title: In vivo metabolism of childhood posterior fossa tumors and primitive neuroectodermal tumors before and after treatment.
abstract: BACKGROUND
  Despite an increasing interest in the clinical application of positron emission tomography (PET) in tumors of the adult patient as a diagnostic and prognostic tool, only a few studies have been concerned with the usefulness of PET with [18F]2-deoxy-2-fluoro-D-glucose (FDG) in childhood tumors.
  
  
  METHODS
  Fifteen children and young adults (0.5-26.0 years of age) with histologically confirmed brain tumors were studied with PET and FDG. Seven children with medulloblastoma (n = 5) or primitive neuroectodermal tumor (PNET) (n = 2) underwent repeated PET studies during their therapy. The other eight children with medulloblastoma (n = 5) or astrocytoma (n = 3) were studied only once before initiation of treatment. A close clinical follow-up was performed in every case.
  
  
  RESULTS
  Comparison of local glucose metabolic rates obtained in the various tumor lesions revealed that the mean rates found in medulloblastomas (mean glucose metabolic rate, 42.8 +/- 14.03 mumol/100 g/min) were twice as high as the rates measured in either PNET (17.3 +/- 4.5 mumol/100g/min) or infratentorial gliomas (21.8 +/- 4.2 mumol/100g/min). The high metabolism of medulloblastomas enabled the observer to identify the tumor more easily and to clearly separate it from the surrounding unaffected brain tissue. In the seven patients with follow-up PET studies during therapy, decreasing or increasing ratios of tumor-to-white matter metabolic rate were not only commensurate with neuroradiologically defined tumor reduction or growth, but also corresponded to the duration of initial clinical improvement.
  
  
  CONCLUSIONS
  These preliminary results suggest that PET with FDG may be a useful tool to evaluate metabolic activity of pediatric brain tumors over time and to assess response to treatment.
authors.affiliation: Max-Planck-Institut für Neurologische Forschung, Köln, Germany.
authors.forename: V A
authors.initials: VA
authors.lastname: Holthoff
authors.forename: K
authors.initials: K
authors.lastname: Herholz
authors.forename: F
authors.initials: F
authors.lastname: Berthold
authors.forename: B
authors.initials: B
authors.lastname: Widemann
authors.forename: R
authors.initials: R
authors.lastname: Schröder
authors.forename: I
authors.initials: I
authors.lastname: Neubauer
authors.forename: W D
authors.initials: WD
authors.lastname: Heiss
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism*; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D003847:Deoxyglucose / Q000031:analogs & derivatives / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007223:Infant; D008297:Male; D008527:Medulloblastoma / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism*; D010865:Pilot Projects; D014055:Tomography, Emission-Computed
chemical_list: D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose; D005947:Glucose