摘要Objective: The aim of the study was to evaluate the clinical value of99mTc-methylene diphosphonic acid (MDP) SPECT/CT fusion imaging and CT scanning in diagnosis of infiltrated mandible by gingival carcinoma. Methods: 18 cases of gingival carcinoma were processed infiltrated mandible by99mTc-MDP SPECT/CT fusion image and CT, and their scanning results compared with pathology findings. Results: Eleven of 13 cases with well-differentiated squamous cell carcinoma showed positive images, one of 11 cases was false positive images by pathology findings, and 10 cases were exhibited infil-trated mandibles; 5 cases with moderately differentiated and poorly differentiated squamous cell carcinoma showed positive images, pathology showed carcinoma cell had infiltrated cavum ossis of mandible. Five of 18 cases were positive images by CT. Conclusion: 99mTc-MDP SPECT/CT fusion imaging is a useful method in diagnosis of infiltrated mandible by gingival carcinoma.