Volumetric Spectroscopic Imaging of Glioblastoma Multiforme Radiation Treatment Volumes

Journal Article · Wed Oct 01 04:00:00 EDT 2014 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2014.03.049· OSTI ID:22423823

Parra, N. Andres ^[1]; Maudsley, Andrew A. ^[2]; Gupta, Rakesh K. ^[3]; Ishkanian, Fazilat; Huang, Kris ^[1]; Walker, Gail R. ^[4]; Padgett, Kyle ^[1]; Roy, Bhaswati ^[3]; Panoff, Joseph; Markoe, Arnold ^[1]; Stoyanova, Radka ^[1]

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1. Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida (United States)
2. Department of Radiology, University of Miami Miller School of Medicine, Miami, Florida (United States)
3. Department of Radiology and Imaging, Fortis Memorial Research Institute, Gurgaon, Haryana (India)
4. Biostatistics and Bioinformatics Core Resource, Sylvester Cancer Center, University of Miami Miller School of Medicine, Miami, Florida (United States)

Purpose: Magnetic resonance (MR) imaging and computed tomography (CT) are used almost exclusively in radiation therapy planning of glioblastoma multiforme (GBM), despite their well-recognized limitations. MR spectroscopic imaging (MRSI) can identify biochemical patterns associated with normal brain and tumor, predominantly by observation of choline (Cho) and N-acetylaspartate (NAA) distributions. In this study, volumetric 3-dimensional MRSI was used to map these compounds over a wide region of the brain and to evaluate metabolite-defined treatment targets (metabolic tumor volumes [MTV]). Methods and Materials: Volumetric MRSI with effective voxel size of ∼1.0 mL and standard clinical MR images were obtained from 19 GBM patients. Gross tumor volumes and edema were manually outlined, and clinical target volumes (CTVs) receiving 46 and 60 Gy were defined (CTV{sub 46} and CTV{sub 60}, respectively). MTV{sub Cho} and MTV{sub NAA} were constructed based on volumes with high Cho and low NAA relative to values estimated from normal-appearing tissue. Results: The MRSI coverage of the brain was between 70% and 76%. The MTV{sub NAA} were almost entirely contained within the edema, and the correlation between the 2 volumes was significant (r=0.68, P=.001). In contrast, a considerable fraction of MTV{sub Cho} was outside of the edema (median, 33%) and for some patients it was also outside of the CTV{sub 46} and CTV{sub 60}. These untreated volumes were greater than 10% for 7 patients (37%) in the study, and on average more than one-third (34.3%) of the MTV{sub Cho} for these patients were outside of CTV{sub 60}. Conclusions: This study demonstrates the potential usefulness of whole-brain MRSI for radiation therapy planning of GBM and revealed that areas of metabolically active tumor are not covered by standard RT volumes. The described integration of MTV into the RT system will pave the way to future clinical trials investigating outcomes in patients treated based on metabolic information.

• OSTI ID: 22423823
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 2 Vol. 90; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BIOMEDICAL RADIOGRAPHY
BRAIN
CHOLINE
CLINICAL TRIALS
COMPUTERIZED TOMOGRAPHY
EDEMA
GLIOMAS
NMR IMAGING
PATIENTS
PLANNING
RADIOTHERAPY