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Stevens RRF, Hazelaar C, Bogowicz M, Ter Bekke RMA, Volders PGA, Verhoeven K, de Ruysscher D, Verhoeff JJC, Fast MF, Mandija S, Cvek J, Knybel L, Dvorak P, Blanck O, van Elmpt W. A Framework for Assessing the Effect of Cardiac and Respiratory Motion for Stereotactic Arrhythmia Radioablation Using a Digital Phantom With a 17-Segment Model: A STOPSTORM.eu Consortium Study. Int J Radiat Oncol Biol Phys 2024; 118:533-542. [PMID: 37652302 DOI: 10.1016/j.ijrobp.2023.08.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/14/2023] [Accepted: 08/22/2023] [Indexed: 09/02/2023]
Abstract
PURPOSE The optimal motion management strategy for patients receiving stereotactic arrhythmia radioablation (STAR) for the treatment of ventricular tachycardia (VT) is not fully known. We developed a framework using a digital phantom to simulate cardiorespiratory motion in combination with different motion management strategies to gain insight into the effect of cardiorespiratory motion on STAR. METHODS AND MATERIALS The 4-dimensional (4D) extended cardiac-torso (XCAT) phantom was expanded with the 17-segment left ventricular (LV) model, which allowed placement of STAR targets in standardized ventricular regions. Cardiac- and respiratory-binned 4D computed tomography (CT) scans were simulated for free-breathing, reduced free-breathing, respiratory-gating, and breath-hold scenarios. Respiratory motion of the heart was set to population-averaged values of patients with VT: 6, 2, and 1 mm in the superior-inferior, posterior-anterior, and left-right direction, respectively. Cardiac contraction was adjusted by reducing LV ejection fraction to 35%. Target displacement was evaluated for all segments using envelopes encompassing the cardiorespiratory motion. Envelopes incorporating only the diastole plus respiratory motion were created to simulate the scenario where cardiac motion is not fully captured on 4D respiratory CT scans used for radiation therapy planning. RESULTS The average volume of the 17 segments was 6 cm3 (1-9 cm3). Cardiac contraction-relaxation resulted in maximum segment (centroid) motion of 4, 6, and 3.5 mm in the superior-inferior, posterior-anterior, and left-right direction, respectively. Cardiac contraction-relaxation resulted in a motion envelope increase of 49% (24%-79%) compared with individual segment volumes, whereas envelopes increased by 126% (79%-167%) if respiratory motion also was considered. Envelopes incorporating only the diastole and respiration motion covered on average 68% to 75% of the motion envelope. CONCLUSIONS The developed LV-segmental XCAT framework showed that free-wall regions display the most cardiorespiratory displacement. Our framework supports the optimization of STAR by evaluating the effect of (cardio)respiratory motion and motion management strategies for patients with VT.
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Affiliation(s)
- Raoul R F Stevens
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, The Netherlands.
| | - Colien Hazelaar
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Marta Bogowicz
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Rachel M A Ter Bekke
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Paul G A Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Karolien Verhoeven
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Dirk de Ruysscher
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Joost J C Verhoeff
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martin F Fast
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Stefano Mandija
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jakub Cvek
- Department of Oncology, University Hospital and Faculty of Medicine, Ostrava, Czech Republic
| | - Lukas Knybel
- Department of Oncology, University Hospital and Faculty of Medicine, Ostrava, Czech Republic
| | - Pavel Dvorak
- Department of Oncology, University Hospital and Faculty of Medicine, Ostrava, Czech Republic
| | - Oliver Blanck
- Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Wouter van Elmpt
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, The Netherlands
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Fedrigo R, Segars WP, Martineau P, Gowdy C, Bloise I, Uribe CF, Rahmim A. Development of scalable lymphatic system in the 4D XCAT phantom: Application to quantitative evaluation of lymphoma PET segmentations. Med Phys 2022; 49:6871-6884. [PMID: 36053829 PMCID: PMC9742182 DOI: 10.1002/mp.15963] [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: 06/27/2022] [Revised: 08/01/2022] [Accepted: 08/16/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Digital anthropomorphic phantoms, such as the 4D extended cardiac-torso (XCAT) phantom, are actively used to develop, optimize, and evaluate a variety of imaging applications, allowing for realistic patient modeling and knowledge of ground truth. The XCAT phantom defines the activity and attenuation for a simulated patient, which includes a complete set of organs, muscle, bone, and soft tissue, while also accounting for cardiac and respiratory motion. However, the XCAT phantom does not currently include the lymphatic system, critical for evaluating medical imaging tasks such as sentinel node detection, node density measurement, and radiation dosimetry. PURPOSE In this study, we aimed to develop a scalable lymphatic system in the XCAT phantom, to facilitate improved research of the lymphatic system in medical imaging. Using this scalable lymphatic system, we modeled the lymph node conglomerate pathology that is characteristically observed in primary mediastinal B-cell lymphoma (PMBCL). As an extended application, we evaluated positron emission tomography (PET) image quantification of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of these simulated lymphomas, though the phantoms may be applied to other imaging modalities and study design paradigms (e.g., image quality, detection). METHODS A template model for the lymphatic system was developed based on anatomical data from the Visible Human Project of the National Library of Medicine. The segmented nodes and vessels were fit with non-uniform rational basis spline surfaces, and multichannel large deformation diffeomorphic metric mapping was used to propagate the template to different XCAT anatomies. To model conglomerates observed in PMBCL, lymph nodes were enlarged, converged within the mediastinum, and tracer concentration was increased. We used the phantoms as inputs to a PET simulation tool, which generated images using ordered subsets expectation maximization reconstruction with 2-8 mm Gaussian filters. Fixed thresholding (FT) and gradient segmentation were used to determine MTV and TLG. Percent bias (%Bias) and coefficient of variation (COV) were computed as measures of accuracy and precision, respectively, for each MTV and TLG measurement. RESULTS Using the methodology described above, we introduced a scalable lymphatic system in the XCAT phantom, which allows for the radioactivity and attenuation ground truth to be generated in 116 ± 2.5 s using a 2.3 GHz processor. Within the Rhinoceros interface, lymph node anatomy and function were modified to create a cohort of 10 phantoms with lymph node conglomerates. Using the lymphoma phantoms to evaluate PET quantification of MTV, mean %Bias values were -9.3%, -41.3%, and 20.9%, while COV values were 4.08%, 7.6%, and 3.4% using 25% FT, 40% FT, and gradient segmentations, respectively. Comparatively for TLG, mean %Bias values were -27.4%, -45.8%, and -16.0%, while COV values were 1.9%, 5.7%, and 1.4%, for the 25% FT, 40% FT, and gradient segmentations, respectively. CONCLUSIONS In this work, we upgraded the XCAT phantom to include a lymphatic system, comprised of a network of 276 scalable lymph nodes and corresponding vessels. As an application, we created a cohort of phantoms with lymph node conglomerates to evaluate lymphoma quantification in PET imaging, which highlights an important application of this work.
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Affiliation(s)
- Roberto Fedrigo
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | | | | | - Claire Gowdy
- Department of Radiology, BC Children’s Hospital, Vancouver, BC V6H 0B3, Canada
| | - Ingrid Bloise
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Carlos F. Uribe
- Functional Imaging, BC Cancer, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Arman Rahmim
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
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Schoen N, Seifert F, Petzold J, Metzger GJ, Speck O, Ittermann B, Schmitter S. The Impact of Respiratory Motion on Electromagnetic Fields and Specific Absorption Rate in Cardiac Imaging at 7T. Magn Reson Med 2022; 88:2645-2661. [PMID: 35906923 DOI: 10.1002/mrm.29402] [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: 02/24/2022] [Revised: 06/30/2022] [Accepted: 07/08/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE To present electromagnetic simulation setups for detailed analyses of respiration's impact on B 1 + $$ {B}_1^{+} $$ and E-fields, local specific absorption rate (SAR) and associated safety-limits for 7T cardiac imaging. METHODS Finite-difference time-domain electromagnetic field simulations were performed at five respiratory states using a breathing body model and a 16-element 7T body transceiver RF-coil array. B 1 + $$ {B}_1^{+} $$ and SAR are analyzed for fixed and moving coil configurations. SAR variations are investigated using phase/amplitude shimming considering (i) a local SAR-controlled mode (here SAR calculations consider RF amplitudes and phases) and (ii) a channel-wise power-controlled mode (SAR boundary calculation is independent of the channels' phases, only dependent on the channels' maximum amplitude). RESULTS Respiration-induced variations of both B 1 + $$ {B}_1^{+} $$ amplitude and phase are observed. The flip angle homogeneity depends on the respiratory state used for B 1 + $$ {B}_1^{+} $$ shimming; best results were achieved for shimming on inhale and exhale simultaneously ( | Δ C V | < 35 % $$ \mid \Delta CV\mid <35\% $$ ). The results reflect that respiration impacts position and amplitude of the local SAR maximum. With the local-SAR-control mode, a safety factor of up to 1.4 is needed to accommodate for respiratory variations while the power control mode appears respiration-robust when the coil moves with respiration (SAR peak decrease: 9% exhale→inhale). Instead, a spatially fixed coil setup yields higher SAR variations with respiration. CONCLUSION Respiratory motion does not only affect the B 1 + $$ {B}_1^{+} $$ distribution and hence the image contrast, but also location and magnitude of the peak spatial SAR. Therefore, respiration effects may need to be included in safety analyses of RF coils applied to the human thorax.
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Affiliation(s)
- Natalie Schoen
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Frank Seifert
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Johannes Petzold
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Gregory J Metzger
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Oliver Speck
- Otto von Guericke University, Magdeburg, Germany
| | - Bernd Ittermann
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
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Lydiard S, Pontré B, Lowe BS, Keall P. Atrial fibrillation cardiac radioablation target visibility on magnetic resonance imaging. Phys Eng Sci Med 2022; 45:757-767. [PMID: 35687311 PMCID: PMC9448688 DOI: 10.1007/s13246-022-01141-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 05/16/2022] [Indexed: 11/27/2022]
Abstract
Magnetic resonance imaging (MRI) guided cardiac radioablation (CR) for atrial fibrillation (AF) is a promising treatment concept. However, the visibility of AF CR targets on MRI acquisitions requires further exploration and MRI sequence and parameter optimization has not yet been performed for this application. This pilot study explores the feasibility of MRI-guided tracking of AF CR targets by evaluating AF CR target visualization on human participants using a selection of 3D and 2D MRI sequences.MRI datasets were acquired in healthy and AF participants using a range of MRI sequences and parameters. MRI acquisition categories included 3D free-breathing acquisitions (3Dacq), 2D breath-hold ECG-gated acquisitions (2DECG-gated), stacks of 2D breath-hold ECG-gated acquisitions which were retrospectively interpolated to 3D datasets (3Dinterp), and 2D breath-hold ungated acquisitions (2Dreal-time). The ease of target delineation and the presence of artifacts were qualitatively analyzed. Image quality was quantitatively analyzed using signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and non-uniformity. Confident 3D target delineation was achievable on all 3Dinterp datasets but was not possible on any of the 3Dacq datasets. Fewer artifacts and significantly better SNR, CNR and non-uniformity metrics were observed with 3Dinterp compared to 3Dacq. 2Dreal-time datasets had slightly lower SNR and CNR than 2DECG-gated and 3Dinterp n datasets. AF CR target visualization on MRI was qualitatively and quantitatively evaluated. The study findings indicate that AF CR target visualization is achievable despite the imaging challenges associated with these targets, warranting further investigation into MRI-guided AF CR treatments.
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Affiliation(s)
- Suzanne Lydiard
- ACRF Image X Institute, University of Sydney, 1 Central Avenue, Eveleigh, NSW, Australia. .,Kathleen Kilgour Centre, 18 Twentieth Avenue, Tauranga South, Tauranga, New Zealand.
| | - Beau Pontré
- Department of Anatomy and Medical Imaging, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
| | - Boris S Lowe
- Green Lane Cardiovascular Service, Auckland City Hospital, 2 Park Road, Grafton, Auckland, New Zealand
| | - Paul Keall
- ACRF Image X Institute, University of Sydney, 1 Central Avenue, Eveleigh, NSW, Australia
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5
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Duetschler A, Bauman G, Bieri O, Cattin PC, Ehrbar S, Engin-Deniz G, Giger A, Josipovic M, Jud C, Krieger M, Nguyen D, Persson GF, Salomir R, Weber DC, Lomax AJ, Zhang Y. Synthetic 4DCT(MRI) lung phantom generation for 4D radiotherapy and image guidance investigations. Med Phys 2022; 49:2890-2903. [PMID: 35239984 PMCID: PMC9313613 DOI: 10.1002/mp.15591] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/26/2021] [Accepted: 02/24/2022] [Indexed: 11/14/2022] Open
Abstract
Purpose Respiratory motion is one of the major challenges in radiotherapy. In this work, a comprehensive and clinically plausible set of 4D numerical phantoms, together with their corresponding “ground truths,” have been developed and validated for 4D radiotherapy applications. Methods The phantoms are based on CTs providing density information and motion from multi‐breathing‐cycle 4D Magnetic Resonance imagings (MRIs). Deformable image registration (DIR) has been utilized to extract motion fields from 4DMRIs and to establish inter‐subject correspondence by registering binary lung masks between Computer Tomography (CT) and MRI. The established correspondence is then used to warp the CT according to the 4DMRI motion. The resulting synthetic 4DCTs are called 4DCT(MRI)s. Validation of the 4DCT(MRI) workflow was conducted by directly comparing conventional 4DCTs to derived synthetic 4D images using the motion of the 4DCTs themselves (referred to as 4DCT(CT)s). Digitally reconstructed radiographs (DRRs) as well as 4D pencil beam scanned (PBS) proton dose calculations were used for validation. Results Based on the CT image appearance of 13 lung cancer patients and deformable motion of five volunteer 4DMRIs, synthetic 4DCT(MRI)s with a total of 871 different breathing cycles have been generated. The 4DCT(MRI)s exhibit an average superior–inferior tumor motion amplitude of 7 ± 5 mm (min: 0.5 mm, max: 22.7 mm). The relative change of the DRR image intensities of the conventional 4DCTs and the corresponding synthetic 4DCT(CT)s inside the body is smaller than 5% for at least 81% of the pixels for all studied cases. Comparison of 4D dose distributions calculated on 4DCTs and the synthetic 4DCT(CT)s using the same motion achieved similar dose distributions with an average 2%/2 mm gamma pass rate of 90.8% (min: 77.8%, max: 97.2%). Conclusion We developed a series of numerical 4D lung phantoms based on real imaging and motion data, which give realistic representations of both anatomy and motion scenarios and the accessible “ground truth” deformation vector fields of each 4DCT(MRI). The open‐source code and motion data allow foreseen users to generate further 4D data by themselves. These numeric 4D phantoms can be used for the development of new 4D treatment strategies, 4D dose calculations, DIR algorithm validations, as well as simulations of motion mitigation and different online image guidance techniques for both proton and photon radiation therapy.
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Affiliation(s)
- Alisha Duetschler
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland.,Department of Physics, ETH Zurich, Zurich, 8092, Switzerland
| | - Grzegorz Bauman
- Department of Biomedical Engineering, University of Basel, Allschwil, 4123, Switzerland.,Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, 4031, Switzerland
| | - Oliver Bieri
- Department of Biomedical Engineering, University of Basel, Allschwil, 4123, Switzerland.,Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, 4031, Switzerland
| | - Philippe C Cattin
- Department of Biomedical Engineering, University of Basel, Allschwil, 4123, Switzerland.,Center for medical Image Analysis & Navigation, University of Basel, Allschwil, 4123, Switzerland
| | - Stefanie Ehrbar
- Department of Radiation Oncology, University Hospital of Zurich, Zurich, 8091, Switzerland.,University of Zurich, Zurich, 8006, Switzerland
| | - Georg Engin-Deniz
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland.,Department of Physics, ETH Zurich, Zurich, 8092, Switzerland
| | - Alina Giger
- Department of Biomedical Engineering, University of Basel, Allschwil, 4123, Switzerland.,Center for medical Image Analysis & Navigation, University of Basel, Allschwil, 4123, Switzerland
| | - Mirjana Josipovic
- Department of Oncology, Rigshospitalet Copenhagen University Hospital, Copenhagen, 2100, Denmark
| | - Christoph Jud
- Department of Biomedical Engineering, University of Basel, Allschwil, 4123, Switzerland.,Center for medical Image Analysis & Navigation, University of Basel, Allschwil, 4123, Switzerland
| | - Miriam Krieger
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland.,Department of Physics, ETH Zurich, Zurich, 8092, Switzerland
| | - Damien Nguyen
- Department of Biomedical Engineering, University of Basel, Allschwil, 4123, Switzerland.,Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, 4031, Switzerland
| | - Gitte F Persson
- Department of Oncology, Rigshospitalet Copenhagen University Hospital, Copenhagen, 2100, Denmark.,Department of Oncology, Herlev-Gentofte Hospital Copenhagen University Hospital, Herlev, 2730, Denmark.,Department of Clinical Medicine, Faculty of Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Rares Salomir
- Image Guided Interventions Laboratory (949), Faculty of Medicine, University of Geneva, Geneva, 1211, Switzerland.,Radiology Division, University Hospitals of Geneva, Geneva, 1205, Switzerland
| | - Damien C Weber
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland.,Department of Radiation Oncology, University Hospital of Zurich, Zurich, 8091, Switzerland.,Department of Radiation Oncology, University of Bern, Bern, 3010, Switzerland
| | - Antony J Lomax
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland.,Department of Physics, ETH Zurich, Zurich, 8092, Switzerland
| | - Ye Zhang
- Center for Proton Therapy, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland
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Lydiard S, Pontré B, Hindley N, Lowe BS, Sasso G, Keall P. MRI-guided cardiac-induced target motion tracking for atrial fibrillation cardiac radioablation. Radiother Oncol 2021; 164:138-145. [PMID: 34597739 DOI: 10.1016/j.radonc.2021.09.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 09/13/2021] [Accepted: 09/22/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND AND PURPOSE Atrial fibrillation (AF) cardiac radioablation (CR) challenges radiotherapy tracking: multiple small targets close to organs-at-risk undergo rapid differential cardiac contraction and respiratory motion. MR-guidance offers a real-time target tracking solution. This work develops and investigates MRI-guided tracking of AF CR targets with cardiac-induced motion. MATERIALS AND METHODS A direct tracking method (Trackingdirect) and two indirect tracking methods leveraging population-based surrogacy relationships with the left atria (Trackingindirect_LA) or other target (Trackingindirect_target) were developed. Tracking performance was evaluated using transverse ECG-gated breathhold MRI images from 15 healthy and 10 AF participants. Geometric and volumetric tracking errors were calculated, defined as the difference between the ground-truth and tracked target centroids and volumes respectively. Transverse, breath-hold, noncardiac-gated cine images were acquired at 4 Hz in 5 healthy and 5 AF participants to qualitatively characterize tracking performance on images more comparable to MRILinac acquisitions. RESULTS The average 3D geometric tracking errors for Trackingdirect, Trackingindirect_LA and Trackingindirect_target respectively were 1.7 ± 1.2 mm, 1.6 ± 1.1 mm and 1.9 ± 1.3 mm in healthy participants and 1.7 ± 1.3 mm, 1.5 ± 1.0 mm and 1.7 ± 1.2 mm in AF participants. For Trackingdirect, 88% of analyzed images had 3D geometric tracking errors <3 mm and the average volume tracking error was 1.7 ± 1.3 cc. For Trackingdirect on non-cardiac-gated cine images, tracked targets overlapped organsat-risk or completely missed the target area on 2.2% and 0.08% of the images respectively. CONCLUSION The feasibility of non-invasive MRI-guided tracking of cardiac-induced AF CR target motion was demonstrated for the first time, showing potential for improving AF CR treatment efficacy.
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Affiliation(s)
- Suzanne Lydiard
- ACRF Image X Institute, University of Sydney, Eveleigh, Australia.
| | - Beau Pontré
- Department of Anatomy and Medical Imaging, University of Auckland, New Zealand
| | - Nicholas Hindley
- ACRF Image X Institute, University of Sydney, Eveleigh, Australia
| | - Boris S Lowe
- Green Lane Cardiovascular Service, Auckland City Hospital, New Zealand
| | - Giuseppe Sasso
- Department of Anatomy and Medical Imaging, University of Auckland, New Zealand; Radiation Oncology Department, Auckland City Hospital, New Zealand; Department of Oncology, University of Auckland, New Zealand
| | - Paul Keall
- ACRF Image X Institute, University of Sydney, Eveleigh, Australia
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Hindley N, Lydiard S, Shieh CC, Keall P. Proof-of-concept for x-ray based real-time image guidance during cardiac radioablation. Phys Med Biol 2021; 66. [PMID: 34315136 DOI: 10.1088/1361-6560/ac1834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/27/2021] [Indexed: 11/11/2022]
Abstract
Cardiac radioablation offers non-invasive treatments for refractory arrhythmias. However, treatment delivery for this technique remains challenging. In this paper, we introduce the first method for real-time image guidance during cardiac radioablation for refractory atrial fibrillation on a standard linear accelerator. Our proposed method utilizes direct diaphragm tracking on intrafraction images to estimate the respiratory component of cardiac substructure motion. We compare this method to treatment scenarios without real-time image guidance using the 4D-XCAT digital phantom. Pre-treatment and intrafraction imaging was simulated for 8 phantoms with unique anatomies programmed using cardiorespiratory motion from healthy volunteers. As every voxel in the 4D-XCAT phantom is labelled precisely according to the corresponding anatomical structure, this provided ground-truth for quantitative evaluation. Tracking performance was compared to the ground-truth for simulations with and without real-time image guidance using the left atrium as an exemplar target. Differences in target volume size, mean volumetric coverage, minimum volumetric coverage and geometric error were recorded for each simulation. We observed that differences in target volume size were statistically significant (p < 0.001) across treatment scenarios and that real-time image guidance enabled reductions in target volume size ranging from 11% to 24%. Differences in mean and minimum volumetric coverage were statistically insignificant (bothp = 0.35) while differences in geometric error were statistically significant (p = 0.039). The results of this study provide proof-of-concept for x-ray based real-time image guidance during cardiac radioablation.
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Affiliation(s)
| | - Suzanne Lydiard
- ACRF Image X Institute, University of Sydney, Sydney, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia
| | - Chun-Chien Shieh
- ACRF Image X Institute, University of Sydney, Sydney, Australia.,Sydney Neuroimaging Analysis Centre, University of Sydney, Sydney, Australia
| | - Paul Keall
- ACRF Image X Institute, University of Sydney, Sydney, Australia
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8
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Lydiard, PGDip S, Blanck O, Hugo G, O’Brien R, Keall P. A Review of Cardiac Radioablation (CR) for Arrhythmias: Procedures, Technology, and Future Opportunities. Int J Radiat Oncol Biol Phys 2021; 109:783-800. [DOI: 10.1016/j.ijrobp.2020.10.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/22/2020] [Accepted: 10/27/2020] [Indexed: 10/23/2022]
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9
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Kroll C, Dietrich O, Bortfeldt J, Kamp F, Neppl S, Belka C, Parodi K, Baroni G, Paganelli C, Riboldi M. Integration of spatial distortion effects in a 4D computational phantom for simulation studies in extra-cranial MRI-guided radiation therapy: Initial results. Med Phys 2020; 48:1646-1660. [PMID: 33220073 DOI: 10.1002/mp.14611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 12/18/2022] Open
Abstract
PURPOSE Spatial distortions in magnetic resonance imaging (MRI) are mainly caused by inhomogeneities of the static magnetic field, nonlinearities in the applied gradients, and tissue-specific magnetic susceptibility variations. These factors may significantly alter the geometrical accuracy of the reconstructed MR image, thus questioning the reliability of MRI for guidance in image-guided radiation therapy. In this work, we quantified MRI spatial distortions and created a quantitative model where different sources of distortions can be separated. The generated model was then integrated into a four-dimensional (4D) computational phantom for simulation studies in MRI-guided radiation therapy at extra-cranial sites. METHODS A geometrical spatial distortion phantom was designed in four modules embedding laser-cut PMMA grids, providing 3520 landmarks in a field of view of (345 × 260 × 480) mm3 . The construction accuracy of the phantom was verified experimentally. Two fast MRI sequences for extra-cranial imaging at 1.5 T were investigated, considering axial slices acquired with online distortion correction, in order to mimic practical use in MRI-guided radiotherapy. Distortions were separated into their sources by acquisition of images with gradient polarity reversal and dedicated susceptibility calculations. Such a separation yielded a quantitative spatial distortion model to be used for MR imaging simulations. Finally, the obtained spatial distortion model was embedded into an anthropomorphic 4D computational phantom, providing registered virtual CT/MR images where spatial distortions in MRI acquisition can be simulated. RESULTS The manufacturing accuracy of the geometrical distortion phantom was quantified to be within 0.2 mm in the grid planes and 0.5 mm in depth, including thickness variations and bending effects of individual grids. Residual spatial distortions after MRI distortion correction were strongly influenced by the applied correction mode, with larger effects in the trans-axial direction. In the axial plane, gradient nonlinearities caused the main distortions, with values up to 3 mm in a 1.5 T magnet, whereas static field and susceptibility effects were below 1 mm. The integration in the 4D anthropomorphic computational phantom highlighted that deformations can be severe in the region of the thoracic diaphragm, especially when using axial imaging with 2D distortion correction. Adaptation of the phantom based on patient-specific measurements was also verified, aiming at increased realism in the simulation. CONCLUSIONS The implemented framework provides an integrated approach for MRI spatial distortion modeling, where different sources of distortion can be quantified in time-dependent geometries. The computational phantom represents a valuable platform to study motion management strategies in extra-cranial MRI-guided radiotherapy, where the effects of spatial distortions can be modeled on synthetic images in a virtual environment.
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Affiliation(s)
- C Kroll
- Department of Medical Physics, Ludwig-Maximilians University, Garching, 85748, Germany
| | - O Dietrich
- Department of Radiology, University Hospital, LMU Munich, Munich, 81377, Germany
| | - J Bortfeldt
- Department of Medical Physics, Ludwig-Maximilians University, Garching, 85748, Germany.,European Organization for Nuclear Research (CERN), Geneva 23, 1211, Switzerland
| | - F Kamp
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, 81377, Germany
| | - S Neppl
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, 81377, Germany
| | - C Belka
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, 81377, Germany.,German Cancer Consortium (DKTK), Munich, 81377, Germany
| | - K Parodi
- Department of Medical Physics, Ludwig-Maximilians University, Garching, 85748, Germany
| | - G Baroni
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, 20133, Italy.,Bioengineering Unit, Centro Nazionale di Adroterapia Oncologica, Pavia, 27100, Italy
| | - C Paganelli
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, 20133, Italy
| | - M Riboldi
- Department of Medical Physics, Ludwig-Maximilians University, Garching, 85748, Germany
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10
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Blanck O, Buergy D, Vens M, Eidinger L, Zaman A, Krug D, Rudic B, Boda-Heggemann J, Giordano FA, Boldt LH, Mehrhof F, Budach V, Schweikard A, Olbrich D, König IR, Siebert FA, Vonthein R, Dunst J, Bonnemeier H. Radiosurgery for ventricular tachycardia: preclinical and clinical evidence and study design for a German multi-center multi-platform feasibility trial (RAVENTA). Clin Res Cardiol 2020; 109:1319-1332. [PMID: 32306083 PMCID: PMC7588361 DOI: 10.1007/s00392-020-01650-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/08/2020] [Indexed: 12/25/2022]
Abstract
Background Single-session high-dose stereotactic radiotherapy (radiosurgery) is a new treatment option for otherwise untreatable patients suffering from refractory ventricular tachycardia (VT). In the initial single-center case studies and feasibility trials, cardiac radiosurgery has led to significant reductions of VT burden with limited toxicities. However, the full safety profile remains largely unknown. Methods/design In this multi-center, multi-platform clinical feasibility trial which we plan is to assess the initial safety profile of radiosurgery for ventricular tachycardia (RAVENTA). High-precision image-guided single-session radiosurgery with 25 Gy will be delivered to the VT substrate determined by high-definition endocardial electrophysiological mapping. The primary endpoint is safety in terms of successful dose delivery without severe treatment-related side effects in the first 30 days after radiosurgery. Secondary endpoints are the assessment of VT burden, reduction of implantable cardioverter defibrillator (ICD) interventions [shock, anti-tachycardia pacing (ATP)], mid-term side effects and quality-of-life (QoL) in the first year after radiosurgery. The planned sample size is 20 patients with the goal of demonstrating safety and feasibility of cardiac radiosurgery in ≥ 70% of the patients. Quality assurance is provided by initial contouring and planning benchmark studies, joint multi-center treatment decisions, sequential patient safety evaluations, interim analyses, independent monitoring, and a dedicated data and safety monitoring board. Discussion RAVENTA will be the first study to provide the initial robust multi-center multi-platform prospective data on the therapeutic value of cardiac radiosurgery for ventricular tachycardia. Trial registration number NCT03867747 (clinicaltrials.gov). Registered March 8, 2019. The study was initiated on November 18th, 2019, and is currently recruiting patients. Graphic abstract ![]()
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Affiliation(s)
- Oliver Blanck
- Klinik für Strahlentherapie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany.
| | - Daniel Buergy
- Klinik für Strahlentherapie und Radioonkologie, Universitätsmedizin Mannheim, Universität Heidelberg, Medizinische Fakultät Mannheim, Mannheim, Germany
| | - Maren Vens
- Universität zu Lübeck, Zentrum für Klinische Studien, Lübeck, Germany.,Institut für Medizinische Biometrie und Statistik, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Lina Eidinger
- Klinik für Strahlentherapie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany.,Klinik für Innere Medizin III, Abteilung für Elektrophysiologie und Rhythmologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Adrian Zaman
- Klinik für Innere Medizin III, Abteilung für Elektrophysiologie und Rhythmologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - David Krug
- Klinik für Strahlentherapie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany
| | - Boris Rudic
- Medizinische Klinik I, Abteilung für Elektrophysiologie und Rhythmologie, Universitätsmedizin Mannheim, Universität Heidelberg, Medizinische Fakultät Mannheim, Mannheim, Germany
| | - Judit Boda-Heggemann
- Klinik für Strahlentherapie und Radioonkologie, Universitätsmedizin Mannheim, Universität Heidelberg, Medizinische Fakultät Mannheim, Mannheim, Germany
| | - Frank A Giordano
- Klinik für Strahlentherapie und Radioonkologie, Universitätsmedizin Mannheim, Universität Heidelberg, Medizinische Fakultät Mannheim, Mannheim, Germany
| | - Leif-Hendrik Boldt
- Medizinische Klinik mit Schwerpunkt Kardiologie (CVK), Abteilung für Elektrophysiologie und Rhythmologie, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Felix Mehrhof
- Klinik für Radioonkologie und Strahlentherapie, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Volker Budach
- Klinik für Radioonkologie und Strahlentherapie, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Achim Schweikard
- Institut für Robotik und Kognitive Systeme, Universität zu Lübeck, Lübeck, Germany
| | - Denise Olbrich
- Universität zu Lübeck, Zentrum für Klinische Studien, Lübeck, Germany
| | - Inke R König
- Institut für Medizinische Biometrie und Statistik, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Frank-Andre Siebert
- Klinik für Strahlentherapie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany
| | - Reinhard Vonthein
- Institut für Medizinische Biometrie und Statistik, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Jürgen Dunst
- Klinik für Strahlentherapie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany
| | - Hendrik Bonnemeier
- Klinik für Innere Medizin III, Abteilung für Elektrophysiologie und Rhythmologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Germany
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11
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Real-time control of respiratory motion: Beyond radiation therapy. Phys Med 2019; 66:104-112. [PMID: 31586767 DOI: 10.1016/j.ejmp.2019.09.241] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/23/2019] [Accepted: 09/26/2019] [Indexed: 12/16/2022] Open
Abstract
Motion management in radiation oncology is an important aspect of modern treatment planning and delivery. Special attention has been paid to control respiratory motion in recent years. However, other medical procedures related to both diagnosis and treatment are likely to benefit from the explicit control of breathing motion. Quantitative imaging - including increasingly important tools in radiology and nuclear medicine - is among the fields where a rapid development of motion control is most likely, due to the need for quantification accuracy. Emerging treatment modalities like focussed-ultrasound tumor ablation are also likely to benefit from a significant evolution of motion control in the near future. In the present article an overview of available respiratory motion systems along with ongoing research in this area is provided. Furthermore, an attempt is made to envision some of the most expected developments in this field in the near future.
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12
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Menten MJ, Fast MF, Wetscherek A, Rank CM, Kachelrieß M, Collins DJ, Nill S, Oelfke U. The impact of 2D cine MR imaging parameters on automated tumor and organ localization for MR-guided real-time adaptive radiotherapy. Phys Med Biol 2018; 63:235005. [PMID: 30465542 PMCID: PMC6372137 DOI: 10.1088/1361-6560/aae74d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/22/2018] [Accepted: 10/10/2018] [Indexed: 12/25/2022]
Abstract
2D cine MR imaging may be utilized to monitor rapidly moving tumors and organs-at-risk for real-time adaptive radiotherapy. This study systematically investigates the impact of geometric imaging parameters on the ability of 2D cine MR imaging to guide template-matching-driven autocontouring of lung tumors and abdominal organs. Abdominal 4D MR images were acquired of six healthy volunteers and thoracic 4D MR images were obtained of eight lung cancer patients. At each breathing phase of the images, the left kidney and gallbladder or lung tumor, respectively, were outlined as volumes of interest. These images and contours were used to create artificial 2D cine MR images, while simultaneously serving as 3D ground truth. We explored the impact of five different imaging parameters (pixel size, slice thickness, imaging plane orientation, number and relative alignment of images as well as strategies to create training images). For each possible combination of imaging parameters, we generated artificial 2D cine MR images as training and test images. A template-matching algorithm used the training images to determine the tumor or organ position in the test images. Subsequently, a 3D base contour was shifted to the determined position and compared to the ground truth via centroid distance and Dice similarity coefficient. The median centroid distance between adapted and ground truth contours was 1.56 mm for the kidney, 3.81 mm for the gallbladder and 1.03 mm for the lung tumor (median Dice similarity coefficient: 0.95, 0.72 and 0.93). We observed that a decrease in image resolution led to a modest decrease in localization accuracy, especially for the small gallbladder. However, for all volumes of interest localization accuracy varied substantially more between subjects than due to the different imaging parameters. Automated tumor and organ localization using 2D cine MR imaging and template-matching-based autocontouring is robust against variation of geometric imaging parameters. Future work and optimization efforts of 2D cine MR imaging for real-time adaptive radiotherapy is needed to characterize the influence of sequence- and anatomical site-specific imaging contrast.
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Affiliation(s)
- Martin J Menten
- Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Martin F Fast
- Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Andreas Wetscherek
- Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Christopher M Rank
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marc Kachelrieß
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - David J Collins
- Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Simeon Nill
- Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Uwe Oelfke
- Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
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13
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A hybrid graph-based approach for right ventricle segmentation in cardiac MRI by long axis information transition. Phys Med 2018; 54:103-116. [DOI: 10.1016/j.ejmp.2018.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 09/16/2018] [Accepted: 09/22/2018] [Indexed: 11/17/2022] Open
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