title: Change induced by radiation therapy in FDG uptake in normal and malignant structures of the head and neck: quantitation with PET.
abstract: OBJECTIVE
  To quantitate the changes induced in uptake of the glucose analog 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in normal structures in the head and neck and compare these to the change in uptake in malignant structures in patients with head and neck tumors undergoing radiation therapy.
  
  
  METHODS
  Eleven patients with biopsy-confirmed squamous cell carcinoma of the head and neck were studied before, during, and after a 6-week course of radiation therapy with positron emission tomography (PET)-FDG imaging. A ratio of FDG uptake in the structure compared with that in the cerebellum (termed metabolic ratio) within and outside of the field of radiation was determined in the adenoids; lingual and palatine tonsils; parotid, submandibular, and sublingual glands; and nasal turbinates, soft palate, and gingiva.
  
  
  RESULTS
  The average metabolic ratio in the tonsils, nasal turbinates, soft palate, and gingiva did not change significantly with treatment.
  
  
  CONCLUSIONS
  FDG uptake in normal structures does not change with radiation therapy. This fact is in marked contrast to the FDG uptake in squamous cell carcinomas in the head and neck, which decrease dramatically with treatment (P < .005).
authors.affiliation: Department of Radiological Sciences, Laboratory of Biomedical and Environmental Sciences, Los Angeles, Calif.
authors.forename: S D
authors.initials: SD
authors.lastname: Rege
authors.forename: L
authors.initials: L
authors.lastname: Chaiken
authors.forename: C K
authors.initials: CK
authors.lastname: Hoh
authors.forename: Y
authors.initials: Y
authors.lastname: Choi
authors.forename: R
authors.initials: R
authors.lastname: Lufkin
authors.forename: Y
authors.initials: Y
authors.lastname: Anzai
authors.forename: G
authors.initials: G
authors.lastname: Juillard
authors.forename: J
authors.initials: J
authors.lastname: Maddahi
authors.forename: M E
authors.initials: ME
authors.lastname: Phelps
authors.forename: R A
authors.initials: RA
authors.lastname: Hawkins
mesh_terms: D000234:Adenoids / Q000528:radiation effects; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D003847:Deoxyglucose / Q000031:analogs & derivatives; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005881:Gingiva / Q000528:radiation effects; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000528:radiation effects; D009960:Oropharynx / Q000528:radiation effects; D014066:Palatine Tonsil / Q000528:radiation effects; D012469:Salivary Glands / Q000528:radiation effects; D014055:Tomography, Emission-Computed
chemical_list: D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose