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Keenan KE, Jordanova KV, Ogier SE, Tamada D, Bruhwiler N, Starekova J, Riek J, McCracken PJ, Hernando D. Phantoms for Quantitative Body MRI: a review and discussion of the phantom value. MAGMA (NEW YORK, N.Y.) 2024:10.1007/s10334-024-01181-8. [PMID: 38896407 DOI: 10.1007/s10334-024-01181-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/18/2024] [Accepted: 06/11/2024] [Indexed: 06/21/2024]
Abstract
In this paper, we review the value of phantoms for body MRI in the context of their uses for quantitative MRI methods research, clinical trials, and clinical imaging. Certain uses of phantoms are common throughout the body MRI community, including measuring bias, assessing reproducibility, and training. In addition to these uses, phantoms in body MRI methods research are used for novel methods development and the design of motion compensation and mitigation techniques. For clinical trials, phantoms are an essential part of quality management strategies, facilitating the conduct of ethically sound, reliable, and regulatorily compliant clinical research of both novel MRI methods and therapeutic agents. In the clinic, phantoms are used for development of protocols, mitigation of cost, quality control, and radiotherapy. We briefly review phantoms developed for quantitative body MRI, and finally, we review open questions regarding the most effective use of a phantom for body MRI.
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Affiliation(s)
- Kathryn E Keenan
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA.
| | - Kalina V Jordanova
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA
| | - Stephen E Ogier
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA
- Department of Physics, University of Colorado Boulder, Boulder, CO, USA
| | | | - Natalie Bruhwiler
- Physical Measurement Laboratory, National Institute of Standards and Technology, NIST, 325 Broadway, Boulder, CO, 80305, USA
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Cahill K, Rienecker S, O'Connor P, Denham M, Gibbons F, Willis D, Vignarajah D, Buddle N, Min M. Implementation of a retrofit MRI simulator for radiation therapy planning. J Med Radiat Sci 2023; 70:498-508. [PMID: 37315100 PMCID: PMC10715355 DOI: 10.1002/jmrs.693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 05/23/2023] [Indexed: 06/16/2023] Open
Abstract
Magnetic resonance imaging (MRI) is being integrated into routine radiation therapy (RT) planning workflows. To reap the benefits of this imaging modality, patient positioning, image acquisition parameters and a quality assurance programme must be considered for accurate use. This paper will report on the implementation of a retrofit MRI Simulator for RT planning, demonstrating an economical, resource efficient solution to improve the accuracy of MRI in this setting.
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Affiliation(s)
- Katelyn Cahill
- Adem Crosby Centre – Radiation OncologySunshine Coast University HospitalBirtinyaQueenslandAustralia
- Sunshine Coast Mind and Neuroscience – Thompson InstituteUniversity of the Sunshine CoastBirtinyaQueenslandAustralia
- University of the Sunshine CoastSippy DownsQueenslandAustralia
| | - Shermiyah Rienecker
- Biomedical Technology ServicesRoyal Brisbane and Women's HospitalHerstonQueenslandAustralia
| | - Patrick O'Connor
- Adem Crosby Centre – Radiation OncologySunshine Coast University HospitalBirtinyaQueenslandAustralia
- University of QueenslandSt LuciaQueenslandAustralia
| | - Mark Denham
- Department of Medical ImagingSunshine Coast University HospitalBirtinyaQueenslandAustralia
| | - Francis Gibbons
- Adem Crosby Centre – Radiation OncologySunshine Coast University HospitalBirtinyaQueenslandAustralia
| | - David Willis
- Adem Crosby Centre – Radiation OncologySunshine Coast University HospitalBirtinyaQueenslandAustralia
| | - Dinesh Vignarajah
- Adem Crosby Centre – Radiation OncologySunshine Coast University HospitalBirtinyaQueenslandAustralia
- Griffith UniversityBrisbaneQueenslandAustralia
| | - Nicole Buddle
- Adem Crosby Centre – Radiation OncologySunshine Coast University HospitalBirtinyaQueenslandAustralia
| | - Myo Min
- Adem Crosby Centre – Radiation OncologySunshine Coast University HospitalBirtinyaQueenslandAustralia
- University of the Sunshine CoastSippy DownsQueenslandAustralia
- Griffith UniversityBrisbaneQueenslandAustralia
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Jin H, Lee SY, An HJ, Choi CH, Chie EK, Wu HG, Park JM, Park S, Kim JI. Development of an anthropomorphic multimodality pelvic phantom for quantitative evaluation of a deep-learning-based synthetic computed tomography generation technique. J Appl Clin Med Phys 2022; 23:e13644. [PMID: 35579090 PMCID: PMC9359037 DOI: 10.1002/acm2.13644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/06/2022] [Accepted: 04/28/2022] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The objective of this study was to fabricate an anthropomorphic multimodality pelvic phantom to evaluate a deep-learning-based synthetic computed tomography (CT) algorithm for magnetic resonance (MR)-only radiotherapy. METHODS Polyurethane-based and silicone-based materials with various silicone oil concentrations were scanned using 0.35 T MR and CT scanner to determine the tissue surrogate. Five tissue surrogates were determined by comparing the organ intensity with patient CT and MR images. Patient-specific organ modeling for three-dimensional printing was performed by manually delineating the structures of interest. The phantom was finally fabricated by casting materials for each structure. For the quantitative evaluation, the mean and standard deviations were measured within the regions of interest on the MR, simulation CT (CTsim ), and synthetic CT (CTsyn ) images. Intensity-modulated radiation therapy plans were generated to assess the impact of different electron density assignments on plan quality using CTsim and CTsyn . The dose calculation accuracy was investigated in terms of gamma analysis and dose-volume histogram parameters. RESULTS For the prostate site, the mean MR intensities for the patient and phantom were 78.1 ± 13.8 and 86.5 ± 19.3, respectively. The mean intensity of the synthetic image was 30.9 Hounsfield unit (HU), which was comparable to that of the real CT phantom image. The original and synthetic CT intensities of the fat tissue in the phantom were -105.8 ± 4.9 HU and -107.8 ± 7.8 HU, respectively. For the target volume, the difference in D95% was 0.32 Gy using CTsyn with respect to CTsim values. The V65Gy values for the bladder in the plans using CTsim and CTsyn were 0.31% and 0.15%, respectively. CONCLUSION This work demonstrated that the anthropomorphic phantom was physiologically and geometrically similar to the patient organs and was employed to quantitatively evaluate the deep-learning-based synthetic CT algorithm.
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Affiliation(s)
- Hyeongmin Jin
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sung Young Lee
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hyun Joon An
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Chang Heon Choi
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Eui Kyu Chie
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hong-Gyun Wu
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Robotics Research Laboratory for Extreme Environments, Advanced Institute of Convergence Technology, Suwon, Republic of Korea
| | - Sukwon Park
- Department of Radiation Oncology, Myongji Hospital, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
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Pilot study comparing dominant intraprostatic lesion volume using Ga-68 prostate-specific membrane antigen PET-computed tomography and multiparametric MRI. Nucl Med Commun 2021; 41:1291-1298. [PMID: 32941400 DOI: 10.1097/mnm.0000000000001283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The standard imaging used for delineation of dominant intraprostatic lesion (DIL) is multiparametric MRI (mpMRI). The use of biologic imaging such as Ga-68 prostate-specific membrane antigen (PSMA) PET-computed tomography (PET-CT) for this purpose is being explored in view of increased sensitivity of this modality and the associated ease of delineation. MATERIALS AND METHODS The primary objective of the study was to compare the autogenerated volumes of the DIL in Ga-68 PSMA PET-CT with the standard volume delineated in mpMRI. Twenty patients with biopsy-proven untreated prostatic adenocarcinoma were included. Multiple percentages of the maximum standardized uptake value (%SUVmax) were used to autogenerate DIL volumes in Ga-68 PSMA PET-CT and these volumes were numerically matched with the consensus DIL volume in mpMRI. PSMA tumor volume (PSMA-TV) and total lesion PSMA (TL-PSMA) were also calculated for each lesion. RESULTS Median volume of DIL in mpMRI was 4 cm (interquartile range, IQR = 2.5-7.6 cm). The IQR for interobserver variability was 0.5-2.5 cm. Median SUVmax of the DIL was 14.1 (IQR = 10.2-22.3). Median %SUVmax corresponding to mpMRI volume was 41% of SUVmax (IQR = 34-55%). There was a strong negative correlation between MRI volume and %SUVmax (r = -0.829, P < 0.001). There was a significant correlation between TL-PSMA and prostate-specific antigen (r = 0.609, P = 0.004). CONCLUSIONS The median DIL volume was 4 cm and median %SUVmax corresponding to MR volume of DIL was 41%. A strong inverse relationship is found between mpMRI-defined DIL volume and the %SUVmax which generates similar volume in Ga-68 PSMA PET-CT. TL-PSMA could be a quantitative biomarker for tumor load and prognosis.
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Liu X, Li Z, Rong Y, Cao M, Li H, Jia C, Shi L, Lu W, Gong G, Yin Y, Qiu J. A Comparison of the Distortion in the Same Field MRI and MR-Linac System With a 3D Printed Phantom. Front Oncol 2021; 11:579451. [PMID: 34150605 PMCID: PMC8209415 DOI: 10.3389/fonc.2021.579451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 04/30/2021] [Indexed: 11/13/2022] Open
Abstract
PURPOSE A 3D printed geometric phantom was developed that can be scanned with computed tomography (CT) and magnetic resonance imaging (MRI) to measure the geometric distortion and determine the relevant dose changes. MATERIALS AND METHODS A self-designed 3D printed photosensitive resin phantom was used, which adopts grid-like structures and has 822 1 cm2 squares. The scanning plan was delivered by three MRI scanners: the Elekta Unity MR-Linac 1.5T, GE Signa HDe 1.5T, and GE Discovery-sim 750 3.0T. The geometric distortion comparison was concentrated on two 1.5T MRI systems, whereas the 3.0T MRI was used as a supplemental experiment. The most central transverse images in each dataset were selected to demonstrate the plane distortion. Some mark points were selected to analyze the distortion in the 3D direction based on the plane geometric distortion. A treatment plan was created with the off-line Monaco system. RESULTS The distortion increases gradually from the center to the outside. The distortion range is 0.79 ± 0.40 mm for the Unity, 1.31 ± 0.56 mm for the GE Signa HDe, and 2.82 ± 1.48 mm for the GE Discovery-sim 750. Additionally, the geometric distortion slightly affects the actual planning dose of the radiotherapy. CONCLUSION Geometric distortion increases gradually from the center to the outside. The distortion values of the Unity were smaller than those of the GE Signa HDe, and the Unity has the smallest geometric distortion. Finally, the Unity's dose variation best matched with the standard treatment plan.
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Affiliation(s)
- Xuechun Liu
- Medical Engineering and Technology Research Center, Department of Radiology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai’an, China
- Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Zhenjiang Li
- Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Yi Rong
- Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA, United States
| | - Minsong Cao
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, CA, United States
| | - Hongyu Li
- Academy of Marine Science and Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Chuntao Jia
- Academy of Marine Science and Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Liting Shi
- Medical Engineering and Technology Research Center, Department of Radiology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai’an, China
| | - Weizhao Lu
- Medical Engineering and Technology Research Center, Department of Radiology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai’an, China
| | - Guanzhong Gong
- Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Yong Yin
- Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Jianfeng Qiu
- Medical Engineering and Technology Research Center, Department of Radiology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai’an, China
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Kavaluus H, Nousiainen K, Kaijaluoto S, Seppälä T, Saarilahti K, Tenhunen M. Determination of acceptance criteria for geometric accuracy of magnetic resonance imaging scanners used in radiotherapy planning. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2021; 17:58-64. [PMID: 33898780 PMCID: PMC8058029 DOI: 10.1016/j.phro.2021.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/23/2022]
Abstract
Geometric accuracy of MRI-scanners in radiotherapy planning must be evaluated. Phantom acquisitions with standard and clinical sequences were performed. Geometric distortions were determined in several volumes of interest. We recommend acceptance criteria for MRI-scanners in radiotherapy planning. Explicit and simple acceptance criteria enable effective regulatory inspections.
Background and Purpose Magnetic resonance imaging is increasingly used in radiotherapy planning; yet, the performance of the utilized scanners is rarely regulated by any authority. The aim of this study was to determine the geometric accuracy of several magnetic resonance imaging scanners used for radiotherapy planning, and to establish acceptance criteria for such scanners. Materials and Methods The geometric accuracy of five different scanners was measured with three sequences using a commercial large-field-of-view phantom. The distortion magnitudes were determined in spherical volumes around the scanner isocenter and in cylindrical volumes along scanner z-axis. The repeatability of the measurements was determined on a single scanner with two quality assurance sequences with three single-setup and seven repeated-setup measurements. Results For all scanners and sequences except one, the mean and median distortion magnitude was <1 mm and <2 mm in spherical volumes with diameters of 400 mm and 500 mm, respectively. For all sequences maximum distortion was <2 mm in spherical volume with diameter of 300 mm. The mean standard deviation of marker-by-marker distortion magnitudes over repeated acquisitions was ≤0.6 mm with both tested sequences. Conclusions All tested scanners were geometrically accurate for their current use in radiotherapy planning. The acceptance criteria of geometric accuracy for regulatory inspections of a supervising authority could be set according to these results.
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Affiliation(s)
- Henna Kavaluus
- Radiation and Nuclear Safety Authority, STUK, Laippatie 4, FI-00880 Helsinki, Finland.,HUS Cancer Center, Helsinki University Hospital and University of Helsinki, P.O. Box 180, FI-00029 Helsinki, Finland.,Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Katri Nousiainen
- Radiation and Nuclear Safety Authority, STUK, Laippatie 4, FI-00880 Helsinki, Finland.,HUS Cancer Center, Helsinki University Hospital and University of Helsinki, P.O. Box 180, FI-00029 Helsinki, Finland.,Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland.,HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, B.O. Box 340, FI-00029 Helsinki, Finland
| | - Sampsa Kaijaluoto
- Radiation and Nuclear Safety Authority, STUK, Laippatie 4, FI-00880 Helsinki, Finland
| | - Tiina Seppälä
- HUS Cancer Center, Helsinki University Hospital and University of Helsinki, P.O. Box 180, FI-00029 Helsinki, Finland
| | - Kauko Saarilahti
- HUS Cancer Center, Helsinki University Hospital and University of Helsinki, P.O. Box 180, FI-00029 Helsinki, Finland
| | - Mikko Tenhunen
- HUS Cancer Center, Helsinki University Hospital and University of Helsinki, P.O. Box 180, FI-00029 Helsinki, Finland
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Alzahrani M, Broadbent DA, Chuter R, Al-Qaisieh B, Jackson S, Michael H, Johnstone RI, Shah S, Wetscherek A, Chick HJ, Wyatt JJ, McCallum HM, Speight R. Audit feasibility for geometric distortion in magnetic resonance imaging for radiotherapy. Phys Imaging Radiat Oncol 2020; 15:80-84. [PMID: 33163632 PMCID: PMC7607582 DOI: 10.1016/j.phro.2020.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 06/27/2020] [Accepted: 07/22/2020] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND AND PURPOSE Magnetic Resonance Imaging (MRI) is increasingly being used in radiotherapy (RT). However, geometric distortions are a known challenge of using MRI in RT. The aim of this study was to demonstrate feasibility of a national audit of MRI geometric distortions. This was achieved by assessing large field of view (FOV) MRI distortions on a number of scanners used clinically for RT. MATERIALS AND METHODS MRI scans of a large FOV MRI geometric distortion phantom were acquired on 11 MRI scanners that are used clinically for RT in the UK. The mean and maximum distortions and variance between scanners were reported at different distances from the isocentre. RESULTS For a small FOV representing a brain (100-150 mm from isocentre) all distortions were < 2 mm except for the maximum distortion of one scanner. For a large FOV representing a head and neck/pelvis (200-250 mm from isocentre) mean distortions were < 2 mm except for one scanner, maximum distortions were > 10 mm in some cases. The variance between scanners was low and was found to increase with distance from isocentre. CONCLUSIONS This study demonstrated feasibility of the technique to be repeated in a country wide geometric distortion audit of all MRI scanners used clinically for RT. Recommendations were made for performing such an audit and how to derive acceptable limits of distortion in such an audit.
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Affiliation(s)
- Meshal Alzahrani
- Department of Diagnostic Radiology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
- Biomedical Imaging Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - David A Broadbent
- Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Robert Chuter
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Bashar Al-Qaisieh
- Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Steven Jackson
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Manchester, UK
| | - Hutton Michael
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Manchester, UK
| | | | - Simon Shah
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - Andreas Wetscherek
- Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, London, UK
| | - H. Joan Chick
- Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, London, UK
| | - Jonathan J Wyatt
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
- Centre for Cancer, Newcastle University, Newcastle, UK
| | - Hazel Mhairi McCallum
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
- Centre for Cancer, Newcastle University, Newcastle, UK
| | - Richard Speight
- Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, UK
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Singhrao K, Fu J, Wu HH, Hu P, Kishan AU, Chin RK, Lewis JH. A novel anthropomorphic multimodality phantom for MRI‐based radiotherapy quality assurance testing. Med Phys 2020; 47:1443-1451. [DOI: 10.1002/mp.14027] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 12/11/2022] Open
Affiliation(s)
- Kamal Singhrao
- Department of Radiation Oncology University of California Los Angeles Los Angeles CA 90095USA
| | - Jie Fu
- Department of Radiation Oncology University of California Los Angeles Los Angeles CA 90095USA
| | - Holden H. Wu
- Department of Radiology University of California Los Angeles Los Angeles CA 90095USA
| | - Peng Hu
- Department of Radiology University of California Los Angeles Los Angeles CA 90095USA
| | - Amar U. Kishan
- Department of Radiation Oncology University of California Los Angeles Los Angeles CA 90095USA
| | - Robert K. Chin
- Department of Radiation Oncology University of California Los Angeles Los Angeles CA 90095USA
| | - John H. Lewis
- Department of Radiation Oncology Cedars‐Sinai Medical Center Los Angeles CA 90048USA
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9
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Bird D, Henry AM, Sebag-Montefiore D, Buckley DL, Al-Qaisieh B, Speight R. A Systematic Review of the Clinical Implementation of Pelvic Magnetic Resonance Imaging-Only Planning for External Beam Radiation Therapy. Int J Radiat Oncol Biol Phys 2019; 105:479-492. [PMID: 31271829 DOI: 10.1016/j.ijrobp.2019.06.2530] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/22/2019] [Accepted: 06/21/2019] [Indexed: 11/24/2022]
Abstract
The use of magnetic resonance (MR) imaging scans alone for radiation therapy treatment planning (MR-only planning) has been highlighted as one method of improving patient outcomes. Recent technologic advances have meant that introducing MR-only planning to the clinic is becoming a reality, with several specialist radiation therapy clinics using this technique for treatment. As such, substantial efforts are being made to introduce this technique into wide-spread clinical implementation. A systematic review of publications investigating the clinical implementation of pelvic MR-only radiation therapy treatment planning was undertaken following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Medline, Embase, Scopus, Science Direct, Cumulative Index to Nursing and Allied Health Literature, and Web of Science databases were searched (timespan: all years to January 2, 2019). Twenty-six articles met the inclusion criteria. The studies were grouped into the following categories: (1) MR acquisition and synthetic computed tomography generation verification, (2) MR distortion quantification and phantom development, (3) clinical validation of patient treatment positioning in an MR-only workflow, and (4) MR-only commissioning processes. Key conclusions from this review are (1) MR-only planning has been implemented clinically for prostate cancer treatments; (2) a substantial amount of work remains to translate MR-only planning into widespread clinical implementation for all pelvic sites; (3) MR scanner distortions are no longer a barrier to MR-only planning, but they must be managed appropriately; (4) MR-only-based patient positioning verification shows promise, but limited evidence is reported in the literature and further investigation is required; and (5) a number of MR-only commissioning processes have been reported, which can aid centers as they undertake local commissioning; however, this needs to be formalized in guidance from national bodies.
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Affiliation(s)
- David Bird
- Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom; Radiotherapy Research Group, Leeds, United Kingdom.
| | - Ann M Henry
- Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom; Radiotherapy Research Group, Leeds, United Kingdom
| | - David Sebag-Montefiore
- Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom; Radiotherapy Research Group, Leeds, United Kingdom
| | - David L Buckley
- Biomedical Imaging, University of Leeds, Leeds, United Kingdom
| | - Bashar Al-Qaisieh
- Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Richard Speight
- Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
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10
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Measuring geometric accuracy in magnetic resonance imaging with 3D-printed phantom and nonrigid image registration. MAGMA (NEW YORK, N.Y.) 2019; 33:401-410. [PMID: 31646408 PMCID: PMC7230057 DOI: 10.1007/s10334-019-00788-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/04/2019] [Accepted: 10/11/2019] [Indexed: 11/16/2022]
Abstract
Objective We aimed to develop a vendor-neutral and interaction-free quality assurance protocol for measuring geometric accuracy of head and brain magnetic resonance (MR) images. We investigated the usability of nonrigid image registration in the analysis and looked for the optimal registration parameters. Materials and methods We constructed a 3D-printed phantom and imaged it with 12 MR scanners using clinical sequences. We registered a geometric-ground-truth computed tomography (CT) acquisition to the MR images using an open-source nonrigid-registration-toolbox with varying parameters. We applied the transforms to a set of control points in the CT image and compared their locations to the corresponding visually verified reference points in the MR images. Results With optimized registration parameters, the mean difference (and standard deviation) of control point locations when compared to the reference method was (0.17 ± 0.02) mm for the 12 studied scanners. The maximum displacements varied from 0.50 to 1.35 mm or 0.89 to 2.30 mm, with vendors’ distortion correction on or off, respectively. Discussion Using nonrigid CT–MR registration can provide a robust and relatively test-object-agnostic method for estimating the intra- and inter-scanner variations of the geometric distortions.
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11
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Vickers AJ, Thiruthaneeswaran N, Coyle C, Manoharan P, Wylie J, Kershaw L, Choudhury A, Mcwilliam A. Does magnetic resonance imaging improve soft tissue sarcoma contouring for radiotherapy? BJR Open 2019; 1:20180022. [PMID: 33178916 PMCID: PMC7592468 DOI: 10.1259/bjro.20180022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 03/27/2019] [Accepted: 03/28/2019] [Indexed: 11/27/2022] Open
Abstract
Objective: Soft tissue sarcomas (STS) are a rare, heterogeneous tumour group. Radiotherapy improves local control. CT is used to plan radiotherapy, but has poor soft tissue definition. MRI has superior soft tissue definition. Contour variation amongst oncologists is an important factor in treatment failure. This study is the first to directly compare STS tumour contouring using CT vs MRI. Methods: Planning CT and T2 weighted MR images of eight patients with STS were distributed to four oncologists. Gross tumour volume was contoured on both imaging modalities using in-house software. Images were recontoured 6 weeks later. The mean distance to agreement (DTA), standard deviation of the DTA, dice similarity coefficient (DSC) and contour volume were calculated for each oncologist and compared to a median contour volume. Results for CT and MRI were compared using a pairwise Student's t-test. Results: When comparing MRI to CT, tumour volumes were significantly smaller, with a difference of 21.4 cm3 across all patients (p = 0.008). There was not a statistically significant difference in the mean distance to agreement or dice similarity coefficient, but the standard deviation of the DTA showed a statistically significant improvement ( p = 0.04). For intraobserver variation, there was no statistically significant improvement using MRI vs CT. Conclusion: Oncologists contour smaller tumour volumes using MRI, with reduced interobserver variation. Improving the reliability and consistency of contouring is needed for improved quality assurance. Advances in knowledge: With further experience, the use of MRI in STS radiotherapy planning may reduce variation between oncologists and contribute to improved local control and reduced treatment toxicities.
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Affiliation(s)
- Alexander John Vickers
- Department of Clinical Oncology, The Christie NHS Foundation Trust, 550 Wilmslow Road, Withington, Manchester, United Kingdom
| | | | - Catherine Coyle
- Department of Clinical Oncology, The Christie NHS Foundation Trust, 550 Wilmslow Road, Withington, Manchester, United Kingdom
| | - Prakash Manoharan
- Department of Clinical Oncology, The Christie NHS Foundation Trust, 550 Wilmslow Road, Withington, Manchester, United Kingdom
| | - James Wylie
- Department of Clinical Oncology, The Christie NHS Foundation Trust, 550 Wilmslow Road, Withington, Manchester, United Kingdom
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12
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Ranta I, Kemppainen R, Keyriläinen J, Suilamo S, Heikkinen S, Kapanen M, Saunavaara J. Quality assurance measurements of geometric accuracy for magnetic resonance imaging-based radiotherapy treatment planning. Phys Med 2019; 62:47-52. [PMID: 31153398 DOI: 10.1016/j.ejmp.2019.04.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/29/2019] [Accepted: 04/24/2019] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Using magnetic resonance imaging (MRI) as the only imaging method for radiotherapy treatment planning (RTP) is becoming more common as MRI-only RTP solutions have evolved. The geometric accuracy of MR images is an essential factor of image quality when determining the suitability of MRI for RTP. The need is therefore clear for clinically feasible quality assurance (QA) methods for the geometric accuracy measurement. MATERIALS AND METHODS This work evaluates long-term stability of geometric accuracy and the validity of a 2D geometric accuracy QA method compared to a prototype 3D method and analysis software in routine QA. The long-term follow-up measurements were conducted on one of the 1.5 T scanners over a period of 19 months using both methods. Inter-scanner variability of geometric distortions was also evaluated in three 1.5 T and three 3 T MRI scanners from a single vendor by using the prototype 3D QA method. RESULTS The geometric accuracy of the magnetic resonance for radiotherapy (MR-RT) platform remained stable within 2 mm at distances of <250 mm from isocenter. All scanners achieved good geometric accuracy with mean geometric distortions of <1 mm at <150 mm and <2 mm at <250 mm from the isocenter. Both measurement methods provided relevant information about geometric distortions. CONCLUSIONS Geometric distortions are often considered a limitation of MRI-only RTP. Results indicate that geometric accuracy of modern scanners remain within acceptable limits by default even after many years of clinical use based on the 3D QA evaluation.
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Affiliation(s)
- Iiro Ranta
- Department of Physics and Astronomy, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland; Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland.
| | | | - Jani Keyriläinen
- Department of Physics and Astronomy, University of Turku, Vesilinnantie 5, FI-20014 Turku, Finland; Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Sami Suilamo
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Samuli Heikkinen
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
| | - Mika Kapanen
- Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, P.O. Box 2000, FI-33521 Tampere, Finland; Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, P.O. Box 2000, FI-33521 Tampere, Finland
| | - Jani Saunavaara
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, P.O. Box 52, FI-20521 Turku, Finland
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13
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Adjeiwaah M, Bylund M, Lundman JA, Söderström K, Zackrisson B, Jonsson JH, Garpebring A, Nyholm T. Dosimetric Impact of MRI Distortions: A Study on Head and Neck Cancers. Int J Radiat Oncol Biol Phys 2018; 103:994-1003. [PMID: 30496879 DOI: 10.1016/j.ijrobp.2018.11.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 11/13/2018] [Accepted: 11/19/2018] [Indexed: 10/27/2022]
Abstract
PURPOSE To evaluate the effect of magnetic resonance (MR) imaging (MRI) geometric distortions on head and neck radiation therapy treatment planning (RTP) for an MRI-only RTP. We also assessed the potential benefits of patient-specific shimming to reduce the magnitude of MR distortions for a 3-T scanner. METHODS AND MATERIALS Using an in-house Matlab algorithm, shimming within entire imaging volumes and user-defined regions of interest were simulated. We deformed 21 patient computed tomography (CT) images with MR distortion fields (gradient nonlinearity and patient-induced susceptibility effects) to create distorted CT (dCT) images using bandwidths of 122 and 488 Hz/mm at 3 T. Field parameters from volumetric modulated arc therapy plans initially optimized on dCT data sets were transferred to CT data to compute a new plan. Both plans were compared to determine the impact of distortions on dose distributions. RESULTS Shimming across entire patient volumes decreased the percentage of voxels with distortions of more than 2 mm from 15.4% to 2.0%. Using the user-defined region of interest (ROI) shimming strategy, (here the Planning target volume (PTV) was the chosen ROI volume) led to increased geometric for volumes outside the PTV, as such voxels within the spinal cord with geometric shifts above 2 mm increased from 11.5% to 32.3%. The worst phantom-measured residual system distortions after 3-dimensional gradient nonlinearity correction within a radial distance of 200 mm from the isocenter was 2.17 mm. For all patients, voxels with distortion shifts of more than 2 mm resulting from patient-induced susceptibility effects were 15.4% and 0.0% using bandwidths of 122 Hz/mm and 488 Hz/mm at 3 T. Dose differences between dCT and CT treatment plans in D50 at the planning target volume were 0.4% ± 0.6% and 0.3% ± 0.5% at 122 and 488 Hz/mm, respectively. CONCLUSIONS The overall effect of MRI geometric distortions on data used for RTP was minimal. Shimming over entire imaging volumes decreased distortions, but user-defined subvolume shimming introduced significant errors in nearby organs and should probably be avoided.
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Affiliation(s)
- Mary Adjeiwaah
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.
| | - Mikael Bylund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Josef A Lundman
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | | | | | | | | | - Tufve Nyholm
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
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14
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Cunningham JM, Barberi EA, Miller J, Kim JP, Glide-Hurst CK. Development and evaluation of a novel MR-compatible pelvic end-to-end phantom. J Appl Clin Med Phys 2018; 20:265-275. [PMID: 30411477 PMCID: PMC6333127 DOI: 10.1002/acm2.12455] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 05/22/2018] [Accepted: 08/22/2018] [Indexed: 12/25/2022] Open
Abstract
MR-only treatment planning and MR-IGRT leverage MRI's powerful soft tissue contrast for high-precision radiation therapy. However, anthropomorphic MR-compatible phantoms are currently limited. This work describes the development and evaluation of a custom-designed, modular, pelvic end-to-end (PETE) MR-compatible phantom to benchmark MR-only and MR-IGRT workflows. For construction considerations, subject data were assessed for phantom/skeletal geometry and internal organ kinematics to simulate average male pelvis anatomy. Various materials for the bone, bladder, and rectum were evaluated for utility within the phantom. Once constructed, PETE underwent CT-SIM, MR-Linac, and MR-SIM imaging to qualitatively assess organ visibility. Scans were acquired with various bladder and rectal volumes to assess component interactions, filling capabilities, and filling reproducibility via volume and centroid differences. PETE simulates average male pelvis anatomy and comprises an acrylic body oval (height/width = 23.0/38.1 cm) and a cast-mold urethane skeleton, with silicone balloons simulating bladder and rectum, a silicone sponge prostate, and hydrophilic poly(vinyl alcohol) foam to simulate fat/tissue separation between organs. Access ports enable retrofitting the phantom with other inserts including point/film-based dosimetry options. Acceptable contrast was achievable in CT-SIM and MR-Linac images. However, the bladder was challenging to distinguish from background in CT-SIM. The desired contrast for T1-weighted and T2-weighted MR-SIM (dark and bright bladders, respectively) was achieved. Rectum and bone exhibited no MR signal. Inputted volumes differed by <5 and <10 mL from delineated rectum (CT-SIM) and bladder (MR-SIM) volumes. Increasing bladder and rectal volumes induced organ displacements and shape variations. Reproduced volumes differed by <4.5 mL, with centroid displacements <1.4 mm. A point dose measurement with an MR-compatible ion chamber in an MR-Linac was within 1.5% of expected. A novel, modular phantom was developed with suitable materials and properties that accurately and reproducibly simulate status changes with multiple dosimetry options. Future work includes integrating more realistic organ models to further expand phantom options.
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Affiliation(s)
| | | | - John Miller
- Modus Medical Devices Inc., London, ON, Canada
| | - Joshua P Kim
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Carri K Glide-Hurst
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
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15
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Geometric distortion in magnetic resonance imaging systems assessed using an open-source plugin for scientific image analysis. Radiol Phys Technol 2018; 11:467-472. [PMID: 30255438 DOI: 10.1007/s12194-018-0477-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 09/18/2018] [Accepted: 09/18/2018] [Indexed: 10/28/2022]
Abstract
Tumor locations are commonly delineated by referring to magnetic resonance (MR) images. However, MR images have geometric distortions that cannot be completely corrected. This study aimed to investigate quantitatively uncorrectable error [residual error (RE)] with the use of an open-source plugin for scientific image analysis. The RE values were calculated by Fiji, which was enhanced by Image J image processing software. The results obtained with the open-source plugin for scientific image analysis agreed with the results obtained with the commercially available software. Obtaining detailed geometric distortion data for each facility and device could facilitate safe treatment because the homogeneous magnetic field in MR imaging varies across devices and over time. Therefore, using an open-source plugin for scientific image analysis may be an accurate and effective technique for evaluating the RE of MR imaging systems.
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16
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Yan Y, Yang J, Beddar S, Ibbott G, Wen Z, Court LE, Hwang KP, Kadbi M, Krishnan S, Fuller CD, Frank SJ, Yang J, Balter P, Kudchadker RJ, Wang J. A methodology to investigate the impact of image distortions on the radiation dose when using magnetic resonance images for planning. Phys Med Biol 2018. [PMID: 29528037 DOI: 10.1088/1361-6560/aab5c3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We developed a novel technique to study the impact of geometric distortion of magnetic resonance imaging (MRI) on intensity-modulated radiation therapy treatment planning. The measured 3D datasets of residual geometric distortion (a 1.5 T MRI component of an MRI linear accelerator system) was fitted with a second-order polynomial model to map the spatial dependence of geometric distortions. Then the geometric distortion model was applied to computed tomography (CT) image and structure data to simulate the distortion of MRI data and structures. Fourteen CT-based treatment plans were selected from patients treated for gastrointestinal, genitourinary, thoracic, head and neck, or spinal tumors. Plans based on the distorted CT and structure data were generated (as the distorted plans). Dose deviations of the distorted plans were calculated and compared with the original plans to study the dosimetric impact of MRI distortion. The MRI geometric distortion led to notable dose deviations in five of the 14 patients, causing loss of target coverage of up to 3.68% and dose deviations to organs at risk in three patients, increasing the mean dose to the chest wall by up to 6.19 Gy in a gastrointestinal patient, and increases the maximum dose to the lung by 5.17 Gy in a thoracic patient.
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Affiliation(s)
- Yue Yan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America. Joint first authors
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17
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Chen X, Dai J. Quantitative analysis of image quality for acceptance and commissioning of an MRI simulator with a semiautomatic method. J Appl Clin Med Phys 2018; 19:326-335. [PMID: 29573140 PMCID: PMC5978956 DOI: 10.1002/acm2.12311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 01/09/2018] [Accepted: 02/06/2018] [Indexed: 11/28/2022] Open
Abstract
Magnetic Resonance Imaging (MRI) simulation differs from diagnostic MRI in purpose, technical requirements, and implementation. We propose a semiautomatic method for image acceptance and commissioning for the scanner, the radiofrequency (RF) coils, and pulse sequences for an MRI simulator. The ACR MRI accreditation large phantom was used for image quality analysis with seven parameters. Standard ACR sequences with a split head coil were adopted to examine the scanner's basic performance. The performance of simulation RF coils were measured and compared using the standard sequence with different clinical diagnostic coils. We used simulation sequences with simulation coils to test the quality of image and advanced performance of the scanner. Codes and procedures were developed for semiautomatic image quality analysis. When using standard ACR sequences with a split head coil, image quality passed all ACR recommended criteria. The image intensity uniformity with a simulation RF coil decreased about 34% compared with the eight‐channel diagnostic head coil, while the other six image quality parameters were acceptable. Those two image quality parameters could be improved to more than 85% by built‐in intensity calibration methods. In the simulation sequences test, the contrast resolution was sensitive to the FOV and matrix settings. The geometric distortion of simulation sequences such as T1‐weighted and T2‐weighted images was well‐controlled in the isocenter and 10 cm off‐center within a range of ±1% (2 mm). We developed a semiautomatic image quality analysis method for quantitative evaluation of images and commissioning of an MRI simulator. The baseline performances of simulation RF coils and pulse sequences have been established for routine QA.
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Affiliation(s)
- Xinyuan Chen
- Department of Radiation Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianrong Dai
- Department of Radiation Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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18
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Abstract
Over the past decade, the application of magnetic resonance imaging (MRI) has increased, and there is growing evidence to suggest that improvements in the accuracy of target delineation in MRI-guided radiation therapy may improve clinical outcomes in a variety of cancer types. However, some considerations should be recognized including patient motion during image acquisition and geometric accuracy of images. Moreover, MR-compatible immobilization devices need to be used when acquiring images in the treatment position while minimizing patient motion during the scan time. Finally, synthetic CT images (i.e. electron density maps) and digitally reconstructed radiograph images should be generated from MRI images for dose calculation and image guidance prior to treatment. A short review of the concepts and techniques that have been developed for implementation of MRI-only workflows in radiation therapy is provided in this document.
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Affiliation(s)
- Amir M. Owrangi
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas
| | - Peter B. Greer
- School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW, 2308, Australia
- Department of Radiation Oncology, Calvary Mater Hospital, Newcastle, NSW, 2298, Australia
| | - Carri K. Glide-Hurst
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan
- Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan
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19
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Padgett KR, Stoyanova R, Pirozzi S, Johnson P, Piper J, Dogan N, Pollack A. Validation of a deformable MRI to CT registration algorithm employing same day planning MRI for surrogate analysis. J Appl Clin Med Phys 2018; 19:258-264. [PMID: 29476603 PMCID: PMC5849829 DOI: 10.1002/acm2.12296] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 11/28/2018] [Accepted: 01/22/2018] [Indexed: 11/10/2022] Open
Abstract
Purpose Validating deformable multimodality image registrations is challenging due to intrinsic differences in signal characteristics and their spatial intensity distributions. Evaluating multimodality registrations using these spatial intensity distributions is also complicated by the fact that these metrics are often employed in the registration optimization process. This work evaluates rigid and deformable image registrations of the prostate in between diagnostic‐MRI and radiation treatment planning‐CT by utilizing a planning‐MRI after fiducial marker placement as a surrogate. The surrogate allows for the direct quantitative analysis that can be difficult in the multimodality domain. Methods For thirteen prostate patients, T2 images were acquired at two different time points, the first several weeks prior to planning (diagnostic‐MRI) and the second on the same day as the planning‐CT (planning‐MRI). The diagnostic‐MRI was deformed to the planning‐CT utilizing a commercially available algorithm which synthesizes a deformable image registration (DIR) algorithm from local rigid registrations. The planning‐MRI provided an independent surrogate for the planning‐CT for assessing registration accuracy using image similarity metrics, including Pearson correlation and normalized mutual information (NMI). A local analysis was performed by looking only within the prostate, proximal seminal vesicles, penile bulb, and combined areas. Results The planning‐MRI provided an excellent surrogate for the planning‐CT with residual error in fiducial alignment between the two datasets being submillimeter, 0.78 mm. DIR was superior to the rigid registration in 11 of 13 cases demonstrating a 27.37% improvement in NMI (P < 0.009) within a regional area surrounding the prostate and associated critical organs. Pearson correlations showed similar results, demonstrating a 13.02% improvement (P < 0.013). Conclusion By utilizing the planning‐MRI as a surrogate for the planning‐CT, an independent evaluation of registration accuracy is possible. This population provides an ideal testing ground for MRI to CT DIR by obviating the need for multimodality comparisons which are inherently more challenging.
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Affiliation(s)
- Kyle R Padgett
- Department of Radiation Oncology, University of Miami School of Medicine, Miami, FL, USA.,Department of Radiology, University of Miami School of Medicine, Miami, FL, USA
| | - Radka Stoyanova
- Department of Radiation Oncology, University of Miami School of Medicine, Miami, FL, USA
| | | | - Perry Johnson
- Department of Radiation Oncology, University of Miami School of Medicine, Miami, FL, USA
| | - Jon Piper
- MIM Software, Inc., Beachwood, OH, USA
| | - Nesrin Dogan
- Department of Radiation Oncology, University of Miami School of Medicine, Miami, FL, USA
| | - Alan Pollack
- Department of Radiation Oncology, University of Miami School of Medicine, Miami, FL, USA
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20
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Wang H, Du K, Qu J, Chandarana H, Das IJ. Dosimetric evaluation of magnetic resonance-generated synthetic CT for radiation treatment of rectal cancer. PLoS One 2018; 13:e0190883. [PMID: 29304105 PMCID: PMC5755922 DOI: 10.1371/journal.pone.0190883] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 12/21/2017] [Indexed: 12/20/2022] Open
Abstract
Purpose The purpose of this study was to assess the dosimetric equivalence of magnetic resonance (MR)-generated synthetic CT (synCT) and simulation CT for treatment planning in radiotherapy of rectal cancer. Methods This study was conducted on eleven patients who underwent whole-body PET/MR and PET/CT examination in a prospective IRB-approved study. For each patient synCT was generated from Dixon MR using a model-based method. Standard treatment planning directives were used to create a four-field box (4F), an oblique four-field (O4F) and a volumetric modulated arc therapy (VMAT) plan on synCT for treatment of rectal cancer. The plans were recalculated on CT with the same monitor units (MUs) as that of synCT. Dose-volume metrics of planning target volume (PTV) and organs at risk (OARs) as well as gamma analysis of dose distributions were evaluated to quantify the difference between synCT and CT plans. All plans were calculated using the analytical anisotropic algorithm (AAA). The VMAT plans on synCT and CT were also calculated using the Acuros XB algorithm for comparison with the AAA calculation. Results Medians of absolute differences in PTV metrics between synCT and CT plans were 0.2%, 0.2% and 0.3% for 4F, O4F and VMAT respectively. No significant differences were observed in OAR dose metrics including bladder V40Gy, mean dose in bladder, bowel V45Gy and femoral head V30Gy in any techniques. Gamma analysis with 2%/2mm dose difference/distance to agreement criteria showed median passing rates of 99.8% (range: 98.5 to 100%), 99.9% (97.2 to 100%), and 99.9% (99.4 to 100%) for 4F, O4F and VMAT, respectively. Using Acuros XB dose calculation, 2%/2mm gamma analysis generated a passing rate of 99.2% (97.7 to 99.9%) for VMAT plans. Conclusion SynCT enabled dose calculation equivalent to conventional CT for treatment planning of 3D conformal treatment as well as VMAT of rectal cancer. The dosimetric agreement between synCT and CT calculated doses demonstrated the potential of MR-only treatment planning for rectal cancer using MR generated synCT.
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Affiliation(s)
- Hesheng Wang
- Department of Radiation Oncology, New York University School of Medicine, New York, NY, United States of America
- * E-mail:
| | - Kevin Du
- Department of Radiation Oncology, New York University School of Medicine, New York, NY, United States of America
| | - Juliet Qu
- Department of Radiation Oncology, New York University School of Medicine, New York, NY, United States of America
| | - Hersh Chandarana
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States of America
| | - Indra J. Das
- Department of Radiation Oncology, New York University School of Medicine, New York, NY, United States of America
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21
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Saint-Jalmes H, Bordelois A, Gambarota G. Virtual phantom magnetic resonance imaging (ViP MRI) on a clinical MRI platform. Med Phys 2017; 45:250-257. [PMID: 29121397 DOI: 10.1002/mp.12658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 07/31/2017] [Accepted: 10/16/2017] [Indexed: 11/10/2022] Open
Abstract
PURPOSE The purpose of this study was to implement Virtual Phantom Magnetic Resonance Imaging (ViP MRI), a technique that allows for generating reference signals in MR images using radiofrequency (RF) signals, on a clinical MR system and to test newly designed virtual phantoms. METHODS MRI experiments were conducted on a 1.5 T MRI scanner. Electromagnetic modelling of the ViP system was done using the principle of reciprocity. The ViP RF signals were generated using a compact waveform generator (dimensions of 26 cm × 18 cm × 16 cm), connected to a homebuilt 25 mm-diameter RF coil. The ViP RF signals were transmitted to the MRI scanner bore, simultaneously with the acquisition of the signal from the object of interest. Different types of MRI data acquisition (2D and 3D gradient-echo) as well as different phantoms, including the Shepp-Logan phantom, were tested. Furthermore, a uniquely designed virtual phantom - in the shape of a grid - was generated; this newly proposed phantom allows for the investigations of the vendor distortion correction field. RESULTS High quality MR images of virtual phantoms were obtained. An excellent agreement was found between the experimental data and the inverse cube law, which was the expected functional dependence obtained from the electromagnetic modelling of the ViP system. Short-term time stability measurements yielded a coefficient of variation in the signal intensity over time equal to 0.23% and 0.13% for virtual and physical phantom, respectively. MR images of the virtual grid-shaped phantom were reconstructed with the vendor distortion correction; this allowed for a direct visualization of the vendor distortion correction field. Furthermore, as expected from the electromagnetic modelling of the ViP system, a very compact coil (diameter ~ cm) and very small currents (intensity ~ mA) were sufficient to generate a signal comparable to that of physical phantoms in MRI experiments. CONCLUSIONS The ViP MRI technique was successfully implemented on a clinical MR system. One of the major advantages of ViP MRI over previous approaches is that the generation and transmission of RF signals can be achieved with a self-contained apparatus. As such, the ViP MRI technique is transposable to different platforms (preclinical and clinical) of different vendors. It is also shown here that ViP MRI could be used to generate signals whose characteristics cannot be reproduced by physical objects. This could be exploited to assess MRI system properties, such as the vendor distortion correction field.
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Affiliation(s)
- Hervé Saint-Jalmes
- INSERM, UMR 1099, Rennes, France.,Université de Rennes 1, LTSI, Rennes, France.,CRLCC, Centre Eugène Marquis, Rennes, France
| | - Alejandro Bordelois
- Université de Rennes 1, LTSI, Rennes, France.,CBM, Universidad de Oriente, Santiago de Cuba, Cuba
| | - Giulio Gambarota
- INSERM, UMR 1099, Rennes, France.,Université de Rennes 1, LTSI, Rennes, France
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22
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Adjeiwaah M, Bylund M, Lundman JA, Karlsson CT, Jonsson JH, Nyholm T. Quantifying the Effect of 3T Magnetic Resonance Imaging Residual System Distortions and Patient-Induced Susceptibility Distortions on Radiation Therapy Treatment Planning for Prostate Cancer. Int J Radiat Oncol Biol Phys 2017; 100:317-324. [PMID: 29229326 DOI: 10.1016/j.ijrobp.2017.10.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/28/2017] [Accepted: 10/12/2017] [Indexed: 12/13/2022]
Abstract
PURPOSE To investigate the effect of magnetic resonance system- and patient-induced susceptibility distortions from a 3T scanner on dose distributions for prostate cancers. METHODS AND MATERIALS Combined displacement fields from the residual system and patient-induced susceptibility distortions were used to distort 17 prostate patient CT images. VMAT dose plans were initially optimized on distorted CT images and the plan parameters transferred to the original patient CT images to calculate a new dose distribution. RESULTS Maximum residual mean distortions of 3.19 mm at a radial distance of 25 cm and maximum mean patient-induced susceptibility shifts of 5.8 mm were found using the lowest bandwidth of 122 Hz per pixel. There was a dose difference of <0.5% between distorted and undistorted treatment plans. The 90% confidence intervals of the mean difference between the dCT and CT treatment plans were all within an equivalence interval of (-0.5, 0.5) for all investigated plan quality measures. CONCLUSIONS Patient-induced susceptibility distortions at high field strengths in closed bore magnetic resonance scanners are larger than residual system distortions after using vendor-supplied 3-dimensional correction for the delineated regions studied. However, errors in dose due to disturbed patient outline and shifts caused by patient-induced susceptibility effects are below 0.5%.
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Affiliation(s)
- Mary Adjeiwaah
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.
| | - Mikael Bylund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Josef A Lundman
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | | | | | - Tufve Nyholm
- Department of Radiation Sciences, Umeå University, Umeå, Sweden; Medical Radiation Physics, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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Arivarasan I, Anuradha C, Subramanian S, Anantharaman A, Ramasubramanian V. Magnetic resonance image guidance in external beam radiation therapy planning and delivery. Jpn J Radiol 2017; 35:417-426. [DOI: 10.1007/s11604-017-0656-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/29/2017] [Indexed: 12/14/2022]
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Gustafsson C, Nordström F, Persson E, Brynolfsson J, Olsson LE. Assessment of dosimetric impact of system specific geometric distortion in an MRI only based radiotherapy workflow for prostate. Phys Med Biol 2017; 62:2976-2989. [DOI: 10.1088/1361-6560/aa5fa2] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Jason Stafford R, Brezovich IA. Image-guided prostate brachytherapy should be MRI-based. Med Phys 2016; 43:6213. [PMID: 27908186 DOI: 10.1118/1.4965810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- R Jason Stafford
- Imaging Physics, UT MD Anderson Cancer Center, Houston, Texas 77030-4009 (Tel: 713-563-5082; E-mail: )
| | - Ivan A Brezovich
- Hazelrig-Salter Radiation Oncology Center, University of Alabama, Birmingham, Alabama 35249-6832 (Tel: 205-934-1758; E-mail: )
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Walker A, Metcalfe P, Liney G, Batumalai V, Dundas K, Glide‐Hurst C, Delaney GP, Boxer M, Yap ML, Dowling J, Rivest‐Henault D, Pogson E, Holloway L. MRI geometric distortion: Impact on tangential whole-breast IMRT. J Appl Clin Med Phys 2016; 17:7-19. [PMID: 28297426 PMCID: PMC5495026 DOI: 10.1120/jacmp.v17i5.6242] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 03/21/2016] [Indexed: 12/04/2022] Open
Abstract
The purpose of this study was to determine the impact of magnetic resonance imaging (MRI) geometric distortions when using MRI for target delineation and planning for whole-breast, intensity-modulated radiotherapy (IMRT). Residual system distortions and combined systematic and patient-induced distortions are considered. This retrospective study investigated 18 patients who underwent whole-breast external beam radiotherapy, where both CT and MRIs were acquired for treatment planning. Distortion phantoms were imaged on two MRI systems, dedicated to radiotherapy planning (a wide, closed-bore 3T and an open-bore 1T). Patient scans were acquired on the 3T system. To simulate MRI-based planning, distortion maps representing residual system distortions were generated via deformable registration between phantom CT and MRIs. Patient CT images and structures were altered to match the residual system distortion measured by the phantoms on each scanner. The patient CTs were also registered to the corresponding patient MRI scans, to assess patient and residual system effects. Tangential IMRT plans were generated and optimized on each resulting CT dataset, then propagated to the original patient CT space. The resulting dose distributions were then evaluated with respect to the standard clinically acceptable DVH and visual assessment criteria. Maximum residual systematic distortion was measured to be 7.9 mm (95%<4.7mm) and 11.9 mm (95%<4.6mm) for the 3T and 1T scanners, respectively, which did not result in clinically unacceptable plans. Eight of the plans accounting for patient and systematic distortions were deemed clinically unacceptable when assessed on the original CT. For these plans, the mean difference in PTV V95 (volume receiving 95% prescription dose) was 0.13±2.51% and -0.73±1.93% for right- and left-sided patients, respectively. Residual system distortions alone had minimal impact on the dosimetry for the two scanners investigated. The combination of MRI systematic and patient-related distortions can result in unacceptable dosimetry for whole-breast IMRT, a potential issue when considering MRI-only radiotherapy treatment planning. PACS number(s): 87.61.-c, 87.57.cp, 87.57.nj, 87.55.D.
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Affiliation(s)
- Amy Walker
- Centre for Medical Radiation Physics, University of WollongongWollongongNSWAustralia
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of WollongongWollongongNSWAustralia
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
| | - Gary Liney
- Centre for Medical Radiation Physics, University of WollongongWollongongNSWAustralia
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
- Institute of Medical Physics, School of Physics, University of SydneySydneyNSWAustralia
| | - Vikneswary Batumalai
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
- South Western Clinical School, University of New South WalesSydneyNSWAustralia
| | - Kylie Dundas
- Centre for Medical Radiation Physics, University of WollongongWollongongNSWAustralia
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
| | - Carri Glide‐Hurst
- Department of Radiation OncologyHenry Ford Health SystemDetroitMIUSA
| | - Geoff P Delaney
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- South Western Clinical School, University of New South WalesSydneyNSWAustralia
- Collaboration for Cancer Outcomes Research and Evaluation, Liverpool HospitalLiverpoolNSWAustralia
- School of Medicine, University of Western SydneySydneyNSWAustralia
| | - Miriam Boxer
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- South Western Clinical School, University of New South WalesSydneyNSWAustralia
| | - Mei Ling Yap
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
- South Western Clinical School, University of New South WalesSydneyNSWAustralia
- Collaboration for Cancer Outcomes Research and Evaluation, Liverpool HospitalLiverpoolNSWAustralia
- School of Medicine, University of Western SydneySydneyNSWAustralia
| | - Jason Dowling
- Commonwealth Scientific and Industrial Research Organisation Computational Informatics, Australian E‐Health Research CentreBrisbaneAustralia
| | - David Rivest‐Henault
- Commonwealth Scientific and Industrial Research Organisation Computational Informatics, Australian E‐Health Research CentreBrisbaneAustralia
| | - Elise Pogson
- Centre for Medical Radiation Physics, University of WollongongWollongongNSWAustralia
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
| | - Lois Holloway
- Centre for Medical Radiation Physics, University of WollongongWollongongNSWAustralia
- Liverpool and Macarthur Cancer Therapy CentresNSWAustralia
- Ingham Institute for Applied Medical Research, Liverpool HospitalSydneyNSWAustralia
- South Western Clinical School, University of New South WalesSydneyNSWAustralia
- Institute of Medical Physics, School of Physics, University of SydneySydneyNSWAustralia
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27
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Xing A, Holloway L, Arumugam S. Commissioning and quality control of a dedicated wide bore 3T MRI simulator for radiotherapy planning. INTERNATIONAL JOURNAL OF CANCER THERAPY AND ONCOLOGY 2016. [DOI: 10.14319/ijcto.42.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Price RG, Kim JP, Zheng W, Chetty IJ, Glide-Hurst C. Image Guided Radiation Therapy Using Synthetic Computed Tomography Images in Brain Cancer. Int J Radiat Oncol Biol Phys 2016; 95:1281-9. [PMID: 27209500 DOI: 10.1016/j.ijrobp.2016.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 02/26/2016] [Accepted: 03/03/2016] [Indexed: 12/01/2022]
Abstract
PURPOSE The development of synthetic computed tomography (CT) (synCT) derived from magnetic resonance (MR) images supports MR-only treatment planning. We evaluated the accuracy of synCT and synCT-generated digitally reconstructed radiographs (DRRs) relative to CT and determined their performance for image guided radiation therapy (IGRT). METHODS AND MATERIALS Magnetic resonance simulation (MR-SIM) and CT simulation (CT-SIM) images were acquired of an anthropomorphic skull phantom and 12 patient brain cancer cases. SynCTs were generated using fluid attenuation inversion recovery, ultrashort echo time, and Dixon data sets through a voxel-based weighted summation of 5 tissue classifications. The DRRs were generated from the phantom synCT, and geometric fidelity was assessed relative to CT-generated DRRs through bounding box and landmark analysis. An offline retrospective analysis was conducted to register cone beam CTs (n=34) to synCTs and CTs using automated rigid registration in the treatment planning system. Planar MV and KV images (n=37) were rigidly registered to synCT and CT DRRs using an in-house script. Planar and volumetric registration reproducibility was assessed and margin differences were characterized by the van Herk formalism. RESULTS Bounding box and landmark analysis of phantom synCT DRRs were within 1 mm of CT DRRs. Absolute planar registration shift differences ranged from 0.0 to 0.7 mm for phantom DRRs on all treatment platforms and from 0.0 to 0.4 mm for volumetric registrations. For patient planar registrations, the mean shift differences were 0.4 ± 0.5 mm (range, -0.6 to 1.6 mm), 0.0 ± 0.5 mm (range, -0.9 to 1.2 mm), and 0.1 ± 0.3 mm (range, -0.7 to 0.6 mm) for the superior-inferior (S-I), left-right (L-R), and anterior-posterior (A-P) axes, respectively. The mean shift differences in volumetric registrations were 0.6 ± 0.4 mm (range, -0.2 to 1.6 mm), 0.2 ± 0.4 mm (range, -0.3 to 1.2 mm), and 0.2 ± 0.3 mm (range, -0.2 to 1.2 mm) for the S-I, L-R, and A-P axes, respectively. The CT-SIM and synCT derived margins were <0.3 mm different. CONCLUSION DRRs generated by synCT were in close agreement with CT-SIM. Planar and volumetric image registrations to synCT-derived targets were comparable with CT for phantom and patients. This validation is the next step toward MR-only planning for the brain.
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Affiliation(s)
- Ryan G Price
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan; Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Joshua P Kim
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan
| | - Weili Zheng
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan
| | - Indrin J Chetty
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan; Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Carri Glide-Hurst
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan; Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan.
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Weygand J, Fuller CD, Ibbott GS, Mohamed ASR, Ding Y, Yang J, Hwang KP, Wang J. Spatial Precision in Magnetic Resonance Imaging-Guided Radiation Therapy: The Role of Geometric Distortion. Int J Radiat Oncol Biol Phys 2016; 95:1304-16. [PMID: 27354136 DOI: 10.1016/j.ijrobp.2016.02.059] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 02/05/2016] [Accepted: 02/25/2016] [Indexed: 12/11/2022]
Abstract
Because magnetic resonance imaging-guided radiation therapy (MRIgRT) offers exquisite soft tissue contrast and the ability to image tissues in arbitrary planes, the interest in this technology has increased dramatically in recent years. However, intrinsic geometric distortion stemming from both the system hardware and the magnetic properties of the patient affects MR images and compromises the spatial integrity of MRI-based radiation treatment planning, given that for real-time MRIgRT, precision within 2 mm is desired. In this article, we discuss the causes of geometric distortion, describe some well-known distortion correction algorithms, and review geometric distortion measurements from 12 studies, while taking into account relevant imaging parameters. Eleven of the studies reported phantom measurements quantifying system-dependent geometric distortion, while 2 studies reported simulation data quantifying magnetic susceptibility-induced geometric distortion. Of the 11 studies investigating system-dependent geometric distortion, 5 reported maximum measurements less than 2 mm. The simulation studies demonstrated that magnetic susceptibility-induced distortion is typically smaller than system-dependent distortion but still nonnegligible, with maximum distortion ranging from 2.1 to 2.6 mm at a field strength of 1.5 T. As expected, anatomic landmarks containing interfaces between air and soft tissue had the largest distortions. The evidence indicates that geometric distortion reduces the spatial integrity of MRI-based radiation treatment planning and likely diminishes the efficacy of MRIgRT. Better phantom measurement techniques and more effective distortion correction algorithms are needed to achieve the desired spatial precision.
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Affiliation(s)
- Joseph Weygand
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas.
| | - Clifton David Fuller
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Geoffrey S Ibbott
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
| | - Abdallah S R Mohamed
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Clinical Oncology and Nuclear Medicine, Alexandria University, Alexandria, Egypt
| | - Yao Ding
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jinzhong Yang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
| | - Ken-Pin Hwang
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jihong Wang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
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30
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Dowling JA, Sun J, Pichler P, Rivest-Hénault D, Ghose S, Richardson H, Wratten C, Martin J, Arm J, Best L, Chandra SS, Fripp J, Menk FW, Greer PB. Automatic Substitute Computed Tomography Generation and Contouring for Magnetic Resonance Imaging (MRI)-Alone External Beam Radiation Therapy From Standard MRI Sequences. Int J Radiat Oncol Biol Phys 2015; 93:1144-53. [PMID: 26581150 DOI: 10.1016/j.ijrobp.2015.08.045] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 08/05/2015] [Accepted: 08/25/2015] [Indexed: 11/28/2022]
Abstract
PURPOSE To validate automatic substitute computed tomography CT (sCT) scans generated from standard T2-weighted (T2w) magnetic resonance (MR) pelvic scans for MR-Sim prostate treatment planning. PATIENTS AND METHODS A Siemens Skyra 3T MR imaging (MRI) scanner with laser bridge, flat couch, and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole-pelvis MRI scan (1.6 mm 3-dimensional isotropic T2w SPACE [Sampling Perfection with Application optimized Contrasts using different flip angle Evolution] sequence) was acquired. Three additional small field of view scans were acquired: T2w, T2*w, and T1w flip angle 80° for gold fiducials. Patients received a routine planning CT scan. Manual contouring of the prostate, rectum, bladder, and bones was performed independently on the CT and MR scans. Three experienced observers contoured each organ on MRI, allowing interobserver quantification. To generate a training database, each patient CT scan was coregistered to their whole-pelvis T2w using symmetric rigid registration and structure-guided deformable registration. A new multi-atlas local weighted voting method was used to generate automatic contours and sCT results. RESULTS The mean error in Hounsfield units between the sCT and corresponding patient CT (within the body contour) was 0.6 ± 14.7 (mean ± 1 SD), with a mean absolute error of 40.5 ± 8.2 Hounsfield units. Automatic contouring results were very close to the expert interobserver level (Dice similarity coefficient): prostate 0.80 ± 0.08, bladder 0.86 ± 0.12, rectum 0.84 ± 0.06, bones 0.91 ± 0.03, and body 1.00 ± 0.003. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same dose prescription was found to be 0.3% ± 0.8%. The 3-dimensional γ pass rate was 1.00 ± 0.00 (2 mm/2%). CONCLUSIONS The MR-Sim setup and automatic sCT generation methods using standard MR sequences generates realistic contours and electron densities for prostate cancer radiation therapy dose planning and digitally reconstructed radiograph generation.
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Affiliation(s)
- Jason A Dowling
- CSIRO Australian e-Health Research Centre, Herston, Queensland, Australia; University of Newcastle, Callaghan, New South Wales, Australia.
| | - Jidi Sun
- University of Newcastle, Callaghan, New South Wales, Australia
| | - Peter Pichler
- Calvary Mater Newcastle Hospital, Waratah, New South Wales, Australia
| | | | - Soumya Ghose
- CSIRO Australian e-Health Research Centre, Herston, Queensland, Australia
| | - Haylea Richardson
- Calvary Mater Newcastle Hospital, Waratah, New South Wales, Australia
| | - Chris Wratten
- University of Newcastle, Callaghan, New South Wales, Australia; Calvary Mater Newcastle Hospital, Waratah, New South Wales, Australia
| | - Jarad Martin
- University of Newcastle, Callaghan, New South Wales, Australia; Calvary Mater Newcastle Hospital, Waratah, New South Wales, Australia
| | - Jameen Arm
- Calvary Mater Newcastle Hospital, Waratah, New South Wales, Australia
| | - Leah Best
- Department of Radiology, Hunter New England Health, New Lambton, New South Wales, Australia
| | - Shekhar S Chandra
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Queensland, Australia
| | - Jurgen Fripp
- CSIRO Australian e-Health Research Centre, Herston, Queensland, Australia
| | | | - Peter B Greer
- University of Newcastle, Callaghan, New South Wales, Australia; Calvary Mater Newcastle Hospital, Waratah, New South Wales, Australia
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