Abstract: Objective: To evaluate the clinical application of ⁹⁹Tc^m-methoxyisobutylis-onitrile (⁹⁹Tc^m-MIBI) SPECT-CT for differential diagnosis of benign and malignant parotid tumors before treatment. Methods: SPECT-CT fusion images of parotid regions were obtained from 30 patients with unilateral parotid gland tumor before surgery. ^99mTc-MIBI was used as the imaging agent. The results were compared with their pathological diagnoses and clinical examination. The chi-square test and t-test were used for statistical analysis. Results: The sensitivity, specificity and accuracy of ⁹⁹Tc^m-MIBI SPECT-CT fusion imaging in determining the malignant parotid tumors were 84.61%, 94.12% and 90.00%, respectively. Sixteen of 17 patients with benign tumors showed negative images (94.11%, 16/17), while 1 of 17 patients showed positive images (5.89%, 1/17). In addition, 12 of 13 patients with malignant tumors showed positive images (92.31%, 12/13), while 1 of 13 patients showed negative image (7.69%, 1/13). There were significant differences between two groups by chi-square test. The uptake ratios of benign and malignant parotid tumors were 1.42±0.6 and 2.32±0.58 (P＜0.05), respectively. Conclusion: ⁹⁹Tc^m-MIBI SPECT-CT might be a useful method for differential diagnosis of benign and malignant parotid tumors before treatment.

Key words: Parotid neoplasms, Radioisotopes, Tomography, SPECT-CT