title: Glucose metabolic changes in nontumoral brain tissue of patients with brain tumor following radiotherapy: a preliminary study.
abstract: OBJECTIVE
  Our goal was to measure the effect of radiotherapy on the brain glucose metabolism of tumoral and nontumoral tissue of patients with brain malignancies.
  
  
  METHODS
  Fifteen patients with primary or metastatic brain tumors were studied with 2-deoxy-2-[18F]fluoro-D-glucose and PET prior to radiotherapy, and nine of them were rescanned 1 week after completing radiotherapy.
  
  
  RESULTS
  Brain metabolism in patients (all brain regions except for tumoral and edematous tissue) was lower than that of matched controls (34.0 +/- 8.3 vs. 46.5 +/- 6.4 mumol/100 g/min; p < or = 0.0001). Five of the nine patients retested after radiotherapy showed decrements in tumor metabolism (47 +/- 10%; p < or = 0.05) and increases in brain metabolism (10 +/- 4%; p < or = 0.004), and the other four showed no changes in tumor or in brain metabolism. Radiotherapy-induced changes in tumor metabolism were negatively correlated with changes in brain metabolism (r = 0.85, p < or = 0.004), but not with changes in tumor volume (assessed with MR images).
  
  
  CONCLUSIONS
  The study indicates that radiotherapy-induced increases in metabolism of nontumoral tissue are secondary to decreased tumor metabolic activity and not just due to volume reduction.
authors.affiliation: Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: G J
authors.initials: GJ
authors.lastname: Wang
authors.forename: N D
authors.initials: ND
authors.lastname: Volkow
authors.forename: Y H
authors.initials: YH
authors.lastname: Lau
authors.forename: J S
authors.initials: JS
authors.lastname: Fowler
authors.forename: A G
authors.initials: AG
authors.lastname: Meek
authors.forename: T L
authors.initials: TL
authors.lastname: Park
authors.forename: C
authors.initials: C
authors.lastname: Wong
authors.forename: C T
authors.initials: CT
authors.lastname: Roque
authors.forename: A J
authors.initials: AJ
authors.lastname: Adler
authors.forename: A P
authors.initials: AP
authors.lastname: Wolf
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000378:metabolism* / Q000528:radiation effects; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy*; D003847:Deoxyglucose / Q000031:analogs & derivatives; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D014055:Tomography, Emission-Computed
chemical_list: D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose; D005947:Glucose