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

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 ([(11)C]MET-PET) findings.

METHODS AND MATERIALS:

Computed tomography (CT), MRI, and [(11)C]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 [(11)C]MET-PET (CTV--[(11)C]MET-PET) uptake by using CT--MRI or CT--[(11)C]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-- [(11)C]MET-PET and the relationship between CTV-T(2) (x mm) and CTV-- [(11)C]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.

• Authors: 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
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 82 Issue 1 Pg. 83-9 (Jan 01 2012) ISSN: 1879-355X [Electronic] United States
• PMID: 21095072 (Publication Type: Comparative Study, Evaluation Study, Journal Article)
• Copyright: Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical References

• Contrast Media
• Radiopharmaceuticals
• carbon-11 methionine
• Methionine
• Gadolinium

Topics

• Adult
• Aged
• Aged, 80 and over
• Brain Neoplasms (diagnostic imaging, pathology, radiotherapy)
• Contrast Media
• Female
• Gadolinium
• Glioblastoma (diagnostic imaging, pathology, radiotherapy)
• Humans
• Magnetic Resonance Imaging (methods)
• Male
• Methionine
• Middle Aged
• Positron-Emission Tomography (methods)
• Radiopharmaceuticals
• Radiotherapy Planning, Computer-Assisted (methods)
• Sensitivity and Specificity
• Tomography, Spiral Computed (methods)
• Tumor Burden
• Young Adult