title: Methionine Uptake and Required Radiation Dose to Control Glioblastoma.
abstract: OBJECTIVE
  The purpose of this study was to retrospectively assess the feasibility of radiation therapy planning for glioblastoma multiforme (GBM) based on the use of methionine (MET) positron emission tomography (PET), and the correlation among MET uptake, radiation dose, and tumor control.
  
  
  METHODS
  Twenty-two patients with GBM who underwent MET-PET prior to radiation therapy were enrolled. MET uptake in 30 regions of interest (ROIs) from 22 GBMs, biologically effective doses (BEDs) for the ROIs and their ratios (MET uptake:BED) were compared in terms of whether the ROIs were controlled for >12 months.
  
  
  RESULTS
  MET uptake was significantly correlated with tumor control (odds ratio [OR], 10.0; P = .005); however, there was a higher level of correlation between MET uptake:BED ratio and tumor control (OR, 40.0; P < .0001). These data indicated that the required BEDs for controlling the ROIs could be predicted in terms of MET uptake; BED could be calculated as [34.0 × MET uptake] Gy from the optimal threshold of the MET uptake:BED ratio for tumor control.
  
  
  CONCLUSIONS
  Target delineation based on MET-PET was demonstrated to be feasible for radiation therapy treatment planning. MET-PET could not only provide precise visualization of infiltrating tumor cells but also predict the required radiation doses to control target regions.
authors.affiliation: Division of Neurological Surgery, Chiba Cancer Center, Chiba, Japan. Electronic address: tiuchi@chiba-cc.jp.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Iuchi
authors.affiliation: Division of Radiation Oncology, Tokyo Bay Advanced Imaging and Radiation Oncology Clinic, Makuhari, Chiba, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hatano
authors.affiliation: Division of Nuclear Medicine, Chiba Ryogo Center, Chiba, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Uchino
authors.affiliation: Division of Surgical Pathology, Chiba Cancer Center, Chiba, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Itami
authors.affiliation: Division of Neurological Surgery, Chiba Cancer Center, Chiba, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: Division of Neurological Surgery, Chiba Cancer Center, Chiba, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kawasaki
authors.affiliation: Division of Neurological Surgery, Chiba Cancer Center, Chiba, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sakaida
authors.affiliation: Division of Radiation Oncology, Chiba Cancer Center, Chiba, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Hara
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy*; D005240:Feasibility Studies; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008715:Methionine / Q000493:pharmacokinetics*; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012062:Relative Biological Effectiveness; D012189:Retrospective Studies
chemical_list: D008715:Methionine