Evaluation of the use of freehand SPECT for sentinel node biopsy in early stage oral carcinoma

Rationale: Inadequate intraoperative visualization of the sentinel node can hamper its harvest. Freehand SPECT is a 3D tomographic imaging modality based on the concepts of SPECT, which can be used for intraoperative visualization and navigation towards the sentinel node in order to improve its localization and removal during surgery.

Patients and methods: The use of freehand SPECT was evaluated during 66 sentinel node biopsy procedures in early stage oral cancer patients. Intraoperative detection of sentinel nodes was compared with preoperative identified sentinel nodes on lymphoscinitigraphic examination. Additional value of freehand SPECT was subjectively scored by the surgeon directly following the biopsy procedure.

Results: Freehand SPECT was able to detect 94% of sentinel nodes intraoperatively. Most sentinel nodes not detected (7 out of 9) were located in level I of the neck. Freehand SPECT appeared to be of additional value for facilitating the intraoperative detection of the sentinel node in 24% of procedures.

Conclusion: The use of the freehand SPECT system is feasible in the intraoperative detection of sentinel nodes in early stage oral cancer. Freehand SPECT provides helpful information facilitating the SN biopsy procedure in a quarter of cases. However, freehand SPECT cannot detect all SNs which are located in the vicinity of the injection site.