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Moreira A, Li W, Berlin A, Carpino-Rocca C, Chung P, Conroy L, Dang J, Dawson LA, Glicksman RM, Hosni A, Keller H, Kong V, Lindsay P, Shessel A, Stanescu T, Taylor E, Winter J, Yan M, Letourneau D, Milosevic M, Velec M. Prospective evaluation of patient-reported anxiety and experiences with adaptive radiation therapy on an MR-linac. Tech Innov Patient Support Radiat Oncol 2024; 29:100240. [PMID: 38445180 PMCID: PMC10912905 DOI: 10.1016/j.tipsro.2024.100240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/13/2024] [Accepted: 02/26/2024] [Indexed: 03/07/2024] Open
Abstract
Purpose An integrated magnetic resonance scanner and linear accelerator (MR-linac) was implemented with daily online adaptive radiation therapy (ART). This study evaluated patient-reported experiences with their overall hospital care as well as treatment in the MR-linac environment. Methods Patients pre-screened for MR eligibility and claustrophobia were referred to simulation on a 1.5 T MR-linac. Patient-reported experience measures were captured using two validated surveys. The 15-item MR-anxiety questionnaire (MR-AQ) was administered immediately after the first treatment to rate MR-related anxiety and relaxation. The 40-item satisfaction with cancer care questionnaire rating doctors, radiation therapists, the services and care organization and their outpatient experience was administered immediately after the last treatment using five-point Likert responses. Results were analyzed using descriptive statistics. Results 205 patients were included in this analysis. Multiple sites were treated across the pelvis and abdomen with a median treatment time per fraction of 46 and 66 min respectively. Patients rated MR-related anxiety as "not at all" (87%), "somewhat" (11%), "moderately" (1%) and "very much so" (1%). Positive satisfaction responses ranged from 78 to 100% (median 93%) across all items. All radiation therapist-specific items were rated positively as 96-100%. The five lowest rated items (range 78-85%) were related to general provision of information, coordination, and communication. Overall hospital care was rated positively at 99%. Conclusion In this large, single-institution prospective cohort, all patients had low MR-related anxiety and completed treatment as planned despite lengthy ART treatments with the MR-linac. Patients overall were highly satisfied with their cancer care involving ART using an MR-linac.
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Affiliation(s)
- Amanda Moreira
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Winnie Li
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Alejandro Berlin
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Cathy Carpino-Rocca
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Peter Chung
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Leigh Conroy
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Jennifer Dang
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Laura A. Dawson
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Rachel M. Glicksman
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Ali Hosni
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Harald Keller
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Vickie Kong
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Patricia Lindsay
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Andrea Shessel
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Teo Stanescu
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Edward Taylor
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Jeff Winter
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Michael Yan
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Daniel Letourneau
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Michael Milosevic
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Michael Velec
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
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Mushonga M, Helou J, Weiss J, Dawson LA, Wong RKS, Hosni A, Kim J, Brierley J, Koch CA, Alrabiah K, Lindsay P, Stanescu T, Barry A. Clinical Outcomes of Patients with Metastatic Breast Cancer Treated with Hypo-Fractionated Liver Radiotherapy. Cancers (Basel) 2023; 15:2839. [PMID: 37345175 DOI: 10.3390/cancers15102839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/11/2023] [Accepted: 05/13/2023] [Indexed: 06/23/2023] Open
Abstract
PURPOSE To retrospectively review the clinical outcomes of patients with metastatic breast cancer (MBCa) following liver directed ablative intent radiotherapy (RT). METHODS Demographics, disease and treatment characteristics of patients with MBCa who received liver metastasis (LM) directed ablative RT between 2004-2020 were analysed. The primary outcome was local control (LC), secondary outcomes included overall survival (OS) and progression-free survival (PFS) analyzed by univariate (UVA) and multi-variable analysis (MVA). RESULTS Thirty MBCa patients with 50 LM treated with 5-10 fraction RT were identified. Median follow-up was 14.6 (range 0.9-156.2) months. Class of metastatic disease was described as induced (12 patients, 40%), repeat (15 patients, 50%) and de novo (three patients, 10%). Median size of treated LM was 3.1 cm (range 1-8.8 cm) and median biologically effective dose delivered was 122 (Q1-Q3; 98-174) Gy3. One-year LC rate was 100%. One year and two-year survival was 89% and 63%, respectively, with size of treated LM predictive of OS (HR 1.35, p = 0.023) on UVA. Patients with induced OMD had a significantly higher rate of progression (HR 4.77, p = 0.01) on UVA, trending to significance on MVA (HR 3.23, p = 0.051). CONCLUSIONS Hypo-fractionated ablative liver RT in patients with MBCa provides safe, tolerable treatment with excellent LC.
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Affiliation(s)
- Melinda Mushonga
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Joelle Helou
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
- Department of Oncology, Division of Radiation Oncology, Western University, London, ON N6A 5W9, Canada
| | - Jessica Weiss
- Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada
| | - Laura A Dawson
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Rebecca K S Wong
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Ali Hosni
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - John Kim
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - James Brierley
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - C Anne Koch
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Khalid Alrabiah
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Patricia Lindsay
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Teo Stanescu
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Aisling Barry
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
- Cancer Research @UCC, University College Cork, T12 R229 Cork, Ireland
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Goodburn RJ, Philippens MEP, Lefebvre TL, Khalifa A, Bruijnen T, Freedman JN, Waddington DEJ, Younus E, Aliotta E, Meliadò G, Stanescu T, Bano W, Fatemi‐Ardekani A, Wetscherek A, Oelfke U, van den Berg N, Mason RP, van Houdt PJ, Balter JM, Gurney‐Champion OJ. The future of MRI in radiation therapy: Challenges and opportunities for the MR community. Magn Reson Med 2022; 88:2592-2608. [PMID: 36128894 PMCID: PMC9529952 DOI: 10.1002/mrm.29450] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/17/2022] [Accepted: 08/22/2022] [Indexed: 01/11/2023]
Abstract
Radiation therapy is a major component of cancer treatment pathways worldwide. The main aim of this treatment is to achieve tumor control through the delivery of ionizing radiation while preserving healthy tissues for minimal radiation toxicity. Because radiation therapy relies on accurate localization of the target and surrounding tissues, imaging plays a crucial role throughout the treatment chain. In the treatment planning phase, radiological images are essential for defining target volumes and organs-at-risk, as well as providing elemental composition (e.g., electron density) information for radiation dose calculations. At treatment, onboard imaging informs patient setup and could be used to guide radiation dose placement for sites affected by motion. Imaging is also an important tool for treatment response assessment and treatment plan adaptation. MRI, with its excellent soft tissue contrast and capacity to probe functional tissue properties, holds great untapped potential for transforming treatment paradigms in radiation therapy. The MR in Radiation Therapy ISMRM Study Group was established to provide a forum within the MR community to discuss the unmet needs and fuel opportunities for further advancement of MRI for radiation therapy applications. During the summer of 2021, the study group organized its first virtual workshop, attended by a diverse international group of clinicians, scientists, and clinical physicists, to explore our predictions for the future of MRI in radiation therapy for the next 25 years. This article reviews the main findings from the event and considers the opportunities and challenges of reaching our vision for the future in this expanding field.
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Affiliation(s)
- Rosie J. Goodburn
- Joint Department of PhysicsInstitute of Cancer Research and Royal Marsden NHS Foundation TrustLondonUnited Kingdom
| | | | - Thierry L. Lefebvre
- Department of PhysicsUniversity of CambridgeCambridgeUnited Kingdom
- Cancer Research UK Cambridge Research InstituteUniversity of CambridgeCambridgeUnited Kingdom
| | - Aly Khalifa
- Department of Medical BiophysicsUniversity of TorontoTorontoOntarioCanada
| | - Tom Bruijnen
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtNetherlands
| | | | - David E. J. Waddington
- Faculty of Medicine and Health, Sydney School of Health Sciences, ACRF Image X InstituteThe University of SydneySydneyNew South WalesAustralia
| | - Eyesha Younus
- Department of Medical Physics, Odette Cancer CentreSunnybrook Health Sciences CentreTorontoOntarioCanada
| | - Eric Aliotta
- Department of Medical PhysicsMemorial Sloan Kettering Cancer CenterNew YorkNew YorkUSA
| | - Gabriele Meliadò
- Unità Operativa Complessa di Fisica SanitariaAzienda Ospedaliera Universitaria Integrata VeronaVeronaItaly
| | - Teo Stanescu
- Department of Radiation Oncology, University of Toronto and Medical Physics, Princess Margaret Cancer CentreUniversity Health NetworkTorontoOntarioCanada
| | - Wajiha Bano
- Joint Department of PhysicsInstitute of Cancer Research and Royal Marsden NHS Foundation TrustLondonUnited Kingdom
| | - Ali Fatemi‐Ardekani
- Department of PhysicsJackson State University (JSU)JacksonMississippiUSA
- SpinTecxJacksonMississippiUSA
- Department of Radiation OncologyCommunity Health Systems (CHS) Cancer NetworkJacksonMississippiUSA
| | - Andreas Wetscherek
- Joint Department of PhysicsInstitute of Cancer Research and Royal Marsden NHS Foundation TrustLondonUnited Kingdom
| | - Uwe Oelfke
- Joint Department of PhysicsInstitute of Cancer Research and Royal Marsden NHS Foundation TrustLondonUnited Kingdom
| | - Nico van den Berg
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtNetherlands
| | - Ralph P. Mason
- Department of RadiologyUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Petra J. van Houdt
- Department of Radiation OncologyNetherlands Cancer InstituteAmsterdamNetherlands
| | - James M. Balter
- Department of Radiation OncologyUniversity of MichiganAnn ArborMichiganUSA
| | - Oliver J. Gurney‐Champion
- Imaging and Biomarkers, Cancer Center Amsterdam, Amsterdam UMCUniversity of AmsterdamAmsterdamNetherlands
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Stanescu T, Shessel A, Carpino-Rocca C, Taylor E, Semeniuk O, Li W, Barry A, Lukovic J, Dawson L, Hosni A. MRI-Guided Online Adaptive Stereotactic Body Radiation Therapy of Liver and Pancreas Tumors on an MR-Linac System. Cancers (Basel) 2022; 14:cancers14030716. [PMID: 35158984 PMCID: PMC8833602 DOI: 10.3390/cancers14030716] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023] Open
Abstract
Simple Summary The hybrid magnetic resonance imaging and medical linear accelerator (MR-Linac) systems are expected to revolutionize radiation therapy, uniquely offering high quality soft-tissue contrast and fast imaging to facilitate the online re-planning and guidance of the treatment delivery. While the clinical procedures for stereotactic body radiotherapy are well-established for conventional linacs (with their strengths and weaknesses), they still require significant development and refinement for the MR-Linac systems. Adjustment of fractionation schemes including clinical goals, patient selection, organ motion management, treatment session length, staff logistics, and overall complexity of the online re-planning sessions are key factors that drive the adoption of MR-Linac technologies. In this report, we present the clinical implementation of an MRI-guided radiation therapy workflow, which was used to treat 16 upper gastro-intestinal cancer patients on a 1.5 T MR-Linac platform. The workflow was proven to be feasible for a wide range of clinical scenarios, and the overall treatment session time was significantly reduced as tasks were optimized and the clinical team gradually gained expertise. Abstract Purpose: To describe a comprehensive workflow for MRI-guided online adaptive stereotactic body radiation therapy (SBRT) specific to upper gastrointestinal cancer patients with abdominal compression on a 1.5T MR-Linac system. Additionally, we discuss the workflow’s clinical feasibility and early experience in the case of 16 liver and pancreas patients. Methods: Eleven patients with liver cancer and five patients with pancreas cancer were treated with online adaptive MRI-guidance under abdominal compression. Two liver patients received single-fraction treatments; the remainder plus all pancreas cancer patients received five fractions. A total of 65 treatment sessions were investigated to provide analytics relevant to the online adaptive processes. The quantification of target and organ motion as well as definition and validation of internal target volume (ITV) margins were performed via multi-contrast imaging provided by three different 2D cine sequences. The plan generation was driven by full re-optimization strategies and using T2-weighted 3D image series acquired by means of a respiratory-triggered exhale phase or a time-averaged imaging protocol. As a pre-requisite for the clinical development of the procedure, the image quality was thoroughly investigated via phantom measurements and numerical simulations specific to upper abdominal sites. The delivery of the online adaptive treatments was facilitated by real-time monitoring with 2D cine imaging. Results: Liver 1-fraction and 5-fraction online adaptive session time were on average 80 and 67.5 min, respectively. The total session length varied between 70–90 min for a single fraction and 55–90 min for five fractions. The pancreas sessions were 54–85 min long with an average session time of 68.2 min. Target visualization on the 2D cine image data varied per patient, with at least one of the 2D cine sequences providing sufficient contrast to confidently identify its location and confirm reproducibility of ITV margins. The mean/range of absolute and relative dose values for all treatment sessions evaluated with ArcCheck were 90.6/80.9–96.1% and 99/95.4–100%, respectively. Conclusion: MR-guidance is feasible for liver and pancreas tumors when abdominal compression is used to reduce organ motion, improve imaging quality, and achieve a robust intra- and inter-fraction patient setup. However, the treatment length is significantly longer than for the conventional linac, and patient compliance is paramount for the successful completion of the treatment. Opportunities for reducing the online adaptive session time should be explored. As the next steps, dose-of-the-day and dose accumulation analysis and tools are needed to enhance the workflow and to help further refine the online re-planning processes.
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Affiliation(s)
- Teo Stanescu
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada
- Correspondence:
| | - Andrea Shessel
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
| | - Cathy Carpino-Rocca
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
| | - Edward Taylor
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Oleksii Semeniuk
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
| | - Winnie Li
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
| | - Aisling Barry
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Jelena Lukovic
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Laura Dawson
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Ali Hosni
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada; (A.S.); (C.C.-R.); (E.T.); (O.S.); (W.L.); (A.B.); (J.L.); (L.D.); (A.H.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
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Stanescu T, Mousavi SH, Cole M, Barberi E, Wachowicz K. Quantification of magnetic susceptibility fingerprint of a 3D linearity medical device. Phys Med 2021; 87:39-48. [PMID: 34116316 DOI: 10.1016/j.ejmp.2021.05.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 02/03/2023] Open
Abstract
PURPOSE The study investigates the numerical modelling as well as experimental validation of magnetic susceptibility effects with respect to a 3D linearity phantom used for the quantification of MR image distortions. METHODS Magnetic field numerical simulations based on finite difference methods were conducted to generate the susceptibility (χ) model of the MRID3D phantom. Experimental data was acquired and analyzed for eight different MR scanners to include a wide range of scanning parameters. Distortion vector fields were generated by applying a harmonic analysis based on finite elements methods. Phantom scans for the same setup but with opposite polarities of the frequency encoding gradient were processed in conjunction with the susceptibility modelling to separately quantify three field components due to gradient non-linearities (GNL), B0 inhomogeneities and χ perturbations. RESULTS The numerical modelling showed a significant range of χ value of up to 8.23 ppm, with a mean value of 2.9 ppm. The χ perturbations were found to be mostly present at the end plates of the cylindrical phantom design. The simulations also showed that setup rotations of up to 10° introduced only negligible variations in the χ model of less than 0.1 ppm. This allows for a straightforward practical implementation of the modelling as a single lookup table. After correcting for the χ perturbations, the B0 inhomogeneities were derived and found to be in good agreement with either the MR system manufacturer specifications or experimental data available in the literature. CONCLUSIONS It is possible to accurately model the magnetic susceptibility signature of a 3D linearity device and remove it as a post-processing correction step. This is important as the procedure unlocks the ability of determining both the GNL field and B0 map of the scanner without the need of extra acquisitions or phantoms.
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Affiliation(s)
- T Stanescu
- Princess Margaret Cancer Centre, University Health Network, Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
| | - S H Mousavi
- Princess Margaret Cancer Centre, University Health Network, Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada
| | - M Cole
- Modus QA, London, Ontario N6H 5L6, Canada
| | - E Barberi
- Modus QA, London, Ontario N6H 5L6, Canada
| | - K Wachowicz
- Cross Cancer Institute, Alberta Health Services, Department of Radiation Oncology, University of Alberta, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
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Lee M, Simeonov A, Stanescu T, Dawson LA, Brock KK, Velec M. MRI evaluation of normal tissue deformation and breathing motion under an abdominal compression device. J Appl Clin Med Phys 2021; 22:90-97. [PMID: 33449447 PMCID: PMC7882116 DOI: 10.1002/acm2.13165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 12/16/2020] [Accepted: 12/22/2020] [Indexed: 11/12/2022] Open
Abstract
Purpose Abdominal compression can minimize breathing motion in stereotactic radiotherapy, though it may impact the positioning of dose‐limiting normal tissues. This study quantified the reproducibility of abdominal normal tissues and respiratory motion with the use of an abdominal compression device using MR imaging. Methods Twenty healthy volunteers had repeat MR over 3 days under an abdominal compression plate device. Normal tissues were delineated on daily axial T2‐weighted MR and compared on days 2 and 3 relative to day 1, after adjusting for baseline shifts relative to bony anatomy. Inter‐fraction organ deformation was computed using deformable registration of axial T2 images. Deformation > 5 mm was assumed to be clinically relevant. Inter‐fraction respiratory amplitude changes and intra‐fraction baseline drifts during imaging were quantified on daily orthogonal cine‐MR (70 s each), and changes > 3 mm were assumed to be relevant. Results On axial MR, the mean inter‐fraction normal tissue deformation was > 5 mm for all organs (range 5.1–13.4 mm). Inter‐fraction compression device misplacements > 5 mm and changes in stomach volume > 50% occurred at a rate of 93% and 38%, respectively, in one or more directions and were associated with larger adjacent organ deformation, in particular for the duodenum. On cine‐MR, inter‐fraction amplitude changes > 3 mm on day 2 and 3 relative to day 1 occurred at a rate of < 12.5% (mean superior–inferior change was 1.6 mm). Intra‐fraction baseline drifts > 3 mm during any cine‐MR acquisition occurred at a rate of 23% (mean superior–inferior changes was 2.4 mm). Conclusions Respiratory motion under abdominal compression is reproducible in most subjects within 3 mm. However, inter‐fraction deformations greater than 5 mm in normal tissues were common and larger than inter‐ and intra‐fraction respiratory changes. Deformations were driven mostly by variable stomach contents and device positioning. The magnitude of this motion may impact normal tissue dosimetry during stereotactic radiotherapy.
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Affiliation(s)
- Maureen Lee
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada
| | - Anna Simeonov
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada
| | - Teo Stanescu
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada.,TECHNA Institute, University Health Network, 100 College Street, Toronto, ON, M5G 1L5, Canada
| | - Laura A Dawson
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada
| | - Kristy K Brock
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Michael Velec
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada.,TECHNA Institute, University Health Network, 100 College Street, Toronto, ON, M5G 1L5, Canada
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Stanescu T, Shessel A, Carpino-Rocca C, Simeonov A, Lukovic J, Velec M, Hosni A, Dawson L. Development of an Online Adaptive Procedure for MRI-Guided Liver SBRT. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.2387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Stanescu T, Shessel A, Carpino-Rocca C, Simeonov A, Velec M, Lukovic J, Hosni A, Dawson L. 24: Preliminary Experience with Mri-Guided Online Adaptive SBRT for Liver on An Mr-Linac System. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(20)30916-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Velec M, Munoz-Schuffenegger P, Simeonov A, Shessel A, Stanescu T, Lindsay P, Hosni A, Wong R, Dawson L. 158: Patient-Reported Experiences with Serial Magnetic Resonance Imaging and Implications for Adaptive Radiotherapy. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(20)31050-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Tadic T, Croke J, Xie J, Stanescu T, Letourneau D, Bissonnette J, Breen S, Simeonov A, Dickie C, Hill C, Li W, Ellis C, Winter J, Velec M, Fyles A, Han K, Jaffray D, Milosevic M. In-Room MRI for Adaptive Radiotherapy for Cervical Cancer Using an Integrated MR-Guided Radiation Therapy System. Int J Radiat Oncol Biol Phys 2019. [DOI: 10.1016/j.ijrobp.2019.06.834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Lee SL, Velec M, Munoz-Schuffenegger P, Stanescu T, Dawson L. Extensive Unpredictable Pancreas Cancer Inter-fraction Motion: A Case Report. Cureus 2019; 11:e5047. [PMID: 31501738 PMCID: PMC6721882 DOI: 10.7759/cureus.5047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present a case of locally advanced pancreatic cancer with duodenal invasion treated with consolidative chemoradiation, where extensive unpredictable interfraction motion was observed. Initially, two attempts were made to treat with volumetric modulated arc therapy technique. However, due to substantial interfractional motion of the pancreatic head mass relative to the regional nodal areas, the patient was eventually replanned and treated with a four-field box technique. This case highlights the difficulty in delivering conformal radiation to the pancreas and quantifies the movement of the target, the adjacent biliary stent, and regional nodes.
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Stanescu T, Jaffray D. Technical Note: Harmonic analysis applied to MR image distortion fields specific to arbitrarily shaped volumes. Med Phys 2018; 45:3705-3712. [PMID: 29799634 DOI: 10.1002/mp.13000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 04/26/2018] [Accepted: 05/15/2018] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Magnetic resonance imaging is expected to play a more important role in radiation therapy given the recent developments in MR-guided technologies. MR images need to consistently show high spatial accuracy to facilitate RT-specific tasks such as treatment planning and in-room guidance. The present study investigates a new harmonic analysis method for the characterization of complex three-dimensional (3D) fields derived from MR images affected by system-related distortions. METHODS An interior Dirichlet problem based on solving the Laplace equation with boundary conditions (BCs) was formulated for the case of a 3D distortion field. The second-order boundary value problem (BVP) was solved using a finite elements method (FEM) for several quadratic geometries - that is, sphere, cylinder, cuboid, D-shaped, and ellipsoid. To stress-test the method and generalize it, the BVP was also solved for more complex surfaces such as a Reuleaux 9-gon and the MR imaging volume of a scanner featuring a high degree of surface irregularities. The BCs were formatted from reference experimental data collected with a linearity phantom featuring a volumetric grid structure. The method was validated by comparing the harmonic analysis results with the corresponding experimental reference fields. RESULTS The harmonic fields were found to be in good agreement with the baseline experimental data for all geometries investigated. In the case of quadratic domains, the percentage of sampling points with residual values larger than 1 mm was 0.5% and 0.2% for the axial components and vector magnitude, respectively. For the general case of a domain defined by the available MR imaging field of view, the reference data showed a peak distortion of about 1 mm and 79% of the sampling points carried a distortion magnitude larger than 1 mm (tolerance intrinsic to the experimental data). The upper limits of the residual values after comparison with the harmonic fields showed max and mean of 1.4 and 0.25 mm, respectively, with only 1.5% of sampling points exceeding 1 mm. CONCLUSIONS A novel harmonic analysis approach relying on finite element methods was introduced and validated for multiple volumes with surface shape functions ranging from simple to highly complex. Since a boundary value problem is solved the method requires input data from only the surface of the desired domain of interest. It is believed that the harmonic method will facilitate (a) the design of new phantoms dedicated for the quantitation of MR image distortions in large volumes and (b) an integrative approach of combining multiple imaging tests specific to radiotherapy into a single test object for routine imaging quality control.
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Affiliation(s)
- T Stanescu
- Princess Margaret Cancer Centre & The Techna Institute, University Health Network, Toronto, ON, M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada
| | - D Jaffray
- Princess Margaret Cancer Centre & The Techna Institute, University Health Network, Toronto, ON, M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada
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Stanescu T, Berlin A, Dawson L, Abed J, Simeonov A, Craig T, Letourneau D, Jaffray D. EP-1761: Workflow development for the clinical implementation of an MR-guided linear accelerator. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)32124-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Stanescu T, Jaffray D. Investigation of the 4D composite MR image distortion field associated with tumor motion for MR-guided radiotherapy. Med Phys 2016; 43:1550-62. [PMID: 26936738 DOI: 10.1118/1.4941958] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Magnetic resonance (MR) images are affected by geometric distortions due to the specifics of the MR scanner and patient anatomy. Quantifying the distortions associated with mobile tumors is particularly challenging due to real anatomical changes in the tumor's volume, shape, and relative location within the MR imaging volume. In this study, the authors investigate the 4D composite distortion field, which combines the effects of the susceptibility-induced and system-related distortion fields, experienced by mobile lung tumors. METHODS The susceptibility (χ) effects were numerically simulated for two specific scenarios: (a) a full motion cycle of a lung tumor due to breathing as depicted on ten phases of a 4D CBCT data set and (b) varying the tumor size and location in lung tissue via a synthetically generated sphere with variable diameter (4-80 mm). The χ simulation procedure relied on the segmentation and generation of 3D susceptibility (χ) masks and computation of the magnetic field by means of finite difference methods. A system-related distortion field, determined with a phantom and image processing algorithm, was used as a reference. The 4D composite distortion field was generated as the vector summation of the χ-induced and system-related fields. The analysis was performed for two orientations of the main magnetic field (B0), which correspond to several MRIgRT system configurations. Specifically, B0 was set along the z-axis as in the case of a cylindrical-bore scanner and in the (x,y)-plane as for a biplanar MR. Computations were also performed for a full revolution at 15° increments in the case of a rotating biplanar magnet. Histograms and metrics such as maximum, mean, and range were used to evaluate the characteristics of the 4D distortion field. RESULTS The χ-induced field depends on the change in volume and shape of the moving tumor as well as the local surrounding anatomy. In the case of system-related distortions, the tumor experiences increased field perturbations as it moves further away from the MR isocenter. For a mobile lung tumor, the 4D composite field, corresponding to a 1.5 T field and a readout gradient of 5 mT/m, amounts to 3.0 and 2.8 mm for the MRIgRT system designs featuring B0 oriented along the z-axis (cylindrical-bore scanner) and in the (x,y)-plane (biplanar scanner), respectively. For a rotating biplanar scanner, the composite distortion field varied nonlinearly with the rotation angle. Overall, the dominant contribution to the composite field was from the system-related distortion field. The tumor centroid experienced a systematic shift of 2 mm and showed a negligible perturbation for different B0 values. The dependency on the tumor size was also investigated, namely the max values varied from 1.2 to 2.5 mm for spherical volumes with a diameter between 4 and 80 mm. CONCLUSIONS The composite distortion field requires adequate quantification for lung radiation therapy applications such as treatment planning, pretreatment patient setup verification, and real-time treatment delivery guidance. For certain scenarios such as small tumor volumes, the spatial distortions may be corrected by applying systematic shifts derived from a single tumor motion phase. In the case of high readout gradients common to fast imaging applications, the χ distortions were found to be less than 1 mm irrespective of scanner configuration.
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Affiliation(s)
- T Stanescu
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada
| | - D Jaffray
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada
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Stanescu T, Schaer N, Breen S, Letourneau D, Shet K, Dickie C, Jaffray D. Magnetic Resonance Guided Radiation Therapy: Feasibility Study of a Linear Accelerator and Magnetic Resonance-on-Rails System. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Stanescu T. WE-H-207B-00: MRgRT. Med Phys 2016. [DOI: 10.1118/1.4958021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T. WE-H-207B-01: Commissioning and QC. Med Phys 2016. [DOI: 10.1118/1.4958022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Breen S, Dickie C, Letourneau D, Jaffray D. OC-0543: Technical development and clinical implementation of an MR-guided radiation therapy environment. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)31793-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Li W, Kratz K, Pellizzari A, Hsu J, Becker N, Stanescu T, Kim J, Moseley D. Evaluation of 3D vs 4D Cone-beam CT (CBCT) Target Localization Methods for Free Breathing Liver Stereotactic Body Radiotherapy (SBRT). J Med Imaging Radiat Sci 2016. [DOI: 10.1016/j.jmir.2015.12.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Stanescu T. WE-D-BRD-03: Novel Methods and Tools for MR Commissioning and QC. Med Phys 2015. [DOI: 10.1118/1.4925923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T. WE-D-BRD-00: New Developments in Hybrid MR-Treatment: Technology. Med Phys 2015. [DOI: 10.1118/1.4925920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Balter J, Nyholm T, Lagendijk J. TU-A-BRF-01: MR Guided Radiation Therapy. Med Phys 2014. [DOI: 10.1118/1.4889233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Tadic T, Jaffray D. WE-G-17A-03: MRIgRT: Quantification of Organ Motion. Med Phys 2014. [DOI: 10.1118/1.4889505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Tadic T, Jaffray D, Stanescu T. A Novel Harmonic Analysis for Quantifying MRI Performance in MRIgRT. Int J Radiat Oncol Biol Phys 2013. [DOI: 10.1016/j.ijrobp.2013.06.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Foltz W, Stanescu T, Lee J, Simeonov A, Jaffray D, Craig T, Chung P, Ménard C. Improved Geometric Performance of Diffusion-Weighted Imaging for Prostate Tumor Delineation Using a Readout-Segmented Echo-Planar-Imaging Technique. Int J Radiat Oncol Biol Phys 2013. [DOI: 10.1016/j.ijrobp.2013.06.448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Stanescu T, Tadic T, Marle J, Winter J, Petropoulos L, Sweitzer M, Jaffray D. WE-G-WAB-02: BEST IN PHYSICS (JOINT IMAGING-THERAPY)-MR and Linac Magnetic Field Mutual Decoupling for An MRI-Guided Radiation Therapy System. Med Phys 2013. [DOI: 10.1118/1.4815644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Winter J, Carlone M, Westmore M, Breen S, Stanescu T, Dahan M, Jaffray D. SU-C-103-06: Isocenter Calibration Concept and Feasibility for MR-Guided Radiation Therapy (MRgRT). Med Phys 2013. [DOI: 10.1118/1.4813973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Tadic T, Jaffray D, Winter J, Petropoulos L, Marle J, Sweitzer M, Stanescu T. WE-G-WAB-07: Commissioning of a Novel Integrated Platform for Online MRIgRT. Med Phys 2013. [DOI: 10.1118/1.4815649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Tadic T, Jaffray D. WE-G-WAB-03: 4D Composite MR Image Distortion Field: Quantification and Applications for MRI-Guided Radiotherapy. Med Phys 2013. [DOI: 10.1118/1.4815645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Tadic T, Jaffray D. PO-0890: MRI-guided stereotactic body radiation therapy for liver. Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)33196-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Stanescu T, Wachowicz K, Jaffray DA. Characterization of tissue magnetic susceptibility-induced distortions for MRIgRT. Med Phys 2012; 39:7185-93. [DOI: 10.1118/1.4764481] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Chung C, Simeonov A, van Prooijen M, Millar B, Menard C. Quantification of the Magnetic Susceptibility Effects During MRI Guided Radiosurgery of Hemorrhagic Brain Metastases. Int J Radiat Oncol Biol Phys 2012. [DOI: 10.1016/j.ijrobp.2012.07.2209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Lamey M, Carlone M, Alasti H, Bissonnette JP, Borg J, Breen S, Coolens C, Heaton R, Islam M, van Proojen M, Sharpe M, Stanescu T, Jaffray D. Poster - Thur Eve - 05: Safety systems and failure modes and effects analysis for a magnetic resonance image guided radiation therapy system. Med Phys 2012; 39:4625. [DOI: 10.1118/1.4740112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Moseley D, Stanescu T. TH-A-BRA-03: Daily IGRT QA Phantom for MR-Guided Linacs. Med Phys 2012. [DOI: 10.1118/1.4736252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Winter J, Carlone M, Stanescu T, Breen S, Foxcroft S, Guyot B, Dahan M, Dahdal R, Jaffray D. SU-D-213CD-06: Workflow and Safety Systems of a Linac-MR Sim-Brachytherapy MRgRT™ Facility. Med Phys 2012; 39:3618-3619. [PMID: 28517391 DOI: 10.1118/1.4734691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop the operational workflow and safety systems of a magnetic resonance-guided radiotherapy system (MRgRT™), which comprises an MR scanner on rails that travels between a linac vault, MR simulation room and brachytherapy suite. METHODS To develop a safe and streamlined clinical workflow, we conducted a comprehensive process review based on a layered approach to overall MRgRT safety that included i) facility design, (ii) workflow iii) system design and interlocks and iv) policies and procedures. We applied existing guidelines for MR and radiation safety, and employed system-level failure modes and effects analyses to design the MRgRT facility and clinical procedures. RESULTS In the MRgRT system configuration, the MR and treatment systems are physically decoupled and used independently requiring novel administration of existing MR and radiation guidelines. A key element for the safe operation of the moving MR unit is the concept that all three rooms represent zone 4 areas (American College of Radiology guidelines). Using this concept, we applied MR guidelines to develop safe procedures for the overall suite, including screening of all persons entering the suite in zone 2 and control of ferromagnetic materials. We generated a clinical workflow that ensures expedient and safe transition between MR imaging and treatment delivery in both the linac and brachytherapy rooms. In addition, we designed emergency protocols for MRgRT, which helped drive requirements for the facility and system design, e.g., need for an accessible MR-safe stretcher. CONCLUSIONS We designed the first comprehensive description of the MRgRT workflow, interlocking systems and safety procedures. With this layered approach to safety, we addressed critical aspects regarding safe operation and workflow for the system and provided multiple redundancies for key processes. Coupled with customized staff training, the proposed design ensures the safe operation of the MRgRT facility. This work has received research personnel support from IMRIS.
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Affiliation(s)
- J Winter
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - M Carlone
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - T Stanescu
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - S Breen
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - S Foxcroft
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - B Guyot
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - M Dahan
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - R Dahdal
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
| | - D Jaffray
- IMRIS, Winnipeg, Manitoba.,Princess Margaret Hospital, Toronto, Ontario
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Stanescu T, Jaffray D. OC-0192 MRIGRT: CHARACTERIZATION OF THE COMPOSITE MR IMAGE DISTORTION FIELD ASSOCIATED WITH ORGAN MOTION. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)70531-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Lamey M, Carlone M, Alasti H, Bissonnette J, Borg J, Breen S, Coolens C, Heaton R, Islam M, Sharpe M, Stanescu T, van Prooijen M, Jaffray D. SU-E-T-252: Safety Systems and Failure Modes and Effects Analysis for a Linear Accelerator - Magnetic Resonance Imager - Brachytherapy System. Med Phys 2011. [DOI: 10.1118/1.3612203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Wachowicz K, Jaffray D. WE-G-214-04: MR Simulation Environment for MR-Guided Radiation Therapy. Med Phys 2011. [DOI: 10.1118/1.3613425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wachowicz K, Stanescu T, Thomas SD, Fallone BG. Implications of tissue magnetic susceptibility-related distortion on the rotating magnet in an MR-linac design. Med Phys 2010; 37:1714-21. [PMID: 20443492 DOI: 10.1118/1.3355856] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE One of the recently published concepts that combine the soft-tissue imaging capabilities of MRI with external beam radiotherapy involves the rigid coupling of a linac with a rotating biplanar low-field MR imaging system. While such a system would prevent possible image distortion resulting from relative motion between the magnet and the linac, the rotation of the magnet around the patient can itself introduce possibilities for image distortion that need to be addressed. While there are straightforward techniques in the literature for correcting distortions from gradient nonlinearities and nonuniform magnetic fields during image reconstruction, the correction of distortions related to tissue magnetic susceptibility is more complex. This work investigates the extent of this latter distortion type under the regime of a rotating magnetic field. METHODS CT images covering patient anatomy in the head, lung, and male pelvic regions were obtained and segmented into components of air, bone, and soft tissue. Each of these three components was assigned bulk magnetic susceptibility values in accordance with those found in the literature. A finite-difference algorithm was then implemented to solve for magnetic field distortion maps should the anatomies be placed in the uniform polarizing field of an MR system. The algorithm was repeated multiple times as the polarizing field was rotated axially about the virtual patient in 15 degrees increments. In this way, a map of maximum distortion, and the range of distortion as the magnetic field is rotated about each anatomical region could be determined. The consequence of these susceptibility distortions in terms of geometric signal shift was calculated for 0.2 T, as well as another low-field system (0.5 T), and a higher field 1.5 T system for comparison, using the assumption of a frequency encoding gradient strength of 5 mT/m. RESULTS At 0.2 T, the susceptibility-related distortion was limited to less than 0.5 mm given an encoding gradient strength of 5 mT/m or higher. To maintain this same level of geometric accuracy, the 0.5 T system would require a moderately higher minimum gradient strength of 11 mT/m, and at a typical MR field strength of 1.5 T this minimum gradient strength would increase to 33 mT/m. The influence of magnetic susceptibility on mean frequency shift as the field orientation was rotated was also investigated and found to account for less than half a millimeter at 1.5 T, and negligible for low-field systems. CONCLUSIONS A study of three sites (head, lung, and prostate) that are vulnerable to magnetic susceptibility-related distortions were studied, and showed that in the context of a rotating polarizing magnet, low-field systems can maintain geometric accuracy of 0.5 mm with at most moderate limitations on sequence parameters. This conclusion will likely apply only to endogenous tissues, as implanted materials such as titanium can create field distortions much in excess of what may normally be induced in the body. Items containing such materials (hip prostheses, for example) will require individual scrutiny.
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Affiliation(s)
- K Wachowicz
- Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada.
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Fallone B, Murray B, Rathee S, Stanescu T, Steciw S, Vidakovic S, Blosser E, Tymofichuk D. TU-E-BRC-05: First MR Images Obtained During Megavoltage Photon Irradiation From An Integrated Linac-MR System. Med Phys 2009. [DOI: 10.1118/1.3182419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Wachowicz K, Fallone B. WE-C-BRB-04: MR Image Susceptibility Distortions: Quantification of Impact On the Radiation Treatment Planning of Cancer Sites. Med Phys 2009. [DOI: 10.1118/1.3182462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fallone BG, Murray B, Rathee S, Stanescu T, Steciw S, Vidakovic S, Blosser E, Tymofichuk D. First MR images obtained during megavoltage photon irradiation from a prototype integrated linac-MR system. Med Phys 2009; 36:2084-8. [DOI: 10.1118/1.3125662] [Citation(s) in RCA: 272] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kirkby C, Stanescu T, Rathee S, Carlone M, Murray B, Fallone BG. Erratum: “Patient dosimetry for hybrid MRI-radiotherapy systems” [Med. Phys. 35, 1019-1027 (2008)]. Med Phys 2009. [DOI: 10.1118/1.3078698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Kirkby C, Jans H, Wachowicz K, Rathee S, Carlone M, Murray B, Fallone G. Sci-Fri PM: Planning-02: MRI-based radiation treatment planning for an MRI-linac system. Med Phys 2008; 35:3412. [DOI: 10.1118/1.2965974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kirkby C, Stanescu T, Murray B, Rathee S, Carlone M, Fallone B. SU-GG-T-502: A Fast Algorithm to Predict Dose Distribution Perturbations in An MRI-Linac Hybrid System. Med Phys 2008. [DOI: 10.1118/1.2962251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Stanescu T, Jans HS, Pervez N, Stavrev P, Fallone BG. A study on the magnetic resonance imaging (MRI)-based radiation treatment planning of intracranial lesions. Phys Med Biol 2008; 53:3579-93. [DOI: 10.1088/0031-9155/53/13/013] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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