[Evaluation of RI scintiscanning to parotid gland tumors]

We retrospectively evaluated preoperative radioisotope (RI) scintiscans in 275 patients (283 glands) with parotid tumors who undergoing surgery between 1987 and 2000. Technetium-99m-pertechnetate (Tc) scintigraphy was conducted on 201 glands. Oncocytoma and Warthin's tumor showed a high positive rate. In evaluating Warthin's tumor with Tc scintigraphy, sensitivity was 75% and specificity 88%; above the age of 40 years, specificity exceeded 90%. Gallium-67-citrate (Ga) scintigraphy was conducted on 207 glands. Malignant parotid tumors showed high positivity (85%), but the specificity of positive findings was quite low (38%) because 44% of benign pleomorphic adenoma, which occupied major material, showed Ga-positive findings. Ga-negative findings indicated high probability (95%) of benign tumors. Thus, Tc scintigraphy is effective in diagnosing Warthin's tumor, while Ga scintigraphy is effective in diagnosing benign tumors.