Added value of intraoperative real-time imaging in searches for difficult-to-locate sentinel nodes

Localization of sentinel lymph nodes can be challenging if they are in difficult anatomic locations or near high radiotracer activity. The purpose of this study was to assess the value of intraoperative real-time imaging using a portable gamma-camera in conjunction with a conventional gamma-counting probe when it is difficult to localize the sentinel node.

After (99m)Tc-nanocolloid injection, patients with various malignancies underwent presurgical lymphoscintigraphy followed by surgery (usually the next day). We evaluated 20 patients who required sentinel lymph node biopsy and in whom the location or other characteristics of the sentinel node would make intraoperative retrieval difficult. During surgery, the sentinel node was localized using a portable gamma-camera together with a hand-held gamma-probe. A (153)Gd pointer or (125)I seed was used to better depict the sentinel node location in real time.

Using only a conventional hand-held gamma-probe, surgeons were able to definitively localize the sentinel node in 15 of 20 patients. Intraoperatively, the portable gamma-camera showed uptake by the definite sentinel node in 19 of 20 patients and helped to precisely localize the node with the hand-held gamma-probe in 4 patients. In 1 of these patients, the sentinel node was metastatic.

The combination of a standard hand-held gamma-probe and real-time imaging provided by a portable gamma-camera offers a high intraoperative detection rate in patients with difficult sentinel node localization as assessed by presurgical lymphoscintigraphy.