title: Pharmacokinetic studies of ⁶⁸Ga-labeled Bombesin (⁶⁸Ga-BZH₃) and F-18 FDG PET in patients with recurrent gliomas and comparison to grading: preliminary results.
abstract: OBJECTIVE
  Dynamic PET studies with a ⁶⁸Ga-Bombesin analog, the ⁶⁸Ga-BZH₃, were performed in patients with highly suspected recurrent gliomas to investigate the effect of the receptor scintigraphy on tumor grading. Furthermore, dynamic F-18 Fluorodeoxyglucose (FDG) studies were performed for comparison.
  
  
  METHODS
  The study consisted of 15 patients with histologically confirmed recurrent gliomas. Dynamic PET scans using ⁶⁸Ga-BZH₃ and FDG were obtained on 2 different days within 1 week. Multivariate analysis was used for the evaluation of the kinetic data. Standardized uptake values were calculated and a compartment (2-tissue) as well as a noncompartment model was used for data evaluation of both tracers.
  
  
  RESULTS
  The evaluation includes 6 patients with a WHO II, 6 patients with a WHO III, and 3 patients with a WHO IV recurrent gliomas. Of the 15 patients, 10 patients demonstrated an increased ⁶⁸Ga-BZH₃ uptake visually, 3 of them with a WHO II, 4 with a WHO III, and 3 with a WHO IV tumor. Of the 15 patients, 6 patients revealed an enhanced FDG metabolism visually, 3 of them with a WHO II, and 3 with a WHO III. None of the 3 patients with WHO IV tumor demonstrated an enhanced FDG-uptake. Discriminant analysis based on a combination of FDG influx and binding potential of ⁶⁸Ga-BZH₃ best discriminated between low- and high-grade gliomas with a correct classification rate of 100%.
  
  
  CONCLUSIONS
  ⁶⁸Ga-BZH₃ seems to be helpful in patients with recurrent gliomas for the differentiation between low- and high-grade gliomas. Overall, the quantitative evaluation was superior to the visual analysis and the parameters of the ⁶⁸Ga-BZH₃ kinetics were more helpful than those of FDG for the differentiation between low- and high-grade gliomas.
authors.affiliation: Medical PET Group--Biological Imaging, Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg, Germany. ads@ads-lgs.de
authors.forename: Antonia
authors.initials: A
authors.lastname: Dimitrakopoulou-Strauss
authors.forename: Marcel
authors.initials: M
authors.lastname: Seiz
authors.forename: Jochen
authors.initials: J
authors.lastname: Tuettenberg
authors.forename: Kirsten
authors.initials: K
authors.lastname: Schmieder
authors.forename: Michael
authors.initials: M
authors.lastname: Eisenhut
authors.forename: Uwe
authors.initials: U
authors.lastname: Haberkorn
authors.forename: Ludwig G
authors.initials: LG
authors.lastname: Strauss
mesh_terms: D001839:Bombesin / Q000493:pharmacokinetics*; D016002:Discriminant Analysis; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D005710:Gallium Radioisotopes; D005910:Glioma / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D049268:Positron-Emission Tomography; D012008:Recurrence
chemical_list: D005710:Gallium Radioisotopes; D019788:Fluorodeoxyglucose F18; D001839:Bombesin