Chiara Paganelli1, Danny Lee2, John Kipritidis3,4, Brendan Whelan4, Peter B Greer2,5, Guido Baroni1,6, Marco Riboldi7, Paul Keall4. 1. Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy. 2. Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, New South Wales, Australia. 3. Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia. 4. ACRF Image X Institute, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia. 5. School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales, Australia. 6. Bioengineering Unit, Centro Nazionale di Adroterapia Oncologica, Pavia, Italy. 7. Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany.
Abstract
INTRODUCTION: In-room MRI is a promising image guidance strategy in external beam radiotherapy to acquire volumetric information for moving targets. However, limitations in spatio-temporal resolution led several authors to use 2D orthogonal images for guidance. The aim of this work is to present a method to concurrently compensate for non-rigid tumour motion and provide an approach for 3D reconstruction from 2D orthogonal cine-MRI slices for MRI-guided treatments. METHODS: Free-breathing sagittal/coronal interleaved 2D cine-MRI were acquired in addition to a pre-treatment 3D volume in two patients. We performed deformable image registration (DIR) between cine-MRI slices and corresponding slices in the pre-treatment 3D volume. Based on an extrapolation of the interleaved 2D motion fields, the 3D motion field was estimated and used to warp the pre-treatment volume. Due to the lack of a ground truth for patients, the method was validated on a digital 4D lung phantom. RESULTS: On the phantom, the 3D reconstruction method was able to compensate for tumour motion and compared favourably to the results of previously adopted strategies. The difference in the 3D motion fields between the phantom and the extrapolated motion was 0.4 ± 0.3 mm for tumour and 0.8 ± 1.5 mm for whole anatomy, demonstrating feasibility of performing a 3D volumetric reconstruction directly from 2D orthogonal cine-MRI slices. Application of the method to patient data confirmed the feasibility of utilizing this method in real world scenarios. CONCLUSION: Preliminary results on phantom and patient cases confirm the feasibility of the proposed approach in an MRI-guided scenario, especially for non-rigid tumour motion compensation.
INTRODUCTION: In-room MRI is a promising image guidance strategy in external beam radiotherapy to acquire volumetric information for moving targets. However, limitations in spatio-temporal resolution led several authors to use 2D orthogonal images for guidance. The aim of this work is to present a method to concurrently compensate for non-rigid tumour motion and provide an approach for 3D reconstruction from 2D orthogonal cine-MRI slices for MRI-guided treatments. METHODS: Free-breathing sagittal/coronal interleaved 2D cine-MRI were acquired in addition to a pre-treatment 3D volume in two patients. We performed deformable image registration (DIR) between cine-MRI slices and corresponding slices in the pre-treatment 3D volume. Based on an extrapolation of the interleaved 2D motion fields, the 3D motion field was estimated and used to warp the pre-treatment volume. Due to the lack of a ground truth for patients, the method was validated on a digital 4D lung phantom. RESULTS: On the phantom, the 3D reconstruction method was able to compensate for tumour motion and compared favourably to the results of previously adopted strategies. The difference in the 3D motion fields between the phantom and the extrapolated motion was 0.4 ± 0.3 mm for tumour and 0.8 ± 1.5 mm for whole anatomy, demonstrating feasibility of performing a 3D volumetric reconstruction directly from 2D orthogonal cine-MRI slices. Application of the method to patient data confirmed the feasibility of utilizing this method in real world scenarios. CONCLUSION: Preliminary results on phantom and patient cases confirm the feasibility of the proposed approach in an MRI-guided scenario, especially for non-rigid tumour motion compensation.
Authors: Jihye Koo; Louis Nardella; Michael Degnan; Jacqueline Andreozzi; Hsiang-Hsuan M Yu; Jose Penagaricano; Peter A S Johnstone; Daniel Oliver; Kamran Ahmed; Stephen A Rosenberg; Evan Wuthrick; Roberto Diaz; Vladimir Feygelman; Kujtim Latifi; Eduardo G Moros; Gage Redler Journal: Technol Cancer Res Treat Date: 2021 Jan-Dec
Authors: Christopher Kurz; Giulia Buizza; Guillaume Landry; Florian Kamp; Moritz Rabe; Chiara Paganelli; Guido Baroni; Michael Reiner; Paul J Keall; Cornelis A T van den Berg; Marco Riboldi Journal: Radiat Oncol Date: 2020-05-05 Impact factor: 3.481
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