TY - JOUR
T1 - Assessing the dosimetric accuracy of magnetic resonance-generated synthetic CT images for focal brain VMAT radiation therapy
AU - Paradis, Eric
AU - Cao, Yue
AU - Lawrence, Theodore S.
AU - Tsien, Christina
AU - Feng, Mary
AU - Vineberg, Karen
AU - Balter, James M.
N1 - Funding Information:
This work was supported by National Institutes of Health grant R01EB016079 . Works-in-progress versions of the ultrashort echo time sequences and pointwise time reduction with radial acquisition scanning sequences were provided under a research agreement with Siemens Medical Systems.
Publisher Copyright:
© 2015 Elsevier Inc.
PY - 2015/12/1
Y1 - 2015/12/1
N2 - Purpose The purpose of this study was to assess the dosimetric accuracy of synthetic CT (MRCT) volumes generated from magnetic resonance imaging (MRI) data for focal brain radiation therapy. Methods and Materials A study was conducted in 12 patients with gliomas who underwent both MR and CT imaging as part of their simulation for external beam treatment planning. MRCT volumes were generated from MR images. Patients' clinical treatment planning directives were used to create 12 individual volumetric modulated arc therapy (VMAT) plans, which were then optimized 10 times on each of their respective CT and MRCT-derived electron density maps. Dose metrics derived from optimization criteria, as well as monitor units and gamma analyses, were evaluated to quantify differences between the imaging modalities. Results Mean differences between planning target volume (PTV) doses on MRCT and CT plans across all patients were 0.0% (range: -0.1 to 0.2%) for D95%; 0.0% (-0.7 to 0.6%) for D5%; and -0.2% (-1.0 to 0.2%) for Dmax. MRCT plans showed no significant changes in monitor units (-0.4%) compared to CT plans. Organs at risk (OARs) had average Dmax differences of 0.0 Gy (-2.2 to 1.9 Gy) over 85 structures across all 12 patients, with no significant differences when calculated doses approached planning constraints. Conclusions Focal brain VMAT plans optimized on MRCT images show excellent dosimetric agreement with standard CT-optimized plans. PTVs show equivalent coverage, and OARs do not show any overdose. These results indicate that MRI-derived synthetic CT volumes can be used to support treatment planning of most patients treated for intracranial lesions.
AB - Purpose The purpose of this study was to assess the dosimetric accuracy of synthetic CT (MRCT) volumes generated from magnetic resonance imaging (MRI) data for focal brain radiation therapy. Methods and Materials A study was conducted in 12 patients with gliomas who underwent both MR and CT imaging as part of their simulation for external beam treatment planning. MRCT volumes were generated from MR images. Patients' clinical treatment planning directives were used to create 12 individual volumetric modulated arc therapy (VMAT) plans, which were then optimized 10 times on each of their respective CT and MRCT-derived electron density maps. Dose metrics derived from optimization criteria, as well as monitor units and gamma analyses, were evaluated to quantify differences between the imaging modalities. Results Mean differences between planning target volume (PTV) doses on MRCT and CT plans across all patients were 0.0% (range: -0.1 to 0.2%) for D95%; 0.0% (-0.7 to 0.6%) for D5%; and -0.2% (-1.0 to 0.2%) for Dmax. MRCT plans showed no significant changes in monitor units (-0.4%) compared to CT plans. Organs at risk (OARs) had average Dmax differences of 0.0 Gy (-2.2 to 1.9 Gy) over 85 structures across all 12 patients, with no significant differences when calculated doses approached planning constraints. Conclusions Focal brain VMAT plans optimized on MRCT images show excellent dosimetric agreement with standard CT-optimized plans. PTVs show equivalent coverage, and OARs do not show any overdose. These results indicate that MRI-derived synthetic CT volumes can be used to support treatment planning of most patients treated for intracranial lesions.
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U2 - 10.1016/j.ijrobp.2015.08.049
DO - 10.1016/j.ijrobp.2015.08.049
M3 - Article
C2 - 26581151
AN - SCOPUS:84946752325
SN - 0360-3016
VL - 93
SP - 1154
EP - 1161
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 5
ER -