['The aim of this study was to prospectively evaluate the feasibility and potential advantages of freehand single-photon emission computed tomography (fhSPECT) compared with conventional intraoperative localization techniques for sentinel lymph node biopsy (SLNB) in oral cancer.', 'Between November 2012 and February 2014, 23 consecutive patients with clinical T1/T2 oral squamous cell carcinoma and a cN0 neck were recruited. All patients underwent SLNB followed by elective neck dissection (END). All patients received preoperative lymphoscintigraphy. To detect the SLNs intraoperatively, fhSPECT with a combination of conventional acoustic SLN localization and 3-D visual navigation was used.', 'All but one of the SLNs detected by preoperative imaging were successfully mapped intraoperatively by fhSPECT (detection rate 98%), including those in six patients with a tumour in the floor of the mouth. A histopathology analysis revealed positive SLNs in 22% of patients. No further metastases were found in LNs resected during END. SLNB correctly predicted the final LN stage in all patients (accuracy 100%). Additional radioactive LNs, which were not present on preoperative lymphoscintigraphy, were observed in three patients.'] Does intraoperative 3-D imaging improve sentinel lymph node biopsy in oral cancer?