[en] Objective: To evaluate the clinical value of bone imaging for the diagnosis and differential diagnosis of oral and maxillofacial surgical patients and to clarify whether the mandible is invaded by the adjacent lesion. Methods: Routine planar three-phase bone scintigraphy and semiquantitative mandibular tomography were performed on 5 controls and 15 patients. Of these 15 patients, 3 cases were with ameloblastoma of mandible, 5 cases with intraoral squamous carcinoma, 2 cases with embryonal rhabdomyosarcoma, 1 case with hemangioma of tongue, 1 case with sarcoma of mandible, 1 case with mandibular cyst, 1 case with chronic parotitis and 1 postextraction patient. Results: All of 3 ameloblastomas of mandible showed high uptake of ⁹⁹Tc^m-MDP. The mandibles invaded by intraoral squamous carcinoma and the embryonal rhabdomyosarcoma showed that the ratio of lesion-to-cervical vertebrae (L/C) was more than 1; the mandibles not invaded by intraoral squamous carcinoma and embryonal rhabdomyosarcoma showed that the L/C was less than 1; the tongue hemangioma showed a high uptake of ⁹⁹Tc^m-MDP in blood flow phase and blood pool phase, but no high uptake of ⁹⁹Tc^m-MDP in bone imaging. For the postextraction case, the alveolar bone showed a high uptake of ⁹⁹Tc^m-MDP in mandibular tomography, but L/C was less than 1; mandibular carcinomas showed a high uptake of ⁹⁹Tc^m-MDP in mandibular tomography, L/C was 1.01. Conclusions: Routine planar three-phase bone scintigraphy and semiquantitative mandibular tomography is a useful method for the diagnosis and differential diagnosis of diseases in oral and maxillofacial surgery, and it is also helpful for finding out the limits of foci and invasion of mandibles by the lesions in adjacent tissue in clinical practising