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Samanci Y, Askeroglu MO, Düzkalir AH, Peker S. Assessing the impact of distortion correction on Gamma Knife radiosurgery for multiple metastasis: Volumetric and dosimetric analysis. BRAIN & SPINE 2024; 4:102791. [PMID: 38584868 PMCID: PMC10995810 DOI: 10.1016/j.bas.2024.102791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 03/11/2024] [Accepted: 03/19/2024] [Indexed: 04/09/2024]
Abstract
Introduction Magnetic resonance imaging (MRI) is a robust neuroimaging technique and is the preferred method for stereotactic radiosurgery (SRS) planning. However, MRI data always contain distortions caused by hardware and patient factors. Research question Can these distortions potentially compromise the effectiveness and safety of SRS treatments? Material and methods Twenty-six MR datasets with multiple metastatic brain tumors (METs) used for Gamma Knife radiosurgery (GKRS) were retrospectively evaluated. A commercially available software was used for distortion correction. Geometrical agreement between corrected and uncorrected tumor volumes was evaluated using MacDonald criteria, Euclidian distance, and Dice similarity coefficient (DSC). SRS plans were generated using uncorrected tumor volumes, which were assessed to determine their coverage of the corrected tumor volumes. Results The median target volume was 0.38 cm3 (range,0.01-12.38 cm3). A maximum displacement of METs of up to 2.87 mm and a median displacement of 0.55 mm (range,0.1-2.87 mm) were noted. The median DSC between uncorrected and corrected MRI was 0.92, and the most concerning case had a DSC of 0.46. Although all plans met the optimization criterion of at least 98% of the uncorrected tumor volume (median 99.55%, range 98.1-100%) receiving at least 100% of the prescription dose, the percent of the corrected tumor volume receiving the total prescription dose was a median of 95.45% (range,23.1-99.5%). Discussion and conclusion MRI distortion, though visually subtle, has significant implications for SRS planning. Regular utilization of corrected MRI is recommended for SRS planning as distortion is sometimes enough to cause a volumetric miss of SRS targets.
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Affiliation(s)
- Yavuz Samanci
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
| | - M. Orbay Askeroglu
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
| | - Ali Haluk Düzkalir
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
- Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
| | - Selcuk Peker
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
- Gamma Knife Center, Department of Neurosurgery, Koc University Hospital, Istanbul, Turkey
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Yang X, Feng B, Yang H, Wang X, Luo H, Chen L, Jin F, Wang Y. CNN-based multi-modal radiomics analysis of pseudo-CT utilization in MRI-only brain stereotactic radiotherapy: a feasibility study. BMC Cancer 2024; 24:59. [PMID: 38200424 PMCID: PMC10782704 DOI: 10.1186/s12885-024-11844-3] [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: 07/21/2023] [Accepted: 01/04/2024] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Pseudo-computed tomography (pCT) quality is a crucial issue in magnetic resonance image (MRI)-only brain stereotactic radiotherapy (SRT), so this study systematically evaluated it from the multi-modal radiomics perspective. METHODS 34 cases (< 30 cm³) were retrospectively included (2021.9-2022.10). For each case, both CT and MRI scans were performed at simulation, and pCT was generated by a convolutional neural network (CNN) from planning MRI. Conformal arc or volumetric modulated arc technique was used to optimize the dose distribution. The SRT dose was compared between pCT and planning CT with dose volume histogram (DVH) metrics and gamma index. Wilcoxon test and Spearman analysis were used to identify key factors associated with dose deviations. Additionally, original image features were extracted for radiomic analysis. Tumor control probability (TCP) and normal tissue complication probability (NTCP) were employed for efficacy evaluation. RESULTS There was no significant difference between pCT and planning CT except for radiomics. The mean value of Hounsfield unit of the planning CT was slightly higher than that of pCT. The Gadolinium-based agents in planning MRI could increase DVH metrics deviation slightly. The median local gamma passing rates (1%/1 mm) between planning CTs and pCTs (non-contrast) was 92.6% (range 63.5-99.6%). Also, differences were observed in more than 85% of original radiomic features. The mean absolute deviation in TCP was 0.03%, and the NTCP difference was below 0.02%, except for the normal brain, which had a 0.16% difference. In addition, the number of SRT fractions and lesions, and lesion morphology could influence dose deviation. CONCLUSIONS This is the first multi-modal radiomics analysis of CNN-based pCT from planning MRI for SRT of small brain lesions, covering dosiomics and radiomics. The findings suggest the potential of pCT in SRT plan design and efficacy prediction, but caution needs to be taken for radiomic analysis.
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Affiliation(s)
- Xin Yang
- Departments of Radiation Oncology, Chongqing University Cancer Hospital, No. 181, Han Yu Road, Shapingba District, Chongqing, 400030, People's Republic of China.
| | - Bin Feng
- Departments of Radiation Oncology, Chongqing University Cancer Hospital, No. 181, Han Yu Road, Shapingba District, Chongqing, 400030, People's Republic of China
| | - Han Yang
- Departments of Radiation Oncology, Chongqing University Cancer Hospital, No. 181, Han Yu Road, Shapingba District, Chongqing, 400030, People's Republic of China
| | - Xiaoqi Wang
- Apodibot Medical, Beijing, People's Republic of China
| | - Huanli Luo
- Departments of Radiation Oncology, Chongqing University Cancer Hospital, No. 181, Han Yu Road, Shapingba District, Chongqing, 400030, People's Republic of China
| | - Liyuan Chen
- Departments of Radiation Oncology, Chongqing University Cancer Hospital, No. 181, Han Yu Road, Shapingba District, Chongqing, 400030, People's Republic of China
| | - Fu Jin
- Departments of Radiation Oncology, Chongqing University Cancer Hospital, No. 181, Han Yu Road, Shapingba District, Chongqing, 400030, People's Republic of China.
| | - Ying Wang
- Departments of Radiation Oncology, Chongqing University Cancer Hospital, No. 181, Han Yu Road, Shapingba District, Chongqing, 400030, People's Republic of China.
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Ohira S, Suzuki Y, Washio H, Yamamoto Y, Tateishi S, Inui S, Kanayama N, Kawamata M, Miyazaki M, Nishio T, Koizumi M, Nakanishi K, Konishi K. Impact of magnetic resonance imaging-related geometric distortion of dose distribution in fractionated stereotactic radiotherapy in patients with brain metastases. Strahlenther Onkol 2024; 200:39-48. [PMID: 37591978 DOI: 10.1007/s00066-023-02120-7] [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: 01/25/2023] [Accepted: 07/10/2023] [Indexed: 08/19/2023]
Abstract
PURPOSE The geometric distortion related to magnetic resonance (MR) imaging in a diagnostic radiology (MRDR) and radiotherapy (MRRT) setup is evaluated, and the dosimetric impact of MR distortion on fractionated stereotactic radiotherapy (FSRT) in patients with brain metastases is simulated. MATERIALS AND METHODS An anthropomorphic skull phantom was scanned using a 1.5‑T MR scanner, and the magnitude of MR distortion was calculated with (MRDR-DC and MRRT-DC) and without (MRDR-nDC and MRRT-nDC) distortion-correction algorithms. Automated noncoplanar volumetric modulated arc therapy (HyperArc, HA; Varian Medical Systems, Palo Alto, CA, USA) plans were generated for 53 patients with 186 brain metastases. The MR distortion at each gross tumor volume (GTV) was calculated using the distance between the center of the GTV and the MR image isocenter (MIC) and the quadratic regression curve derived from the phantom study (MRRT-DC and MRRT-nDC). Subsequently, the radiation isocenter of the HA plans was shifted according to the MR distortion at each GTV (HADC and HAnDC). RESULTS The median MR distortions were approximately 0.1 mm when the distance from the MIC was < 30 mm, whereas the median distortion varied widely when the distance was > 60 mm (0.23, 0.47, 0.37, and 0.57 mm in MRDR-DC, MRDR-nDC, MRRT-DC, and MRRT-nDC, respectively). The dose to the 98% of the GTV volume (D98%) decreased as the distance from the MIC increased. In the HADC plans, the relative dose difference of D98% was less than 5% when the GTV was located within 70 mm from the MIC, whereas the underdose of GTV exceeded 5% when it was 48 mm (-26.5% at maximum) away from the MIC in the HAnDC plans. CONCLUSION Use of a distortion-correction algorithm in the studied MR diagnoses is essential, and the dosimetric impact of MR distortion is not negligible, particularly for tumors located far away from the MIC.
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Affiliation(s)
- Shingo Ohira
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan.
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan.
| | - Yuta Suzuki
- Department of Diagnostic and Interventional Radiology, Osaka International Cancer Institute, Osaka, Japan
| | - Hayate Washio
- Department of Diagnostic and Interventional Radiology, Osaka International Cancer Institute, Osaka, Japan
| | - Yuki Yamamoto
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Soichiro Tateishi
- Department of Diagnostic and Interventional Radiology, Osaka International Cancer Institute, Osaka, Japan
| | - Shoki Inui
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Naoyuki Kanayama
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Minoru Kawamata
- Department of Diagnostic and Interventional Radiology, Osaka International Cancer Institute, Osaka, Japan
| | - Masayoshi Miyazaki
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Teiji Nishio
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masahiko Koizumi
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Katsuyuki Nakanishi
- Department of Diagnostic and Interventional Radiology, Osaka International Cancer Institute, Osaka, Japan
| | - Koji Konishi
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
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Putz F, Bock M, Schmitt D, Bert C, Blanck O, Ruge MI, Hattingen E, Karger CP, Fietkau R, Grigo J, Schmidt MA, Bäuerle T, Wittig A. Quality requirements for MRI simulation in cranial stereotactic radiotherapy: a guideline from the German Taskforce "Imaging in Stereotactic Radiotherapy". Strahlenther Onkol 2024; 200:1-18. [PMID: 38163834 PMCID: PMC10784363 DOI: 10.1007/s00066-023-02183-6] [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: 09/01/2023] [Accepted: 11/06/2023] [Indexed: 01/03/2024]
Abstract
Accurate Magnetic Resonance Imaging (MRI) simulation is fundamental for high-precision stereotactic radiosurgery and fractionated stereotactic radiotherapy, collectively referred to as stereotactic radiotherapy (SRT), to deliver doses of high biological effectiveness to well-defined cranial targets. Multiple MRI hardware related factors as well as scanner configuration and sequence protocol parameters can affect the imaging accuracy and need to be optimized for the special purpose of radiotherapy treatment planning. MRI simulation for SRT is possible for different organizational environments including patient referral for imaging as well as dedicated MRI simulation in the radiotherapy department but require radiotherapy-optimized MRI protocols and defined quality standards to ensure geometrically accurate images that form an impeccable foundation for treatment planning. For this guideline, an interdisciplinary panel including experts from the working group for radiosurgery and stereotactic radiotherapy of the German Society for Radiation Oncology (DEGRO), the working group for physics and technology in stereotactic radiotherapy of the German Society for Medical Physics (DGMP), the German Society of Neurosurgery (DGNC), the German Society of Neuroradiology (DGNR) and the German Chapter of the International Society for Magnetic Resonance in Medicine (DS-ISMRM) have defined minimum MRI quality requirements as well as advanced MRI simulation options for cranial SRT.
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Affiliation(s)
- Florian Putz
- Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
| | - Michael Bock
- Klinik für Radiologie-Medizinphysik, Universitätsklinikum Freiburg, Freiburg, Germany
| | - Daniela Schmitt
- Klinik für Strahlentherapie und Radioonkologie, Universitätsmedizin Göttingen, Göttingen, Germany
| | - Christoph Bert
- Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Oliver Blanck
- Klinik für Strahlentherapie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Maximilian I Ruge
- Klinik für Stereotaxie und funktionelle Neurochirurgie, Zentrum für Neurochirurgie, Universitätsklinikum Köln, Cologne, Germany
| | - Elke Hattingen
- Institut für Neuroradiologie, Universitätsklinikum Frankfurt, Frankfurt am Main, Germany
| | - Christian P Karger
- Abteilung Medizinische Physik in der Strahlentherapie, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- Nationales Zentrum für Strahlenforschung in der Onkologie (NCRO), Heidelberger Institut für Radioonkologie (HIRO), Heidelberg, Germany
| | - Rainer Fietkau
- Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Johanna Grigo
- Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Manuel A Schmidt
- Neuroradiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Tobias Bäuerle
- Radiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Andrea Wittig
- Klinik und Poliklinik für Strahlentherapie und Radioonkologie, Universitätsklinikum Würzburg, Würzburg, Germany
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Koori N, Kamekawa H, Mukawa N, Fuse H, Miyakawa S, Yasue K, Takahashi M, Yamada M, Henmi A, Kusumoto T, Kurata K. Relationship between imaging parameters and distortion in magnetic resonance images for gamma knife treatment planning. J Appl Clin Med Phys 2023; 24:e14205. [PMID: 37975638 PMCID: PMC10691626 DOI: 10.1002/acm2.14205] [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: 07/04/2023] [Revised: 09/27/2023] [Accepted: 10/23/2023] [Indexed: 11/19/2023] Open
Abstract
In magnetic resonance imaging (MRI), it is necessary to reduce image distortion as much as possible because it suppresses the increase in the planning target volume. This study investigated the relationship between imaging parameters and image distortion when using G-frames. The images were obtained using a 1.5-T MRI system with a 09-101 Pro-MRI phantom. Image distortion was measured by changing the RF pulse mode, gradient mode, asymmetric echo, and bandwidth (BW). The image distortion was increased in the high RF mode than in the Normal mode. The image distortion increased in the following order: Whisper ≦ Normal < Fast in the different gradient modes. The image distortion increased in the following order: Without ≦ Weak < Strong in the different asymmetric echo modes. The image distortion increased in the following order: 300 Hz/pixel > 670 Hz/pixel ≧ REF (150 Hz/pixel) in the different Bw. The relationship between parameters and image distortion was clarified in this study when G-frames were used for gamma knife therapy. There is had relationship between the parameters causing variation in the gradient magnetic field and image distortion. Therefore, these parameters should be adjusted to minimize distortion.
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Affiliation(s)
- Norikazu Koori
- School of Health SciencesIbaraki Prefectural University of Health SciencesAmiIbarakiJapan
- Division of Health SciencesKanazawa University Graduate School of Medical SciencesKanazawaIshikawaJapan
| | | | - Nanami Mukawa
- School of Health SciencesIbaraki Prefectural University of Health SciencesAmiIbarakiJapan
| | - Hiraku Fuse
- School of Health SciencesIbaraki Prefectural University of Health SciencesAmiIbarakiJapan
| | - Shin Miyakawa
- School of Health SciencesIbaraki Prefectural University of Health SciencesAmiIbarakiJapan
| | - Kenji Yasue
- School of Health SciencesIbaraki Prefectural University of Health SciencesAmiIbarakiJapan
| | - Masato Takahashi
- School of Health SciencesIbaraki Prefectural University of Health SciencesAmiIbarakiJapan
| | | | - Atsushi Henmi
- Department of RadiologyKomaki City HospitalKomakiAichiJapan
| | | | - Kazuma Kurata
- Department of RadiologyKomaki City HospitalKomakiAichiJapan
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Kraft J, Lutyj P, Grabenbauer F, Ströhle SP, Tamihardja J, Razinskas G, Weick S, Richter A, Huflage H, Wittig A, Flentje M, Lisowski D. Assessment of dual-energy computed tomography derived virtual monoenergetic imaging for target volume delineation of brain metastases. Radiother Oncol 2023; 187:109840. [PMID: 37536377 DOI: 10.1016/j.radonc.2023.109840] [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: 02/20/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/05/2023]
Abstract
BACKGROUND Objective and subjective assessment of image quality of brain metastases on dual-energy computed tomography (DECT) virtual monoenergetic imaging (VMI) and its impact on target volume delineation. MATERIALS AND METHODS 26 patients with 37 brain metastases receiving Magnetic Resonance Imaging (MRI) and DECT for stereotactic radiotherapy planning were included in this retrospective analysis. Lesion contrast (LC), contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were assessed for reconstructed VMI at 63 keV and artificial 120 kV Computed Tomography (CT). Image contrast and demarcation of metastases between 120 kV CT, VMI and MRI were subjectively assessed. Brain metastases were delineated by four radiation oncologists on VMI with a fixed or free brain window and contours were compared to solely MRI-based delineation using the Dice similarity coefficient. RESULTS LC, CNR and SNR were significantly higher in VMI than in 120 kV CT (p < 0.0001). Image contrast and lesion demarcation were significantly better on VMI compared to 120 kV CT (p < 0.0001). Mean gross tumor volume (GTV)/planning target volume (PTV) Dice similarity coefficients were 0.87/0.9 for metastases without imaging uncertainties (no artifacts, calcification or impaired visibility with MRI) but worse for metastases with imaging uncertainties (0.71/0.74). Target volumes delineated on VMI were around 5-10% smaller compared to MRI. CONCLUSION Image quality of VMI is objectively and subjectively superior to conventional CT. VMI provides significant advantages in stereotactic radiotherapy planning with improved visibility of brain metastases and geometrically distortion-free representation of brain metastases. Beside a plausibility check of MRI-based target volume delineation, VMI might improve reliability and accuracy in target volume definition particularly in cases with imaging uncertainties with MRI.
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Affiliation(s)
- Johannes Kraft
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany.
| | - Paul Lutyj
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Felix Grabenbauer
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Serge-Peer Ströhle
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Jörg Tamihardja
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Gary Razinskas
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Stefan Weick
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Anne Richter
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Andrea Wittig
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Michael Flentje
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Dominik Lisowski
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
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Marasini S, Zhang H, Dyke L, Cole M, Quinn B, Curcuru A, Gu B, Flores R, Kim T. Comprehensive MR imaging QA of 0.35 T MR-Linac using a multi-purpose large FOV phantom: A single-institution experience. J Appl Clin Med Phys 2023; 24:e14066. [PMID: 37307238 PMCID: PMC10562018 DOI: 10.1002/acm2.14066] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/27/2023] [Accepted: 05/31/2023] [Indexed: 06/14/2023] Open
Abstract
PURPOSE Magnetic resonance-guided radiotherapy (MRgRT) is desired for the treatment of diseases in the abdominothoracic region, which has a broad imaging area and continuous motion. To ensure accurate treatment delivery, an effective image quality assurance (QA) program, with a phantom that covers the field of view (FOV) similar to a human torso, is required. However, routine image QA for a large FOV is not readily available at many MRgRT centers. In this work, we present the clinical experience of the large FOV MRgRT Insight phantom for periodic daily and monthly comprehensive magnetic resonance imaging (MRI)-QA and its feasibility compared to the existing institutional routine MRI-QA procedures in 0.35 T MRgRT. METHODS Three phantoms; ViewRay cylindrical water phantom, Fluke 76-907 uniformity and linearity phantom, and Modus QA large FOV MRgRT Insight phantom, were imaged on the 0.35 T MR-Linac. The measurements were made in MRI mode with the true fast imaging with steady-state free precession (TRUFI) sequence. The ViewRay cylindrical water phantom was imaged in a single-position setup whereas the Fluke phantom and Insight phantom were imaged in three different orientations: axial, sagittal, and coronal. Additionally, the phased array coil QA was performed using the horizontal base plate of the Insight phantom by placing the desired coil around the base section which was compared to an in-house built Polyurethane foam phantom for reference. RESULT The Insight phantom captured image artifacts across the entire planar field of view, up to 400 mm, in a single image acquisition, which is beyond the FOV of the conventional phantoms. The geometric distortion test showed a similar distortion of 0.45 ± 0.01 and 0.41 ± 0.01 mm near the isocenter, that is, within 300 mm lengths for Fluke and Insight phantoms, respectively, but showed higher geometric distortion of 0.8 ± 0.4 mm in the peripheral region between 300 and 400 mm of the imaging slice for the Insight phantom. The Insight phantom with multiple image quality features and its accompanying software utilized the modulation transform function (MTF) to evaluate the image spatial resolution. The average MTF values were 0.35 ± 0.01, 0.35 ± 0.01, and 0.34 ± 0.03 for axial, coronal, and sagittal images, respectively. The plane alignment and spatial accuracy of the ViewRay water phantom were measured manually. The phased array coil test for both the Insight phantom and the Polyurethane foam phantoms ensured the proper functionality of each coil element. CONCLUSION The multifunctional large FOV Insight phantom helps in tracking MR imaging quality of the system to a larger extent compared to the routine daily and monthly QA phantoms currently used in our institute. Also, the Insight phantom is found to be more feasible for routine QA with easy setup.
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Affiliation(s)
- Shanti Marasini
- Department of Radiation OncologyWashington University School of MedicineSt. LouisUSA
| | - Hailei Zhang
- Department of Radiation OncologyWashington University School of MedicineSt. LouisUSA
| | - Lara Dyke
- Department of Radiation OncologyWashington University School of MedicineSt. LouisUSA
| | | | | | - Austen Curcuru
- Department of Biomedical EngineeringWashington University School of MedicineSt. LouisUSA
| | - Bruce Gu
- Department of Radiation OncologyWashington University School of MedicineSt. LouisUSA
| | | | - Taeho Kim
- Department of Radiation OncologyWashington University School of MedicineSt. LouisUSA
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Marasini S, Quinn B, Cole M, Flores R, Kim T. System-dependent image distortion related to gantry positions of a 0.35 T MRgRT: Characterization and the corresponding correction. J Appl Clin Med Phys 2022; 24:e13826. [PMID: 36354747 PMCID: PMC9903949 DOI: 10.1002/acm2.13826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/06/2022] [Accepted: 10/04/2022] [Indexed: 11/12/2022] Open
Abstract
PURPOSE MR-guided radiotherapy with high accuracy treatment planning requires addressing MR imaging artifacts that originate from system imperfections. This work presents the characterization and corresponding correction of gantry-related imaging distortions including geometric distortion and isocenter shift in a 0.35 T magnetic resonance imaging (MRI)-guided radiotherapy (MRgRT) system using distortion vector fields (DVFs). METHODS Two phantoms, the magnetic resonance imaging distortion in 3D (MRID3D ) phantom and the Fluke phantom, along with a human volunteer were imaged at different gantry angles on a 0.35 T MR-Linac. The geometric distortion and isocenter shift were characterized for both phantom images. DVFs with a field of view extended beyond the physical boundary of the MRID3D phantom were extracted from images taken at 30° gantry angle increments, with vendor-provided distortion correction turned on and off (DstOff). These extended DVFs were then applied to the relevant phantom images to correct their geometric distortions and isocenter shift at the respective gantry angles. The extended DVFs produced from the MRID3D phantom were also applied to Fluke phantom and human MR images at their respective gantry angles. The resampled images were evaluated using structural similarity index measure (SSIM) comparison with the vendor corrected images from the MRgRT system. RESULTS Geometric distortion with "mean (± SD) distortion" of 3.2 ± 0.02, 2.9 ± 0.02, and 1.8 ± 0.01 mm and isocenter shift (±SD) of 0.49 ± 0.3, 0.05 ± 0.2, and 0.01 ± 0.03 mm were present in the DstOff MRID3D phantom images in right-left (RL), anterior-posterior (AP), and superior-inferior (SI) directions, respectively. After resampling the originally acquired images by applying extended DVFs, the distortion was corrected to 0.18 ± 0.02, 0.09 ± 0.01, 0.15 ± 0.01 mm, and isocenter shift was corrected to 0.14 ± 0.05, -0.02 ± 0.04, and -0.07 ± 0.05 mm in RL, AP, and SI directions, respectively. The Fluke phantom average geometric distortion with "mean (± SD) distortion" of 2.7 ± 0.1 mm was corrected to 0.2 ± 0. 1 mm and the average isocenter shift (± SD) of 0.51 ± 0.2 mm, and 0.05 ± 0.03 was corrected to -0.08 ± 0.03 mm, and -0.05 ± 0.01 in RL and AP directions, respectively. SSIM (mean ± SD) of the original images to resampled images was increased from 0.49 ± 0.02 to 0.78 ± 0.01, 0.45 ± 0.02 to 0.75 ± 0.01, and 0.86 ± 0.25 to 0.98 ± 0.08 for MRID3D phantom, Fluke phantom, and human MR images, respectively, for all the gantry angles compared to the vendor corrected images. CONCLUSION The gantry-related MR imaging distortion including geometric distortion and isocenter shift was characterized and a corresponding correction was demonstrated using extended DVFs on 0.35 T MRgRT system. The characterized gantry-related isocenter shift can be combined with geometric distortion correction to provide a technique for the correction of the full system-dependent distortion in an MRgRT system.
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Affiliation(s)
- Shanti Marasini
- Department of Radiation OncologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Benjamin Quinn
- Department of the Modus MedicalModus Medical Devices Inc.LondonOntarioCanada
| | - Mike Cole
- Department of the Modus MedicalModus Medical Devices Inc.LondonOntarioCanada
| | - Rocco Flores
- Department of the Modus MedicalModus Medical Devices Inc.LondonOntarioCanada
| | - Taeho Kim
- Department of Radiation OncologyWashington University School of MedicineSt. LouisMissouriUSA
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Retif P, Djibo Sidikou A, Mathis C, Letellier R, Verrecchia-Ramos E, Dupres R, Michel X. Evaluation of the ability of the Brainlab Elements Cranial Distortion Correction algorithm to correct clinically relevant MRI distortions for cranial SRT. Strahlenther Onkol 2022; 198:907-918. [PMID: 35980455 DOI: 10.1007/s00066-022-01988-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 07/10/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE Cranial stereotactic radiotherapy (SRT) requires highly accurate lesion delineation. However, MRI can have significant inherent geometric distortions. We investigated how well the Elements Cranial Distortion Correction algorithm of Brainlab (Munich, Germany) corrects the distortions in MR image-sets of a phantom and patients. METHODS A non-distorted reference computed tomography image-set of a CIRS Model 603-GS (CIRS, Norfolk, VA, USA) phantom was acquired. Three-dimensional T1-weighted images were acquired with five MRI scanners and reconstructed with vendor-derived distortion correction. Some were reconstructed without correction to generate heavily distorted image-sets. All MR image-sets were corrected with the Brainlab algorithm relative to the computed tomography acquisition. CIRS Distortion Check software measured the distortion in each image-set. For all uncorrected and corrected image-sets, the control points that exceeded the 0.5-mm clinically relevant distortion threshold and the distortion maximum, mean, and standard deviation were recorded. Empirical cumulative distribution functions (eCDF) were plotted. Intraclass correlation coefficient (ICC) was calculated. The algorithm was evaluated with 10 brain metastases using Dice similarity coefficients (DSC). RESULTS The algorithm significantly reduced mean and standard deviation distortion in all image-sets. It reduced the maximum distortion in the heavily distorted image-sets from 2.072 to 1.059 mm and the control points with > 0.5-mm distortion fell from 50.2% to 4.0%. Before and especially after correction, the eCDFs of the four repeats were visually similar. ICC was 0.812 (excellent-good agreement). The algorithm increased the DSCs for all patients and image-sets. CONCLUSION The Brainlab algorithm significantly and reproducibly ameliorated MRI distortion, even with heavily distorted images. Thus, it increases the accuracy of cranial SRT lesion delineation. After further testing, this tool may be suitable for SRT of small lesions.
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Affiliation(s)
- Paul Retif
- Medical Physics Unit, CHR Metz-Thionville, Metz, France. .,Université de Lorraine, CNRS, CRAN, 54000, Nancy, France.
| | | | | | | | | | - Rémi Dupres
- Medical Imaging Department, CHR Metz-Thionville, Metz, France
| | - Xavier Michel
- Radiation Therapy Department, CHR Metz-Thionville, Metz, France
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10
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Prentou G, Pappas EP, Prentou E, Yakoumakis N, Paraskevopoulou C, Koutsouveli E, Pantelis E, Papagiannis P, Karaiskos P. Impact of systematic MLC positional uncertainties on the quality of single-isocenter multi-target VMAT-SRS treatment plans. J Appl Clin Med Phys 2022; 23:e13708. [PMID: 35733367 PMCID: PMC9359048 DOI: 10.1002/acm2.13708] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 06/08/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose To study the impact of systematic MLC leaf positional uncertainties (stemming from mechanical inaccuracies or sub‐optimal MLC modeling) on the quality of intracranial single‐isocenter multi‐target VMAT‐SRS treatment plans. An estimation of appropriate tolerance levels is attempted. Methods Five patients, with three to four metastases and at least one target lying in close proximity to organs‐at‐risk (OARs) were included in this study. A single‐isocenter multi‐arc VMAT plan per patient was prepared, which served as the reference for dosimetric impact evaluation. A range of leaf offsets was introduced (±0.03 mm up to ±0.30 mm defined at the MLC plane) to both leaf banks, by varying the leaf offset MLC modeling parameter in Monaco for all the prepared plans, in order to simulate projected leaf offsets of ±0.09 mm up to ±0.94 mm at the isocenter plane, respectively. For all offsets simulated and cases studied, dose distributions were re‐calculated and compared with the corresponding reference ones. An experimental dosimetric procedure using the SRS mapCHECK diode array was also performed to support the simulation study results and investigate its suitability to detect small systematic leaf positional errors. Results Projected leaf offsets of ±0.09 mm were well‐tolerated with respect to both target dosimetry and OAR‐sparing. A linear relationship was found between D95% percentage change and projected leaf offset (slope: 12%/mm). Impact of projected offset on target dosimetry was strongly associated with target volume. In two cases, plans that could be considered potentially clinically unacceptable (i.e., clinical dose constraint violation) were obtained even for projected offsets as small as 0.19 mm. The performed experimental dosimetry check can detect potential small systematic leaf errors. Conclusions Plan quality indices and dose–volume metrics are very sensitive to systematic sub‐millimeter leaf positional inaccuracies, projected at the isocenter plane. Acceptable and tolerance levels in systematic MLC uncertainties need to be tailored to VMAT‐SRS spatial and dosimetric accuracy requirements.
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Affiliation(s)
- Georgia Prentou
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleftherios P Pappas
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleni Prentou
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | | | | | - Evaggelos Pantelis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis Papagiannis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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11
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Nousiainen K, Mäkelä T, Peltonen JI. Characterizing geometric distortions of 3D sequences in clinical head MRI. MAGNETIC RESONANCE MATERIALS IN PHYSICS, BIOLOGY AND MEDICINE 2022; 35:983-995. [PMID: 35657535 PMCID: PMC9596562 DOI: 10.1007/s10334-022-01020-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/20/2022] [Accepted: 05/12/2022] [Indexed: 11/25/2022]
Abstract
Objective Phantoms are often used to estimate the geometric accuracy in magnetic resonance imaging (MRI). However, the distortions may differ between anatomical and phantom images. This study aimed to investigate the applicability of a phantom-based and a test-subject-based method in evaluating geometric distortion present in clinical head-imaging sequences. Materials and methods We imaged a 3D-printed phantom and test subjects with two MRI scanners using two clinical head-imaging 3D sequences with varying patient-table positions and receiver bandwidths. The geometric distortions were evaluated through nonrigid registrations: the displaced acquisitions were compared against the ideal isocenter positioning, and the varied bandwidth volumes against the volume with the highest bandwidth. The phantom acquisitions were also registered to a computed tomography scan. Results Geometric distortion magnitudes increased with larger table displacements and were in good agreement between the phantom and test-subject acquisitions. The effect of increased distortions with decreasing receiver bandwidth was more prominent for test-subject acquisitions. Conclusion Presented results emphasize the sensitivity of the geometric accuracy to positioning and imaging parameters. Phantom limitations may become an issue with some sequence types, encouraging the use of anatomical images for evaluating the geometric accuracy.
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Affiliation(s)
- Katri Nousiainen
- HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
- Department of Physics, University of Helsinki, Helsinki, Finland.
| | - Teemu Mäkelä
- HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Juha I Peltonen
- HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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12
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Theocharis S, Pappas EP, Seimenis I, Kouris P, Dellios D, Kollias G, Karaiskos P. Geometric distortion assessment in 3T MR images used for treatment planning in cranial Stereotactic Radiosurgery and Radiotherapy. PLoS One 2022; 17:e0268925. [PMID: 35605005 PMCID: PMC9126373 DOI: 10.1371/journal.pone.0268925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 05/10/2022] [Indexed: 12/31/2022] Open
Abstract
Magnetic Resonance images (MRIs) are employed in brain Stereotactic Radiosurgery and Radiotherapy (SRS/SRT) for target and/or critical organ localization and delineation. However, MRIs are inherently distorted, which also impacts the accuracy of the Magnetic Resonance Imaging/Computed Tomography (MRI/CT) co-registration process. In this phantom-based study, geometric distortion is assessed in 3T T2-weighted images (T2WIs), while the efficacy of an MRI distortion correction technique is also evaluated. A homogeneous polymer gel-filled phantom was CT-imaged before being irradiated with 26 4-mm Gamma Knife shots at predefined locations (reference control points). The irradiated phantom was MRI-scanned at 3T, implementing a T2-weighted protocol suitable for SRS/SRT treatment planning. The centers of mass of all shots were identified in the 3D image space by implementing an iterative localization algorithm and served as the evaluated control points for MRI distortion detection. MRIs and CT images were spatially co-registered using a mutual information algorithm. The inverse transformation matrix was applied to the reference control points and compared with the corresponding MRI-identified ones to evaluate the overall spatial accuracy of the MRI/CT dataset. The mean image distortion correction technique was implemented, and resulting MRI-corrected control points were compared against the corresponding reference ones. For the scanning parameters used, increased MRI distortion (>1mm) was detected at areas distant from the MRI isocenter (>5cm), while median radial distortion was 0.76mm. Detected offsets were slightly higher for the MRI/CT dataset (0.92mm median distortion). The mean image distortion correction improves geometric accuracy, but residual distortion cannot be considered negligible (0.51mm median distortion). For all three datasets studied, a statistically significant positive correlation between detected spatial offsets and their distance from the MRI isocenter was revealed. This work contributes towards the wider adoption of 3T imaging in SRS/SRT treatment planning. The presented methodology can be employed in commissioning and quality assurance programmes of corresponding treatment workflows.
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Affiliation(s)
- Stefanos Theocharis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleftherios P. Pappas
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Ioannis Seimenis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis Kouris
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios Dellios
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Kollias
- Medical Physics and Gamma Knife Department, Hygeia Hospital, Marousi, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- * E-mail:
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13
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Pappas EP, Seimenis I, Kouris P, Theocharis S, Lampropoulos KI, Kollias G, Karaiskos P. Target localization accuracy in frame‐based stereotactic radiosurgery: Comparison between MR‐only and MR/CT co‐registration approaches. J Appl Clin Med Phys 2022; 23:e13580. [PMID: 35285583 PMCID: PMC9121047 DOI: 10.1002/acm2.13580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 11/28/2022] Open
Abstract
Purpose In frame‐based Gamma Knife (GK) stereotactic radiosurgery two treatment planning workflows are commonly employed; one based solely on magnetic resonance (MR) images and the other based on magnetic resonance/computed tomography (MR/CT) co‐registered images. In both workflows, target localization accuracy (TLA) can be deteriorated due to MR‐related geometric distortions and/or MR/CT co‐registration uncertainties. In this study, the overall TLA following both clinical workflows is evaluated for cases of multiple brain metastases. Methods A polymer gel‐filled head phantom, having the Leksell stereotactic headframe attached, was CT‐imaged and irradiated by a GK Perfexion unit. A total of 26 4‐mm shots were delivered at 26 locations directly defined in the Leksell stereotactic space (LSS), inducing adequate contrast in corresponding T2‐weighted (T2w) MR images. Prescribed shot coordinates served as reference locations. An additional MR scan was acquired to implement the “mean image” distortion correction technique. The TLA for each workflow was assessed by comparing the radiation‐induced target locations, identified in MR images, with corresponding reference locations. Using T1w MR and CT images of 15 patients (totaling 81 lesions), TLA in clinical cases was similarly assessed, considering MR‐corrected data as reference. For the MR/CT workflow, both global and region of interest (ROI)‐based MR/CT registration approaches were studied. Results In phantom measurements, the MR‐corrected workflow demonstrated unsurpassed TLA (median offset of 0.2 mm) which deteriorated for MR‐only and MR/CT workflows (median offsets of 0.8 and 0.6 mm, respectively). In real‐patient cases, the MR‐only workflow resulted in offsets that exhibit a significant positive correlation with the distance from the MR isocenter, reaching 1.1 mm (median 0.6 mm). Comparable results were obtained for the MR/CT‐global workflow, although a maximum offset of 1.4 mm was detected. TLA was improved with the MR/CT‐ROI workflow resulting in median/maximum offsets of 0.4 mm/1.1 mm. Conclusions Subpixel TLA is achievable in all workflows. For the MR/CT workflow, a ROI‐based MR/CT co‐registration approach could considerably increase TLA and should be preferred instead of a global registration.
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Affiliation(s)
- Eleftherios P. Pappas
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | - Ioannis Seimenis
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | - Panagiotis Kouris
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | - Stefanos Theocharis
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
| | | | - Georgios Kollias
- Medical Physics and Gamma Knife Department Hygeia Hospital Marousi Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory Medical School National and Kapodistrian University of Athens Athens Greece
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14
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Lewis BC, Shin J, Maraghechi B, Quinn B, Cole M, Barberi E, Kim JS, Green O, Kim T. Assessment of a novel commercial large field of view phantom for comprehensive MR imaging quality assurance of a 0.35T MRgRT system. J Appl Clin Med Phys 2022; 23:e13535. [PMID: 35194946 PMCID: PMC8992932 DOI: 10.1002/acm2.13535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 12/25/2021] [Accepted: 12/28/2021] [Indexed: 12/03/2022] Open
Abstract
Consistent quality assurance (QA) programs are vital to MR‐guided radiotherapy (MRgRT), for ensuring treatment is delivered accurately and the onboard MRI system is providing the expected image quality. However, daily imaging QA with a dedicated phantom is not common at many MRgRT centers, especially with large phantoms that cover a field of view (FOV), similar to the human torso. This work presents the first clinical experience with a purpose‐built phantom for large FOV daily and periodic comprehensive quality assurance (QUASAR™ MRgRT Insight Phantom (beta)) from Modus Medical Devices Inc. (Modus QA) on an MRgRT system. A monthly American College of Radiology (ACR) QA phantom was also imaged for reference. Both phantoms were imaged on a 0.35T MR‐Linac, a 1.5T Philips wide bore MRI, and a 3.0T Siemens MRI, with T1‐weighted and T2‐weighted acquisitions. The Insight phantom was imaged in axial and sagittal orientations. Image quality tests including geometric accuracy, spatial resolution accuracy, slice thickness accuracy, slice position accuracy, and image intensity uniformity were performed on each phantom, following their respective instruction manuals. The geometric distortion test showed similar distortions of –1.7 mm and –1.9 mm across a 190 mm and a 283 mm lengths for the ACR and MRgRT Insight phantoms, respectively. The MRgRT Insight phantom utilized a modulation transform function (MTF) for spatial resolution evaluation, which showed decreased performance on the lower B0 strength MRIs, as expected, and could provide a good daily indicator of machine performance. Both the Insight and ACR phantoms showed a match with scan parameters for slice thickness analysis. During the imaging and analysis of this novel MRgRT Insight phantom the authors found setup to be straightforward allowing for easy acquisition each day, and useful image analysis parameters for tracking MRI performance.
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Affiliation(s)
- Benjamin C Lewis
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri
| | - Jaeik Shin
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.,Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Borna Maraghechi
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri
| | | | - Mike Cole
- Modus Medical Devices Inc., London, Ontario, Canada
| | - Enzo Barberi
- Modus Medical Devices Inc., London, Ontario, Canada
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Olga Green
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri
| | - Taeho Kim
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri
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15
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Kato Y, Okudaira K, Kamomae T, Kumagai M, Nagai Y, Taoka T, Itoh Y, Naganawa S. <Editors' Choice> Evaluation of system-related magnetic resonance imaging geometric distortion in radiation therapy treatment planning: two approaches and effectiveness of three-dimensional distortion correction. NAGOYA JOURNAL OF MEDICAL SCIENCE 2022; 84:29-41. [PMID: 35391999 PMCID: PMC8971027 DOI: 10.18999/nagjms.84.1.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/14/2021] [Indexed: 11/15/2022]
Abstract
We propose two methods to evaluate system-related distortion in magnetic resonance imaging (MRI) in radiation therapy treatment planning (RTP) and demonstrate the importance of three-dimensional (3D) distortion correction (DC) by quantitatively measuring the distortion magnitude. First, a small pin phantom was scanned at multiple positions using an external laser guide for accurate phantom placement and combined into one image encompassing a large area. Direct plane images were used for evaluating in-plane distortion and multiplanar reconstruction images for through-plane distortion with no DC, two-dimensional (2D) DC, and 3D DC. Second, a large grid sheet was scanned as the direct plane of the phantom placement. The distortion magnitude was determined by measuring the displacement between the MRI and reference coordinates. The measured distortions were compared between in- and through-plane when applying DC and between the two methods. The small pin phantom method can be used to evaluate a wide range of distortions, whereas data from the entire plane can be obtained with a single scan using the grid sheet without a laser guide. The mean distortion magnitudes differed between the methods. Furthermore, the 3D DC reduced in- and through-plane distortions. In conclusion, the small pin phantom method can be used to evaluate a wide range of distortions by creating a combined image, whereas the grid sheet method is simpler, accurate, repeatable, and does not require a special-order phantom or laser guide. As 3D DC reduces both in- and through-plane distortions, it can be used to improve RTP quality.
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Affiliation(s)
- Yutaka Kato
- Department of Radiological Technology, Nagoya University Hospital, Nagoya, Japan
| | - Kuniyasu Okudaira
- Department of Radiological Technology, Nagoya University Hospital, Nagoya, Japan
| | - Takeshi Kamomae
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Motoki Kumagai
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Youta Nagai
- Department of Radiological Technology, Nagoya University Hospital, Nagoya, Japan
| | - Toshiaki Taoka
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshiyuki Itoh
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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16
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Yuan J, Poon DMC, Lo G, Wong OL, Cheung KY, Yu SK. A narrative review of MRI acquisition for MR-guided-radiotherapy in prostate cancer. Quant Imaging Med Surg 2022; 12:1585-1607. [PMID: 35111651 PMCID: PMC8739116 DOI: 10.21037/qims-21-697] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/20/2021] [Indexed: 08/24/2023]
Abstract
Magnetic resonance guided radiotherapy (MRgRT), enabled by the clinical introduction of the integrated MRI and linear accelerator (MR-LINAC), is a novel technique for prostate cancer (PCa) treatment, promising to further improve clinical outcome and reduce toxicity. The role of prostate MRI has been greatly expanded from the traditional PCa diagnosis to also PCa screening, treatment and surveillance. Diagnostic prostate MRI has been relatively familiar in the community, particularly with the development of Prostate Imaging - Reporting and Data System (PI-RADS). But, on the other hand, the use of MRI in the emerging clinical practice of PCa MRgRT, which is substantially different from that in PCa diagnosis, has been so far sparsely presented in the medical literature. This review attempts to give a comprehensive overview of MRI acquisition techniques currently used in the clinical workflows of PCa MRgRT, from treatment planning to online treatment guidance, in order to promote MRI practice and research for PCa MRgRT. In particular, the major differences in the MRI acquisition of PCa MRgRT from that of diagnostic prostate MRI are demonstrated and explained. Limitations in the current MRI acquisition for PCa MRgRT are analyzed. The future developments of MRI in the PCa MRgRT are also discussed.
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Affiliation(s)
- Jing Yuan
- Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Hong Kong, China
| | - Darren M. C. Poon
- Comprehensive Oncology Centre, Hong Kong Sanatorium & Hospital, Hong Kong, China
| | - Gladys Lo
- Department of Diagnostic & Interventional Radiology, Hong Kong Sanatorium & Hospital, Hong Kong, China
| | - Oi Lei Wong
- Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Hong Kong, China
| | - Kin Yin Cheung
- Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Hong Kong, China
| | - Siu Ki Yu
- Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Hong Kong, China
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17
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Digma LA, Feng CH, Conlin CC, Rodríguez-Soto AE, Zhong AY, Hussain TS, Lui AJ, Batra K, Simon AB, Karunamuni R, Kuperman J, Rakow-Penner R, Hahn ME, Dale AM, Seibert TM. Correcting B 0 inhomogeneity-induced distortions in whole-body diffusion MRI of bone. Sci Rep 2022; 12:265. [PMID: 34997164 PMCID: PMC8741963 DOI: 10.1038/s41598-021-04467-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/23/2021] [Indexed: 01/05/2023] Open
Abstract
Diffusion-weighted magnetic resonance imaging (DWI) of the musculoskeletal system has various applications, including visualization of bone tumors. However, DWI acquired with echo-planar imaging is susceptible to distortions due to static magnetic field inhomogeneities. This study aimed to estimate spatial displacements of bone and to examine whether distortion corrected DWI images more accurately reflect underlying anatomy. Whole-body MRI data from 127 prostate cancer patients were analyzed. The reverse polarity gradient (RPG) technique was applied to DWI data to estimate voxel-level distortions and to produce a distortion corrected DWI dataset. First, an anatomic landmark analysis was conducted, in which corresponding vertebral landmarks on DWI and anatomic T2-weighted images were annotated. Changes in distance between DWI- and T2-defined landmarks (i.e., changes in error) after distortion correction were calculated. In secondary analyses, distortion estimates from RPG were used to assess spatial displacements of bone metastases. Lastly, changes in mutual information between DWI and T2-weighted images of bone metastases after distortion correction were calculated. Distortion correction reduced anatomic error of vertebral DWI up to 29 mm. Error reductions were consistent across subjects (Wilcoxon signed-rank p < 10-20). On average (± SD), participants' largest error reduction was 11.8 mm (± 3.6). Mean (95% CI) displacement of bone lesions was 6.0 mm (95% CI 5.0-7.2); maximum displacement was 17.1 mm. Corrected diffusion images were more similar to structural MRI, as evidenced by consistent increases in mutual information (Wilcoxon signed-rank p < 10-12). These findings support the use of distortion correction techniques to improve localization of bone on DWI.
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Affiliation(s)
- Leonardino A Digma
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA
| | - Christine H Feng
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA
| | - Christopher C Conlin
- Department of Radiology, School of Medicine, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Ana E Rodríguez-Soto
- Department of Radiology, School of Medicine, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Allison Y Zhong
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA
| | - Troy S Hussain
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA
| | - Asona J Lui
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA
| | - Kanha Batra
- Department of Electrical and Computer Engineering, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Aaron B Simon
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA
| | - Roshan Karunamuni
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA
| | - Joshua Kuperman
- Department of Radiology, School of Medicine, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Rebecca Rakow-Penner
- Department of Radiology, School of Medicine, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Michael E Hahn
- Department of Radiology, School of Medicine, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Anders M Dale
- Department of Radiology, School of Medicine, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Tyler M Seibert
- Department of Radiation Medicine and Applied Sciences, School of Medicine, University of California San Diego, 9500 Gilman Drive, Mail Code 0861, La Jolla, CA, 92093-0861, USA. .,Department of Radiology, School of Medicine, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA. .,Department of Bioengineering, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
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18
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Lewis BC, Shin J, Quinn B, Barberi E, Sievert D, Kim JS, Kim T. First clinical experience of correcting phantom-based image distortion related to gantry position on a 0.35T MR-Linac. J Appl Clin Med Phys 2021; 22:21-28. [PMID: 34612567 PMCID: PMC8598146 DOI: 10.1002/acm2.13404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/17/2021] [Accepted: 08/07/2021] [Indexed: 12/04/2022] Open
Abstract
MR‐guided radiotherapy requires strong imaging spatial integrity to deliver high quality plans and provide accurate dose calculation. The MRI system, however, can be compromised by the integrated linear accelerator (Linac), resulting in inaccurate imaging isocenter position and geometric distortion. Dependence on gantry position further complicates the correction of distortions. This work presents a new clinical application of a commercial phantom and software system that quantifies isocenter alignment and geometric distortion, as well as providing a deformation vector field (DVF). A large distortion phantom and a smaller grid phantom were imaged at multiple gantry angles from 0 to 330° on a 0.35 T integrated MR‐Linac. The software package was used to assess geometric distortion and generate DVFs to correct distortions within the phantom volume. The DVFs were applied to the grid phantom with resampling software then evaluated using structural similarity index measure (SSIM). Scans were also performed with a ferromagnetic clip near the phantom to investigate the correction of more severe artifacts. The mean magnitude isocenter shift was 0.67 mm, ranging from 0.25 to 1.04 mm across all angles. The DVF had a mean component value of 0.27 ± 0.02, 0.24 ± 0.01, and 0.19 ± 0.01 mm in the right‐left (RL), anterior‐posterior (AP), and superior‐inferior (SI) directions. The ferromagnetic clip increased isocenter position error from 1.98 mm to 2.20 mm and increased mean DVF component values in the RL and AP directions. The resampled grid phantom had an increased SSIM for all gantry angles compared to original images, increasing from 0.26 ± 0.001 to 0.70 ± 0.004. Through this clinical assessment, we were able to correct geometric distortion and isocenter shift related to gantry position on a 0.35 T MR‐Linac using the distortion phantom and software package. This provides encouragement that it could be used for quality assurance and clinically to correct systematic distortion caused by imaging at different gantry angles.
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Affiliation(s)
- Benjamin C Lewis
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jaeik Shin
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Benjamin Quinn
- Department for the Modus Medical, Modus Medical Devices Inc., London, Ontario, Canada
| | - Enzo Barberi
- Department for the Modus Medical, Modus Medical Devices Inc., London, Ontario, Canada
| | - Domenic Sievert
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Taeho Kim
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
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Jacobson S, Jones C, Lusk R, Jenkins M, Chamunyonga C, Pinkham MB, Brown E. Clinical impact of magnetic resonance imaging distortions on gamma knife radiosurgery. J Med Radiat Sci 2021; 68:274-281. [PMID: 33942565 PMCID: PMC8424314 DOI: 10.1002/jmrs.472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 04/01/2021] [Indexed: 11/08/2022] Open
Abstract
INTRODUCTION Magnetic resonance imaging (MRI) is the preferred imaging modality for Leksell Gamma Knife® (LGK) stereotactic radiosurgery (SRS) treatment planning (TP) due to superior soft tissue definition compared to computed tomography (CT). However, inherent distortions in MRI can affect treatment accuracy. The aim of this study was to develop a model to visualise the effect of MRI distortion on LGK SRS target coverage. METHODS A model was developed using MR images of a QUASARTM GRID3D QA phantom. One hundred and twenty-five points were compared against known phantom geometry. Using linear interpolation, the model was applied retrospectively to 10 brain metastases patient data sets treated with LGK. The model estimated the corrected shot position accounting for distortion. A total of 44 metastases were investigated regarding the effects of MRI distortion on target coverage. RESULTS The model indicated significantly reduced mean error by 0.30 mm and variance by 0.09 mm (P = 0.008). After model application, 23 (53%) metastases showed reduced coverage. Six of the 23 metastases were deemed to be potentially clinically significant changes. Results indicated MRI distortion had a greater effect on smaller targets (mean 0.06cc) located further away from the image isocentre (mean 64.88 mm). CONCLUSION This study developed a model to visualise the effect of MRI distortion on LGK SRS target coverage. Results suggest that MRI distortion can affect target coverage and the developed model may be one method to assess its impact. These results indicate that MRI distortion may have a greater effect on smaller targets located at the image periphery.
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Affiliation(s)
- Sinead Jacobson
- School of Clinical SciencesQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Catherine Jones
- Gamma Knife Centre of QueenslandPrincess Alexandra HospitalBrisbaneQueenslandAustralia
| | - Ryan Lusk
- Gamma Knife Centre of QueenslandPrincess Alexandra HospitalBrisbaneQueenslandAustralia
| | - Mike Jenkins
- Gamma Knife Centre of QueenslandPrincess Alexandra HospitalBrisbaneQueenslandAustralia
| | - Crispen Chamunyonga
- School of Clinical SciencesQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Mark B Pinkham
- School of Clinical SciencesQueensland University of TechnologyBrisbaneQueenslandAustralia
- Gamma Knife Centre of QueenslandPrincess Alexandra HospitalBrisbaneQueenslandAustralia
| | - Elizabeth Brown
- School of Clinical SciencesQueensland University of TechnologyBrisbaneQueenslandAustralia
- Princess Alexandra Hospital Radiation Oncology DepartmentBrisbaneQueenslandAustralia
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20
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Yuan J, Law SCK, Wong KK, Lo GG, Kam MKM, Kwan WH, Xue C, Wong OL, Yu SK, Cheung KY. 3D T1-weighted turbo spin echo contrast-enhanced MRI at 1.5 T for frameless brain metastases radiotherapy. J Cancer Res Clin Oncol 2021; 148:1749-1759. [PMID: 34363123 DOI: 10.1007/s00432-021-03755-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/31/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE Performance of 3D-T1W-TSE has been proven superior to 3D-MP-GRE at 3 T on brain metastases (BM) contrast-enhanced (CE) MRI. However, its performance at 1.5 T is largely unknown and sparsely reported. This study aims to assess image quality, lesion detectability and conspicuity of 1.5 T 3D-T1W-TSE on planning MRI of frameless BM radiotherapy. METHODS 94 BM patients to be treated by frameless brain radiotherapy were scanned using 3D-T1W-TSE with immobilization on multi-vendor 1.5 T MRI-simulators. BMs were jointly diagnosed by 4 reviewers. Enhanced lesion conspicuity was quantitatively assessed by calculating contrast ratio (CR) and contrast-to-noise ratio (CNR). Signal-to-noise ratio (SNR) reduction of white matter due to the use of flexible coil was assessed. Lesion detectability and conspicuity were compared between 1.5 T planning MRI and 3 T diagnostic MRI by an oncologist and a radiologist in 10 patients. RESULTS 497 BMs were jointly diagnosed. The CR and CNR were 75.2 ± 39.9% and 14.2 ± 8.1, respectively. SNR reduced considerably from 31.7 ± 8.3 to 21.9 ± 5.4 with the longer distance to coils. 3 T diagnostic MRI and 1.5 T planning MRI yielded exactly the same detection of 84 BMs. Qualitatively, lesion conspicuity at 1.5 T was not inferior to that at 3 T. Quantitatively, lower brain SNR and lesion CNR were found at 1.5 T, while lesion CR at 1.5 T was highly comparable to that at 3 T. CONCLUSION 1.5 T 3D-T1W-TSE planning MRI of frameless BM radiotherapy was comprehensively assessed. Highly comparable BM detectability and conspicuity were achieved by 1.5 T planning MRI compared to 3 T diagnostic MRI. 1.5 T 3D-T1W-TSE should be valuable for frameless brain radiotherapy planning.
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Affiliation(s)
- Jing Yuan
- Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, 8/F, Li Shu Fan Block, 2 Village Road, Happy Valley, Hong Kong SAR, China.
| | - Stephen C K Law
- Comprehensive Oncology Centre, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong SAR, China
| | - Ka Kin Wong
- Department of Diagnostic and Interventional Radiology, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong SAR, China
| | - Gladys G Lo
- Department of Diagnostic and Interventional Radiology, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong SAR, China
| | - Michael K M Kam
- Comprehensive Oncology Centre, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong SAR, China
| | - Wing Hong Kwan
- Comprehensive Oncology Centre, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong SAR, China
| | - Cindy Xue
- Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, 8/F, Li Shu Fan Block, 2 Village Road, Happy Valley, Hong Kong SAR, China
| | - Oi Lei Wong
- Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, 8/F, Li Shu Fan Block, 2 Village Road, Happy Valley, Hong Kong SAR, China
| | - Siu Ki Yu
- Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, 8/F, Li Shu Fan Block, 2 Village Road, Happy Valley, Hong Kong SAR, China
| | - Kin Yin Cheung
- Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, 8/F, Li Shu Fan Block, 2 Village Road, Happy Valley, Hong Kong SAR, China
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21
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Dumoncel J, Subsol G, Durrleman S, Bertrand A, de Jager E, Oettlé AC, Lockhat Z, Suleman FE, Beaudet A. Are endocasts reliable proxies for brains? A 3D quantitative comparison of the extant human brain and endocast. J Anat 2021; 238:480-488. [PMID: 32996582 PMCID: PMC7812123 DOI: 10.1111/joa.13318] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 12/24/2022] Open
Abstract
Endocasts (i.e., replicas of the inner surface of the bony braincase) constitute a critical proxy for qualifying and quantifying variations in brain shape and organization in extinct taxa. In the absence of brain tissues preserved in the fossil record, endocasts provide the only direct evidence of brain evolution. However, debates on whether or not information inferred from the study of endocasts reflects brain shape and organization have polarized discussions in paleoneurology since the earliest descriptions of cerebral imprints in fossil hominin crania. By means of imaging techniques (i.e., MRIs and CT scans) and 3D modelling methods (i.e., surface-based comparisons), we collected consistent morphological (i.e., shape) and structural (i.e., sulci) information on the variation patterns between the brain and the endocast based on a sample of extant human individuals (N = 5) from the 3D clinical image database of the Steve Biko Academic Hospital in Pretoria (South Africa) and the Hôpitaux Universitaires Pitié Salpêtrière in Paris (France). Surfaces of the brain and endocast of the same individual were segmented from the 3D MRIs and CT images, respectively. Sulcal imprints were automatically detected. We performed a deformation-based shape analysis to compare both the shape and the sulcal pattern of the brain and the endocast. We demonstrated that there is close correspondence in terms of morphology and organization between the brain and the corresponding endocast with the exception of the superior region. By comparatively quantifying the shape and organization of the brain and endocast, this work represents an important reference for paleoneurological studies.
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Affiliation(s)
- Jean Dumoncel
- Laboratoire d’Anthropobiologie Moléculaire et Imagerie de SynthèseUMR 5288 CNRSUniversité Toulouse 3 Paul SabatierToulouseFrance
| | - Gérard Subsol
- Research‐Team ICARLaboratoire d’Informatiquede Robotique et de Microélectronique de MontpellierCNRSUniversité de MontpellierMontpellierFrance
| | - Stanley Durrleman
- Aramis teamINRIA ParisSorbonne UniversitésUPMC Université Paris 06 UMR S 1127Inserm U 1127CNRS UMR 7225Institut du Cerveau et de la Moelle épinièreParisFrance
| | - Anne Bertrand
- Aramis teamINRIA ParisSorbonne UniversitésUPMC Université Paris 06 UMR S 1127Inserm U 1127CNRS UMR 7225Institut du Cerveau et de la Moelle épinièreParisFrance
- Department of NeuroradiologyHôpital Pitié‐SalpêtrièreAssistance Publique–Hôpitaux de ParisParisFrance
| | - Edwin de Jager
- Department of AnatomyFaculty of Health SciencesUniversity of PretoriaPretoriaSouth Africa
| | - Anna C. Oettlé
- Department of AnatomyFaculty of Health SciencesUniversity of PretoriaPretoriaSouth Africa
- Department of Anatomy and HistologySchool of MedicineSefako Makgatho Health Sciences UniversityGa‐RankuwaSouth Africa
| | - Zarina Lockhat
- Department of RadiologyFaculty of Health SciencesUniversity of PretoriaPretoriaSouth Africa
| | - Farhana E. Suleman
- Department of RadiologyFaculty of Health SciencesUniversity of PretoriaPretoriaSouth Africa
| | - Amélie Beaudet
- Department of AnatomyFaculty of Health SciencesUniversity of PretoriaPretoriaSouth Africa
- Department of ArchaeologyUniversity of CambridgeCambridgeUnited Kingdom
- School of Geography, Archaeology and Environmental StudiesUniversity of the WitwatersrandJohannesburgSouth Africa
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22
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Dellios D, Pappas EP, Seimenis I, Paraskevopoulou C, Lampropoulos KI, Lymperopoulou G, Karaiskos P. Evaluation of patient-specific MR distortion correction schemes for improved target localization accuracy in SRS. Med Phys 2020; 48:1661-1672. [PMID: 33230923 DOI: 10.1002/mp.14615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 10/16/2020] [Accepted: 11/16/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE This work aims at promoting target localization accuracy in cranial stereotactic radiosurgery (SRS) applications by focusing on the correction of sequence-dependent (also patient induced) magnetic resonance (MR) distortions at the lesion locations. A phantom-based quality assurance (QA) methodology was developed and implemented for the evaluation of three distortion correction techniques. The same approach was also adapted to cranial MR images used for SRS treatment planning purposes in single or multiple brain metastases cases. METHODS A three-dimensional (3D)-printed head phantom was filled with a 3D polymer gel dosimeter. Following treatment planning and dose delivery, volumes of radiation-induced polymerization served as hypothetical lesions, offering adequate MR contrast with respect to the surrounding unirradiated areas. T1-weighted (T1w) MR imaging was performed at 1.5 T using the clinical scanning protocol for SRS. Additional images were acquired to implement three distortion correction methods; the field mapping (FM), mean image (MI) and signal integration (SI) techniques. Reference lesion locations were calculated as the averaged centroid positions of each target identified in the forward and reverse read gradient polarity MRI scans. The same techniques and workflows were implemented for the correction of contrast-enhanced T1w MR images of 10 patients with a total of 27 brain metastases. RESULTS All methods employed in the phantom study diminished spatial distortion. Median and maximum distortion magnitude decreased from 0.7 mm (2.10 ppm) and 0.8 mm (2.36 ppm), respectively, to <0.2 mm (0.61 ppm) at all target locations, using any of the three techniques. Image quality of the corrected images was acceptable, while contrast-to-noise ratio slightly increased. Results of the patient study were in accordance with the findings of the phantom study. Residual distortion in corrected patient images was found to be <0.3 mm in the vast majority of targets. Overall, the MI approach appears to be the most efficient correction method from the three investigated. CONCLUSIONS In cranial SRS applications, patient-specific distortion correction at the target location(s) is feasible and effective, despite the expense of longer imaging time since additional MRI scan(s) need to be performed. A phantom-based QA methodology was developed and presented to reassure efficient implementation of correction techniques for sequence-dependent spatial distortion.
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Affiliation(s)
- Dimitrios Dellios
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, 115 27, Greece
| | - Eleftherios P Pappas
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, 115 27, Greece
| | - Ioannis Seimenis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, 115 27, Greece
| | | | - Kostas I Lampropoulos
- Medical Physics and Gamma Knife Department, Hygeia Hospital, Marousi, 151 23, Greece
| | - Georgia Lymperopoulou
- 1st Department of Radiology, Medical School, National and Kapodistrian University of Athens, Athens, 115 28, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, 115 27, Greece.,Medical Physics and Gamma Knife Department, Hygeia Hospital, Marousi, 151 23, Greece
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23
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A Cancer Care Ontario Organizational Guideline for the Delivery of Stereotactic Radiosurgery for Brain Metastasis in Ontario, Canada. Pract Radiat Oncol 2020; 10:243-254. [PMID: 31783171 DOI: 10.1016/j.prro.2019.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/31/2022]
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24
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Respiratory Motion Prediction Using Fusion-Based Multi-Rate Kalman Filtering and Real-Time Golden-Angle Radial MRI. IEEE Trans Biomed Eng 2020; 67:1727-1738. [DOI: 10.1109/tbme.2019.2944803] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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25
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Magnetic resonance imaging for brain stereotactic radiotherapy : A review of requirements and pitfalls. Strahlenther Onkol 2020; 196:444-456. [PMID: 32206842 PMCID: PMC7182639 DOI: 10.1007/s00066-020-01604-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/03/2020] [Indexed: 12/29/2022]
Abstract
Due to its superior soft tissue contrast, magnetic resonance imaging (MRI) is essential for many radiotherapy treatment indications. This is especially true for treatment planning in intracranial tumors, where MRI has a long-standing history for target delineation in clinical practice. Despite its routine use, care has to be taken when selecting and acquiring MRI studies for the purpose of radiotherapy treatment planning. Requirements on MRI are particularly demanding for intracranial stereotactic radiotherapy, where accurate imaging has a critical role in treatment success. However, MR images acquired for routine radiological assessment are frequently unsuitable for high-precision stereotactic radiotherapy as the requirements for imaging are significantly different for radiotherapy planning and diagnostic radiology. To assure that optimal imaging is used for treatment planning, the radiation oncologist needs proper knowledge of the most important requirements concerning the use of MRI in brain stereotactic radiotherapy. In the present review, we summarize and discuss the most relevant issues when using MR images for target volume delineation in intracranial stereotactic radiotherapy.
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26
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Prentou G, Pappas EP, Logothetis A, Koutsouveli E, Pantelis E, Papagiannis P, Karaiskos P. Dosimetric impact of rotational errors on the quality of VMAT-SRS for multiple brain metastases: Comparison between single- and two-isocenter treatment planning techniques. J Appl Clin Med Phys 2020; 21:32-44. [PMID: 32022447 PMCID: PMC7075408 DOI: 10.1002/acm2.12815] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 11/21/2019] [Accepted: 12/10/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose In the absence of a 6D couch and/or assuming considerable intrafractional patient motion, rotational errors could affect target coverage and OAR‐sparing especially in multiple metastases VMAT‐SRS cranial cases, which often involve the concurrent irradiation of off‐axis targets. This work aims to study the dosimetric impact of rotational errors in such applications, under a comparative perspective between the single‐ and two‐isocenter treatment techniques. Methods Ten patients (36 metastases) were included in this study. Challenging cases were only considered, with several targets lying in close proximity to OARs. Two multiarc VMAT plans per patient were prepared, involving one and two isocenters, serving as the reference plans. Different degrees of angular offsets at various orientations were introduced, simulating rotational errors. Resulting dose distributions were evaluated and compared using commonly employed dose‐volume and plan quality indices. Results For single‐isocenter plans and 1⁰ rotations, plan quality indices, such as coverage, conformity index and D95%, deteriorated significantly (>5%) for distant targets from the isocenter (at> 4–6 cm). Contrarily, for two‐isocenter plans, target distances to nearest isocenter were always shorter (≤4 cm), and, consequently, 1⁰ errors were well‐tolerated. In the most extreme case considered (2⁰ around all axes) conformity index deteriorated by on‐average 7.2%/cm of distance to isocenter, if one isocenter is used, and 2.6%/cm, for plans involving two isocenters. The effect is, however, strongly associated with target volume. Regarding OARs, for single‐isocenter plans, significant increase (up to 63%) in Dmax and D0.02cc values was observed for any angle of rotation. Plans that could be considered clinically unacceptable were obtained even for the smallest angle considered, although rarer for the two‐isocenter planning approach. Conclusion Limiting the lesion‐to‐isocenter distance to ≤4 cm by introducing additional isocenter(s) appears to partly mitigate severe target underdosage, especially for smaller target sizes. If OAR‐sparing is also a concern, more stringent rotational error tolerances apply.
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Affiliation(s)
- Georgia Prentou
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleftherios P Pappas
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Andreas Logothetis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Evaggelos Pantelis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis Papagiannis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Hubley E, Mooney KE, Schelin M, Shi W, Yu Y, Liu H. Geometric and dosimetric effects of image co-registration workflows for Gamma Knife frameless radiosurgery. JOURNAL OF RADIOSURGERY AND SBRT 2020; 7:47-55. [PMID: 32802578 PMCID: PMC7406343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
The Gamma Knife® Icon™ CBCT facilitates frameless radiosurgery. In the vendor-recommended workflow, MRI is co-registered directly to CBCT for planning. Alternatively, MRI is co-registered to a diagnostic CT, which is then co-registered to CBCT. Our objective is to evaluate if this additional CT is necessary for more accurate registrations. Nine small spherical targets were generated onto 14 patient data-sets. Single-shot treatment plans were created. Geometric and dosimetric differences between the two workflows were determined. Mean target displacement was 0.5±0.3mm; average PTV coverage loss was 4.3±5.0%. For 19 clinical targets in 14 patients, the mean displacement and coverage change was 0.6±0.4mm and 1.3±1.6%. Eleven surrogate landmarks were contoured on a phantom MRI and registered to the CBCT using both workflows. The registration uncertainty was 0.50±0.65mm and 0.32±0.47mm for the MRI-CT-CBCT and MRI-CBCT respectively. As neither workflow was significantly more accurate, the additional CT is unnecessary for most cases.
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Affiliation(s)
- Emily Hubley
- Department of Radiation Oncology Sidney Kimmel Medical College, Thomas Jefferson University, 111 S. 11th St, Philadelphia, PA 19107, USA
| | - Karen E Mooney
- Department of Radiation Oncology Sidney Kimmel Medical College, Thomas Jefferson University, 111 S. 11th St, Philadelphia, PA 19107, USA
| | - Matthew Schelin
- Department of Radiation Oncology Sidney Kimmel Medical College, Thomas Jefferson University, 111 S. 11th St, Philadelphia, PA 19107, USA
| | - Wenyin Shi
- Department of Radiation Oncology Sidney Kimmel Medical College, Thomas Jefferson University, 111 S. 11th St, Philadelphia, PA 19107, USA
| | - Yan Yu
- Department of Radiation Oncology Sidney Kimmel Medical College, Thomas Jefferson University, 111 S. 11th St, Philadelphia, PA 19107, USA
| | - Haisong Liu
- Department of Radiation Oncology Sidney Kimmel Medical College, Thomas Jefferson University, 111 S. 11th St, Philadelphia, PA 19107, USA
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Becker SJ, Niu Y, Mutaf Y, Chen S, Poirier Y, Nichols EM, Yi B. Development and validation of a comprehensive patient-specific quality assurance program for a novel stereotactic radiation delivery system for breast lesions. J Appl Clin Med Phys 2019; 20:138-148. [PMID: 31833640 PMCID: PMC6909122 DOI: 10.1002/acm2.12778] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 10/18/2019] [Accepted: 10/20/2019] [Indexed: 11/22/2022] Open
Abstract
PURPOSE The GammaPod is a dedicated prone breast stereotactic radiosurgery (SRS) machine composed of 25 cobalt-60 sources which rotate around the breast to create highly conformal dose distributions for boosts, partial-breast irradiation, or neo-adjuvant SRS. We describe the development and validation of a patient-specific quality assurance (PSQA) system for the GammaPod. METHODS We present two PSQA methods: measurement based and calculation based PSQA. The measurements are performed with a combination of absolute and relative dose measurements. Absolute dosimetry is performed in a single point using a 0.053-cc pinpoint ionization chamber in the center of a polymethylmethacrylate (PMMA) breast phantom and a water-filled breast cup. Relative dose distributions are verified with EBT3 film in the PMMA phantom. The calculation-based method verifies point doses with a novel semi-empirical independent-calculation software. RESULTS The average (± standard deviation) breast and target sizes were 1263 ± 335.3 cc and 66.9 ± 29.9 cc, respectively. All ion chamber measurements performed in water and the PMMA phantom agreed with the treatment planning system (TPS) within 2.7%, with average (max) difference of -1.3% (-1.9%) and -1.3% (-2.7%), respectively. Relative dose distributions measured by film showed an average gamma pass rate of 97.0 ± 3.2 when using a 3%/1 mm criteria. The lowest gamma analysis pass rate was 90.0%. The independent calculation software had average agreements (max) with the patient and QA plan calculation of 0.2% (2.2%) and -0.1% (2.0%), respectively. CONCLUSION We successfully implemented the first GammaPod PSQA program. These results show that the GammaPod can be used to calculate and deliver the predicted dose precisely and accurately. For routine PSQA performed prior to treatments, the independent calculation is recommended as it verifies the accuracy of the planned dose without increasing the risk of losing vacuum due to prolonged waiting times.
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Affiliation(s)
- Stewart J. Becker
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Ying Niu
- MedStar Georgetown University HospitalWashingtonDCUSA
| | - Yildirim Mutaf
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Shifeng Chen
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Yannick Poirier
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Elizabeth M. Nichols
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - ByongYong Yi
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMDUSA
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Liu Y, Lei Y, Wang Y, Shafai-Erfani G, Wang T, Tian S, Patel P, Jani AB, McDonald M, Curran WJ, Liu T, Zhou J, Yang X. Evaluation of a deep learning-based pelvic synthetic CT generation technique for MRI-based prostate proton treatment planning. Phys Med Biol 2019; 64:205022. [PMID: 31487698 DOI: 10.1088/1361-6560/ab41af] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The purpose of this work is to validate the application of a deep learning-based method for pelvic synthetic CT (sCT) generation that can be used for prostate proton beam therapy treatment planning. We propose to integrate dense block minimization into 3D cycle-consistent generative adversarial networks (cycleGAN) framework to effectively learn the nonlinear mapping between MRI and CT pairs. A cohort of 17 patients with co-registered CT and MR pairs were used to test the deep learning-based sCT generation method by leave-one-out cross-validation. Image quality between the sCT and CT images, gamma analysis passing rate, dose-volume metrics, distal range displacement, and the individual pencil beam Bragg peak shift between sCT- and CT-based proton plans were evaluated. The average mean absolute error (MAE) was 51.32 ± 16.91 HU. The relative differences of the statistics of the PTV dose-volume histogram (DVH) metrics in between sCT and CT were generally less than 1%. Mean values of dose difference, absolute dose difference (in percent of the prescribed dose) were -0.07% ± 0.07% and 0.23% ± 0.08%. Mean gamma analysis pass rate of 1 mm/1%, 2 mm/2%, 3 mm/3% criteria with 10% dose threshold were 92.39% ± 5.97%, 97.95% ± 2.95% and 98.97% ± 1.62% respectively. The median, mean and standard deviation of absolute maximum range differences were 0.09 cm and 0.23 ± 0.25 cm. The median and mean Bragg peak shifts among the 17 patients were 0.09 cm and 0.18 ± 0.07 cm. The image similarity, dosimetric and distal range agreement between sCT and original CT suggests the feasibility of further development of an MRI-only workflow for prostate proton radiotherapy.
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Affiliation(s)
- Yingzi Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States of America
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MRI quality control for the Italian Neuroimaging Network Initiative: moving towards big data in multiple sclerosis. J Neurol 2019; 266:2848-2858. [PMID: 31422457 DOI: 10.1007/s00415-019-09509-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 01/19/2023]
Abstract
The Italian Neuroimaging Network Initiative (INNI) supports the creation of a repository, where MRI, clinical, and neuropsychological data from multiple sclerosis (MS) patients and healthy controls are collected from Italian Research Centers with internationally recognized expertise in MRI applied to MS. However, multicenter MRI data integration needs standardization and quality control (QC). This study aimed to implement quantitative measures for characterizing the standardization and quality of MRI collected within INNI. MRI scans of 423 MS patients, including 3D T1- and T2-weighted, were obtained from INNI repository (from Centers A, B, C, and D). QC measures were implemented to characterize: (1) head positioning relative to the magnet isocenter; (2) intensity inhomogeneity; (3) relative image contrast between brain tissues; and (4) image artefacts. Centers A and D showed the most accurate subject positioning within the MR scanner (median z-offsets = - 2.6 ± 1.7 cm and - 1.1 ± 2 cm). A low, but significantly different, intensity inhomogeneity on 3D T1-weighted MRI was found between all centers (p < 0.05), except for Centers A and C that showed comparable image bias fields. Center D showed the highest relative contrast between gray and normal appearing white matter (NAWM) on 3D T1-weighed MRI (0.63 ± 0.04), while Center B showed the highest relative contrast between NAWM and MS lesions on FLAIR (0.21 ± 0.06). Image artefacts were mainly due to brain movement (60%) and ghosting (35%). The implemented QC procedure ensured systematic data quality assessment within INNI, thus making available a huge amount of high-quality MRI to better investigate pathophysiological substrates and validate novel MRI biomarkers in MS.
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Liu Y, Lei Y, Wang Y, Wang T, Ren L, Lin L, McDonald M, Curran WJ, Liu T, Zhou J, Yang X. MRI-based treatment planning for proton radiotherapy: dosimetric validation of a deep learning-based liver synthetic CT generation method. Phys Med Biol 2019; 64:145015. [PMID: 31146267 PMCID: PMC6635951 DOI: 10.1088/1361-6560/ab25bc] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Magnetic resonance imaging (MRI) has been widely used in combination with computed tomography (CT) radiation therapy because MRI improves the accuracy and reliability of target delineation due to its superior soft tissue contrast over CT. The MRI-only treatment process is currently an active field of research since it could eliminate systematic MR-CT co-registration errors, reduce medical cost, avoid diagnostic radiation exposure, and simplify clinical workflow. The purpose of this work is to validate the application of a deep learning-based method for abdominal synthetic CT (sCT) generation by image evaluation and dosimetric assessment in a commercial proton pencil beam treatment planning system (TPS). This study proposes to integrate dense block into a 3D cycle-consistent generative adversarial networks (cycle GAN) framework in an effort to effectively learn the nonlinear mapping between MRI and CT pairs. A cohort of 21 patients with co-registered CT and MR pairs were used to test the deep learning-based sCT image quality by leave-one-out cross validation. The CT image quality, dosimetric accuracy and the distal range fidelity were rigorously checked, using side-by-side comparison against the corresponding original CT images. The average mean absolute error (MAE) was 72.87±18.16 HU. The relative differences of the statistics of the PTV dose volume histogram (DVH) metrics between sCT and CT were generally less than 1%. Mean 3D gamma analysis passing rate of 1mm/1%, 2mm/2%, 3mm/3% criteria with 10% dose threshold were 90.76±5.94%, 96.98±2.93% and 99.37±0.99%, respectively. The median, mean and standard deviation of absolute maximum range differences were 0.170 cm, 0.186 cm and 0.155 cm. The image similarity, dosimetric and distal range agreement between sCT and original CT suggests the feasibility of further development of an MRI-only workflow for liver proton radiotherapy.
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Affiliation(s)
- Yingzi Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States of America
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Joe H, Pahk KJ, Park S, Kim H. Development of a subject-specific guide system for Low-Intensity Focused Ultrasound (LIFU) brain stimulation. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2019; 176:105-110. [PMID: 31200898 DOI: 10.1016/j.cmpb.2019.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/05/2019] [Accepted: 05/05/2019] [Indexed: 06/09/2023]
Abstract
Low-Intensity Focused Ultrasound (LIFU) has recently been considered as a promising neuromodulation technique because it can noninvasively stimulate the brain with a high spatial resolution. As spatial resolution is improved, there is a growing demand for developing more accurate and convenient guide systems. Therefore, in the present study, we have developed and prototyped a 3D printed wearable subject-specific helmet for LIFU stimulation that is guaranteed to be accurate. The spatial relationship between the target position and the full-width at half-maximum (FWHM) of acoustic pressure of the transducer, i.e. focal volume, was compared using the conventional image-guided navigation system. According to the distribution of positional errors, the target position was located well within the focal volume.
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Affiliation(s)
- Haeyoung Joe
- Center for Bionics, Biomedical Research Institute, Korea Institute Science and Technology (KIST), 5, Hwarangro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea; Human-Machine Systems Laboratory, Dept. of Mechanical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Ki Joo Pahk
- Center for Bionics, Biomedical Research Institute, Korea Institute Science and Technology (KIST), 5, Hwarangro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Shinsuk Park
- Human-Machine Systems Laboratory, Dept. of Mechanical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
| | - Hyungmin Kim
- Center for Bionics, Biomedical Research Institute, Korea Institute Science and Technology (KIST), 5, Hwarangro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea.
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MRI in medical practice and its future use in radiation oncology. Resume of XXV GOCO Congress (Montpellier) 2017. Rep Pract Oncol Radiother 2019; 24:355-362. [DOI: 10.1016/j.rpor.2019.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/11/2019] [Indexed: 11/21/2022] Open
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Liu Y, Lei Y, Wang T, Kayode O, Tian S, Liu T, Patel P, Curran WJ, Ren L, Yang X. MRI-based treatment planning for liver stereotactic body radiotherapy: validation of a deep learning-based synthetic CT generation method. Br J Radiol 2019; 92:20190067. [PMID: 31192695 DOI: 10.1259/bjr.20190067] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE The purpose of this work is to develop and validate a learning-based method to derive electron density from routine anatomical MRI for potential MRI-based SBRT treatment planning. METHODS We proposed to integrate dense block into cycle generative adversarial network (GAN) to effectively capture the relationship between the CT and MRI for CT synthesis. A cohort of 21 patients with co-registered CT and MR pairs were used to evaluate our proposed method by the leave-one-out cross-validation. Mean absolute error, peak signal-to-noise ratio and normalized cross-correlation were used to quantify the imaging differences between the synthetic CT (sCT) and CT. The accuracy of Hounsfield unit (HU) values in sCT for dose calculation was evaluated by comparing the dose distribution in sCT-based and CT-based treatment planning. Clinically relevant dose-volume histogram metrics were then extracted from the sCT-based and CT-based plans for quantitative comparison. RESULTS The mean absolute error, peak signal-to-noise ratio and normalized cross-correlation of the sCT were 72.87 ± 18.16 HU, 22.65 ± 3.63 dB and 0.92 ± 0.04, respectively. No significant differences were observed in the majority of the planning target volume and organ at risk dose-volume histogram metrics ( p > 0.05). The average pass rate of γ analysis was over 99% with 1%/1 mm acceptance criteria on the coronal plane that intersects with isocenter. CONCLUSION The image similarity and dosimetric agreement between sCT and original CT warrant further development of an MRI-only workflow for liver stereotactic body radiation therapy. ADVANCES IN KNOWLEDGE This work is the first deep-learning-based approach to generating abdominal sCT through dense-cycle-GAN. This method can successfully generate the small bony structures such as the rib bones and is able to predict the HU values for dose calculation with comparable accuracy to reference CT images.
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Affiliation(s)
- Yingzi Liu
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Yang Lei
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Tonghe Wang
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Oluwatosin Kayode
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Sibo Tian
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Tian Liu
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Pretesh Patel
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Walter J Curran
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Lei Ren
- 2 Department of Radiation Oncology, Duke University, Durham, North Carolina
| | - Xiaofeng Yang
- 1 Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
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Nejad-Davarani SP, Kim JP, Du D, Glide-Hurst C. Large field of view distortion assessment in a low-field MR-linac. Med Phys 2019; 46:2347-2355. [PMID: 30838680 DOI: 10.1002/mp.13467] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/07/2019] [Accepted: 02/21/2019] [Indexed: 01/04/2023] Open
Abstract
PURPOSE MR-guided radiation therapy (RT) offers unparalleled soft tissue contrast for localization and target tracking. However, MRI distortions may be detrimental to high precision RT. This work characterizes the gradient nonlinearity (GNL) and total distortions over the first year of clinical operation of a 0.35T MR-linac. METHODS For GNL characterization, an in-house large field of view (FOV) phantom (60 × 42.5 × 55 cm3 , >6000 spherical landmarks) was configured and scanned at four timepoints with forward/reverse read polarities (Gradient Echo sequence, FA/TR/TE = 28°/30 ms/6 ms). GNL was measured in Anterior-Posterior (AP), Left-Right (LR), and Superior-Inferior (SI) frequency-encoding directions based on deviation of the auto-segmented landmark centroids between rigidly registered MR and CT images and assessed based on radial distance from magnet isocenter. Total distortion was assessed using a 30 × 30 cm2 grid phantom oriented along the cardinal axes over >1 year of operation. RESULTS The scanner's spatial integrity within the first ~10 months was stable (maximum total distortion variation = 10/6/8%, maximum distortion = 1.41/0.99/1.56 mm in Axial/Coronal/Sagittal planes, respectively). GNL distortions measured during this time period <10 cm from isocenter were (-0.74, 0.45), (-0.67, 0.53), and (-0.86, 0.70) mm in AP/LR/SI directions. In the 10-20 cm range, <1.5% of the distortions exceeded 2 mm in the AP and LR axes while <4% of the distortions exceeded 2 mm for SI. After major repairs and magnet re-shim, detectable changes were observed in total and GNL distortions (20% reduction in AP and 36% increase in SI direction in the 20-25 cm range). Across all timepoints and axes, 38-53% of landmarks in the 20-25 cm range were displaced by >1 mm. CONCLUSIONS GNL distortions were negligible within a 10 cm radius from isocenter. However, in the periphery, non-negligible distortions of up to ~7 mm were observed, which may necessitate GNL corrections for MR-IGRT for treatment sites distant from magnet isocenter.
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Affiliation(s)
- Siamak P Nejad-Davarani
- Department of Radiation Oncology, Henry Ford Cancer Institute, 2799 West Grand Blvd., Detroit, MI, 48202, USA
| | - Joshua P Kim
- Department of Radiation Oncology, Henry Ford Cancer Institute, 2799 West Grand Blvd., Detroit, MI, 48202, USA
| | - Dongsu Du
- Department of Radiation Oncology, Henry Ford Cancer Institute, 2799 West Grand Blvd., Detroit, MI, 48202, USA
| | - Carri Glide-Hurst
- Department of Radiation Oncology, Henry Ford Cancer Institute, 2799 West Grand Blvd., Detroit, MI, 48202, USA
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Peerlings J, Compter I, Janssen F, Wiggins CJ, Postma AA, Mottaghy FM, Lambin P, Hoffmann AL. Characterizing geometrical accuracy in clinically optimised 7T and 3T magnetic resonance images for high-precision radiation treatment of brain tumours. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2019; 9:35-42. [PMID: 33458423 PMCID: PMC7807620 DOI: 10.1016/j.phro.2018.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 11/23/2018] [Accepted: 12/05/2018] [Indexed: 11/27/2022]
Abstract
Background and purpose In neuro-oncology, high spatial accuracy is needed for clinically acceptable high-precision radiation treatment planning (RTP). In this study, the clinical applicability of anatomically optimised 7-Tesla (7T) MR images for reliable RTP is assessed with respect to standard clinical imaging modalities. Materials and methods System- and phantom-related geometrical distortion (GD) were quantified on clinically-relevant MR sequences at 7T and 3T, and on CT images using a dedicated anthropomorphic head phantom incorporating a 3D grid-structure, creating 436 points-of-interest. Global GD was assessed by mean absolute deviation (MADGlobal). Local GD relative to the magnetic isocentre was assessed by MADLocal. Using 3D displacement vectors of individual points-of-interest, GD maps were created. For clinically acceptable radiotherapy, 7T images need to meet the criteria for accurate dose delivery (GD < 1 mm) and present comparable GD as tolerated in clinically standard 3T MR/CT-based RTP. Results MADGlobal in 7T and 3T images ranged from 0.3 to 2.2 mm and 0.2-0.8 mm, respectively. MADLocal increased with increasing distance from the isocentre, showed an anisotropic distribution, and was significantly larger in 7T MR sequences (MADLocal = 0.2-1.2 mm) than in 3T (MADLocal = 0.1-0.7 mm) (p < 0.05). Significant differences in GD were detected between 7T images (p < 0.001). However, maximum MADLocal remained ≤1 mm within 68.7 mm diameter spherical volume. No significant differences in GD were found between 7T and 3T protocols near the isocentre. Conclusions System- and phantom-related GD remained ≤1 mm in central brain regions, suggesting that 7T MR images could be implemented in radiotherapy with clinically acceptable spatial accuracy and equally tolerated GD as in 3T MR/CT-based RTP. For peripheral regions, GD should be incorporated in safety margins for treatment uncertainties. Moreover, the effects of sequence-related factors on GD needs further investigation to obtain RTP-specific MR protocols.
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Affiliation(s)
- Jurgen Peerlings
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre+, Maastricht, The Netherlands.,Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Inge Compter
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Fiere Janssen
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | | | - Alida A Postma
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Felix M Mottaghy
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands.,Department of Nuclear Medicine, University Hospital RWTH Aachen University, Aachen, Germany
| | - Philippe Lambin
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Aswin L Hoffmann
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre+, Maastricht, The Netherlands.,Institute of Radiooncology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.,OncoRay National Center for Radiation Research in Oncology, Dresden, Germany.,Department of Radiotherapy, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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Edwards CA, Rusheen AE, Oh Y, Paek SB, Jacobs J, Lee KH, Dennis KD, Bennet KE, Kouzani AZ, Lee KH, Goerss SJ. A novel re-attachable stereotactic frame for MRI-guided neuronavigation and its validation in a large animal and human cadaver model. J Neural Eng 2018; 15:066003. [PMID: 30124202 DOI: 10.1088/1741-2552/aadb49] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Stereotactic frame systems are the gold-standard for stereotactic surgeries, such as implantation of deep brain stimulation (DBS) devices for treatment of medically resistant neurologic and psychiatric disorders. However, frame-based systems require that the patient is awake with a stereotactic frame affixed to their head for the duration of the surgical planning and implantation of the DBS electrodes. While frameless systems are increasingly available, a reusable re-attachable frame system provides unique benefits. As such, we created a novel reusable MRI-compatible stereotactic frame system that maintains clinical accuracy through the detachment and reattachment of its stereotactic devices used for MRI-guided neuronavigation. APPROACH We designed a reusable arc-centered frame system that includes MRI-compatible anchoring skull screws for detachment and re-attachment of its stereotactic devices. We validated the stability and accuracy of our system through phantom, in vivo mock-human porcine DBS-model and human cadaver testing. MAIN RESULTS Phantom testing achieved a root mean square error (RMSE) of 0.94 ± 0.23 mm between the ground truth and the frame-targeted coordinates; and achieved an RMSE of 1.11 ± 0.40 mm and 1.33 ± 0.38 mm between the ground truth and the CT- and MRI-targeted coordinates, respectively. In vivo and cadaver testing achieved a combined 3D Euclidean localization error of 1.85 ± 0.36 mm (p < 0.03) between the pre-operative MRI-guided placement and the post-operative CT-guided confirmation of the DBS electrode. SIGNIFICANCE Our system demonstrated consistent clinical accuracy that is comparable to conventional frame and frameless stereotactic systems. Our frame system is the first to demonstrate accurate relocation of stereotactic frame devices during in vivo MRI-guided DBS surgical procedures. As such, this reusable and re-attachable MRI-compatible system is expected to enable more complex, chronic neuromodulation experiments, and lead to a clinically available re-attachable frame that is expected to decrease patient discomfort and costs of DBS surgery.
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Affiliation(s)
- Christine A Edwards
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia. Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States of America. Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, United States of America
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Ruschin M, Sahgal A, Soliman H, Myrehaug S, Tseng CL, Bola R, Yeboah C, Sarfehnia A, Chugh B, Eriksson M, Nordström H, Lee Y. Clinical Image Coregistration Variability on a Dedicated Radiosurgery Unit. Neurosurgery 2018; 85:E101-E108. [DOI: 10.1093/neuros/nyy334] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 06/19/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mark Ruschin
- Department of Medical Physics, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Arjun Sahgal
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
- Department of Radiation Oncology, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
| | - Hany Soliman
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
- Department of Radiation Oncology, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
| | - Sten Myrehaug
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
- Department of Radiation Oncology, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
| | - Chia-Lin Tseng
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
- Department of Radiation Oncology, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
| | - Ruby Bola
- Department of Radiation Oncology, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
| | - Collins Yeboah
- Department of Medical Physics, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Arman Sarfehnia
- Department of Medical Physics, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Brige Chugh
- Department of Medical Physics, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Young Lee
- Department of Medical Physics, Sunnybrook Odette Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
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Pappas EP, Seimenis I, Dellios D, Kollias G, Lampropoulos KI, Karaiskos P. Assessment of sequence dependent geometric distortion in contrast-enhanced MR images employed in stereotactic radiosurgery treatment planning. ACTA ACUST UNITED AC 2018; 63:135006. [DOI: 10.1088/1361-6560/aac7bf] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Dinkla AM, Wolterink JM, Maspero M, Savenije MHF, Verhoeff JJC, Seravalli E, Išgum I, Seevinck PR, van den Berg CAT. MR-Only Brain Radiation Therapy: Dosimetric Evaluation of Synthetic CTs Generated by a Dilated Convolutional Neural Network. Int J Radiat Oncol Biol Phys 2018; 102:801-812. [PMID: 30108005 DOI: 10.1016/j.ijrobp.2018.05.058] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 05/15/2018] [Accepted: 05/22/2018] [Indexed: 01/01/2023]
Abstract
PURPOSE This work aims to facilitate a fast magnetic resonance (MR)-only workflow for radiation therapy of intracranial tumors. Here, we evaluate whether synthetic computed tomography (sCT) images generated with a dilated convolutional neural network (CNN) enable accurate MR-based dose calculations in the brain. METHODS AND MATERIALS We conducted a retrospective study of 52 patients with brain tumors who underwent both computed tomography (CT) and MR imaging for radiation therapy treatment planning. To generate the sCTs, a T1-weighted gradient echo MR sequence was selected from the clinical protocol for multiple types of brain tumors. sCTs were created for all 52 patients with a dilated CNN using 2-fold cross validation; in each fold, 26 patients were used for training and the remaining 26 patients were used for evaluation. For each patient, the clinical CT-based treatment plan was recalculated on sCT. We calculated dose differences and gamma pass rates between CT- and sCT-based plans inside body and planning target volume. Geometric fidelity of the sCT and differences in beam depth and equivalent path length were assessed between both treatment plans. RESULTS sCT generation took 1 minute per patient. Over the patient population, the mean absolute error of the sCT within the intersection of body contours was 67 ± 11 HU (±1 standard deviation [SD], range: 51-117 HU), and the mean error was 13 ± 9 HU (±1 SD, range: -2 to 38 HU). Dosimetric analysis showed mean deviations of 0.00% ± 0.02% (±1 SD, range: -0.05 to 0.03) for dose within the body contours and -0.13% ± 0.39% (±1 SD, range: -1.43 to 0.80) inside the planning target volume. Mean γ1mm/1% was 98.8% ± 2.2% for doses >50% of the prescribed dose. CONCLUSIONS The presented dilated CNN generated sCTs from conventional MR images without adding scan time to the acquisition. Dosimetric evaluation suggests that dose calculations performed on the sCTs are accurate and can therefore be used for MR-only intracranial radiation therapy treatment planning.
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Affiliation(s)
- Anna M Dinkla
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Jelmer M Wolterink
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Matteo Maspero
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands; Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mark H F Savenije
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Joost J C Verhoeff
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Enrica Seravalli
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ivana Išgum
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter R Seevinck
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
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Calvo-Ortega JF, Mateos J, Alberich Á, Moragues S, Acebes JJ, José SS, Casals J. Evaluation of a novel software application for magnetic resonance distortion correction in cranial stereotactic radiosurgery. Med Dosim 2018; 44:136-143. [PMID: 29752157 DOI: 10.1016/j.meddos.2018.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 03/13/2018] [Accepted: 04/09/2018] [Indexed: 11/25/2022]
Abstract
This study aimed to validate a novel commercially available software for correcting spatial distortion in cranial magnetic resonance (MR) images. This software has been used to assess the dosimetric impact of MR distortion in stereotactic radiosurgery (SRS) treatments of vestibular schwannomas (VSs). Five MR datasets were intentionally distorted. Each distorted MR dataset was corrected using the Cranial Distortion software, obtaining a new corrected MR dataset (MRcorr). The accuracy of the correction was quantified by calculating the target registration error (TRE) for 6 anatomical landmarks identified in the co-registered MRcorr and planning computed tomography (pCT) images. Nine VS cases were included to investigate the impact of the MR distortion in SRS plans. Each SRS plan was calculated on the pCT (1 × 1 × 1 mm3 voxel) with the target and organs at risk (OARs) delineated using the planning MR dataset. This MR dataset was then corrected (MRcorr) using the Cranial Distortion software. Geometrical agreement between the original target and the corresponding corrected target was assessed using several metrics: MacDonald criteria, mean distance to agreement (MDA), and Dice similarity coefficient (DSC). Target coverage (D99%) and maximum doses (D2%) to ipsilateral cochlea and brainstem resulting on the MRcorr dataset were compared with the original values. TRE values (0.6 mm ± 0.3 mm) and differences found in Macdonald criteria (0.3 mm ± 0.4 mm and 0.3 mm ± 0.3 mm) and MDA (0.8 mm ± 0.2 mm) were mostly within the voxel size dimension of the pCT scan (1 × 1 × 1 mm3). High similarity (DSC > 0.7) between the original and corrected targets was found. Small dose differences for the original and corrected structures were found: 0.1 Gy ± 0.1 Gy for target D99%, 0.2 Gy ± 0.3 Gy for cochlea D2%, and 0.1 Gy ± 0.1 Gy for brainstem D2%. Our study shows that Distortion Correction software can be a helpful tool to detect and adequately correct brain MR distortions. However, a negligible dosimetric impact of MR distortion has been detected in our clinical practice.
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Affiliation(s)
- Juan-Francisco Calvo-Ortega
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain; Servicio de Oncología Radioterápica, Hospital Universitari Dexeus, Barcelona, Spain.
| | - José Mateos
- Imagen Ensayos Clínicos (IEC), Hospital Quirónsalud, Barcelona, Spain
| | - Ángel Alberich
- Biomedical Imaging Research Group (GIBI230), La Fe Health Research Institute, Valencia, Spain
| | - Sandra Moragues
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain; Servicio de Oncología Radioterápica, Hospital Universitari Dexeus, Barcelona, Spain
| | - Juan-José Acebes
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain
| | - Sol San José
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain; Servicio de Oncología Radioterápica, Hospital Universitari Dexeus, Barcelona, Spain
| | - Joan Casals
- Servicio de Oncología Radioterápica, Hospital Quirónsalud, Barcelona, Spain; Servicio de Oncología Radioterápica, Hospital Universitari Dexeus, Barcelona, Spain
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Dosimetric Impact of Using a Virtual Couch Shift for Online Correction of Setup Errors for Brain Patients on an Integrated High-Field Magnetic Resonance Imaging Linear Accelerator. Int J Radiat Oncol Biol Phys 2017; 98:699-708. [DOI: 10.1016/j.ijrobp.2017.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/16/2017] [Accepted: 03/02/2017] [Indexed: 11/19/2022]
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Cao Y, Tseng CL, Balter JM, Teng F, Parmar HA, Sahgal A. MR-guided radiation therapy: transformative technology and its role in the central nervous system. Neuro Oncol 2017; 19:ii16-ii29. [PMID: 28380637 DOI: 10.1093/neuonc/nox006] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
This review article describes advancement of magnetic resonance imaging technologies in radiation therapy planning, guidance, and adaptation of brain tumors. The potential for MR-guided radiation therapy to improve outcomes and the challenges in its adoption are discussed.
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Affiliation(s)
- Yue Cao
- Departments of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
- Radiology, University of Michigan, Ann Arbor, Michigan, USA
- Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Chia-Lin Tseng
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - James M Balter
- Departments of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
| | - Feifei Teng
- Departments of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Radiation Oncology, Shandong Cancer Hospital, Shandong University, Jinan, China
| | | | - Arjun Sahgal
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
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Seibert TM, Karunamuni R, Kaifi S, Burkeen J, Connor M, Krishnan AP, White NS, Farid N, Bartsch H, Murzin V, Nguyen TT, Moiseenko V, Brewer JB, McDonald CR, Dale AM, Hattangadi-Gluth JA. Cerebral Cortex Regions Selectively Vulnerable to Radiation Dose-Dependent Atrophy. Int J Radiat Oncol Biol Phys 2017; 97:910-918. [PMID: 28333012 PMCID: PMC5403140 DOI: 10.1016/j.ijrobp.2017.01.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/08/2016] [Accepted: 01/01/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE AND OBJECTIVES Neurologic deficits after brain radiation therapy (RT) typically involve decline in higher-order cognitive functions such as attention and memory rather than sensory defects or paralysis. We sought to determine whether areas of the cortex critical to cognition are selectively vulnerable to radiation dose-dependent atrophy. METHODS AND MATERIALS We measured change in cortical thickness in 54 primary brain tumor patients who underwent fractionated, partial brain RT. The study patients underwent high-resolution, volumetric magnetic resonance imaging (T1-weighted; T2 fluid-attenuated inversion recovery, FLAIR) before RT and 1 year afterward. Semiautomated software was used to segment anatomic regions of the cerebral cortex for each patient. Cortical thickness was measured for each region before RT and 1 year afterward. Two higher-order cortical regions of interest (ROIs) were tested for association between radiation dose and cortical thinning: entorhinal (memory) and inferior parietal (attention/memory). For comparison, 2 primary cortex ROIs were also tested: pericalcarine (vision) and paracentral lobule (somatosensory/motor). Linear mixed-effects analyses were used to test all other cortical regions for significant radiation dose-dependent thickness change. Statistical significance was set at α = 0.05 using 2-tailed tests. RESULTS Cortical atrophy was significantly associated with radiation dose in the entorhinal (P=.01) and inferior parietal ROIs (P=.02). By contrast, no significant radiation dose-dependent effect was found in the primary cortex ROIs (pericalcarine and paracentral lobule). In the whole-cortex analysis, 9 regions showed significant radiation dose-dependent atrophy, including areas responsible for memory, attention, and executive function (P≤.002). CONCLUSIONS Areas of cerebral cortex important for higher-order cognition may be most vulnerable to radiation-related atrophy. This is consistent with clinical observations that brain radiation patients experience deficits in domains of memory, executive function, and attention. Correlations of regional cortical atrophy with domain-specific cognitive functioning in prospective trials are warranted.
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Affiliation(s)
- Tyler M Seibert
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | - Roshan Karunamuni
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | - Samar Kaifi
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | - Jeffrey Burkeen
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | - Michael Connor
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | | | - Nathan S White
- Department of Radiology, University of California, San Diego, La Jolla, California
| | - Nikdokht Farid
- Department of Radiology, University of California, San Diego, La Jolla, California
| | - Hauke Bartsch
- Department of Radiology, University of California, San Diego, La Jolla, California
| | - Vyacheslav Murzin
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | - Tanya T Nguyen
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Vitali Moiseenko
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California
| | - James B Brewer
- Department of Radiology, University of California, San Diego, La Jolla, California; Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Carrie R McDonald
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California; Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Anders M Dale
- Department of Radiology, University of California, San Diego, La Jolla, California; Department of Psychiatry, University of California, San Diego, La Jolla, California; Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Jona A Hattangadi-Gluth
- Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California.
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Edmund JM, Nyholm T. A review of substitute CT generation for MRI-only radiation therapy. Radiat Oncol 2017; 12:28. [PMID: 28126030 PMCID: PMC5270229 DOI: 10.1186/s13014-016-0747-y] [Citation(s) in RCA: 236] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/21/2016] [Indexed: 12/13/2022] Open
Abstract
Radiotherapy based on magnetic resonance imaging as the sole modality (MRI-only RT) is an area of growing scientific interest due to the increasing use of MRI for both target and normal tissue delineation and the development of MR based delivery systems. One major issue in MRI-only RT is the assignment of electron densities (ED) to MRI scans for dose calculation and a similar need for attenuation correction can be found for hybrid PET/MR systems. The ED assigned MRI scan is here named a substitute CT (sCT). In this review, we report on a collection of typical performance values for a number of main approaches encountered in the literature for sCT generation as compared to CT. A literature search in the Scopus database resulted in 254 papers which were included in this investigation. A final number of 50 contributions which fulfilled all inclusion criteria were categorized according to applied method, MRI sequence/contrast involved, number of subjects included and anatomical site investigated. The latter included brain, torso, prostate and phantoms. The contributions geometric and/or dosimetric performance metrics were also noted. The majority of studies are carried out on the brain for 5–10 patients with PET/MR applications in mind using a voxel based method. T1 weighted images are most commonly applied. The overall dosimetric agreement is in the order of 0.3–2.5%. A strict gamma criterion of 1% and 1mm has a range of passing rates from 68 to 94% while less strict criteria show pass rates > 98%. The mean absolute error (MAE) is between 80 and 200 HU for the brain and around 40 HU for the prostate. The Dice score for bone is between 0.5 and 0.95. The specificity and sensitivity is reported in the upper 80s% for both quantities and correctly classified voxels average around 84%. The review shows that a variety of promising approaches exist that seem clinical acceptable even with standard clinical MRI sequences. A consistent reference frame for method benchmarking is probably necessary to move the field further towards a widespread clinical implementation.
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Affiliation(s)
- Jens M Edmund
- Radiotherapy Research Unit, Department of Oncology, Herlev & Gentofte Hospital, Copenhagen University, Herlev, Denmark. .,Niels Bohr Institute, Copenhagen University, Copenhagen, Denmark.
| | - Tufve Nyholm
- Department of Radiation Sciences, Umeå University, Umeå, SE-901 87, Sweden.,Medical Radiation Physics, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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Glide-Hurst CK, Wen N, Hearshen D, Kim J, Pantelic M, Zhao B, Mancell T, Levin K, Movsas B, Chetty IJ, Siddiqui MS. Initial clinical experience with a radiation oncology dedicated open 1.0T MR-simulation. J Appl Clin Med Phys 2015; 16:5201. [PMID: 26103190 PMCID: PMC5690096 DOI: 10.1120/jacmp.v16i2.5201] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 12/10/2014] [Accepted: 12/10/2014] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to describe our experience with 1.0T MR-SIM including characterization, quality assurance (QA) program, and features necessary for treatment planning. Staffing, safety, and patient screening procedures were developed. Utilization of an external laser positioning system (ELPS) and MR-compatible couchtop were illustrated. Spatial and volumetric analyses were conducted between CT-SIM and MR-SIM using a stereotactic QA phantom with known landmarks and volumes. Magnetic field inhomogeneity was determined using phase difference analysis. System-related, in-plane distortion was evaluated and temporal changes were assessed. 3D distortion was characterized for regions of interest (ROIs) 5-20 cm away from isocenter. American College of Radiology (ACR) recommended tests and impact of ELPS on image quality were analyzed. Combined ultrashort echotime Dixon (UTE/Dixon) sequence was evaluated. Amplitude-triggered 4D MRI was implemented using a motion phantom (2-10 phases, ~ 2 cm excursion, 3-5 s periods) and a liver cancer patient. Duty cycle, acquisition time, and excursion were evaluated between maximum intensity projection (MIP) datasets. Less than 2% difference from expected was obtained between CT-SIM and MR-SIM volumes, with a mean distance of < 0.2 mm between landmarks. Magnetic field inhomogeneity was < 2 ppm. 2D distortion was < 2 mm over 28.6-33.6 mm of isocenter. Within 5 cm radius of isocenter, mean 3D geometric distortion was 0.59 ± 0.32 mm (maximum = 1.65 mm) and increased 10-15 cm from isocenter (mean = 1.57 ± 1.06 mm, maximum = 6.26 mm). ELPS interference was within the operating frequency of the scanner and was characterized by line patterns and a reduction in signal-to-noise ratio (4.6-12.6% for TE = 50-150 ms). Image quality checks were within ACR recommendations. UTE/Dixon sequences yielded detectability between bone and air. For 4D MRI, faster breathing periods had higher duty cycles than slow (50.4% (3 s) and 39.4% (5 s), p < 0.001) and ~fourfold acquisition time increase was measured for ten-phase versus two-phase. Superior-inferior object extent was underestimated 8% (6 mm) for two-phase as compared to ten-phase MIPs, although < 2% difference was obtained for ≥ 4 phases. 4D MRI for a patient demonstrated acceptable image quality in ~ 7 min. MR-SIM was integrated into our workflow and QA procedures were developed. Clinical applicability was demonstrated for 4D MRI and UTE imaging to support MR-SIM for single modality treatment planning.
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