SALIVARY-GLAND TUMORS - PRETHERAPY EVALUATION WITH PET

PURPOSE: To determine whether positron emission tomography (PET) can h elp differentiate benign from malignant lesions of the salivary glands before surgery.MATERIALS AND METHODS: Masses of the salivary glands w ere examined in 26 patients by means of computed tomography, magnetic resonance imaging, PET, biopsy (n = 18), and surgery. Contiguous PET s cans were obtained from the midcranium to the lower chest 45 minutes a fter administration of 370 MBq (10 mCi) of fluorine-18 fluorodeoxygluc ose (FDG). Standard uptake values (SUVs) were determined for all suspe ct lesions and for normal parotid glands and cerebellum. RESULTS: All lesions were visualized, and all but two showed some increase in FDG u ptake. PET findings helped correctly differentiate benign from maligna nt masses in 18 (69%) but were false-positive for malignancy in eight (31%). SUV analysis, lesion-to-normal SUV ratios, and lesion-to-cerebe llar SUV ratios also failed to differentiate the lesions. CONCLUSION: FDG PET is not useful in classifying salivary gland tumors as benign o r malignant.