SPECT-CT and intraoperative portable gamma-camera detection protocol for sentinel lymph node biopsy in oral cavity squamous cell carcinoma.

OBJECTIVE: The aim of this study was to evaluate a multimodality approach to sentinel lymph node biopsy (SLNB) detection with lymphoscintigraphy and single-photon emission computed tomography (SPECT)/computed tomography (CT). When combined with intraoperative imaging by a portable gamma camera (PGC), improved SLNB accuracy and detection rate may result. MATERIAL AND METHODS: A total of 42 patients selected for SLNB in node-negative T1 and T2 oral squamous cell carcinoma were retrospectively analyzed. The detection protocol consisted of preoperative lymphoscintigraphy and SPECT/CT performed the day before surgery. Intraoperative sentinel lymph node (SLN) detection was done with the aid of a PGC in association with hand-held gamma probe. RESULTS: All SLN detected in the preoperative study could be harvested except for one case. A total of 131 SLN were resected. This number was higher than the SLN depicted on lymphoscintigraphy (119 SLNs) and SPECT/CT (123 SLNs). Sublingual SLNs were observed in two cases (4.76%). These SLNs were detected by SPECT/CT but not by lymphoscintigraphy. Five (3.8%) additional SLNs not previously visualized on lymphoscintigraphy or on SPECT/CT were detected intraoperatively with the aid of the PGC. Positive SLNs were detected in eight cases (19%). Micrometastases were detected in five cases (62%) and macrometastases in three cases (38%). CONCLUSION: The SLNB detection protocol described contributes to more accurate study and detection.