Prospective comparison of 18 F-NaF PET/CT versus 18 F-FDG PET/CT imaging in mandibular extension of head and neck squamous cell carcinoma with dedicated analysis software and validation with surgical specimen. A preliminary study.

BACKGROUND: The aim of this study is to propose a new method to quantify radioactivity with PET/CT imaging in mandibular extension in head and neck squamous cell carcinoma (HNSCC), using innovative software, and to compare results with microscopic surgical specimens.

PATIENTS AND METHODS: This prospective study enrolled 15 patients who underwent 18 F-NaF and 18 F-FDG PET/CT. We compared the delineations of bone invasions obtained with 18 F-NaF PET/CT and 18 F-FDG PET/CT with the results of histopathological analysis of mandibular resections (from right and left bone borders). A method for visualization and quantification of PET images was developed.

RESULTS: For all patients, a significant difference (p = 0.032 for right limits and p = 0.011 for left limits) was observed between 18 F-FDG PET/CT imaging and histopathology results, and no significant difference (p = 0.88 for right limits and p = 0.55 for left limits) was observed between 18 F-NaF PET/CT imaging and histopathology results. The right limits were less than 10 mm in 93% of patients, and the left limits were less than 10 mm in 86% of patients.

CONCLUSIONS: The dedicated software enabled the objective delineation of radioactivity within the bone. We can confirm that 18 F-NaF is a precise and specific bone marker for the assessment of intraosseous mandibular extensions of head and neck cancers.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.