Impact of [ 11C]methionine positron emission tomography for target definition of glioblastoma multiforme in radiation therapy planning

Masayuki Matsuo, Kazuhiro Miwa, Osamu Tanaka, Jun Shinoda, Hironori Nishibori, Yusuke Tsuge, Hirohito Yano, Toru Iwama, Shinya Hayashi, Hiroaki Hoshi, Jitsuhiro Yamada, Masayuki Kanematsu, Hidefumi Aoyama

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60 Citations (Scopus)

Abstract

Purpose: The purpose of this work was to define the optimal margins for gadolinium-enhanced T 1-weighted magnetic resonance imaging (Gd-MRI) and T 2-weighted MRI (T 2-MRI) for delineating target volumes in planning radiation therapy for postoperative patients with newly diagnosed glioblastoma multiforme (GBM) by comparison to carbon-11-labeled methionine positron emission tomography ([ 11C]MET-PET) findings. Methods and Materials: Computed tomography (CT), MRI, and [ 11C]MET- PET were separately performed for radiation therapy planning for 32 patients newly diagnosed with GBM within 2 weeks after undergoing surgery. The extent of Gd-MRI (Gd-enhanced clinical target volume [CTV-Gd]) uptake and that of T 2-MRI of the CTV (CTV-T 2) were compared with the extent of [ 11C]MET-PET (CTV - [ 11C]MET-PET) uptake by using CT - MRI or CT - [ 11C]MET-PET fusion imaging. We defined CTV-Gd (x mm) and CTV-T 2 (x mm) as the x-mm margins (where x = 0, 2, 5, 10, and 20 mm) outside the CTV-Gd and the CTV-T 2, respectively. We evaluated the relationship between CTV-Gd (x mm) and CTV - [ 11C]MET-PET and the relationship between CTV-T 2 (x mm) and CTV - [ 11C]MET-PET. Results: The sensitivity of CTV-Gd (20 mm) (86.4%) was significantly higher than that of the other CTV-Gd. The sensitivity of CTV-T 2 (20 mm) (96.4%) was significantly higher than that of the other CTV-T 2 (x = 0, 2, 5, 10 mm). The highest sensitivity and lowest specificity was found with CTV-T 2 (x = 20 mm). Conclusions: It is necessary to use a margin of at least 2 cm for CTV-T 2 for the initial target planning of radiation therapy. However, there is a limit to this setting in defining the optimal margin for Gd-MRI and T 2-MRI for the precise delineation of target volumes in radiation therapy planning for postoperative patients with GBM.

Original languageEnglish
Pages (from-to)83-89
Number of pages7
JournalInternational Journal of Radiation Oncology Biology Physics
Volume82
Issue number1
DOIs
Publication statusPublished - 01-01-2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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