Tongue depressor-assisted FDG PET/CT scans in oral cancer: a prospective study with a feasibility protocol

Abstract Background F-18 Fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) is a powerful tool in oral cancer. However, the oral cavity is a small cavity with complex components. An invasive cancer or post-therapy change frequently cause difficulty in interpretation. In this study, we established a tongue depressor (TD)-assisted FDG PET/CT protocol to solve this problem. Methods We enrolled 264 patients with oral cancers. Early and delayed images were acquired in each FDG PET/CT examination. A wooden tongue depressor was placed either between buccal mucosa and teeth or between tongue border and teeth in delayed image. TD placed delayed image was compared with early images to analyze the extent of tumor. The discrimination ratio (DR) of the tumor was calculated as: (images that can clearly distinguish features /all images) × 100%. Results In tongue cancer group, the DR of the tumors were 26.1% on early images and 99.3% on TD placed delayed images (p < 0.001). In buccal cancer group, the DR of the tumors were 10.9% on early images and 98.2% on TD placed delayed images (p < 0.001). Conclusions The TD-assisted FDG PET/CT protocol is patient-friendly and effective in analyzing the tumor when evaluating oral cancer.