Gamma camera imaging of sentinel lymph nodes in early stage oral cancer

Abstract

Sentinel node biopsy has gained acceptance as an efficacious and cost-effective means to the management of patients presenting with early oral cavity cancer and whom may have occult cervical nodal metastases not detectable by conventional staging strategies (cT1-2N0). Sentinel node detection using radionuclide tracers allows a pipeline for pre-operative visualization, intraoperative localization and confirmation and it is often preferred modality for the biopsy. SPECT-CT extends the usefulness of the technique by allowing visualization in 3D. This is highly advantageous in the head and neck where lymphatic drainage is rich and complex. SPECT-CT has the potential to improve pre-operative planning leading to more controlled and precise surgical retrieval of sentinel nodes. Nonetheless, despite its strength, there remains pitfalls which are important for the correct interpretation of the images. Recognition of these limitations and pitfalls may contribute to part of the observed improved surgical outcomes in high volume centers compared to those with lesser caseload and experience. Radiopharmaceutical development, including dual modality tracers, augmentation with complementary imaging techniques, as well as visualization with augmented reality represent exciting areas for future development. This chapter focuses specifically on the utility of SPECT-CT in the early oral cavity cancer.