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Buckley JG, Dong B, Liney GP. Imaging performance of a high-field in-line magnetic resonance imaging linear accelerator with a patient rotation system for fixed-gantry radiotherapy. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2020; 16:130-133. [PMID: 33458355 PMCID: PMC7807630 DOI: 10.1016/j.phro.2020.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023]
Abstract
This paper describes the imaging performance of a high-field in-line MRI linear accelerator with a patient rotation system in-situ. Signal quality was quantified using signal-to-noise ratio (SNR) and RF uniformity maps. B0-field inhomogeneity was assessed using magnetic field mapping. SNR was evaluated with various entries into the Faraday cage which were required for extended couch translations. SNR varied between 103 and 87 across PRS rotation angles. Maximum B0-field inhomogeneity corresponded to 0.7 mm of geometric distortion. A 45 × 55 cm2 aperture allowed PRS translation with no reduction in SNR. Imaging performance with the PRS in-situ was found to be acceptable.
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Affiliation(s)
- Jarryd G Buckley
- Centre for Medical Radiation Physics, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia.,Ingham Institute for Applied Medical Research, 1 Campbell St, Liverpool, NSW 2170, Australia
| | - Bin Dong
- Ingham Institute for Applied Medical Research, 1 Campbell St, Liverpool, NSW 2170, Australia.,Liverpool and Macarthur Cancer Therapy Centre, Liverpool Hospital, 75 Elizabeth St, Liverpool, NSW 2170, Australia
| | - Gary P Liney
- Ingham Institute for Applied Medical Research, 1 Campbell St, Liverpool, NSW 2170, Australia.,Liverpool and Macarthur Cancer Therapy Centre, Liverpool Hospital, 75 Elizabeth St, Liverpool, NSW 2170, Australia
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Ferrer L, Josset S, Moignier A, Delpon G. [Hybrid radiotherapy machines: Evolution or revolution?]. Cancer Radiother 2019; 23:761-764. [PMID: 31471254 DOI: 10.1016/j.canrad.2019.07.140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 11/19/2022]
Abstract
The arrival of new hybrid radiotherapy machines with MRI or PET is announced as a milestone in radiotherapy management. Based on recent literature, we will describe the contribution of each of these modalities and the technological challenges that have already been or are still to be addressed.
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Affiliation(s)
- L Ferrer
- Service de physique médicale, institut de cancérologie de l'Ouest, boulevard Jacques-Monod, 44805 Saint-Herblain, France.
| | - S Josset
- Service de physique médicale, institut de cancérologie de l'Ouest, boulevard Jacques-Monod, 44805 Saint-Herblain, France
| | - A Moignier
- Service de physique médicale, institut de cancérologie de l'Ouest, boulevard Jacques-Monod, 44805 Saint-Herblain, France
| | - G Delpon
- Service de physique médicale, institut de cancérologie de l'Ouest, boulevard Jacques-Monod, 44805 Saint-Herblain, France
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Oborn BM, Dowdell S, Metcalfe PE, Crozier S, Mohan R, Keall PJ. Proton beam deflection in MRI fields: Implications for MRI-guided proton therapy. Med Phys 2015; 42:2113-24. [DOI: 10.1118/1.4916661] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kim JI, Park SY, Lee YH, Shin KH, Wu HG, Park JM. Effect of Low Magnetic Field on Dose Distribution in the Partial-Breast Irradiation. ACTA ACUST UNITED AC 2015. [DOI: 10.14316/pmp.2015.26.4.208] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Jung-in Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, Korea
| | - So-Yeon Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul, Korea
| | - Yang Hoon Lee
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea
| | - Kyung Hwan Shin
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea
| | - Hong-Gyun Wu
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, Korea
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Sun J, Pichler P, Dowling J, Menk F, Stanwell P, Arm J, Greer PB. MR simulation for prostate radiation therapy: effect of coil mounting position on image quality. Br J Radiol 2014; 87:20140325. [PMID: 25061776 DOI: 10.1259/bjr.20140325] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To eliminate the effects of body deformation for MR-based prostate treatment planning, coil mounts are essential. In this study, we evaluated the effect of the coil set-up on image quality. METHODS A custom-designed pelvic-shaped phantom was scanned by systematically increasing the anterior body-to-coil (BTC) distance from 30 to 90 mm. The image quality near the organs of interest was determined in order to characterize the relationship between image quality and BTC distance at the critical organ structures. The half intensity reduction (HIR) was calculated to determine the sensitivity of each organ structure to the BTC distance change. RESULTS As the BTC distance increased, the uniformity reduced at 3% per millimetre. The HIR value indicated that the bladder signal is most sensitive to the change in BTC distance. By maintaining a constant BTC distance set-up, the intensity uniformity was improved by 28% along the B0 directions. CONCLUSION Positioning the MRI coil on mounts can reduce body deformation but adversely degrades the image quality. The magnitude of this effect has been quantified for prostate MR simulation scanning. The coil needs to be positioned not only with a minimal but also uniform BTC distance in order to maximize image quality. ADVANCES IN KNOWLEDGE A method to characterize the effect on image quality due to the use of coil mounts was demonstrated. Coil mounts whose height can be adjusted individually to keep BTC distance constant are necessary to maintain a uniform image across the entire field of view.
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Affiliation(s)
- J Sun
- 1 School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW, Australia
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Kolling S, Oborn B, Keall P. Impact of the MLC on the MRI field distortion of a prototype MRI-linac. Med Phys 2013; 40:121705. [DOI: 10.1118/1.4828792] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Allison RR, Sibata C, Patel R. Future radiation therapy: photons, protons and particles. Future Oncol 2013; 9:493-504. [DOI: 10.2217/fon.13.13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Radiation therapy plays a critical role in the current management of cancer patients. The most common linear accelerator-based treatment device delivers photons of radiation. In an ever more precise fashion, state-of-the-art technology has recently allowed for both modulation of the radiation beam and imaging for this treatment delivery. This has resulted in better patient outcome with far fewer side effects than were achieved even a decade ago. Recently, a push has begun for proton therapy, which may have clinical advantage in select indications, although significant limitations for these devices have become apparent. In addition, currently, heavy particle therapy has been touted as a potential means to improve cancer patient outcomes. This article will highlight current benefits and drawbacks to modern radiation therapy and speculate on future tools that will likely dramatically improve radiation oncology.
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Affiliation(s)
- Ron R Allison
- 21st Century Oncology, 801 WH Smith Blvd., Greenville, NC 27834, USA.
| | | | - Rajen Patel
- 21st Century Oncology, 801 WH Smith Blvd., Greenville, NC 27834, USA
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Hoogcarspel SJ, Crijns SPM, Lagendijk JJW, van Vulpen M, Raaymakers BW. The feasibility of using a conventional flexible RF coil for an online MR-guided radiotherapy treatment. Phys Med Biol 2013; 58:1925-32. [DOI: 10.1088/0031-9155/58/6/1925] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Yang YM, Bednarz B. Consistency evaluation between EGSnrc and Geant4 charged particle transport in an equilibrium magnetic field. Phys Med Biol 2013; 58:N47-58. [PMID: 23370042 DOI: 10.1088/0031-9155/58/4/n47] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Following the proposal by several groups to integrate magnetic resonance imaging (MRI) with radiation therapy, much attention has been afforded to examining the impact of strong (on the order of a Tesla) transverse magnetic fields on photon dose distributions. The effect of the magnetic field on dose distributions must be considered in order to take full advantage of the benefits of real-time intra-fraction imaging. In this investigation, we compared the handling of particle transport in magnetic fields between two Monte Carlo codes, EGSnrc and Geant4, to analyze various aspects of their electromagnetic transport algorithms; both codes are well-benchmarked for medical physics applications in the absence of magnetic fields. A water-air-water slab phantom and a water-lung-water slab phantom were used to highlight dose perturbations near high- and low-density interfaces. We have implemented a method of calculating the Lorentz force in EGSnrc based on theoretical models in literature, and show very good consistency between the two Monte Carlo codes. This investigation further demonstrates the importance of accurate dosimetry for MRI-guided radiation therapy (MRIgRT), and facilitates the integration of a ViewRay MRIgRT system in the University of Wisconsin-Madison's Radiation Oncology Department.
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Affiliation(s)
- Y M Yang
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin-Madison, Madison, WI 53703, USA
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Burke B, Wachowicz K, Fallone BG, Rathee S. Effect of radiation induced current on the quality of MR images in an integrated linac-MR system. Med Phys 2012; 39:6139-47. [DOI: 10.1118/1.4752422] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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