Prospective comparison of 18F-NaF PET/CT versus 18F-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

Abstract 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.