Page 111 - Fluorescence-guided cancer surgery

Intraoperative guidance in parathyroid surgery 109
clinically available yet, and development of these probes is expensive and time consuming. Therefore, it is important to exploit clinically available contrast agents, such as MB21.
Recently, several studies reported the use of auto uorescence characteristics of parathyroid tissue for discrimination between di erent tissue types using spectroscopy22;23. They found auto uorescent properties in parathyroid and thyroid glands with a peak uorescence at 822 nm when excited with 785 nm light. Using auto uorescence would make the development of exogenous contrast agents super uous. However, no 2-D optical guidance from spectroscopy is yet possible. And, although the spectroscopy results were validated in a larger patient cohort using a customized endoscopic imaging system24, this auto uorescent signal has not been seen in previous studies by our research group using our imaging system in humans or di erent animal species14;20.
NIR uorescence imaging is a growing eld of interest worldwide, more imaging systems have been introduced for both open and endoscopic imaging25;26. Prices of NIR uorescence imaging systems are starting from $40.000. NIR uorescence imaging in parathyroid surgery has the potential to speed up the surgical procedure by assisting in the identi cation of parathyroid adenomas and normal parathyroid gland. In the current study, time interval between administration and detection of adenomas are reported, however they could not be compared to patients not undergoing NIR uorescence- assisted surgery. Therefore, randomized controlled trials in which patients are receiving NIR uorescence imaging or not are needed.
To conclude, NIR uorescence imaging using MB can provide guidance during parathyroid surgery by identifying both parathyroid adenomas and normal parathyroid glands, for at least 145 minutes after MB administration. In patients where di cult identi cation of the parathyroid adenoma is expected, or when normal glands have to be identi ed, administration of MB could potentially improve surgical outcome.