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Oar B, Brown A, Newman G, Boles A, Rumley CN, Doyle R, Baines J, Tan A. Improvement in male pelvis magnetic resonance image contouring following radiologist-delivered training. J Med Radiat Sci 2024; 71:114-122. [PMID: 37740640 PMCID: PMC10920942 DOI: 10.1002/jmrs.727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 09/07/2023] [Indexed: 09/24/2023] Open
Abstract
INTRODUCTION The magnetic resonance linear accelerator (MRL) combines both magnetic resonance imaging and a linear accelerator, allowing for daily treatment adaptation. This study aimed to assess the impact of radiologist-delivered training in magnetic resonance (MR) contouring of relevant structures within the male pelvis. METHODS Two radiation oncologists, two radiation oncology registrars and seven radiation therapists completed contouring on 10 male pelvis MR datasets both pre- and post-training. A 2-hour MR anatomy training session was delivered by a radiologist, who also provided the 'gold standard' contours. The pre- and post-training contours were compared against the gold standard with Dice similarity coefficient (DSC) and Hausdorff distances calculated; and the pre- and post-confidence scores and timing were compared. RESULTS The improvement in DSC were significant in prostate, rectum and seminal vesicles, with a post-training median DSC of 0.87 ± 0.06, 0.92 ± 0.04 and 0.80 ± 0.14, respectively. The median Hausdorff improved with a median of 1.46 ± 0.78 mm, 0.52 ± 0.32 mm and 1.11 ± 0.86 mm for prostate, rectum and seminal vesicles, respectively. Bladder concordance was high both pre- and post-training. Urethra contours improved post-training, however, remained difficult to contour with a median post-DSC of 0.51 ± 0.24. Overall, confidence scoring improved (P < 0.001) and timing decreased by an average of 4.4 ± 16.4 min post-training. CONCLUSION Radiologist-delivered training improved concordance of male pelvis contouring on MR datasets. Further work is required in the identification of urethra on MRs. These findings are of importance in the MRL adaptive workflow.
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Affiliation(s)
- Bronwyn Oar
- Townsville University HospitalTownsvilleQueenslandAustralia
| | - Amy Brown
- Townsville University HospitalTownsvilleQueenslandAustralia
- Queensland University of TechnologyBrisbaneQueenslandAustralia
- James Cook UniversityTownsvilleQueenslandAustralia
| | - Glen Newman
- Townsville University HospitalTownsvilleQueenslandAustralia
| | - Alan Boles
- Queensland XRayTownsvilleQueenslandAustralia
| | - Christopher N. Rumley
- Townsville University HospitalTownsvilleQueenslandAustralia
- James Cook UniversityTownsvilleQueenslandAustralia
| | - Rachel Doyle
- Townsville University HospitalTownsvilleQueenslandAustralia
| | - John Baines
- Townsville University HospitalTownsvilleQueenslandAustralia
- James Cook UniversityTownsvilleQueenslandAustralia
| | - Alex Tan
- Townsville University HospitalTownsvilleQueenslandAustralia
- James Cook UniversityTownsvilleQueenslandAustralia
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2
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Molière S, Hamzaoui D, Granger B, Montagne S, Allera A, Ezziane M, Luzurier A, Quint R, Kalai M, Ayache N, Delingette H, Renard-Penna R. Reference standard for the evaluation of automatic segmentation algorithms: Quantification of inter observer variability of manual delineation of prostate contour on MRI. Diagn Interv Imaging 2024; 105:65-73. [PMID: 37822196 DOI: 10.1016/j.diii.2023.08.001] [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: 05/02/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 10/13/2023]
Abstract
PURPOSE The purpose of this study was to investigate the relationship between inter-reader variability in manual prostate contour segmentation on magnetic resonance imaging (MRI) examinations and determine the optimal number of readers required to establish a reliable reference standard. MATERIALS AND METHODS Seven radiologists with various experiences independently performed manual segmentation of the prostate contour (whole-gland [WG] and transition zone [TZ]) on 40 prostate MRI examinations obtained in 40 patients. Inter-reader variability in prostate contour delineations was estimated using standard metrics (Dice similarity coefficient [DSC], Hausdorff distance and volume-based metrics). The impact of the number of readers (from two to seven) on segmentation variability was assessed using pairwise metrics (consistency) and metrics with respect to a reference segmentation (conformity), obtained either with majority voting or simultaneous truth and performance level estimation (STAPLE) algorithm. RESULTS The average segmentation DSC for two readers in pairwise comparison was 0.919 for WG and 0.876 for TZ. Variability decreased with the number of readers: the interquartile ranges of the DSC were 0.076 (WG) / 0.021 (TZ) for configurations with two readers, 0.005 (WG) / 0.012 (TZ) for configurations with three readers, and 0.002 (WG) / 0.0037 (TZ) for configurations with six readers. The interquartile range decreased slightly faster between two and three readers than between three and six readers. When using consensus methods, variability often reached its minimum with three readers (with STAPLE, DSC = 0.96 [range: 0.945-0.971] for WG and DSC = 0.94 [range: 0.912-0.957] for TZ, and interquartile range was minimal for configurations with three readers. CONCLUSION The number of readers affects the inter-reader variability, in terms of inter-reader consistency and conformity to a reference. Variability is minimal for three readers, or three readers represent a tipping point in the variability evolution, with both pairwise-based metrics or metrics with respect to a reference. Accordingly, three readers may represent an optimal number to determine references for artificial intelligence applications.
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Affiliation(s)
- Sébastien Molière
- Department of Radiology, Hôpitaux Universitaire de Strasbourg, Hôpital de Hautepierre, 67200, Strasbourg, France; Breast and Thyroid Imaging Unit, Institut de Cancérologie Strasbourg Europe, 67200, Strasbourg, France; IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67400, Illkirch, France.
| | - Dimitri Hamzaoui
- Inria, Epione Team, Sophia Antipolis, Université Côte d'Azur, 06902, Nice, France
| | - Benjamin Granger
- Sorbonne Université, INSERM, Institut Pierre Louis d'Epidémiologie et de Santé Publique, IPLESP, AP-HP, Hôpital Pitié Salpêtrière, Département de Santé Publique, 75013, Paris, France
| | - Sarah Montagne
- Department of Radiology, Hôpital Tenon, Assistance Publique-Hôpitaux de Paris, 75020, Paris, France; Department of Radiology, Hôpital Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris, 75013, Paris, France; GRC N° 5, Oncotype-Uro, Sorbonne Université, 75020, Paris, France
| | - Alexandre Allera
- Department of Radiology, Hôpital Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris, 75013, Paris, France
| | - Malek Ezziane
- Department of Radiology, Hôpital Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris, 75013, Paris, France
| | - Anna Luzurier
- Department of Radiology, Hôpital Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris, 75013, Paris, France
| | - Raphaelle Quint
- Department of Radiology, Hôpital Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris, 75013, Paris, France
| | - Mehdi Kalai
- Department of Radiology, Hôpital Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris, 75013, Paris, France
| | - Nicholas Ayache
- Department of Radiology, Hôpitaux Universitaire de Strasbourg, Hôpital de Hautepierre, 67200, Strasbourg, France
| | - Hervé Delingette
- Department of Radiology, Hôpitaux Universitaire de Strasbourg, Hôpital de Hautepierre, 67200, Strasbourg, France
| | - Raphaële Renard-Penna
- Department of Radiology, Hôpital Tenon, Assistance Publique-Hôpitaux de Paris, 75020, Paris, France; Department of Radiology, Hôpital Pitié-Salpétrière, Assistance Publique-Hôpitaux de Paris, 75013, Paris, France; GRC N° 5, Oncotype-Uro, Sorbonne Université, 75020, Paris, France
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Palacios MA, Gerganov G, Cobussen P, Tetar SU, Finazzi T, Slotman BJ, Senan S, Haasbeek CJ, Kawrakow I. Accuracy of deformable image registration-based intra-fraction motion management in Magnetic Resonance-guided radiotherapy. Phys Imaging Radiat Oncol 2023; 26:100437. [PMID: 37089906 PMCID: PMC10113900 DOI: 10.1016/j.phro.2023.100437] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/07/2023] Open
Abstract
Background and Purpose Intra-fraction motion management is key in Stereotactic Ablative Radiotherapy (SABR) gated delivery. This study assessed the accuracy of automatic tumor segmentation in the delivery of MR-guided radiotherapy (MRgRT) by comparing it to manual delineations performed by experienced observers. Materials and Methods Twenty patients previously treated with MR-guided SABR for thoracic and abdominal tumors were included. Five observers with at least two years of experience in MRgRT manually delineated the gross tumor volume (GTV) for 20 patients on 240 frames of a cine MRI on a sagittal plane. Deformable Image Registration (DIR) based GTV contours were propagated using four different algorithms from a reference frame to subsequent frames.Geometrical analysis based on the Dice Similarity Coefficient (DSC), centroid distance and Hausdorff Distance (HDD) were performed to assess the inter-observer variability and the accuracy of automatic segmentation. A Confidence Value (CV) metric for the reliability of the tumor auto-contouring was also calculated. Results Inter-observer delineation variability resulted in mean DSC of 0.89, HDD of 5.8 mm and centroid distance of 1.7 mm. Tumor auto-contouring by the four DIR algorithms resulted in an excellent agreement with the manual delineations by the experienced observers. Mean DSC for each algorithm across all patients was greater than 0.90, whereas the HDD and centroid distances were below 4.0 mm and 1.5 mm, respectively. The CV showed a strong correlation with the DSC. Conclusions DIR-based auto-contouring in MRgRT exhibited a high level of agreement with the manual contouring performed by experts, allowing accurate gated delivery.
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C Monte-Rubio G, Segura B, P Strafella A, van Eimeren T, Ibarretxe-Bilbao N, Diez-Cirarda M, Eggers C, Lucas-Jiménez O, Ojeda N, Peña J, Ruppert MC, Sala-Llonch R, Theis H, Uribe C, Junque C. Parameters from site classification to harmonize MRI clinical studies: Application to a multi-site Parkinson's disease dataset. Hum Brain Mapp 2022; 43:3130-3142. [PMID: 35305545 PMCID: PMC9188966 DOI: 10.1002/hbm.25838] [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: 08/01/2021] [Revised: 02/10/2022] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
Multi‐site MRI datasets are crucial for big data research. However, neuroimaging studies must face the batch effect. Here, we propose an approach that uses the predictive probabilities provided by Gaussian processes (GPs) to harmonize clinical‐based studies. A multi‐site dataset of 216 Parkinson's disease (PD) patients and 87 healthy subjects (HS) was used. We performed a site GP classification using MRI data. The outcomes estimated from this classification, redefined like Weighted HARMonization PArameters (WHARMPA), were used as regressors in two different clinical studies: A PD versus HS machine learning classification using GP, and a VBM comparison (FWE‐p < .05, k = 100). Same studies were also conducted using conventional Boolean site covariates, and without information about site belonging. The results from site GP classification provided high scores, balanced accuracy (BAC) was 98.39% for grey matter images. PD versus HS classification performed better when the WHARMPA were used to harmonize (BAC = 78.60%; AUC = 0.90) than when using the Boolean site information (BAC = 56.31%; AUC = 0.71) and without it (BAC = 57.22%; AUC = 0.73). The VBM analysis harmonized using WHARMPA provided larger and more statistically robust clusters in regions previously reported in PD than when the Boolean site covariates or no corrections were added to the model. In conclusion, WHARMPA might encode global site‐effects quantitatively and allow the harmonization of data. This method is user‐friendly and provides a powerful solution, without complex implementations, to clean the analyses by removing variability associated with the differences between sites.
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Affiliation(s)
- Gemma C Monte-Rubio
- Institute of Neurosciences, University of Barcelona, Barcelona, Catalonia, Spain.,Medical Psychology Unit, Department of Medicine, University of Barcelona, Barcelona, Catalonia, Spain
| | - Barbara Segura
- Institute of Neurosciences, University of Barcelona, Barcelona, Catalonia, Spain.,Medical Psychology Unit, Department of Medicine, University of Barcelona, Barcelona, Catalonia, Spain.,Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED: CB06/05/0018-ISCIII) Barcelona, Barcelona, Catalonia, Spain
| | - Antonio P Strafella
- Edmond J. Safra Parkinson Disease Program & Morton and Gloria Shulman Movement Disorder Unit, Neurology Division, University Health Network, University of Toronto, Toronto, Ontario, Canada.,Krembil Brain Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada.,Brain Health Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health University of Toronto, Toronto, Ontario, Canada
| | - Thilo van Eimeren
- Department of Nuclear Medicine, University of Cologne, Cologne, Germany.,Department of Neurology, University of Cologne, Cologne, Germany
| | - Naroa Ibarretxe-Bilbao
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Maria Diez-Cirarda
- Brain Health Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health University of Toronto, Toronto, Ontario, Canada
| | - Carsten Eggers
- Department of Neurology, University Hospital Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior - CMBB, Universities Marburg and Gießen, Marburg and Gießen, Germany.,Department of Neurology, Knappschaftskrankenhaus Bottrop, Bottrop, Germany
| | - Olaia Lucas-Jiménez
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Natalia Ojeda
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Javier Peña
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Marina C Ruppert
- Department of Neurology, University Hospital Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior - CMBB, Universities Marburg and Gießen, Marburg and Gießen, Germany
| | - Roser Sala-Llonch
- Institute of Neurosciences, University of Barcelona, Barcelona, Catalonia, Spain.,Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.,Department of Biomedicine, University of Barcelona, Barcelona, Catalonia, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Catalonia, Spain
| | - Hendrik Theis
- Department of Neurology, University of Cologne, Cologne, Germany
| | - Carme Uribe
- Institute of Neurosciences, University of Barcelona, Barcelona, Catalonia, Spain.,Medical Psychology Unit, Department of Medicine, University of Barcelona, Barcelona, Catalonia, Spain.,Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.,Brain Health Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health University of Toronto, Toronto, Ontario, Canada
| | - Carme Junque
- Institute of Neurosciences, University of Barcelona, Barcelona, Catalonia, Spain.,Medical Psychology Unit, Department of Medicine, University of Barcelona, Barcelona, Catalonia, Spain.,Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED: CB06/05/0018-ISCIII) Barcelona, Barcelona, Catalonia, Spain
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Federated learning for multi-center imaging diagnostics: a simulation study in cardiovascular disease. Sci Rep 2022; 12:3551. [PMID: 35241683 PMCID: PMC8894335 DOI: 10.1038/s41598-022-07186-4] [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: 07/05/2021] [Accepted: 02/02/2022] [Indexed: 12/25/2022] Open
Abstract
Deep learning models can enable accurate and efficient disease diagnosis, but have thus far been hampered by the data scarcity present in the medical world. Automated diagnosis studies have been constrained by underpowered single-center datasets, and although some results have shown promise, their generalizability to other institutions remains questionable as the data heterogeneity between institutions is not taken into account. By allowing models to be trained in a distributed manner that preserves patients’ privacy, federated learning promises to alleviate these issues, by enabling diligent multi-center studies. We present the first simulated federated learning study on the modality of cardiovascular magnetic resonance and use four centers derived from subsets of the M&M and ACDC datasets, focusing on the diagnosis of hypertrophic cardiomyopathy. We adapt a 3D-CNN network pretrained on action recognition and explore two different ways of incorporating shape prior information to the model, and four different data augmentation set-ups, systematically analyzing their impact on the different collaborative learning choices. We show that despite the small size of data (180 subjects derived from four centers), the privacy preserving federated learning achieves promising results that are competitive with traditional centralized learning. We further find that federatively trained models exhibit increased robustness and are more sensitive to domain shift effects.
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Kawula M, Purice D, Li M, Vivar G, Ahmadi SA, Parodi K, Belka C, Landry G, Kurz C. Dosimetric impact of deep learning-based CT auto-segmentation on radiation therapy treatment planning for prostate cancer. Radiat Oncol 2022; 17:21. [PMID: 35101068 PMCID: PMC8805311 DOI: 10.1186/s13014-022-01985-9] [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: 07/26/2021] [Accepted: 01/10/2022] [Indexed: 12/19/2022] Open
Abstract
Background The evaluation of automatic segmentation algorithms is commonly performed using geometric metrics. An analysis based on dosimetric parameters might be more relevant in clinical practice but is often lacking in the literature. The aim of this study was to investigate the impact of state-of-the-art 3D U-Net-generated organ delineations on dose optimization in radiation therapy (RT) for prostate cancer patients. Methods A database of 69 computed tomography images with prostate, bladder, and rectum delineations was used for single-label 3D U-Net training with dice similarity coefficient (DSC)-based loss. Volumetric modulated arc therapy (VMAT) plans have been generated for both manual and automatic segmentations with the same optimization settings. These were chosen to give consistent plans when applying perturbations to the manual segmentations. Contours were evaluated in terms of DSC, average and 95% Hausdorff distance (HD). Dose distributions were evaluated with the manual segmentation as reference using dose volume histogram (DVH) parameters and a 3%/3 mm gamma-criterion with 10% dose cut-off. A Pearson correlation coefficient between DSC and dosimetric metrics, i.e. gamma index and DVH parameters, has been calculated. Results 3D U-Net-based segmentation achieved a DSC of 0.87 (0.03) for prostate, 0.97 (0.01) for bladder and 0.89 (0.04) for rectum. The mean and 95% HD were below 1.6 (0.4) and below 5 (4) mm, respectively. The DVH parameters, V\documentclass[12pt]{minimal}
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\begin{document}$$_{60/65/70\,{\mathrm{Gy}}}$$\end{document}60/65/70Gy for the bladder and V\documentclass[12pt]{minimal}
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\begin{document}$$_{50/65/70\,{\mathrm{Gy}}}$$\end{document}50/65/70Gy for the rectum, showed agreement between dose distributions within \documentclass[12pt]{minimal}
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\begin{document}$$\pm \,2\%$$\end{document}±2%, respectively. The D\documentclass[12pt]{minimal}
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\begin{document}$$_{98/2\%}$$\end{document}98/2% and V\documentclass[12pt]{minimal}
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\begin{document}$$_{95\%}$$\end{document}95%, for prostate and its 3 mm expansion (surrogate clinical target volume) showed agreement with the reference dose distribution within 2% and 3 Gy with the exception of one case. The average gamma pass-rate was 85%. The comparison between geometric and dosimetric metrics showed no strong statistically significant correlation. Conclusions The 3D U-Net developed for this work achieved state-of-the-art geometrical performance. Analysis based on clinically relevant DVH parameters of VMAT plans demonstrated neither excessive dose increase to OARs nor substantial under/over-dosage of the target in all but one case. Yet the gamma analysis indicated several cases with low pass rates. The study highlighted the importance of adding dosimetric analysis to the standard geometric evaluation.
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Sadeghi S, Siavashpour Z, Vafaei Sadr A, Farzin M, Sharp R, Gholami S. A rapid review of influential factors and appraised solutions on organ delineation uncertainties reduction in radiotherapy. Biomed Phys Eng Express 2021; 7. [PMID: 34265746 DOI: 10.1088/2057-1976/ac14d0] [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: 05/10/2021] [Accepted: 07/15/2021] [Indexed: 11/11/2022]
Abstract
Background and purpose.Accurate volume delineation plays an essential role in radiotherapy. Contouring is a potential source of uncertainties in radiotherapy treatment planning that could affect treatment outcomes. Therefore, reducing the degree of contouring uncertainties is crucial. The role of utilized imaging modality in the organ delineation uncertainties has been investigated. This systematic review explores the influential factors on inter-and intra-observer uncertainties of target volume and organs at risk (OARs) delineation focusing on the used imaging modality for these uncertainties reduction and the reported subsequent histopathology and follow-up assessment.Methods and materials.An inclusive search strategy has been conducted to query the available online databases (Scopus, Google Scholar, PubMed, and Medline). 'Organ at risk', 'target', 'delineation', 'uncertainties', 'radiotherapy' and their relevant terms were utilized using every database searching syntax. Final article extraction was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Included studies were limited to the ones published in English between 1995 and 2020 and that just deal with computed tomography (CT) and magnetic resonance imaging (MRI) modalities.Results.A total of 923 studies were screened and 78 were included of which 31 related to the prostate 20 to the breast, 18 to the head and neck, and 9 to the brain tumor site. 98% of the extracted studies performed volumetric analysis. Only 24% of the publications reported the dose deviations resulted from variation in volume delineation Also, heterogeneity in studied populations and reported geometric and volumetric parameters were identified such that quantitative synthesis was not appropriate.Conclusion.This review highlightes the inter- and intra-observer variations that could lead to contouring uncertainties and impede tumor control in radiotherapy. For improving volume delineation and reducing inter-observer variability, the implementation of well structured training programs, homogeneity in following consensus and guidelines, reliable ground truth selection, and proper imaging modality utilization could be clinically beneficial.
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Affiliation(s)
- Sogand Sadeghi
- Department of Nuclear Physics, Faculty of Sciences, University of Mazandaran, Babolsar, Iran
| | - Zahra Siavashpour
- Department of Radiation Oncology, Shohada-e Tajrish Educational Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Alireza Vafaei Sadr
- Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, Geneva, Switzerland
| | - Mostafa Farzin
- Radiation Oncology Research Center (RORC), Tehran University of Medical Science, Tehran, Iran.,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ryan Sharp
- Department of Health Physics and Diagnostic Sciences, University of Nevada, Las Vegas, NV, United States of America
| | - Somayeh Gholami
- Radiotherapy Oncology Department, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
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Nowee ME, van Pelt VWJ, Walraven I, Simões R, Liskamp CP, Lambregts DMJ, Heijmink S, Schaake E, van der Heide UA, Janssen TM. The impact of image acquisition time on registration, delineation and image quality for magnetic resonance guided radiotherapy of prostate cancer patients. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2021; 19:85-89. [PMID: 34355071 PMCID: PMC8325094 DOI: 10.1016/j.phro.2021.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/03/2021] [Accepted: 07/01/2021] [Indexed: 12/22/2022]
Abstract
Background and Purpose Magnetic resonance (MR) guided radiotherapy utilizes MR images for (online) plan adaptation and image guidance. The aim of this study was to investigate the impact of variation in MR acquisition time and scan resolution on image quality, interobserver variation in contouring and interobserver variation in registration. Materials and Methods Nine patients with prostate cancer were included. Four T2-weighted 3D turbo spin echo (T2w 3D TSE) sequences were acquired with different acquisition times and resolutions. Two radiologists assessed image quality, conspicuity of the capsule, peripheral zone and central gland architecture and motion artefacts on a 5 point scale. Images were delineated by two radiation oncologists and interobserver variation was assessed by the 95% Hausdorff distance. Seven observers registered the MR images on the planning CT. Registrations were compared on systematic offset and interobserver variation. Results Acquisition times ranged between 1.3 and 6.3 min. Overall image quality and capsule definition were significantly worse for the MR sequence with an acquisition time of 1.3 min compared to the other sequences. Median 95% Hausdorff distance showed no significant differences in interobserver variation of contouring. Systematic offset and interobserver variation in registration were small (<1 mm) and of no clinical significance. Conclusions Our results can be used to effectively shorten overall fraction time for online adaptive MR guided radiotherapy by optimising the imaging sequence used for registration. From the sequences studied, a sequence of 3.1 min with anisotropic voxels of 1.2 × 1.2 × 2.4 mm3 provided the shortest acquisition time without compromising image quality.
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Affiliation(s)
- M E Nowee
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - V W J van Pelt
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - I Walraven
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - R Simões
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - C P Liskamp
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - D M J Lambregts
- Department of Radiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - S Heijmink
- Department of Radiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - E Schaake
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - U A van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - T M Janssen
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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Keyriläinen J, Sjöblom O, Turnbull-Smith S, Hovirinta T, Minn H. Clinical experience and cost evaluation of magnetic resonance imaging -only workflow in radiation therapy planning of prostate cancer. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2021; 19:66-71. [PMID: 34307921 PMCID: PMC8295845 DOI: 10.1016/j.phro.2021.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/31/2021] [Accepted: 07/01/2021] [Indexed: 12/24/2022]
Abstract
Using MRI-only for prostate cancer radiation therapy planning (RTP) can reduce costs. An MRI-only workflow is particularly suitable for medium-sized and large departments. Omitting CT in the RTP workflow saves scanner, staff, and patient time.
Background and purpose In radiation therapy (RT), significant improvements have been made recently particularly in the practices of planning imaging. This study aimed to conduct a cost evaluation between magnetic resonance imaging (MRI) -only and combined computed tomography (CT) and MRI workflows. Materials and methods The time-driven activity-based costing (TDABC) model was used to conduct a cost evaluation between the two workflows in those steps, where cost differences were expected. Costs were divided into capital costs and operational costs. The former consisted of fixed, one-time expenses, e.g. the purchase of a scanner, whereas the latter were partially based on the amount of activity consumed i.e. time required for image acquisition, image registration and structure contouring. Results In a review over a period of 10 years for 300 annual prostate cancer patients, the total cost of the workflow steps included in the study for an individual patient applying the MRI-only workflow was 903 € (100%), comprised of 537 € (59%) capital costs and 366 € (41%) operational costs. The corresponding total cost for an individual patient applying the CT + MRI workflow was 922 € (100%), comprised of 197 € (21%) capital costs and 726 € (79%) operational costs. In 10 years for 3000 patients, a total saving of 58,544 € (2%) was achieved with the MRI-only workflow compared with the dual imaging workflow. Conclusions MRI-only workflow is a feasible and economic way to perform clinical RT for localized prostate cancer, in particular for medium- and large-sized departments treating a sufficient number of patients.
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Affiliation(s)
- Jani Keyriläinen
- Department of Medical Physics, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
- Corresponding author at: Hämeentie 11, FIN-20521 Turku, Finland.
| | - Olli Sjöblom
- Turku University School of Economics, Information Systems Science, Rehtorinpellonkatu 3, FI-20500 Turku, Finland
| | - Sonja Turnbull-Smith
- Philips Oy, Philips Medical Systems MR Finland, Radiation Oncology Helsinki, Äyritie 4, FI-01510 Vantaa, Finland
| | - Taru Hovirinta
- Department of Finance, The Hospital District of Southwest Finland, Kiinamyllynkatu 4-8, FI-20521 Turku, Finland
| | - Heikki Minn
- Department of Oncology and Radiotherapy, Turku University Hospital, Hämeentie 11, FI-20521 Turku, Finland
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10
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Jenkins A, Mullen TS, Johnson-Hart C, Green A, McWilliam A, Aznar M, van Herk M, Vasquez Osorio E. Novel methodology to assess the effect of contouring variation on treatment outcome. Med Phys 2021; 48:3234-3242. [PMID: 33772803 DOI: 10.1002/mp.14865] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/24/2022] Open
Abstract
PURPOSE Contouring variation is one of the largest systematic uncertainties in radiotherapy, yet its effect on clinical outcome has never been analyzed quantitatively. We propose a novel, robust methodology to locally quantify target contour variation in a large patient cohort and find where this variation correlates with treatment outcome. We demonstrate its use on biochemical recurrence for prostate cancer patients. METHOD We propose to compare each patient's target contours to a consistent and unbiased reference. This reference was created by auto-contouring each patient's target using an externally trained deep learning algorithm. Local contour deviation measured from the reference to the manual contour was projected to a common frame of reference, creating contour deviation maps for each patient. By stacking the contour deviation maps, time to event was modeled pixel-wise using a multivariate Cox proportional hazards model (CPHM). Hazard ratio (HR) maps for each covariate were created, and regions of significance found using cluster-based permutation testing on the z-statistics. This methodology was applied to clinical target volume (CTV) contours, containing only the prostate gland, from 232 intermediate- and high-risk prostate cancer patients. The reference contours were created using ADMIRE® v3.4 (Elekta AB, Sweden). Local contour deviations were computed in a spherical coordinate frame, where differences between reference and clinical contours were projected in a 2D map corresponding to sampling across the coronal and transverse angles every 3°. Time to biochemical recurrence was modeled using the pixel-wise CPHM analysis accounting for contour deviation, patient age, Gleason score, and treated CTV volume. RESULTS We successfully applied the proposed methodology to a large patient cohort containing data from 232 patients. In this patient cohort, our analysis highlighted regions where the contour variation was related to biochemical recurrence, producing expected and unexpected results: (a) the interface between prostate-bladder and prostate-seminal vesicle interfaces where increase in the manual contour relative to the reference was related to a reduction of risk of biochemical recurrence by 4-8% per mm and (b) the prostate's right, anterior and posterior regions where an increase in the manual contour relative to the reference contours was related to an increase in risk of biochemical recurrence by 8-24% per mm. CONCLUSION We proposed and successfully applied a novel methodology to explore the correlation between contour variation and treatment outcome. We analyzed the effect of contour deviation of the prostate CTV on biochemical recurrence for a cohort of more than 200 prostate cancer patients while taking basic clinical variables into account. Applying this methodology to a larger dataset including additional clinically important covariates and externally validating it can more robustly identify regions where contour variation directly relates to treatment outcome. For example, in the prostate case we use to demonstrate our novel methodology, external validation will help confirm or reject the counter-intuitive results (larger contours resulting in higher risk). Ultimately, the results of this methodology could inform contouring protocols based on actual patient outcomes.
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Affiliation(s)
- Alexander Jenkins
- School of Physics & Astronomy - Faculty of Science and Engineering, University of Manchester, Manchester, M13 9PL, UK.,Division of Cancer Studies - School of Medical Sciences - Faculty of Biology- Medicine and Health, University of Manchester, Manchester, M20 4BX, UK
| | - Thomas Soares Mullen
- School of Physics & Astronomy - Faculty of Science and Engineering, University of Manchester, Manchester, M13 9PL, UK.,Champalimaud Research, Champalimaud Centre for the Unknown, Avenida Brasília, Doca de Pedrouços, Lisboa, 1400-038, Portugal
| | - Corinne Johnson-Hart
- Division of Cancer Studies - School of Medical Sciences - Faculty of Biology- Medicine and Health, University of Manchester, Manchester, M20 4BX, UK.,Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Wilmslow Road, Manchester, M20 4BX, UK
| | - Andrew Green
- Division of Cancer Studies - School of Medical Sciences - Faculty of Biology- Medicine and Health, University of Manchester, Manchester, M20 4BX, UK
| | - Alan McWilliam
- Division of Cancer Studies - School of Medical Sciences - Faculty of Biology- Medicine and Health, University of Manchester, Manchester, M20 4BX, UK
| | - Marianne Aznar
- Division of Cancer Studies - School of Medical Sciences - Faculty of Biology- Medicine and Health, University of Manchester, Manchester, M20 4BX, UK
| | - Marcel van Herk
- Division of Cancer Studies - School of Medical Sciences - Faculty of Biology- Medicine and Health, University of Manchester, Manchester, M20 4BX, UK
| | - Eliana Vasquez Osorio
- Division of Cancer Studies - School of Medical Sciences - Faculty of Biology- Medicine and Health, University of Manchester, Manchester, M20 4BX, UK
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11
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Patrick HM, Souhami L, Kildea J. Reduction of inter-observer contouring variability in daily clinical practice through a retrospective, evidence-based intervention. Acta Oncol 2021; 60:229-236. [PMID: 32988249 DOI: 10.1080/0284186x.2020.1825801] [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] [Indexed: 10/23/2022]
Abstract
BACKGROUND Inter-observer variations (IOVs) arising during contouring can potentially impact plan quality and patient outcomes. Regular assessment of contouring IOV is not commonly performed in clinical practice due to the large time commitment required of clinicians from conventional methods. This work uses retrospective information from past treatment plans to facilitate a time-efficient, evidence-based intervention to reduce contouring IOV. METHODS The contours of 492 prostate cancer treatment plans created by four radiation oncologists were analyzed in this study. Structure volumes, lengths, and DVHs were extracted from the treatment planning system and stratified based on primary oncologist and inclusion of a pelvic lymph node (PLN) target. Inter-observer variations and their dosimetric consequences were assessed using Student's t-tests. Results of this analysis were presented at an intervention meeting, where new consensus contour definitions were agreed upon. The impact of the intervention was assessed one-year later by repeating the analysis on 152 new plans. RESULTS Significant IOV in prostate and PLN target delineation existed pre-intervention between oncologists, impacting dose to nearby OARs. IOV was also present for rectum and penile-bulb structures. Post-intervention, IOV decreased for all previously discordant structures. Dosimetric variations were also reduced. Although target contouring concordance increased significantly, some variations still persisted for PLN structures, highlighting remaining areas for improvement. CONCLUSION We detected significant contouring IOV in routine practice using easily accessible retrospective data and successfully decreased IOV in our clinic through a reflective intervention. Continued application of this approach may aid improvements in practice standardization and enhance quality of care.
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Affiliation(s)
- H. M. Patrick
- Medical Physics Unit, McGill University, Montreal, Canada
| | - L. Souhami
- Department of Oncology, McGill University Health Centre, Montreal, Canada
| | - J. Kildea
- Medical Physics Unit, McGill University, Montreal, Canada
- Department of Oncology, McGill University Health Centre, Montreal, Canada
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12
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Sanford TH, Zhang L, Harmon SA, Sackett J, Yang D, Roth H, Xu Z, Kesani D, Mehralivand S, Baroni RH, Barrett T, Girometti R, Oto A, Purysko AS, Xu S, Pinto PA, Xu D, Wood BJ, Choyke PL, Turkbey B. Data Augmentation and Transfer Learning to Improve Generalizability of an Automated Prostate Segmentation Model. AJR Am J Roentgenol 2020; 215:1403-1410. [PMID: 33052737 PMCID: PMC8974988 DOI: 10.2214/ajr.19.22347] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE. Deep learning applications in radiology often suffer from overfitting, limiting generalization to external centers. The objective of this study was to develop a high-quality prostate segmentation model capable of maintaining a high degree of performance across multiple independent datasets using transfer learning and data augmentation. MATERIALS AND METHODS. A retrospective cohort of 648 patients who underwent prostate MRI between February 2015 and November 2018 at a single center was used for training and validation. A deep learning approach combining 2D and 3D architecture was used for training, which incorporated transfer learning. A data augmentation strategy was used that was specific to the deformations, intensity, and alterations in image quality seen on radiology images. Five independent datasets, four of which were from outside centers, were used for testing, which was conducted with and without fine-tuning of the original model. The Dice similarity coefficient was used to evaluate model performance. RESULTS. When prostate segmentation models utilizing transfer learning were applied to the internal validation cohort, the mean Dice similarity coefficient was 93.1 for whole prostate and 89.0 for transition zone segmentations. When the models were applied to multiple test set cohorts, the improvement in performance achieved using data augmentation alone was 2.2% for the whole prostate models and 3.0% for the transition zone segmentation models. However, the best test-set results were obtained with models fine-tuned on test center data with mean Dice similarity coefficients of 91.5 for whole prostate segmentation and 89.7 for transition zone segmentation. CONCLUSION. Transfer learning allowed for the development of a high-performing prostate segmentation model, and data augmentation and fine-tuning approaches improved performance of a prostate segmentation model when applied to datasets from external centers.
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Affiliation(s)
- Thomas H Sanford
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | | | - Stephanie A Harmon
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
- Clinical Research Directorate, Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Jonathan Sackett
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | | | | | - Ziyue Xu
- NVIDIA Corporation, Bethesda, MD
| | - Deepak Kesani
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | - Sherif Mehralivand
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | - Ronaldo H Baroni
- Diagnostic Imaging Department, Albert Einstein Hospital, Sao Paulo, Brazil
| | - Tristan Barrett
- University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | | | - Aytekin Oto
- Department of Radiology, University of Chicago, Chicago, IL
| | | | - Sheng Xu
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | - Peter A Pinto
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | | | - Bradford J Wood
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | - Peter L Choyke
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
| | - Baris Turkbey
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, Rm B3B85, Bethesda MD 20892
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13
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Eckl M, Hoppen L, Sarria GR, Boda-Heggemann J, Simeonova-Chergou A, Steil V, Giordano FA, Fleckenstein J. Evaluation of a cycle-generative adversarial network-based cone-beam CT to synthetic CT conversion algorithm for adaptive radiation therapy. Phys Med 2020; 80:308-316. [PMID: 33246190 DOI: 10.1016/j.ejmp.2020.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/29/2020] [Accepted: 11/05/2020] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Image-guided radiation therapy could benefit from implementing adaptive radiation therapy (ART) techniques. A cycle-generative adversarial network (cycle-GAN)-based cone-beam computed tomography (CBCT)-to-synthetic CT (sCT) conversion algorithm was evaluated regarding image quality, image segmentation and dosimetric accuracy for head and neck (H&N), thoracic and pelvic body regions. METHODS Using a cycle-GAN, three body site-specific models were priorly trained with independent paired CT and CBCT datasets of a kV imaging system (XVI, Elekta). sCT were generated based on first-fraction CBCT for 15 patients of each body region. Mean errors (ME) and mean absolute errors (MAE) were analyzed for the sCT. On the sCT, manually delineated structures were compared to deformed structures from the planning CT (pCT) and evaluated with standard segmentation metrics. Treatment plans were recalculated on sCT. A comparison of clinically relevant dose-volume parameters (D98, D50 and D2 of the target volume) and 3D-gamma (3%/3mm) analysis were performed. RESULTS The mean ME and MAE were 1.4, 29.6, 5.4 Hounsfield units (HU) and 77.2, 94.2, 41.8 HU for H&N, thoracic and pelvic region, respectively. Dice similarity coefficients varied between 66.7 ± 8.3% (seminal vesicles) and 94.9 ± 2.0% (lungs). Maximum mean surface distances were 6.3 mm (heart), followed by 3.5 mm (brainstem). The mean dosimetric differences of the target volumes did not exceed 1.7%. Mean 3D gamma pass rates greater than 97.8% were achieved in all cases. CONCLUSIONS The presented method generates sCT images with a quality close to pCT and yielded clinically acceptable dosimetric deviations. Thus, an important prerequisite towards clinical implementation of CBCT-based ART is fulfilled.
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Affiliation(s)
- Miriam Eckl
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany
| | - Lea Hoppen
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany.
| | - Gustavo R Sarria
- Department of Radiology and Radiation Oncology, University Hospital Bonn, Germany
| | - Judit Boda-Heggemann
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany
| | - Anna Simeonova-Chergou
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany
| | - Volker Steil
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany
| | - Frank A Giordano
- Department of Radiology and Radiation Oncology, University Hospital Bonn, Germany
| | - Jens Fleckenstein
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany
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14
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Pinto MS, Paolella R, Billiet T, Van Dyck P, Guns PJ, Jeurissen B, Ribbens A, den Dekker AJ, Sijbers J. Harmonization of Brain Diffusion MRI: Concepts and Methods. Front Neurosci 2020; 14:396. [PMID: 32435181 PMCID: PMC7218137 DOI: 10.3389/fnins.2020.00396] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 03/30/2020] [Indexed: 11/13/2022] Open
Abstract
MRI diffusion data suffers from significant inter- and intra-site variability, which hinders multi-site and/or longitudinal diffusion studies. This variability may arise from a range of factors, such as hardware, reconstruction algorithms and acquisition settings. To allow a reliable comparison and joint analysis of diffusion data across sites and over time, there is a clear need for robust data harmonization methods. This review article provides a comprehensive overview of diffusion data harmonization concepts and methods, and their limitations. Overall, the methods for the harmonization of multi-site diffusion images can be categorized in two main groups: diffusion parametric map harmonization (DPMH) and diffusion weighted image harmonization (DWIH). Whereas DPMH harmonizes the diffusion parametric maps (e.g., FA, MD, and MK), DWIH harmonizes the diffusion-weighted images. Defining a gold standard harmonization technique for dMRI data is still an ongoing challenge. Nevertheless, in this paper we provide two classification tools, namely a feature table and a flowchart, which aim to guide the readers in selecting an appropriate harmonization method for their study.
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Affiliation(s)
- Maíra Siqueira Pinto
- Department of Radiology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium.,imec-Vision Lab, University of Antwerp, Antwerp, Belgium
| | - Roberto Paolella
- imec-Vision Lab, University of Antwerp, Antwerp, Belgium.,Icometrix, Leuven, Belgium
| | | | - Pieter Van Dyck
- Department of Radiology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | | | - Ben Jeurissen
- imec-Vision Lab, University of Antwerp, Antwerp, Belgium
| | | | | | - Jan Sijbers
- imec-Vision Lab, University of Antwerp, Antwerp, Belgium
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15
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Kuisma A, Ranta I, Keyriläinen J, Suilamo S, Wright P, Pesola M, Warner L, Löyttyniemi E, Minn H. Validation of automated magnetic resonance image segmentation for radiation therapy planning in prostate cancer. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2020; 13:14-20. [PMID: 33458302 PMCID: PMC7807774 DOI: 10.1016/j.phro.2020.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/23/2019] [Accepted: 02/24/2020] [Indexed: 01/06/2023]
Abstract
Background and purpose Magnetic resonance imaging (MRI) is increasingly used in radiation therapy planning of prostate cancer (PC) to reduce target volume delineation uncertainty. This study aimed to assess and validate the performance of a fully automated segmentation tool (AST) in MRI based radiation therapy planning of PC. Material and methods Pelvic structures of 65 PC patients delineated in an MRI-only workflow according to established guidelines were included in the analysis. Automatic vs manual segmentation by an experienced oncologist was compared with geometrical parameters, such as the dice similarity coefficient (DSC). Fifteen patients had a second MRI within 15 days to assess repeatability of the AST for prostate and seminal vesicles. Furthermore, we investigated whether hormonal therapy or body mass index (BMI) affected the AST results. Results The AST showed high agreement with manual segmentation expressed as DSC (mean, SD) for delineating prostate (0.84, 0.04), bladder (0.92, 0.04) and rectum (0.86, 0.04). For seminal vesicles (0.56, 0.17) and penile bulb (0.69, 0.12) the respective agreement was moderate. Performance of AST was not influenced by neoadjuvant hormonal therapy, although those on treatment had significantly smaller prostates than the hormone-naïve patients (p < 0.0001). In repeat assessment, consistency of prostate delineation resulted in mean DSC of 0.89, (SD 0.03) between the paired MRI scans for AST, while mean DSC of manual delineation was 0.82, (SD 0.05). Conclusion Fully automated MRI segmentation tool showed good agreement and repeatability compared with manual segmentation and was found clinically robust in patients with PC. However, manual review and adjustment of some structures in individual cases remain important in clinical use.
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Affiliation(s)
- Anna Kuisma
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland
| | - Iiro Ranta
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland.,University of Turku, Department of Physics and Astronomy, Vesilinnantie 5, FI-20014 University of Turku, Finland
| | - Jani Keyriläinen
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland.,University of Turku, Department of Physics and Astronomy, Vesilinnantie 5, FI-20014 University of Turku, Finland
| | - Sami Suilamo
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland
| | - Pauliina Wright
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland.,Turku University Hospital, Department of Medical Physics, Hämeentie 11, FI-20521 Turku, Finland
| | - Marko Pesola
- Philips MR Therapy Oy, Äyritie 4, FI-01510 Vantaa, Finland
| | - Lizette Warner
- Philips MR Oncology, 3000 Minuteman Road, Andover, MA 01810, United States
| | - Eliisa Löyttyniemi
- University of Turku, Department of Biostatistics, Kiinamyllynkatu 10, FI-20014 University of Turku, Finland
| | - Heikki Minn
- Turku University Hospital, Department of Oncology and Radiotherapy, Hämeentie 11, FI-20521 Turku, Finland
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16
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Wong J, Fong A, McVicar N, Smith S, Giambattista J, Wells D, Kolbeck C, Giambattista J, Gondara L, Alexander A. Comparing deep learning-based auto-segmentation of organs at risk and clinical target volumes to expert inter-observer variability in radiotherapy planning. Radiother Oncol 2020; 144:152-158. [DOI: 10.1016/j.radonc.2019.10.019] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 12/29/2022]
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17
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Tanabe Y, Ishida T. Optimizing multiple acquisition planning CT for prostate cancer IMRT. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab0dc7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Pathmanathan AU, McNair HA, Schmidt MA, Brand DH, Delacroix L, Eccles CL, Gordon A, Herbert T, van As NJ, Huddart RA, Tree AC. Comparison of prostate delineation on multimodality imaging for MR-guided radiotherapy. Br J Radiol 2019; 92:20180948. [PMID: 30676772 PMCID: PMC6540870 DOI: 10.1259/bjr.20180948] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/14/2018] [Accepted: 12/18/2018] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE: With increasing incorporation of MRI in radiotherapy, we investigate two MRI sequences for prostate delineation in radiographer-led image guidance. METHODS: Five therapeutic radiographers contoured the prostate individually on CT, T2 weighted (T2W) and T2* weighted (T2*W) imaging for 10 patients. Contours were analysed with Monaco ADMIRE (research v. 2.0) to assess interobserver variability and accuracy by comparison with a gold standard clinician contour. Observers recorded time taken for contouring and scored image quality and confidence in contouring. RESULTS: There is good agreement when comparing radiographer contours to the gold-standard for all three imaging types with Dice similarity co-efficient 0.91-0.94, Cohen's κ 0.85-0.91, Hausdorff distance 4.6-7.6 mm and mean distance between contours 0.9-1.2 mm. In addition, there is good concordance between radiographers across all imaging modalities. Both T2W and T2*W MRI show reduced interobserver variability and improved accuracy compared to CT, this was statistically significant for T2*W imaging compared to CT across all four comparison metrics. Comparing MRI sequences reveals significantly reduced interobserver variability and significantly improved accuracy on T2*W compared to T2W MRI for DSC and Cohen's κ. Both MRI sequences scored significantly higher compared to CT for image quality and confidence in contouring, particularly T2*W. This was also reflected in the shorter time for contouring, measuring 15.4, 9.6 and 9.8 min for CT, T2W and T2*W MRI respectively. Conclusion: Therapeutic radiographer prostate contours are more accurate, show less interobserver variability and are more confidently and quickly outlined on MRI compared to CT, particularly using T2*W MRI. Advances in knowledge: Our work is relevant for MRI sequence choice and development of the roles of the interprofessional team in the advancement of MRI-guided radiotherapy.
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Affiliation(s)
| | - Helen A McNair
- The Royal Marsden Hospital NHS Foundation Trust, Downs Road, Sutton, United Kingdom
| | | | | | - Louise Delacroix
- The Royal Marsden Hospital NHS Foundation Trust, Downs Road, Sutton, United Kingdom
| | | | - Alexandra Gordon
- The Royal Marsden Hospital NHS Foundation Trust, Downs Road, Sutton, United Kingdom
| | - Trina Herbert
- The Royal Marsden Hospital NHS Foundation Trust, Downs Road, Sutton, United Kingdom
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19
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Olsson LE, Johansson M, Zackrisson B, Blomqvist LK. Basic concepts and applications of functional magnetic resonance imaging for radiotherapy of prostate cancer. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2019; 9:50-57. [PMID: 33458425 PMCID: PMC7807726 DOI: 10.1016/j.phro.2019.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/27/2018] [Accepted: 02/08/2019] [Indexed: 12/30/2022]
Abstract
Recently, the interest to integrate magnetic resonance imaging (MRI) in radiotherapy for prostate cancer has increased considerably. MRI can contribute in all steps of the radiotherapy workflow from diagnosis, staging, and target definition to treatment follow-up. Of particular interest is the ability of MRI to provide a wide range of functional measures. The complexity of MRI as an imaging modality combined with the growing interest of the application to prostate cancer radiotherapy, emphasize the need for dedicated education within the radiation oncology community. In this context, an overview of the most common as well as a few upcoming functional MR imaging techniques is presented: the basic methodology and measurement is described, the link between the functional measures and the underlying biology is established, and finally relevant applications of functional MRI useful for prostate cancer radiotherapy are given.
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Affiliation(s)
- Lars E Olsson
- Department of Medical Radiation Physics, Translational Medicine, Lund University, Sweden.,Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden
| | | | | | - Lennart K Blomqvist
- Department of Radiology, Molecular Medicine and Surgery, Karolinska University, Sweden
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Pathmanathan AU, Schmidt MA, Brand DH, Kousi E, van As NJ, Tree AC. Improving fiducial and prostate capsule visualization for radiotherapy planning using MRI. J Appl Clin Med Phys 2019; 20:27-36. [PMID: 30756456 PMCID: PMC6414142 DOI: 10.1002/acm2.12529] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 11/06/2018] [Accepted: 12/10/2018] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Intraprostatic fiducial markers (FM) improve the accuracy of radiotherapy (RT) delivery. Here we assess geometric integrity and contouring consistency using a T2*-weighted (T2*W) sequence alone, which allows visualization of the FM. MATERIAL AND METHODS Ten patients scanned within the Prostate Advances in Comparative Evidence (PACE) trial (NCT01584258) had prostate images acquired with computed tomography (CT) and Magnetic Resonance (MR) Imaging: T2-weighted (T2W) and T2*W sequences. The prostate was contoured independently on each imaging dataset by three clinicians. Interobserver variability was assessed using comparison indices with Monaco ADMIRE (research version 2.0, Elekta AB) and examined for statistical differences between imaging sets. CT and MR images of two test objects were acquired to assess geometric distortion and accuracy of marker positioning. The first was a linear test object comprising straight tubes in three orthogonal directions, the second was a smaller test object with markers suspended in gel. RESULTS Interobserver variability for prostate contouring was lower for both T2W and T2*W compared to CT, this was statistically significant when comparing CT and T2*W images. All markers are visible in T2*W images with 29/30 correctly identified, only 3/30 are visible in T2W images. Assessment of geometric distortion revealed in-plane displacements were under 0.375 mm in MRI, and through plane displacements could not be detected. The signal loss in the MR images is symmetric in relation to the true marker position shown in CT images. CONCLUSION Prostate T2*W images are geometrically accurate, and yield consistent prostate contours. This single sequence can be used to identify FM and for prostate delineation in a mixed MR-CT workflow.
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Affiliation(s)
- Angela U Pathmanathan
- The Royal Marsden Hospital NHS Foundation Trust, London, UK.,The Institute of Cancer Research, London, UK
| | - Maria A Schmidt
- The Royal Marsden Hospital NHS Foundation Trust, London, UK.,The Institute of Cancer Research, London, UK
| | - Douglas H Brand
- The Royal Marsden Hospital NHS Foundation Trust, London, UK.,The Institute of Cancer Research, London, UK
| | - Evanthia Kousi
- The Royal Marsden Hospital NHS Foundation Trust, London, UK.,The Institute of Cancer Research, London, UK
| | - Nicholas J van As
- The Royal Marsden Hospital NHS Foundation Trust, London, UK.,The Institute of Cancer Research, London, UK
| | - Alison C Tree
- The Royal Marsden Hospital NHS Foundation Trust, London, UK.,The Institute of Cancer Research, London, UK
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21
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Dinis Fernandes C, Dinh CV, Walraven I, Heijmink SW, Smolic M, van Griethuysen JJM, Simões R, Losnegård A, van der Poel HG, Pos FJ, van der Heide UA. Biochemical recurrence prediction after radiotherapy for prostate cancer with T2w magnetic resonance imaging radiomic features. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 7:9-15. [PMID: 33458399 PMCID: PMC7807756 DOI: 10.1016/j.phro.2018.06.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 06/06/2018] [Accepted: 06/14/2018] [Indexed: 11/30/2022]
Abstract
Background and purpose High-risk prostate cancer patients are frequently treated with external-beam radiotherapy (EBRT). Of all patients receiving EBRT, 15–35% will experience biochemical recurrence (BCR) within five years. Magnetic resonance imaging (MRI) is commonly acquired as part of the diagnostic procedure and imaging-derived features have shown promise in tumour characterisation and biochemical recurrence prediction. We investigated the value of imaging features extracted from pre-treatment T2w anatomical MRI to predict five year biochemical recurrence in high-risk patients treated with EBRT. Materials and methods In a cohort of 120 high-risk patients, imaging features were extracted from the whole-prostate and a margin surrounding it. Intensity, shape and textural features were extracted from the original and filtered T2w-MRI scans. The minimum-redundancy maximum-relevance algorithm was used for feature selection. Random forest and logistic regression classifiers were used in our experiments. The performance of a logistic regression model using the patient’s clinical features was also investigated. To assess the prediction accuracy we used stratified 10-fold cross validation and receiver operating characteristic analysis, quantified by the area under the curve (AUC). Results A logistic regression model built using whole-prostate imaging features obtained an AUC of 0.63 in the prediction of BCR, outperforming a model solely based on clinical variables (AUC = 0.51). Combining imaging and clinical features did not outperform the accuracy of imaging alone. Conclusions These results illustrate the potential of imaging features alone to distinguish patients with an increased risk of recurrence, even in a clinically homogeneous cohort.
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Affiliation(s)
| | - Cuong V Dinh
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Iris Walraven
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Stijn W Heijmink
- Department of Radiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Milena Smolic
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Joost J M van Griethuysen
- Department of Radiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,GROW - School of Oncology and Developmental Biology, Maastricht University, Maastricht, The Netherlands
| | - Rita Simões
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Are Losnegård
- University of Bergen, Norway.,Haukeland University Hospital, Bergen, Norway
| | - Henk G van der Poel
- Department of Urology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Floris J Pos
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Uulke A van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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22
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Nyholm T, Svensson S, Andersson S, Jonsson J, Sohlin M, Gustafsson C, Kjellén E, Söderström K, Albertsson P, Blomqvist L, Zackrisson B, Olsson LE, Gunnlaugsson A. MR and CT data with multiobserver delineations of organs in the pelvic area-Part of the Gold Atlas project. Med Phys 2018; 45:1295-1300. [DOI: 10.1002/mp.12748] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/20/2017] [Accepted: 12/20/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Tufve Nyholm
- Department of Radiation Sciences; Umeå University; Umeå Sweden
| | | | | | - Joakim Jonsson
- Department of Radiation Sciences; Umeå University; Umeå Sweden
| | - Maja Sohlin
- Department of Radiation Physics; Institute of Clinical Sciences; Sahlgrenska University Hospital; Göteborg Sweden
| | - Christian Gustafsson
- Department of Hematology, Oncology and Radiation Physics; Skåne University Hospital; Lund Sweden
- Department of Medical Physics; Lund University; Malmö Sweden
| | - Elisabeth Kjellén
- Department of Hematology, Oncology and Radiation Physics; Skåne University Hospital; Lund Sweden
| | | | - Per Albertsson
- Department of Oncology; Institute of Clinical Sciences; Sahlgrenska Academy; University of Gothenburg; Gothenburg Sweden
| | - Lennart Blomqvist
- Department of Radiation Sciences; Umeå University; Umeå Sweden
- Department of Molecular Medicine and Surgery; Karolinska Institutet; Stockholm Sweden
| | | | - Lars E. Olsson
- Department of Hematology, Oncology and Radiation Physics; Skåne University Hospital; Lund Sweden
| | - Adalsteinn Gunnlaugsson
- Department of Hematology, Oncology and Radiation Physics; Skåne University Hospital; Lund Sweden
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23
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Kershaw L, van Zadelhoff L, Heemsbergen W, Pos F, van Herk M. Image Guided Radiation Therapy Strategies for Pelvic Lymph Node Irradiation in High-Risk Prostate Cancer: Motion and Margins. Int J Radiat Oncol Biol Phys 2018; 100:68-77. [DOI: 10.1016/j.ijrobp.2017.08.044] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 08/02/2017] [Accepted: 08/30/2017] [Indexed: 02/07/2023]
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Abstract
The use of prostate MR imaging in radiotherapy continues to evolve. This article describes its current application in the selection of treatment regimens, integration in treatment planning or simulation, and assessment of response. An expert consensus statement from the annual MR in RT symposium is presented, as a list of 21 key quality indicators for the practice of MR imaging simulation in prostate cancer. Although imaging requirements generally follow PIRADSv2 guidelines, additional requirements specific to radiotherapy planning are described. MR imaging-only workflows and MR imaging-guided treatment systems are expected to replace conventional computed tomography-based practice, further adding specific requirements for MR imaging in radiotherapy.
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25
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Tyagi N, Fontenla S, Zelefsky M, Chong-Ton M, Ostergren K, Shah N, Warner L, Kadbi M, Mechalakos J, Hunt M. Clinical workflow for MR-only simulation and planning in prostate. Radiat Oncol 2017; 12:119. [PMID: 28716090 PMCID: PMC5513123 DOI: 10.1186/s13014-017-0854-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 07/06/2017] [Indexed: 11/22/2022] Open
Abstract
Purpose To describe the details and experience of implementing a MR-only workflow in the clinic for simulation and planning of prostate cancer patients. Methods Forty-eight prostate cancer patients from June 2016 - Dec 2016 receiving external beam radiotherapy were scheduled to undergo MR-only simulation. MR images were acquired for contouring (T2w axial, coronal, sagittal), synthetic-CT generation (3D FFE-based) and fiducial identification (3D bFFE-based). The total acquisition time was 25 min. Syn-CT was generated at the console using commercial software called MRCAT. As part of acceptance testing of the MRCAT package, external laser positioning system QA (< 2 mm) and geometric fidelity QA (< 2 mm within 50 cm LR and 30 cm AP) were performed and baseline values were set. Our current combined CT + MR simulation process was modified to accommodate a MRCAT-based MR-only simulation workflow. An automated step-by-step process using a MIM™ workflow was created for contouring on the MR images. Patient setup for treatment was achieved by matching the MRCAT DRRs with the orthogonal KV radiographs based on either fiducial ROIs or bones. 3-D CBCTs were acquired and compared with the MR/syn-CT to assess the rectum and bladder filling compared to simulation conditions. Results Forty-two patients successfully underwent MR-only simulation and met all of our institutional dosimetric objectives that were developed based on a CT + MR-based workflow. The remaining six patients either had a hip prosthesis or their large body size fell outside of the geometric fidelity QA criteria and thus they were not candidates for MR-only simulation. A total time saving of ~15 min was achieved with MR-based simulation as compared to CT + MR-based simulation. An automated and organized MIM workflow made contouring on MR much easier, quicker and more accurate compared with combined CT + MR images because the temporal variations in normal structure was minimal. 2D and 3D treatment setup localization based on bones/fiducials using a MRCAT reference image was successfully achieved for all cases. Conclusions MR-only simulation and planning with equivalent or superior target delineation, planning and treatment setup localization accuracy is feasible in a clinical setting. Future work will focus on implementing a robust 3D isotropic acquisition for contouring. Electronic supplementary material The online version of this article (doi:10.1186/s13014-017-0854-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Neelam Tyagi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
| | - Sandra Fontenla
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Michael Zelefsky
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Marcia Chong-Ton
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | | | - Niral Shah
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Lizette Warner
- Philips Healthcare, 595 Milner Road, Cleveland, OH, 44143, USA
| | - Mo Kadbi
- Philips Healthcare, 595 Milner Road, Cleveland, OH, 44143, USA
| | - Jim Mechalakos
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Margie Hunt
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
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26
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Harvey H, Orton MR, Morgan VA, Parker C, Dearnaley D, Fisher C, deSouza NM. Volumetry of the dominant intraprostatic tumour lesion: intersequence and interobserver differences on multiparametric MRI. Br J Radiol 2017; 90:20160416. [PMID: 28055249 PMCID: PMC5601508 DOI: 10.1259/bjr.20160416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/10/2016] [Accepted: 01/03/2017] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE To establish the interobserver reproducibility of tumour volumetry on individual multiparametric (mp) prostate MRI sequences, validate measurements with histology and determine whether functional to morphological volume ratios reflect Gleason score. METHODS 41 males with prostate cancer treated with prostatectomy (Cohort 1) or radical radiotherapy (Cohort 2), who had pre-treatment mpMRI [T2 weighted (T2W) MRI, diffusion-weighted (DW)-MRI and dynamic contrast-enhanced (DCE)-MRI], were studied retrospectively. Dominant intraprostatic lesions (DIPLs) were manually delineated on each sequence and volumes were compared between observers (n = 40 analyzable) and with radical prostatectomy (n = 20). Volume ratios of DW-MRI and DCE-MRI to T2W MRI were documented and compared between Gleason grade 3 + 3, 3 + 4 and 4 + 3 or greater categories. RESULTS Limits of agreement of DIPL volumes between observers were: T2W MRI 0.9, -1.1 cm3, DW-MRI 1.3, -1.7 cm3 and DCE-MRI 0.74, -0.89 cm3. In Cohort 1, T2W volumes overestimated fixed specimen histological volumes (+33% Observer 1, +16% Observer 2); DW- and DCE-MRI underestimated histological volume, the latter markedly so (-32% Observer 1, -79% Observer 2). Differences between T2W, DW- and DCE-MRI volumes were significant (p < 10-8). The ratio of DW-MRI volume (73.9 ± 18.1% Observer 1, 72.5 ± 21.9% Observer 2) and DCE-MRI volume (42.6 ± 24.6% Observer 1, 34.3 ± 24.9% Observer 2) to T2W volume was significantly different (p < 10-8), but these volume ratios did not differ between the Gleason grades. CONCLUSION The low variability of the DIPL volume on T2W MRI between Observers and agreement with histology indicates its suitability for delineation of gross tumour volume for radiotherapy planning. The volume of cellular tumour represented by DW-MRI is greater than the vascular (DCE) abnormality; ratios of both to T2W volume are independent of Gleason score. Advances in knowledge: (1) Manual volume measurement of tumour is reproducible within 1 cm3 between observers on all sequences, confirming suitability across observers for radiotherapy planning. (2) Volumes derived on T2W MRI most accurately represent in vivo lesion volumes. (3) The proportion of cellular (DW-MRI) or vascular (DCE-MRI) volume to morphological (T2W MRI) volume is not affected by Gleason score.
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Affiliation(s)
- Hugh Harvey
- Cancer Research UK Imaging Centre, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | - Matthew R Orton
- Cancer Research UK Imaging Centre, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | - Veronica A Morgan
- Cancer Research UK Imaging Centre, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | - Chris Parker
- Academic Urology Unit, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | - David Dearnaley
- Academic Urology Unit, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | - Cyril Fisher
- Department of Histopathology, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | - Nandita M deSouza
- Cancer Research UK Imaging Centre, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
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27
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Tyagi N, Fontenla S, Zhang J, Cloutier M, Kadbi M, Mechalakos J, Zelefsky M, Deasy J, Hunt M. Dosimetric and workflow evaluation of first commercial synthetic CT software for clinical use in pelvis. Phys Med Biol 2016; 62:2961-2975. [PMID: 27983520 DOI: 10.1088/1361-6560/aa5452] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy. Twenty-five prostate patients underwent CT and MR simulation scans in treatment position on a 3T MR scanner. A commercially available MR protocol was used that included a T2w turbo spin-echo sequence for soft-tissue contrast and a dual echo 3D mDIXON fast field echo (FFE) sequence for generating syn-CT. A dual-echo 3D FFE B 0 map was used for patient-induced susceptibility distortion analysis and a new 3D balanced-FFE sequence was evaluated for identification of implanted gold fiducial markers and subsequent image-guidance during radiotherapy delivery. Tissues were classified as air, adipose, water, trabecular/spongy bone and compact/cortical bone and assigned bulk HU values. The accuracy of syn-CT for treatment planning was analyzed by transferring the structures and plan from planning CT to syn-CT and recalculating the dose. Accuracy of localization at the treatment machine was evaluated by comparing registration of kV radiographs to either digitally reconstructed radiographs (DRRs) generated from syn-CT or traditional DRRs generated from the planning CT. Similarly, accuracy of setup using CBCT and syn-CT was compared to that using the planning CT. Finally, a MR-only simulation workflow was established and end-to-end testing was completed on five patients undergoing MR-only simulation. Dosimetric comparison between the original CT and syn-CT plans was within 0.5% on average for all structures. The de-novo optimized plans on the syn-CT met institutional clinical objectives for target and normal structures. Patient-induced susceptibility distortion based on B 0 maps was within 1 mm and 0.5 mm in the body and prostate respectively. DRR and CBCT localization based on MR-localized fiducials showed a standard deviation of <1 mm. End-to-end testing and MR simulation workflow was successfully validated. MRI derived synthetic CT can be successfully used for a MR-only planning and treatment for prostate radiotherapy.
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Affiliation(s)
- Neelam Tyagi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, NY, NY 10065, United States of America
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28
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Vinod SK, Jameson MG, Min M, Holloway LC. Uncertainties in volume delineation in radiation oncology: A systematic review and recommendations for future studies. Radiother Oncol 2016; 121:169-179. [PMID: 27729166 DOI: 10.1016/j.radonc.2016.09.009] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/27/2016] [Accepted: 09/25/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE Volume delineation is a well-recognised potential source of error in radiotherapy. Whilst it is important to quantify the degree of interobserver variability (IOV) in volume delineation, the resulting impact on dosimetry and clinical outcomes is a more relevant endpoint. We performed a literature review of studies evaluating IOV in target volume and organ-at-risk (OAR) delineation in order to analyse these with respect to the metrics used, reporting of dosimetric consequences, and use of statistical tests. METHODS AND MATERIALS Medline and Pubmed databases were queried for relevant articles using keywords. We included studies published in English between 2000 and 2014 with more than two observers. RESULTS 119 studies were identified covering all major tumour sites. CTV (n=47) and GTV (n=38) were most commonly contoured. Median number of participants and data sets were 7 (3-50) and 9 (1-132) respectively. There was considerable heterogeneity in the use of metrics and methods of analysis. Statistical analysis of results was reported in 68% (n=81) and dosimetric consequences in 21% (n=25) of studies. CONCLUSION There is a lack of consistency in conducting and reporting analyses from IOV studies. We suggest a framework to use for future studies evaluating IOV.
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Affiliation(s)
- Shalini K Vinod
- Cancer Therapy Centre, Liverpool Hospital, Australia; South Western Sydney Clinical School, University of New South Wales, Australia; Western Sydney University, Australia.
| | - Michael G Jameson
- Cancer Therapy Centre, Liverpool Hospital, Australia; Ingham Institute of Applied Medical Research, Liverpool Hospital, Australia; Centre for Medical Radiation Physics, University of Wollongong, Australia
| | - Myo Min
- Cancer Therapy Centre, Liverpool Hospital, Australia; South Western Sydney Clinical School, University of New South Wales, Australia; Ingham Institute of Applied Medical Research, Liverpool Hospital, Australia
| | - Lois C Holloway
- Cancer Therapy Centre, Liverpool Hospital, Australia; South Western Sydney Clinical School, University of New South Wales, Australia; Ingham Institute of Applied Medical Research, Liverpool Hospital, Australia; Centre for Medical Radiation Physics, University of Wollongong, Australia
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29
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Vinod SK, Min M, Jameson MG, Holloway LC. A review of interventions to reduce inter-observer variability in volume delineation in radiation oncology. J Med Imaging Radiat Oncol 2016; 60:393-406. [DOI: 10.1111/1754-9485.12462] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/16/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Shalini K Vinod
- Cancer Therapy Centre; Liverpool Hospital; Liverpool New South Wales Australia
- South Western Sydney Clinical School; University of NSW; Sydney New South Wales Australia
- Western Sydney University; Sydney New South Wales Australia
| | - Myo Min
- Cancer Therapy Centre; Liverpool Hospital; Liverpool New South Wales Australia
- South Western Sydney Clinical School; University of NSW; Sydney New South Wales Australia
| | - Michael G Jameson
- Cancer Therapy Centre; Liverpool Hospital; Liverpool New South Wales Australia
- Ingham Institute of Applied Medical Research; Liverpool Hospital; Liverpool New South Wales Australia
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong New South Wales Australia
| | - Lois C Holloway
- Cancer Therapy Centre; Liverpool Hospital; Liverpool New South Wales Australia
- South Western Sydney Clinical School; University of NSW; Sydney New South Wales Australia
- Western Sydney University; Sydney New South Wales Australia
- Ingham Institute of Applied Medical Research; Liverpool Hospital; Liverpool New South Wales Australia
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30
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Mirzaalian H, Ning L, Savadjiev P, Pasternak O, Bouix S, Michailovich O, Grant G, Marx CE, Morey RA, Flashman LA, George MS, McAllister TW, Andaluz N, Shutter L, Coimbra R, Zafonte RD, Coleman MJ, Kubicki M, Westin CF, Stein MB, Shenton ME, Rathi Y. Inter-site and inter-scanner diffusion MRI data harmonization. Neuroimage 2016; 135:311-23. [PMID: 27138209 DOI: 10.1016/j.neuroimage.2016.04.041] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/15/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022] Open
Abstract
We propose a novel method to harmonize diffusion MRI data acquired from multiple sites and scanners, which is imperative for joint analysis of the data to significantly increase sample size and statistical power of neuroimaging studies. Our method incorporates the following main novelties: i) we take into account the scanner-dependent spatial variability of the diffusion signal in different parts of the brain; ii) our method is independent of compartmental modeling of diffusion (e.g., tensor, and intra/extra cellular compartments) and the acquired signal itself is corrected for scanner related differences; and iii) inter-subject variability as measured by the coefficient of variation is maintained at each site. We represent the signal in a basis of spherical harmonics and compute several rotation invariant spherical harmonic features to estimate a region and tissue specific linear mapping between the signal from different sites (and scanners). We validate our method on diffusion data acquired from seven different sites (including two GE, three Philips, and two Siemens scanners) on a group of age-matched healthy subjects. Since the extracted rotation invariant spherical harmonic features depend on the accuracy of the brain parcellation provided by Freesurfer, we propose a feature based refinement of the original parcellation such that it better characterizes the anatomy and provides robust linear mappings to harmonize the dMRI data. We demonstrate the efficacy of our method by statistically comparing diffusion measures such as fractional anisotropy, mean diffusivity and generalized fractional anisotropy across multiple sites before and after data harmonization. We also show results using tract-based spatial statistics before and after harmonization for independent validation of the proposed methodology. Our experimental results demonstrate that, for nearly identical acquisition protocol across sites, scanner-specific differences can be accurately removed using the proposed method.
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Affiliation(s)
- H Mirzaalian
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA.
| | - L Ning
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
| | - P Savadjiev
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
| | - O Pasternak
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
| | - S Bouix
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
| | | | - G Grant
- Stanford University Medical Center, Palo Alto, CA, USA (Previously Duke University)
| | - C E Marx
- Duke University Medical Center and VA Mid-Atlantic MIRECC, NC, USA
| | - R A Morey
- Duke University Medical Center and VA Mid-Atlantic MIRECC, NC, USA
| | - L A Flashman
- Dartmouth University, Hanover and Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - M S George
- Medical University of South Carolina, Charleston, SC, USA, Ralph H. Johnson VA Medical Center, Charleston
| | - T W McAllister
- Geisel School of Medicine at Dartmouth (original) and Indiana University School of Medicine (current)
| | - N Andaluz
- Department of Neurosurgery, University of Cincinnati (UC) College of Medicine; Neurotrauma Center at UC Neuroscience Institute; and Mayfield Clinic, Cincinnati, OH
| | - L Shutter
- University of Pittsburgh School of Medicine, Pittsburgh, PA, USA (Previously Duke University)
| | - R Coimbra
- Department of Surgery, University of California, San Diego
| | - R D Zafonte
- Spaulding Rehabilitation Hospital and Harvard Medical School, Boston, USA
| | - M J Coleman
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
| | - M Kubicki
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
| | - C F Westin
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
| | - M B Stein
- University of California, San Diego, San Diego, CA, USA
| | - M E Shenton
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA; VA Boston Healthcare System, Boston, MA, USA
| | - Y Rathi
- Harvard Medical School and Brigham and Women's Hospital, Boston, USA
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31
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Pasquier D, Boutaud de la Combe-Chossiere L, Carlier D, Darloy F, Degrendel-Courtecuisse AC, Dufour C, Fares M, Gilbeau L, Liem X, Martin P, Meyer P, Minne JF, Olszyk O, Rhliouch H, Tokarski M, Viot C, Castelain B, Lartigau E. Harmonization of the Volume of Interest Delineation among All Eleven Radiotherapy Centers in the North of France. PLoS One 2016; 11:e0150917. [PMID: 26987121 PMCID: PMC4795685 DOI: 10.1371/journal.pone.0150917] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 02/21/2016] [Indexed: 11/19/2022] Open
Abstract
Background Inter-observer delineation variation has been detailed for many years in almost every tumor location. Inadequate delineation can impair the chance of cure and/or increase toxicity. The aim of our original work was to prospectively improve the homogeneity of delineation among all of the senior radiation oncologists in the Nord-Pas de Calais region, irrespective of the conditions of practice. Methods All 11 centers were involved. The first studied cancer was prostate cancer. Three clinical cases were studied: a low-risk prostate cancer case (case 1), a high-risk prostate cancer case (pelvic nodes, case 2) and a case of post-operative biochemical elevated PSA (case 3). All of the involved physicians delineated characteristically the clinical target volume (CTV) and organs at risk. The volumes were compared using validated indexes: the volume ratio (VR), common and additional volumes (CV and AV), volume overlap (VO) and Dice similarity coefficient (DSC). A second delineation of the same three cases was performed after discussion of the slice results and the choice of shared guidelines to evaluate homogenization. A comparative analysis of the indexes before and after discussion was conducted using the Wilcoxon test for paired samples. A p-value less than 0.05 was considered to indicate statistical significance. Results The indexes were not improved in case 1, for which the inter-observer agreement was considered good after the first comparison (DSC = 0.83±0.06). In case 2, the second comparison showed homogenization of the CTV delineation with a significant improvement in CV (81.4±11.7 vs. 88.6±10.26, respectively, p = 0.048), VO (0.41±0.09 vs. 0.47±0.07, respectively; p = 0.009) and DSC (0.58±0.09 vs. 0.63±0.07, respectively; p = 0.0098). In case 3, VR and AV were significantly improved: VR: 1.71(±0.6) vs. 1.34(±0.46), respectively, p = 0.0034; AV: 46.58(±14.50) vs. 38.08(±15.10), respectively, p = 0.0024. DSC was not improved, but it was already superior to 0.6 in the first comparison. Conclusion Our prospective work showed that a collaborative discussion about clinical cases and the choice of shared guidelines within an established framework improved the homogeneity of CTV delineation among the senior radiation oncologists in our region.
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Affiliation(s)
- David Pasquier
- Academic Radiation Oncology Department, Centre Oscar Lambret, Lille University, Lille, France
- CRISTAL, UMR CNRS 9189, Lille, France
- * E-mail:
| | | | | | | | | | - Chantal Dufour
- Centre de Cancérologie Les Dentellières, Valenciennes, France
| | | | | | - Xavier Liem
- Academic Radiation Oncology Department, Centre Oscar Lambret, Lille University, Lille, France
| | | | | | | | | | | | | | - Chloé Viot
- Réseau Onco Nord Pas de Calais, Loos, France
| | - Bernard Castelain
- Academic Radiation Oncology Department, Centre Oscar Lambret, Lille University, Lille, France
| | - Eric Lartigau
- Academic Radiation Oncology Department, Centre Oscar Lambret, Lille University, Lille, France
- CRISTAL, UMR CNRS 9189, Lille, France
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Korsager AS, Fortunati V, van der Lijn F, Carl J, Niessen W, Østergaard LR, van Walsum T. The use of atlas registration and graph cuts for prostate segmentation in magnetic resonance images. Med Phys 2015; 42:1614-24. [PMID: 25832052 DOI: 10.1118/1.4914379] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE An automatic method for 3D prostate segmentation in magnetic resonance (MR) images is presented for planning image-guided radiotherapy treatment of prostate cancer. METHODS A spatial prior based on intersubject atlas registration is combined with organ-specific intensity information in a graph cut segmentation framework. The segmentation is tested on 67 axial T2-weighted MR images in a leave-one-out cross validation experiment and compared with both manual reference segmentations and with multiatlas-based segmentations using majority voting atlas fusion. The impact of atlas selection is investigated in both the traditional atlas-based segmentation and the new graph cut method that combines atlas and intensity information in order to improve the segmentation accuracy. Best results were achieved using the method that combines intensity information, shape information, and atlas selection in the graph cut framework. RESULTS A mean Dice similarity coefficient (DSC) of 0.88 and a mean surface distance (MSD) of 1.45 mm with respect to the manual delineation were achieved. CONCLUSIONS This approaches the interobserver DSC of 0.90 and interobserver MSD 0f 1.15 mm and is comparable to other studies performing prostate segmentation in MR.
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Affiliation(s)
- Anne Sofie Korsager
- Department of Health Science and Technology, Aalborg University, Aalborg 9220, Denmark
| | - Valerio Fortunati
- Biomedical Imaging Group of Rotterdam, Department of Medical Informatics and Radiology, Erasmus MC, Rotterdam 3015 GE Rotterdam, The Netherlands
| | - Fedde van der Lijn
- Biomedical Imaging Group of Rotterdam, Department of Medical Informatics and Radiology, Erasmus MC, Rotterdam 3015 GE Rotterdam, The Netherlands
| | - Jesper Carl
- Department of Medical Physics, Oncology, Aalborg University Hospital, Aalborg 9220, Denmark
| | - Wiro Niessen
- Biomedical Imaging Group of Rotterdam, Department of Medical Informatics and Radiology, Erasmus MC, Rotterdam 3015 GE Rotterdam, The Netherlands
| | - Lasse Riis Østergaard
- Department of Health Science and Technology, Aalborg University, Aalborg 9220, Denmark
| | - Theo van Walsum
- Biomedical Imaging Group of Rotterdam, Department of Medical Informatics and Radiology, Erasmus MC, Rotterdam 3015 GE Rotterdam, The Netherlands
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Li M, Ballhausen H, Hegemann NS, Ganswindt U, Manapov F, Tritschler S, Roosen A, Gratzke C, Reiner M, Belka C. A comparative assessment of prostate positioning guided by three-dimensional ultrasound and cone beam CT. Radiat Oncol 2015; 10:82. [PMID: 25890013 PMCID: PMC4465303 DOI: 10.1186/s13014-015-0380-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/16/2015] [Indexed: 12/25/2022] Open
Abstract
Background The accuracy of the Elekta Clarity™ three-dimensional ultrasound system (3DUS) was assessed for prostate positioning and compared to seed- and bone-based positioning in kilo-voltage cone-beam computed tomography (CBCT) during a definitive radiotherapy. Methods The prostate positioning of 6 patients, with fiducial markers implanted into the prostate, was controlled by 3DUS and CBCT. In total, 78 ultrasound scans were performed trans-abdominally and compared to bone-matches and seed-matches in CBCT scans. Setup errors detected by the different modalities were compared. Systematic and random errors were analysed, and optimal setup margins were calculated. Results The discrepancy between 3DUS and seed-match in CBCT was −0.2 ± 2.7 mm laterally, −1.9 ± 2.3 mm longitudinally and 0.0 ± 3.0 mm vertically and significant only in longitudinal direction. Using seed-match as reference, systematic errors of 3DUS were 1.3 mm laterally, 0.8 mm longitudinally and 1.4 mm vertically, and random errors were 2.5 mm laterally, 2.3 mm longitudinally, and 2.7 mm vertically. No significant difference could be detected for 3DUS in comparison to bone-match in CBCT. Conclusions 3DUS is feasible for image guidance for patients with prostate cancer and appears comparable to CBCT based image guidance in the retrospective study. While 3DUS offers some distinct advantages such as no need of invasive fiducial implantation and avoidance of extra radiation, its disadvantages include the operator dependence of the technique and dependence on sufficient bladder filling. Further study of 3DUS for image guidance in a large patient cohort is warranted.
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Affiliation(s)
- Minglun Li
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Hendrik Ballhausen
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Nina-Sophie Hegemann
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Ute Ganswindt
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Farkhad Manapov
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Stefan Tritschler
- Department of Urology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Alexander Roosen
- Department of Urology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Christian Gratzke
- Department of Urology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Michael Reiner
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Claus Belka
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
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Liney GP, Moerland MA. Magnetic resonance imaging acquisition techniques for radiotherapy planning. Semin Radiat Oncol 2015; 24:160-8. [PMID: 24931086 DOI: 10.1016/j.semradonc.2014.02.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Magnetic resonance imaging (MRI) has a number of benefits for the planning of radiotherapy (RT), but its uptake into clinical practice has often been restricted to specialist research sites. There is often a lack of detailed MRI knowledge within the RT community and an apprehension of geometric distortions, both of which prevent its best utilization and merit the introduction of a standardized approach and common guidelines. This review sets out to address some of the issues involved in acquiring MRI scans for RT planning in the context of a number of clinical sites of interest and concludes with recommendations for its best practice in terms of imaging protocol and quality assurance. The article is of particular interest to the growing number of cancer therapy centers that are embarking on MRI simulation on either existing systems or their own dedicated scanners.
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Affiliation(s)
- Gary P Liney
- Ingham Institute for Applied Medical Research, Liverpool, Sydney, New South Wales, Australia; Department of Medical Physics, University of Wollongong, Wollongong, New South Wales, Australia.
| | - Marinus A Moerland
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
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Gunnlaugsson A, Kjellén E, Hagberg O, Thellenberg-Karlsson C, Widmark A, Nilsson P. Change in prostate volume during extreme hypo-fractionation analysed with MRI. Radiat Oncol 2014; 9:22. [PMID: 24410739 PMCID: PMC3901329 DOI: 10.1186/1748-717x-9-22] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 01/03/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hypo-fractionated external beam radiotherapy with narrow CTV-PTV margins is increasingly applied for prostate cancer. This demands a precise target definition and knowledge on target location and extension during treatment. It is unclear how increase in fraction size affects changes in prostate volume during treatment. Our aim was to study prostate volume changes during extreme hypo-fractionation (7 × 6.1 Gy) by using sequential MRIs. METHODS Twenty patients treated with extreme hypo-fractionation were recruited from an on-going prospective randomized phase III trial. An MRI scan was done before start of treatment, at mid treatment and at the end of radiotherapy. The prostate was delineated at each MRI and the volume and maximum extension in left-right, anterior-posterior and cranial-caudal directions were measured. RESULTS There was a significant increase in mean prostate volume (14%) at mid treatment as compared to baseline. The prostate volume remained enlarged (9%) at the end of radiotherapy. Prostate swelling was most pronounced in the anterior-posterior and cranial-caudal directions. CONCLUSIONS Extreme hypo-fractionation induced a significant prostate swelling during treatment that was still present at the time of last treatment fraction. Our results indicate that prostate swelling is an important factor to take into account when applying treatment margins during short extreme hypo-fractionation, and that tight margins should be applied with caution.
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Crehange G, Krishnamurthy D, Cunha JA, Pickett B, Kurhanewicz J, Hsu IC, Gottschalk AR, Shinohara K, Roach M, Pouliot J. Cold spot mapping inferred from MRI at time of failure predicts biopsy-proven local failure after permanent seed brachytherapy in prostate cancer patients: implications for focal salvage brachytherapy. Radiother Oncol 2013; 109:246-50. [PMID: 24231238 DOI: 10.1016/j.radonc.2013.10.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/22/2013] [Accepted: 10/14/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE (1) To establish a method to evaluate dosimetry at the time of primary prostate permanent implant (pPPI) using MRI of the shrunken prostate at the time of failure (tf). (2) To compare cold spot mapping with sextant-biopsy mapping at tf. MATERIAL AND METHODS Twenty-four patients were referred for biopsy-proven local failure (LF) after pPPI. Multiparametric MRI and combined-sextant biopsy with a central review of the pathology at tf were systematically performed. A model of the shrinking pattern was defined as a Volumetric Change Factor (VCF) as a function of time from time of pPPI (t0). An isotropic expansion to both prostate volume (PV) and seed position (SP) coordinates determined at tf was performed using a validated algorithm using the VCF. RESULTS pPPI CT-based evaluation (at 4weeks) vs. MR-based evaluation: Mean D90% was 145.23±19.16Gy [100.0-167.5] vs. 85.28±27.36Gy [39-139] (p=0.001), respectively. Mean V100% was 91.6±7.9% [70-100%] vs. 73.1±13.8% [55-98%] (p=0.0006), respectively. Seventy-seven per cent of the pathologically positive sextants were classified as cold. CONCLUSIONS Patients with biopsy-proven LF had poorer implantation quality when evaluated by MRI several years after implantation. There is a strong relationship between microscopic involvement at tf and cold spots.
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Affiliation(s)
- Gilles Crehange
- Department of Radiation Oncology, Helen Diller Family Comprehensive Cancer Center, UCSF, San Francisco, USA; Department of Radiation Oncology, Dijon University Hospital, France.
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Rischke HC, Nestle U, Fechter T, Doll C, Volegova-Neher N, Henne K, Scholber J, Knippen S, Kirste S, Grosu AL, Jilg CA. 3 Tesla multiparametric MRI for GTV-definition of Dominant Intraprostatic Lesions in patients with Prostate Cancer--an interobserver variability study. Radiat Oncol 2013; 8:183. [PMID: 23875672 PMCID: PMC3828667 DOI: 10.1186/1748-717x-8-183] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 07/20/2013] [Indexed: 01/28/2023] Open
Abstract
PURPOSE To evaluate the interobserver variability of gross tumor volume (GTV) - delineation of Dominant Intraprostatic Lesions (DIPL) in patients with prostate cancer using published MRI criteria for multiparametric MRI at 3 Tesla by 6 different observers. MATERIAL AND METHODS 90 GTV-datasets based on 15 multiparametric MRI sequences (T2w, diffusion weighted (DWI) and dynamic contrast enhanced (DCE)) of 5 patients with prostate cancer were generated for GTV-delineation of DIPL by 6 observers. The reference GTV-dataset was contoured by a radiologist with expertise in diagnostic imaging of prostate cancer using MRI. Subsequent GTV-delineation was performed by 5 radiation oncologists who received teaching of MRI-features of primary prostate cancer before starting contouring session. GTV-datasets were contoured using Oncentra Masterplan® and iplan® Net. For purposes of comparison GTV-datasets were imported to the Artiview® platform (Aquilab®), GTV-values and the similarity indices or Kappa indices (KI) were calculated with the postulation that a KI > 0.7 indicates excellent, a KI > 0.6 to < 0.7 substantial and KI > 0.5 to < 0.6 moderate agreement. Additionally all observers rated difficulties of contouring for each MRI-sequence using a 3 point rating scale (1 = easy to delineate, 2 = minor difficulties, 3 = major difficulties). RESULTS GTV contouring using T2w (KI-T2w = 0.61) and DCE images (KI-DCE = 0.63) resulted in substantial agreement. GTV contouring using DWI images resulted in moderate agreement (KI-DWI = 0.51). KI-T2w and KI-DCE was significantly higher than KI-DWI (p = 0.01 and p = 0.003). Degree of difficulty in contouring GTV was significantly lower using T2w and DCE compared to DWI-sequences (both p < 0.0001). Analysis of delineation differences revealed inadequate comparison of functional (DWI, DCE) to anatomical sequences (T2w) and lack of awareness of non-specific imaging findings as a source of erroneous delineation. CONCLUSIONS Using T2w and DCE sequences at 3 Tesla for GTV-definition of DIPL in prostate cancer patients by radiation oncologists with knowledge of MRI features results in substantial agreement compared to an experienced MRI-radiologist, but for radiotherapy purposes higher KI are desirable, strengthen the need for expert surveillance. DWI sequence for GTV delineation was considered as difficult in application.
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Affiliation(s)
- Hans Christian Rischke
- Department of Radiation Oncology, University of Freiburg, Robert Koch Str. 3, 79106 Freiburg, Germany.
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