantom model for sarcoma with near infrared fluorophore IRDye800 CW that defined different tissue properties. We compare the detection sensitivity of two commercially available near infrared (NIR) surgical imaging systems, Solaris (Perkin Elmer) and SPY PHI (Novadaq) using the phantom models of sarcoma. We also determine targeted fluorescence signal on both systems for blinded surgical phantom dissection by a surgeon. The fluorescence intensities are higher for Solaris than for SPY-PHI. On average, the fluorescence increased with an increase in intralipid concentration and decreased with an increase in blood concentration. The depth of imaging was higher for Solaris than for SPY PHI. Using the target values, the surgeon successfully dissected all phantoms using Solaris. Using fat phantoms for SPY PHI, the surgeon cut through four out of the total. Further improvement in FGS will improve cancer recurrence and morbidity.