Salivary gland tumors: pretherapy evaluation with PET.

PURPOSE

To determine whether positron emission tomography (PET) can help differentiate benign from malignant lesions of the salivary glands before surgery.

MATERIALS AND METHODS

Masses of the salivary glands were examined in 26 patients by means of computed tomography, magnetic resonance imaging, PET, biopsy (n = 18), and surgery. Contiguous PET scans were obtained from the midcranium to the lower chest 45 minutes after administration of 370 MBq (10 mCi) of fluorine-18 fluorodeoxyglucose (FDG). Standard uptake values (SUVs) were determined for all suspect lesions and for normal parotid glands and cerebellum.

RESULTS

All lesions were visualized, and all but two showed some increase in FDG uptake. PET findings helped correctly differentiate benign from malignant masses in 18 (69%) but were false-positive for malignancy in eight (31%). SUV analysis, lesion-to-normal SUV ratios, and lesion-to-cerebellar SUV ratios also failed to differentiate the lesions.

CONCLUSION

FDG PET is not useful in classifying salivary gland tumors as benign or malignant.