CHANGE INDUCED BY RADIATION-THERAPY IN FDG UPTAKE IN NORMAL AND MALIGNANT STRUCTURES OF THE HEAD AND NECK - QUANTITATION WITH PET

PURPOSE: To quantitate the changes induced in uptake of the glucose an alog 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in normal structure s in the head and neck and compare these to the change in uptake in ma lignant structures in patients with head and neck tumors undergoing ra diation therapy. MATERIALS AND METHODS: Eleven patients with biopsy-co nfirmed squamous cell carcinoma of the head and neck were studied befo re, during, and after a 6-week course of radiation therapy with positr on emission tomography (PET)-FDG imaging. A ratio of FDG uptake in the structure compared with that in the cerebellum (termed metabolic rati o) within and outside of the field of radiation was determined in the adenoids; lingual and palatine tonsils; parotid, submandibular, and su blingual glands; and nasal turbinates, soft palate, and gingiva. RESUL TS: The average metabolic ratio in the tonsils, nasal turbinates, soft palate, and gingiva did not change significantly with treatment. CONC LUSION: FDG uptake in normal structures does not change with radiation therapy. This fact is in marked contrast to the FDG uptake in squamou s cell carcinomas in the head and neck, which decrease dramatically wi th treatment (P < .005).