Figure 1

PET-CT scan of a patient with locally advanced laryngeal cancer illustrating the importance of this imaging technique for radiotherapy treatment planning. The tumor invades the cricoid cartilage inferiorly in addition to the contralateral neck nodes which was not observed on the pre-treatment diagnostic CT scan. The gross tumor and the contralateral neck nodes would have been underdosed without the planning PET-CT scan. On the other hand, despite the presence of bilateral cervical lymph nodes, no retropharyngeal (RP) lymph node metastases was observed. Thus, regional control may be achieved with a prophylactic radiation dose (56 Gy) to the RP area while a curative dose (70 Gy) is required for the PET positive gross tumor and lymph nodes. Patients with supraglottic laryngeal cancer and cervical lymph nodes metastases may be at higher risk for RP nodal failure. The patient is free of disease eight months following treatment. Axial fused PET/CT (A) shows extent of metabolic activity inferior to the cricoid cartilage [yellow arrow] which is not anatomically visible on the CT alone (B). Sagittal PET/CT (C) and CT (D) showing cranial-caudal extent of tumor. Axial and Coronal PET/CT (E&G) showing a metabolic contralateral node [green arrow], also difficult to appreciate on the CT alone (F&H).