Eric Paradis1, Yue Cao2, Theodore S Lawrence3, Christina Tsien3, Mary Feng3, Karen Vineberg3, James M Balter3. 1. Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan. Electronic address: eparadis@umich.edu. 2. Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan; Department of Radiology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan; Department of Biomedical Engineering, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan. 3. Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan.
Abstract
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 D(95%); 0.0% (-0.7 to 0.6%) for D(5%); and -0.2% (-1.0 to 0.2%) for D(max). MRCT plans showed no significant changes in monitor units (-0.4%) compared to CT plans. Organs at risk (OARs) had average D(max) 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.
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 D(95%); 0.0% (-0.7 to 0.6%) for D(5%); and -0.2% (-1.0 to 0.2%) for D(max). MRCT plans showed no significant changes in monitor units (-0.4%) compared to CT plans. Organs at risk (OARs) had average D(max) 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.
Authors: Jan J W Lagendijk; Bas W Raaymakers; Alexander J E Raaijmakers; Johan Overweg; Kevin J Brown; Ellen M Kerkhof; Richard W van der Put; Björn Hårdemark; Marco van Vulpen; Uulke A van der Heide Journal: Radiother Oncol Date: 2007-11-26 Impact factor: 6.280
Authors: Lili Chen; Robert A Price; Lu Wang; Jinsheng Li; Lihong Qin; Shawn McNeeley; C-M Charlie Ma; Gary M Freedman; Alan Pollack Journal: Int J Radiat Oncol Biol Phys Date: 2004-10-01 Impact factor: 7.038
Authors: Shangjie Ren; Wendy Hara; Lei Wang; Mark K Buyyounouski; Quynh-Thu Le; Lei Xing; Ruijiang Li Journal: Int J Radiat Oncol Biol Phys Date: 2016-12-14 Impact factor: 7.038