title: Imaging tumor perfusion and oxidative metabolism in patients with head-and-neck cancer using 1- [11C]-acetate PET during radiotherapy: preliminary results.
abstract: BACKGROUND
  A growing body of in vitro evidence links alterations of the intermediary metabolism in cancer to treatment outcome. This study aimed to characterize tumor oxidative metabolism and perfusion in vivo using dynamic positron emission tomography (PET) with 1- [(11)C]-acetate (ACE) during radiotherapy.
  
  
  METHODS
  Nine patients with head-and-neck cancer were studied. Oxidative metabolic rate (k(mono)) and perfusion (rF) of the primary tumors were assessed by dynamic ACE-PET at baseline and after 15, 30, and 55 Gy was delivered. Tumor glucose uptake (Tglu) was evaluated with [(18)F]-fluorodeoxyglucose PET at baseline. Patients were grouped into complete (CR, n = 6) and partial responders (PR, n = 3) to radiotherapy.
  
  
  RESULTS
  The 3 PR patients died within a median follow-up period of 33 months. Baseline k(mono) was almost twice as high in CR as in PR (p = 0.02) and Tglu was lower in CR than in PR (p = 0.04). k(mono) increased during radiotherapy in PR (p = 0.004) but remained unchanged in CR. There were no differences in rF between CR and PR at any dosage. k(mono) and rF were coupled in CR (p = 0.001), but not in PR.
  
  
  CONCLUSIONS
  This study shows that radiosensitive tumors might rely predominantly on oxidative metabolism for their bioenergetic needs. The impairment of oxidative metabolism in radioresistant tumors is potentially reversible, suggesting that therapies targeting the intermediary metabolism might improve treatment outcome.
authors.affiliation: Section of Nuclear Medicine, Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Aijun
authors.initials: A
authors.lastname: Sun
authors.forename: Silvia
authors.initials: S
authors.lastname: Johansson
authors.forename: Ingela
authors.initials: I
authors.lastname: Turesson
authors.forename: Alexandru
authors.initials: A
authors.lastname: Daşu
authors.forename: Jens
authors.initials: J
authors.lastname: Sörensen
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000293:Adolescent; D000368:Aged; D002250:Carbon Radioisotopes; D002294:Carcinoma, Squamous Cell / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis / Q000502:physiology; D006258:Head and Neck Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods*; D011836:Radiation Tolerance; D019275:Radiopharmaceuticals / Q000378:metabolism; D011879:Radiotherapy Dosage; D012039:Regional Blood Flow; D012074:Remission Induction
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose; D019342:Acetic Acid; D010100:Oxygen