Validation of echo planar imaging based diffusion-weighted magnetic resonance imaging on a 0.35 T MR-Linac.

Autor:	Wallimann P; Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Piccirelli M; Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Nowakowska S; Institute for Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Armstrong T; ViewRay Inc., 2 Thermo Fisher Way, Oakwood Village, OH 44146, USA., Mayinger M; Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Boss A; Institute for Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Bink A; Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Guckenberger M; Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Tanadini-Lang S; Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Andratschke N; Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland., Pouymayou B; Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.; Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
Jazyk:	angličtina
Zdroj:	Physics and imaging in radiation oncology [Phys Imaging Radiat Oncol] 2024 Apr 20; Vol. 30, pp. 100579. Date of Electronic Publication: 2024 Apr 20 (Print Publication: 2024).
DOI:	10.1016/j.phro.2024.100579
Abstrakt:	Background and Purpose: The feasibility of acquiring diffusion-weighted imaging (DWI) images on an MR-Linac for quantitative response assessment during radiotherapy was explored. DWI data obtained with a Spin Echo Echo Planar Imaging sequence adapted for a 0.35 T MR-Linac were examined and compared with DWI data from a conventional 3 T scanner. Materials and Methods: Apparent diffusion coefficient (ADC) measurements and a distortion correction technique were investigated using DWI-calibrated phantoms and in the brains of seven volunteers. All DWI utilized two phase-encoding directions for distortion correction and off-resonance field estimation. ADC maps in the brain were analyzed for automatically segmented normal tissues. Results: Phantom ADC measurements on the MR-Linac were within a 3 % margin of those recorded by the 3 T scanner. The maximum distortion observed in the phantom was 2.0 mm prior to correction and 1.1 mm post-correction on the MR-Linac, compared to 6.0 mm before correction and 3.6 mm after correction at 3 T. In vivo, the average ADC values for gray and white matter exhibited variations of 14 % and 4 %, respectively, for different selections of b-values on the MR-Linac. Distortions in brain images before correction, estimated through the off-resonance field, reached 2.7 mm on the MR-Linac and 12 mm at 3 T. Conclusion: Accurate ADC measurements are achievable on a 0.35 T MR-Linac, both in phantom and in vivo. The selection of b-values significantly influences ADC values in vivo. DWI on the MR-Linac demonstrated lower distortion levels, with a maximum distortion reduced to 1.1 mm after correction. Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: PW, MM, NA, BP have previously received compensation from ViewRay, Inc. for consulting work. For a time period during this project, TA was employed at ViewRay, Inc. and owned stocks in ViewRay, Inc. (© 2024 The Authors.)
Databáze:	MEDLINE
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