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Wang L, McQuaid D, Blackledge M, McNair H, Harris E, Lalondrelle S. Predicting cervical cancer target motion using a multivariate regression model to enable patient selection for adaptive external beam radiotherapy. Phys Imaging Radiat Oncol 2024; 29:100554. [PMID: 38419803 PMCID: PMC10901141 DOI: 10.1016/j.phro.2024.100554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 03/02/2024] Open
Abstract
Background and purpose Interfraction motion during cervical cancer radiotherapy is substantial in some patients, minimal in others. Non-adaptive plans may miss the target and/or unnecessarily irradiate normal tissue. Adaptive radiotherapy leads to superior dose-volume metrics but is resource-intensive. The aim of this study was to predict target motion, enabling patient selection and efficient resource allocation. Materials and methods Forty cervical cancer patients had CT with full-bladder (CT-FB) and empty-bladder (CT-EB) at planning, and daily cone-beam CTs (CBCTs). The low-risk clinical target volume (CTVLR) was contoured. Mean coverage of the daily CTVLR by the CT-FB CTVLR was calculated for each patient. Eighty-three investigated variables included measures of organ geometry, patient, tumour and treatment characteristics. Models were trained on 29 patients (171 fractions). The Two-CT multivariate model could use all available data. The Single-CT multivariate model excluded data from the CT-EB. A univariate model was trained using the distance moved by the uterine fundus tip between CTs, the only method of patient selection found in published cervix plan-of-the-day studies. Models were tested on 11 patients (68 fractions). Accuracy in predicting mean coverage was reported as mean absolute error (MAE), mean squared error (MSE) and R2. Results The Two-CT model was based upon rectal volume, dice similarity coefficient between CT-FB and CT-EB CTVLR, and uterine thickness. The Single-CT model was based upon rectal volume, uterine thickness and tumour size. Both performed better than the univariate model in predicting mean coverage (MAE 7 %, 7 % and 8 %; MSE 82 %2, 65 %2, 110 %2; R2 0.2, 0.4, -0.1). Conclusion Uterocervix motion is complex and multifactorial. We present two multivariate models which predicted motion with reasonable accuracy using pre-treatment information, and outperformed the only published method.
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Affiliation(s)
- Lei Wang
- The Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
| | - Dualta McQuaid
- The Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
| | - Matthew Blackledge
- The Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
| | - Helen McNair
- The Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
| | - Emma Harris
- The Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
| | - Susan Lalondrelle
- The Joint Department of Physics at the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
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2
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Zhou H, Cao M, Ma M, Yoon S, Kishan A, Ruan D. Technical Note: Air bubble-induced performance degradation in automatic rectum segmentation from cone-beam CT. Med Phys 2022; 49:1754-1758. [PMID: 35015908 DOI: 10.1002/mp.15443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/17/2021] [Accepted: 12/12/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Cone-beam CT (CBCT) is widely used for daily anatomy monitoring and can be a potential source to support adaptation. However, low image quality and artifacts limit CBCT's clinical utility. Peristalsis and air bubbles can cause severe artifacts in pelvic CBCT. We have observed that severe air bubble-induced Feldkamp artifacts in the rectum may contribute to low automatic segmentation accuracy. MATERIALS AND METHODS In this study, air bubbles within the rectum were extracted and automatic rectum segmentation performance was measured in Dice similarity coefficient (DSC). A Gaussian mixture model (GMM) was used to characterize their correlation, and an expectation-maximization (EM) approach was used to solve the corresponding parameter estimation and decouple the impact from air bubbles vs. other image attributes based on cluster memberships. Post-prostatectomy patient data with high variability in air bubble size and shape were used in this study to reveal the regression relationship. RESULTS GMM identified two distinct correlative relations between the air-bubble severity in the rectum and the rectum prediction DSC: one showed strong negative dependency of segmentation performance on air bubble presence, and the other one had mild-to-moderate dependency which suggested another group of contributing factors influencing rectum segmentation, such as the inconsistent presence of fiducial seeds and shape extremes. CONCLUSION The presence of severe air bubbles contributes semi-linearly to performance degradation in automatic rectum segmentation. A good correction mechanism may boost the accuracy and consistency of pelvic segmentation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hanyue Zhou
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA
| | - Minsong Cao
- Department of Radiation Oncology, University of California, Los Angeles, CA, 90095, USA
| | - Martin Ma
- Department of Radiation Oncology, University of California, Los Angeles, CA, 90095, USA
| | - Stephanie Yoon
- Department of Radiation Oncology, University of California, Los Angeles, CA, 90095, USA
| | - Amar Kishan
- Department of Radiation Oncology, University of California, Los Angeles, CA, 90095, USA
| | - Dan Ruan
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA.,Department of Radiation Oncology, University of California, Los Angeles, CA, 90095, USA
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Utility of deformable image registration for adaptive prostate cancer treatment. Analysis and comparison of two commercially available algorithms. Z Med Phys 2021; 32:369-377. [PMID: 34906406 PMCID: PMC9948872 DOI: 10.1016/j.zemedi.2021.10.001] [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: 07/13/2021] [Revised: 09/24/2021] [Accepted: 10/17/2021] [Indexed: 11/23/2022]
Abstract
INTRODUCTION This study aimed to assess and compare the capabilities of two commercially available deformable image registration algorithms implemented in Raystation 9A (A1) and Velocity AI (A2) for possible usage in adaptive prostate radiotherapy based on the propagation of anatomical contours from computed tomography (CT) images to cone-beam CT (CBCT) images. MATERIAL AND METHODS Ten patients were retrospectively selected from a group treated for localized prostate cancer. The propagation of rectum contours was analyzed in a set of CT-CBCT pairs. Two independent observers carried out qualitative analysis using the two-level descriptive scale (meet/fail). Quantitative analysis was done using landmark points distances based on implanted markers as navigation points and differently obtained contours (manually and automatically using DIR algorithms). Quantitative analysis was taken on sets preselected by qualitative analysis. RESULTS Qualitative analysis shows that 83.7% of the rectum contours were scored identically (meet or fail) for both algorithms, from which 53.5% and 55.8% are failed results for A1 and A2, respectively. For the rectum size (RWD parameter), differences between referenced and deformation-based values were 5.5 and 5.8mm, and for the rectum wall, the prostate marker distance (WMD parameter) was 4.5 and 5.5mm for A1 and A2, respectively. The differences between the WMD parameters were statistically significant (p=0.007). CONCLUSIONS In both tested algorithms, neither effectiveness nor measured uncertainties in the propagation of rectum contour process in prostate patient cases were satisfactory. Careful selection of input images followed by case/set-based verification of every deformable registration is a substantial step to avoid inappropriate results.
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Khalifa J, Supiot S, Pignot G, Hennequin C, Blanchard P, Pasquier D, Magné N, de Crevoisier R, Graff-Cailleaud P, Riou O, Cabaillé M, Azria D, Latorzeff I, Créhange G, Chapet O, Rouprêt M, Belhomme S, Mejean A, Culine S, Sargos P. Recommendations for planning and delivery of radical radiotherapy for localized urothelial carcinoma of the bladder. Radiother Oncol 2021; 161:95-114. [PMID: 34118357 DOI: 10.1016/j.radonc.2021.06.011] [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: 02/05/2021] [Revised: 05/05/2021] [Accepted: 06/03/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE Curative radio-chemotherapy is recognized as a standard treatment option for muscle-invasive bladder cancer (MIBC). Nevertheless, the technical aspects for MIBC radiotherapy are heterogeneous with a lack of practical recommendations. METHODS AND MATERIALS In 2018, a workshop identified the need for two cooperative groups to develop consistent, evidence-based guidelines for irradiation technique in the delivery of curative radiotherapy. Two radiation oncologists performed a review of the literature addressing several topics relative to radical bladder radiotherapy: planning computed tomography acquisition, target volume delineation, radiation schedules (total dose and fractionation) and dose delivery (including radiotherapy techniques, image-guided radiotherapy (IGRT) and adaptive treatment modalities). Searches for original and review articles in the PubMed and Google Scholar databases were conducted from January 1990 until March 2020. During a meeting conducted in October 2020, results on 32 topics were presented and discussed with a working group involving 15 radiation oncologists, 3 urologists and one medical oncologist. We applied the American Urological Association guideline development's method to define a consensus strategy. RESULTS A consensus was obtained for all 34 except 4 items. The group did not obtain an agreement on CT enhancement added value for planning, PTV margins definition for empty bladder and full bladder protocols, and for pelvic lymph-nodes irradiation. High quality evidence was shown in 6 items; 8 items were considered as low quality of evidence. CONCLUSION The current recommendations propose a homogenized modality of treatment both for routine clinical practice and for future clinical trials, following the best evidence to date, analyzed with a robust methodology. The XXX group formulates practical guidelines for the implementation of innovative techniques such as adaptive radiotherapy.
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Affiliation(s)
- Jonathan Khalifa
- Department of Radiotherapy, Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse Oncopole, France
| | - Stéphane Supiot
- Department of Radiotherapy, Institut de Cancérologie de l'Ouest, Nantes Saint-Herblain, France
| | - Géraldine Pignot
- Department of Urology, Institut Paoli Calmettes, Marseille, France
| | | | - Pierre Blanchard
- Department of Radiotherapy, Institut Gustave Roussy, Villejuif, France
| | - David Pasquier
- Department of Radiotherapy, Centre Oscar Lambret, Lille, France
| | - Nicolas Magné
- Department of Radiotherapy, Institut de Cancérologie Lucien Neuwirth, Saint Priest en Jarez, France
| | | | - Pierre Graff-Cailleaud
- Department of Radiotherapy, Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse Oncopole, France
| | - Olivier Riou
- Department of Radiotherapy, Institut du Cancer de Montpellier, France
| | | | - David Azria
- Department of Radiotherapy, Institut du Cancer de Montpellier, France
| | - Igor Latorzeff
- Department of Radiotherapy, Clinique Pasteur, Toulouse, France
| | | | - Olivier Chapet
- Department of Radiotherapy, Hospices Civils de Lyon, France
| | - Morgan Rouprêt
- Department of Urology, Hôpital Pitié-Salpétrière, APHP Sorbonne Université, Paris, France
| | - Sarah Belhomme
- Department of Medical Physics, Institut Bergonié, Bordeaux, France
| | - Arnaud Mejean
- Department of Urology, Hôpital Européen Georges-Pompidou, Paris, France
| | - Stéphane Culine
- Department of Medical Oncology, Hôpital Saint-Louis, Paris, France
| | - Paul Sargos
- Department of Radiotherapy, Institut Bergonié, Bordeaux, France.
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5
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Kong V, Hansen VN, Hafeez S. Image-guided Adaptive Radiotherapy for Bladder Cancer. Clin Oncol (R Coll Radiol) 2021; 33:350-368. [PMID: 33972024 DOI: 10.1016/j.clon.2021.03.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 03/30/2021] [Indexed: 12/12/2022]
Abstract
Technological advancement has facilitated patient-specific radiotherapy in bladder cancer. This has been made possible by developments in image-guided radiotherapy (IGRT). Particularly transformative has been the integration of volumetric imaging into the workflow. The ability to visualise the bladder target using cone beam computed tomography and magnetic resonance imaging initially assisted with determining the magnitude of inter- and intra-fraction target change. It has led to greater confidence in ascertaining true anatomy at each fraction. The increased certainty of dose delivered to the bladder has permitted the safe reduction of planning target volume margins. IGRT has therefore improved target coverage with a reduction in integral dose to the surrounding tissue. Use of IGRT to feed back into plan and dose delivery optimisation according to the anatomy of the day has enabled adaptive radiotherapy bladder solutions. Here we undertake a review of the stepwise developments underpinning IGRT and adaptive radiotherapy strategies for external beam bladder cancer radiotherapy. We present the evidence in accordance with the framework for systematic clinical evaluation of technical innovations in radiation oncology (R-IDEAL).
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Affiliation(s)
- V Kong
- Radiation Medicine, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - V N Hansen
- Laboratory of Radiation Physics, Odense University Hospital, Odense, Denmark
| | - S Hafeez
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, UK; Department of Radiotherapy, The Royal Marsden NHS Foundation Trust, London, UK.
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6
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Lawrence LSP, Chin LCL, Chan RW, Nguyen TK, Sahgal A, Tseng CL, Lau AZ. Method of computing direction-dependent margins for the development of consensus contouring guidelines. Radiat Oncol 2021; 16:71. [PMID: 33849576 PMCID: PMC8045331 DOI: 10.1186/s13014-021-01799-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/31/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Clinical target volume (CTV) contouring guidelines are frequently developed through studies in which experts contour the CTV for a representative set of cases for a given treatment site and the consensus CTVs are analyzed to generate margin recommendations. Measures of interobserver variability are used to quantify agreement between experts. In cases where an isotropic margin is not appropriate, however, there is no standard method to compute margins in specified directions that represent possible routes of tumor spread. Moreover, interobserver variability metrics are often measures of volume overlap that do not account for the dependence of disagreement on direction. To aid in the development of consensus contouring guidelines, this study demonstrates a novel method of quantifying CTV margins and interobserver variability in clinician-specified directions. METHODS The proposed algorithm was applied to 11 cases of non-spine bone metastases to compute the consensus CTV margin in each direction of intraosseous and extraosseous disease. The median over all cases for each route of spread yielded the recommended margins. The disagreement between experts on the CTV margin was quantified by computing the median of the coefficients of variation for intraosseous and extraosseous margins. RESULTS The recommended intraosseous and extraosseous margins were 7.0 mm and 8.0 mm, respectively. The median coefficient of variation quantifying the margin disagreement between experts was 0.59 and 0.48 for intraosseous and extraosseous disease. CONCLUSIONS The proposed algorithm permits the generation of margin recommendations in relation to adjacent anatomy and quantifies interobserver variability in specified directions. This method can be applied to future consensus CTV contouring studies.
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Affiliation(s)
- Liam S P Lawrence
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Lee C L Chin
- Department of Medical Physics, Odette Cancer Centre, Toronto, ON, Canada.,Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Rachel W Chan
- Physical Sciences Platform, Sunnybrook Research Institute, 2075 Bayview Ave., Toronto, M4N 3M5, ON, Canada
| | - Timothy K Nguyen
- Department of Radiation Oncology, London Health Sciences Centre, Western University, London, ON, Canada
| | - Arjun Sahgal
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Chia-Lin Tseng
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Angus Z Lau
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada. .,Physical Sciences Platform, Sunnybrook Research Institute, 2075 Bayview Ave., Toronto, M4N 3M5, ON, Canada.
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7
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Hansen AE, Henriksen JR, Jølck RI, Fliedner FP, Bruun LM, Scherman J, Jensen AI, Munck af Rosenschöld P, Moorman L, Kurbegovic S, de Blanck SR, Larsen KR, Clementsen PF, Christensen AN, Clausen MH, Wang W, Kempen P, Christensen M, Viby NE, Persson G, Larsen R, Conradsen K, McEvoy FJ, Kjaer A, Eriksen T, Andresen TL. Multimodal soft tissue markers for bridging high-resolution diagnostic imaging with therapeutic intervention. SCIENCE ADVANCES 2020; 6:eabb5353. [PMID: 32875113 PMCID: PMC7438096 DOI: 10.1126/sciadv.abb5353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/07/2020] [Indexed: 05/11/2023]
Abstract
Diagnostic imaging often outperforms the surgeon's ability to identify small structures during therapeutic procedures. Smart soft tissue markers that translate the sensitivity of diagnostic imaging into optimal therapeutic intervention are therefore highly warranted. This paper presents a unique adaptable liquid soft tissue marker system based on functionalized carbohydrates (Carbo-gel). The liquid state of these markers allows for high-precision placement under image guidance using thin needles. Based on step-by-step modifications, the image features and mechanical properties of markers can be optimized to bridge diagnostic imaging and specific therapeutic interventions. The performance of Carbo-gel is demonstrated for markers that (i) have radiographic, magnetic resonance, and ultrasound visibility; (ii) are palpable and visible; and (iii) are localizable by near-infrared fluorescence and radio guidance. The study demonstrates encouraging proof of concept for the liquid marker system as a well-tolerated multimodal imaging marker that can improve image-guided radiotherapy and surgical interventions, including robotic surgery.
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Affiliation(s)
- Anders E. Hansen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Jonas R. Henriksen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Rasmus I. Jølck
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Frederikke P. Fliedner
- Dept. of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Dept. of Biomedical Sciences, Copenhagen University Hospital (Rigshospitalet) and University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Linda M. Bruun
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Jonas Scherman
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund SE-222 42, Sweden
| | - Andreas I. Jensen
- DTU Health Technology, The Hevesy Laboratory, Technical University of Denmark, Roskilde DK-4000, Denmark
| | - Per. Munck af Rosenschöld
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund SE-222 42, Sweden
| | - Lilah Moorman
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
| | - Sorel Kurbegovic
- Dept. of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Dept. of Biomedical Sciences, Copenhagen University Hospital (Rigshospitalet) and University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Steen R. de Blanck
- Department of Oncology, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Klaus R. Larsen
- Department of Respiratory Medicine, Copenhagen University Hospital (Bispebjerg and Frederiksberg Hospital), Copenhagen DK-2400, Denmark
| | - Paul F. Clementsen
- Copenhagen Academy for Medical Education and Simulation (CAMES), Department of Internal Medicine, Zealand University Hospital, Roskilde, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, DK-2100, Denmark
| | - Anders N. Christensen
- DTU Compute, Section for Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Mads H. Clausen
- Department of Cardiothoracic Surgery, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Wenbo Wang
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Paul Kempen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Merete Christensen
- Department of Cardiothoracic Surgery, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Niels-Erik Viby
- Department of Cardiothoracic Surgery, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Gitte Persson
- Department of Oncology, Herlev-Gentofte Hospital, Department of Clinical Medicine, Faculty of Health Science, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Rasmus Larsen
- DTU Compute, Section for Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Knut Conradsen
- DTU Compute, Section for Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Fintan J. McEvoy
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
| | - Andreas Kjaer
- Dept. of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Dept. of Biomedical Sciences, Copenhagen University Hospital (Rigshospitalet) and University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Thomas Eriksen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
| | - Thomas L. Andresen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
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8
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Rodgers J, Hales R, Whiteside L, Parker J, McHugh L, Cree A, van Herk M, Choudhury A, Hoskin P, McWilliam A, Eccles CL. Comparison of radiographer interobserver image registration variability using cone beam CT and MR for cervix radiotherapy. Br J Radiol 2020; 93:20200169. [PMID: 32543946 PMCID: PMC7446016 DOI: 10.1259/bjr.20200169] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The aim of this study was to assess the consistency of therapy radiographers performing image registration using cone beam computed tomography (CBCT)-CT, magnetic resonance (MR)-CT, and MR-MR image guidance for cervix cancer radiotherapy and to assess that MR-based image guidance is not inferior to CBCT standard practice. METHODS 10 patients receiving cervix radiation therapy underwent daily CBCT guidance and magnetic resonance (MR) imaging weekly during treatment. Offline registration of each MR image, and corresponding CBCT, to planning CT was performed by five radiographers. MR images were also registered to the earliest MR interobserver variation was assessed using modified Bland-Altman analysis with clinically acceptable 95% limits of agreement (LoA) defined as ±5.0 mm. RESULTS 30 CBCT-CT, 30 MR-CT and 20 MR-MR registrations were performed by each observer. Registration variations between CBCT-CT and MR-CT were minor and both strategies resulted in 95% LoA over the clinical threshold in the anteroposterior direction (CBCT-CT ±5.8 mm, MR-CT ±5.4 mm). MR-MR registrations achieved a significantly improved 95% LoA in the anteroposterior direction (±4.3 mm). All strategies demonstrated similar results in lateral and longitudinal directions. CONCLUSION The magnitude of interobserver variations between CBCT-CT and MR-CT were similar, confirming that MR-CT radiotherapy workflows are comparable to CBCT-CT image-guided radiotherapy. Our results suggest MR-MR radiotherapy workflows may be a superior registration strategy. ADVANCES IN KNOWLEDGE This is the first publication quantifying interobserver registration of multimodality image registration strategies for cervix radical radiotherapy patients.
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Affiliation(s)
- John Rodgers
- Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester, UK,
| | - Rosie Hales
- Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester, UK,
| | - Lee Whiteside
- Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester, UK,
| | - Jacqui Parker
- Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester, UK,
| | - Louise McHugh
- Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester, UK,
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9
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Shelley LEA, Sutcliffe MPF, Harrison K, Scaife JE, Parker MA, Romanchikova M, Thomas SJ, Jena R, Burnet NG. Autosegmentation of the rectum on megavoltage image guidance scans. Biomed Phys Eng Express 2019; 5:025006. [PMID: 31057946 PMCID: PMC6466640 DOI: 10.1088/2057-1976/aaf1db] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/07/2018] [Accepted: 11/19/2018] [Indexed: 11/12/2022]
Abstract
Autosegmentation of image guidance (IG) scans is crucial for streamlining and optimising delivered dose calculation in radiotherapy. By accounting for interfraction motion, daily delivered dose can be accumulated and incorporated into automated systems for adaptive radiotherapy. Autosegmentation of IG scans is challenging due to poorer image quality than typical planning kilovoltage computed tomography (kVCT) systems, and the resulting reduction of soft tissue contrast in regions such as the pelvis makes organ boundaries less distinguishable. Current autosegmentation solutions generally involve propagation of planning contours to the IG scan by deformable image registration (DIR). Here, we present a novel approach for primary autosegmentation of the rectum on megavoltage IG scans acquired during prostate radiotherapy, based on the Chan-Vese algorithm. Pre-processing steps such as Hounsfield unit/intensity scaling, identifying search regions, dealing with air, and handling the prostate, are detailed. Post-processing features include identification of implausible contours (nominally those affected by muscle or air), 3D self-checking, smoothing, and interpolation. In cases where the algorithm struggles, the best estimate on a given slice may revert to the propagated kVCT rectal contour. Algorithm parameters were optimised systematically for a training cohort of 26 scans, and tested on a validation cohort of 30 scans, from 10 patients. Manual intervention was not required. Comparing Chan-Vese autocontours with contours manually segmented by an experienced clinical oncologist achieved a mean Dice Similarity Coefficient of 0.78 (SE < 0.011). This was comparable with DIR methods for kVCT and CBCT published in the literature. The autosegmentation system was developed within the VoxTox Research Programme for accumulation of delivered dose to the rectum in prostate radiotherapy, but may have applicability to further anatomical sites and imaging modalities.
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Affiliation(s)
- L E A Shelley
- University of Cambridge, Department of Engineering, Cambridge, United Kingdom
- Addenbrooke's Hospital, Department of Medical Physics and Clinical Engineering, Cambridge, United Kingdom
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
| | - M P F Sutcliffe
- University of Cambridge, Department of Engineering, Cambridge, United Kingdom
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
| | - K Harrison
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
- University of Cambridge, Cavendish Laboratory, Cambridge, United Kingdom
| | - J E Scaife
- Gloucestershire Oncology Centre, Cheltenham General Hospital, Cheltenham, United Kingdom
| | - M A Parker
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
- University of Cambridge, Cavendish Laboratory, Cambridge, United Kingdom
| | - M Romanchikova
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
- National Physical Laboratory, Teddington, United Kingdom
| | - S J Thomas
- Addenbrooke's Hospital, Department of Medical Physics and Clinical Engineering, Cambridge, United Kingdom
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
| | - R Jena
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
- Addenbrooke's Hospital, Oncology Centre, Cambridge, United Kingdom
| | - N G Burnet
- Cambridge University Hospitals NHS Foundation Trust, Cancer Research UK VoxTox Research Group, Cambridge, United Kingdom
- University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
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10
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Hargrave C, Deegan T, Bednarz T, Poulsen M, Harden F, Mengersen K. An image‐guided radiotherapy decision support framework incorporating a Bayesian network and visualization tool. Med Phys 2018; 45:2884-2897. [DOI: 10.1002/mp.12979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/01/2018] [Accepted: 04/14/2018] [Indexed: 11/10/2022] Open
Affiliation(s)
- Catriona Hargrave
- Radiation Oncology Princess Alexandra Hospital – Raymond Terrace Queensland Health Brisbane 4101 Australia
- School of Mathematical Sciences Science and Engineering Faculty Queensland University of Technology Brisbane 4000 Australia
- School of Clinical Sciences Faculty of Health Queensland University of Technology Brisbane 4000 Australia
| | - Timothy Deegan
- Radiation Oncology Princess Alexandra Hospital – Raymond Terrace Queensland Health Brisbane 4101 Australia
| | - Tomasz Bednarz
- School of Mathematical Sciences Science and Engineering Faculty Queensland University of Technology Brisbane 4000 Australia
- Data 61 Commonwealth Scientific and Industrial Research Organisation Brisbane 4102 Australia
- Expanded Perception and Interaction Centre University of New South Wales Paddington 2021 Australia
| | - Michael Poulsen
- Radiation Oncology Princess Alexandra Hospital – Raymond Terrace Queensland Health Brisbane 4101 Australia
- Faculty of Medicine University of Queensland Brisbane 4072 Australia
| | - Fiona Harden
- School of Mathematical Sciences Science and Engineering Faculty Queensland University of Technology Brisbane 4000 Australia
- Hunter Industrial Medicine Maitland 2320 Australia
| | - Kerrie Mengersen
- School of Mathematical Sciences Science and Engineering Faculty Queensland University of Technology Brisbane 4000 Australia
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11
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Altunbas C, Kavanagh B, Alexeev T, Miften M. Transmission characteristics of a two dimensional antiscatter grid prototype for CBCT. Med Phys 2017; 44:3952-3964. [PMID: 28513847 DOI: 10.1002/mp.12346] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/13/2017] [Accepted: 05/03/2017] [Indexed: 12/13/2022] Open
Abstract
AIM High fraction of scattered radiation in cone-beam CT (CBCT) imaging degrades CT number accuracy and visualization of low contrast objects. To suppress scatter in CBCT projections, we developed a focused, two-dimensional antiscatter grid (2DASG) prototype. In this work, we report on the primary and scatter transmission characteristics of the 2DASG prototype aimed for linac mounted, offset detector geometry CBCT systems in radiation therapy, and compared its performance to a conventional one-dimensional ASG (1DASG). METHODS The 2DASG is an array of through-holes separated by 0.1 mm septa that was fabricated from tungsten using additive manufacturing techniques. Through-holes' focusing geometry was designed for offset detector CBCT in Varian TrueBeam system. Two types of ASGs were evaluated: (a) a conventional 1DASG with a grid ratio of 10, (b) the 2DASG prototype with a grid ratio of 8.2. To assess the scatter suppression performance of both ASGs, Scatter-to-primary ratio (SPR) and scatter transmission fraction (Ts) were measured using the beam stop method. Scatter and primary intensities were modulated by varying the phantom thickness between 10 and 40 cm. Additionally, the effect of air gap and bow tie (BT) filter on SPR and Ts were evaluated. Average primary transmission fraction (TP ) and pixel specific primary transmission were also measured for both ASGs. To assess the effect of transmission characteristics on projection image signal-to-noise ratio (SNR), SNR improvement factor was calculated. Improvement in contrast to noise ratio (CNR) was demonstrated using a low contrast object. RESULTS In comparison to 1DASG, 2DASG reduced SPRs by a factor of 3 to 6 across the range of phantom setups investigated. Ts values for 1D and 2DASGs were in the range of 21 to 29%, and 5 to 14% respectively. 2DASG continued to provide lower SPR and Ts at increased air gap and with BT filter. Tp of 1D and 2DASGs were 70.6% and 84.7% respectively. Due to the septal shadow of the 2DASG, its pixel specific primary transmission values varied between 32.5% and 99.1%. With respect to 1DASG, 2DASG provided up to factor of 1.7 more improvement in SNR across the SPR range investigated. Moreover, 2DASG provided improved visualization of low contrast objects with respect to 1DASG and NOASG setups. CONCLUSIONS When compared to a conventional 1DASG, 2DASG prototype provided noticeably lower SPR and Ts values, indicating its superior scatter suppression performance. 2DASG also provided 19% higher average primary transmission that was attributed to the absence of interseptal spacers and optimized grid geometry. Our results indicate that the combined effect of lower scatter and higher primary transmission provided by 2DASG may potentially translate into more accurate CT numbers and improved contrast resolution in CBCT images.
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Affiliation(s)
- Cem Altunbas
- Department of Radiation Oncology, University of Colorado School of Medicine, 1665 Aurora Court, Suite 1032, Mail stop, F-706, Aurora, CO, 80045, USA
| | - Brian Kavanagh
- Department of Radiation Oncology, University of Colorado School of Medicine, 1665 Aurora Court, Suite 1032, Mail stop, F-706, Aurora, CO, 80045, USA
| | - Timur Alexeev
- Department of Radiation Oncology, University of Colorado School of Medicine, 1665 Aurora Court, Suite 1032, Mail stop, F-706, Aurora, CO, 80045, USA
| | - Moyed Miften
- Department of Radiation Oncology, University of Colorado School of Medicine, 1665 Aurora Court, Suite 1032, Mail stop, F-706, Aurora, CO, 80045, USA
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12
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Hou Y, Lee S, Agrawal V, Romano J, Baldini EH, Chen AB, Kozono DE, Killoran JH, Wagar M, Hacker FL, Aerts HJWL, Lewis JH, Mak RH. Inter-scan and inter-observer tumour volume delineation variability on cone beam computed tomography in patients treated with stereotactic body radiation therapy for early-stage non-small cell lung cancer. J Med Imaging Radiat Oncol 2016; 61:93-98. [DOI: 10.1111/1754-9485.12537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/14/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Ying Hou
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
| | - Stephanie Lee
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
| | - Vishesh Agrawal
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
| | - John Romano
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
| | - Elizabeth H Baldini
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - Aileen B Chen
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - David E Kozono
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - Joseph H Killoran
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - Matthew Wagar
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - Fred L Hacker
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - Hugo JWL Aerts
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - John H Lewis
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
| | - Raymond H Mak
- Department of Radiation Oncology; Dana-Farber Cancer Institute/Brigham and Women's Hospital; Boston Massachusetts USA
- Harvard Medical School; Boston Massachusetts USA
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13
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Cante D, Petrucci E, Piva C, Borca VC, Sciacero P, Bertodatto M, Marta C, Franco P, Viale M, La Valle G, La Porta MR, Bertetto O. Delineation of the larynx as organ at risk in radiotherapy: a contouring course within "Rete Oncologica Piemonte-Valle d'Aosta" network to reduce inter- and intraobserver variability. Radiol Med 2016; 121:867-872. [PMID: 27422528 DOI: 10.1007/s11547-016-0668-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/04/2016] [Indexed: 12/13/2022]
Abstract
AIMS To evaluate the usefulness of a contouring course in reducing inter- and intraobserver variability in the definition of the larynx as organ at risk (OAR). METHODS Within the "Rete Oncologica Piemonte-Valle d'Aosta" network, a contouring course focusing on larynx delineation was proposed. Twenty-six radiotherapist technicians (RTTs) experienced in delineating OARs were asked to contour larynx before and after the training. An expert radiation oncologist defined the reference volume for educational purpose. The contoured volumes obtained before and after the course were compared using descriptive statistics (mean value, standard deviation-SD, and coefficient of variation-COV) of volumes and maximum diameters. Conformity index (CI), dice coefficient (DC), and percentage of overlap were used to evaluate the spatial accuracy of the different volumes compared to the reference. Further analysis regarding the variation in the centre of mass (COM) displacement was performed. RESULTS The mean volume was 40.4 cm3 before and 65.9 cm3 after the course, approaching the reference value. Mean anteroposterior, laterolateral, and craniocaudal diameters improved, getting each closer to the reference. Moreover, the COM moved approaching reference coordinates. Mean percentage of intersection and DC strongly increased after the course, rising from 57.76 to 93.83 % and from 0.68 to 0.89, respectively. CI enhanced from 0.06 to 0.31. CONCLUSIONS This study shows an improvement in larynx definition after the contouring course with lower interobserver variability and major consistency compared to the reference volume. Other specific educational activities may further increase the quality of radiation therapy contouring in this setting.
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Affiliation(s)
- Domenico Cante
- Radiotherapy Department, Ivrea Community Hospital, A.S.L. TO4, Ivrea, Italy.
| | | | - Cristina Piva
- Radiotherapy Department, Ivrea Community Hospital, A.S.L. TO4, Ivrea, Italy
| | | | - Piera Sciacero
- Radiotherapy Department, Ivrea Community Hospital, A.S.L. TO4, Ivrea, Italy
| | | | - Caterina Marta
- Radiotherapy Department, Ivrea Community Hospital, A.S.L. TO4, Ivrea, Italy
| | | | - Monica Viale
- Department of Rete Oncologica Piemonte e Valle d'Aosta, Turin, Italy
| | | | | | - Oscar Bertetto
- Department of Rete Oncologica Piemonte e Valle d'Aosta, Turin, Italy
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14
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Xu H, Gordon JJ, Siebers JV. Coverage-based treatment planning to accommodate delineation uncertainties in prostate cancer treatment. Med Phys 2016; 42:5435-43. [PMID: 26328992 DOI: 10.1118/1.4928490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To compare two coverage-based planning (CP) techniques with fixed margin-based (FM) planning for high-risk prostate cancer treatments, with the exclusive consideration of the dosimetric impact of delineation uncertainties of target structures and normal tissues. METHODS In this work, 19-patient data sets were involved. To estimate structure dose for each delineated contour under the influence of interobserver contour variability and CT image quality limitations, 1000 alternative structures were simulated by an average-surface-of-standard-deviation model, which utilized the patient-specific information of delineated structure and CT image contrast. An IMRT plan with zero planning-target-volume (PTV) margin on the delineated prostate and seminal vesicles [clinical-target-volume (CTV prostate) and CTVSV] was created and dose degradation due to contour variability was quantified by the dosimetric consequences of 1000 alternative structures. When D98 failed to achieve a 95% coverage probability objective D98,95 ≥ 78 Gy (CTV prostate) or D98,95 ≥ 66 Gy (CTVSV), replanning was performed using three planning techniques: (1) FM (PTV prostate margin = 4,5,6 mm and PTVSV margin = 4,5,7 mm for RL, PA, and SI directions, respectively), (2) CPOM which optimized uniform PTV margins for CTV prostate and CTVSV to meet the D98,95 objectives, and (3) CPCOP which directly optimized coverage-based objectives for all the structures. These plans were intercompared by computing percentile dose-volume histograms and tumor-control probability/normal tissue complication probability (TCP/NTCP) distributions. RESULTS Inherent contour variability resulted in unacceptable CTV coverage for the zero-PTV-margin plans for all patients. For plans designed to accommodate contour variability, 18/19 CP plans were most favored by achieving desirable D98,95 and TCP/NTCP values. The average improvement of probability of complication free control was 9.3% for CPCOP plans and 3.4% for CPOM plans. CONCLUSIONS When the delineation uncertainties need to be considered for prostate patients, CP techniques can produce more desirable plans than FM plans for most patients. The relative advantages between CPCOP and CPOM techniques are patient specific.
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Affiliation(s)
- Huijun Xu
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 and Department of Radiation Oncology, University of Maryland, Baltimore, Maryland 21201
| | - J James Gordon
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan 48202
| | - Jeffrey V Siebers
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 and Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908
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Li W, Vassil A, Godley A, Mossolly LM, Shang Q, Xia P. Using daily diagnostic quality images to validate planning margins for prostate interfractional variations. J Appl Clin Med Phys 2016; 17:61-74. [PMID: 27167262 PMCID: PMC5690910 DOI: 10.1120/jacmp.v17i3.5923] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 12/18/2015] [Accepted: 12/15/2015] [Indexed: 12/31/2022] Open
Abstract
The purpose of this study is to use the same diagnostic-quality verification and planning CTs to validate planning margin account for residual interfractional variations with image-guided soft tissue alignment of the prostate. For nine pros-tate cancer patients treated with IMRT to 78 Gy in 39 fractions, daily verification CT-on-rails images of the first seven and last seven fractions (n = 126) were retrospectively selected for this study. On these images, prostate, bladder, and rectum were delineated by the same attending physician. Clinical plans were cre-ated with a margin of 8 mm except for 5 mm posteriorly, referred to as 8/5mm. Three additional plans were created for each patient with the margins of 6/4 mm, 4/2mm, and 2 mm uniform. These plans were subsequently applied to daily images and radiation doses were recalculated. The isocenters of these plans were placed according to clinical online shifts, which were based on soft tissue alignment to the prostate. Retrospective offline shifts by aligning prostate contours were com-pared to online shifts. The resultant daily target dose was analyzed using D99, the percentage of the prescription dose received by 99% of CTV. The percent of blad-der volume receiving 65 Gy (V65Gy) and rectum V70Gy were also analyzed. After interfractional correction, using CTV D99 > 97% criteria, 8/5 mm, 6/4 mm, 4/2 mm, and 2 mm planning margins met the CTV dose coverage in 95%, 91%, 65%, and 53% of the 126 fractions with online shifts, and 99%, 98%, 85%, and 68% with offline shifts. The rectum V70Gy and bladder V65Gy were significantly decreased at each level of margin reduction (p < 0.05). With daily diagnostic quality imaging-guidance, the interfractional planning margin may be reduced from 8/5mm to 6/4 mm. The residual interfractional uncertainties most likely stem from prostate rotation anddeformation.
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16
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Automated Delineation of the Normal Urinary Bladder on Planning CT and Cone Beam CT. J Med Imaging Radiat Sci 2016; 47:21-29. [DOI: 10.1016/j.jmir.2015.09.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 09/25/2015] [Accepted: 09/29/2015] [Indexed: 11/19/2022]
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Comparative Analysis of Bilateral Temporomandibular Joints in Patients With Unilateral Temporomandibular Joint Complaints Using Cone Beam Computed Tomography. J Craniofac Surg 2015; 26:e773-6. [PMID: 26595003 DOI: 10.1097/scs.0000000000002253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE This study was to determine if there was any temporomandibular joint (TMJ) indicator that was not statistically different in the controls but was with statistical difference between the bilateral sides in patients with unilateral TMJ complaints using cone beam computed tomography (CBCT). METHODS TMJ CBCT images of 123 patients were used to preliminarily determine the indicators suitable for the measuring method. TMJ CBCT image reconstruction was performed and 19 indicators were measured. Thirty-six patients without TMJ complaint were used as controls. These bilateral TMJs were analyzed by paired t test to find out the indicators without statistical significance in the control group. Fifty patients with TMJ complaints unilaterally were used to determine the indicators that showed no statistical difference in the control group and showed statistical difference in the unilateral TMJ complaints group. RESULTS All measured values showed no difference statistically in the control group, except the radius value. In the group of unilateral TMJ complaints, sagittal 60° joint space was statistically different (P < 0.05); parallel 120° and sagittal 90° joint space were significantly different (P < 0.01); the rest of the measured values proved to be of no statistical difference. CONCLUSIONS Sagittal 60° joint space, parallel 120°, and sagittal 90° joint space were suggested to be the indicators with statistical difference between symptomatic side and asymptomatic side in patients with unilateral TMJ complaints. Comparing with the asymptomatic side, there is a significant joint space increase in symptomatic side in the patients with unilateral TMJ complaint.
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18
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Kong VC, Marshall A, Chan HB. Cone Beam Computed Tomography: The Challenges and Strategies in Its Application for Dose Accumulation. J Med Imaging Radiat Sci 2015; 47:92-97. [PMID: 31047170 DOI: 10.1016/j.jmir.2015.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 11/25/2022]
Abstract
Online image guidance using cone beam computed tomography (CBCT) has greatly improved the geometric precision of radiotherapy. Changes in anatomy are common during a course of fractionated treatment, resulting in dose deviation from the planned distribution. There is increased interest in performing dose accumulation to compute the actual delivered dose and to adapt the treatment when necessary. This can be achieved by delineating the volume of interest and by generating "dose of the day" through dose computation on the CBCT. However, the image quality and the accuracy of the CT number of CBCT are deemed to be inferior to fan beam CT, which increases the uncertainty associated in this process. A review of literature was conducted to assess the reliability of and to examine strategies for overcoming the challenges in using CBCT for volume delineation and dose computation. The review demonstrates that the uncertainty varies across body sites, and different strategies have been recommended to generate comparable results to images from CT simulators. This facilitates a better understanding of the potential and the limitation of using CBCT for dose accumulation.
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Affiliation(s)
- Vickie C Kong
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
| | - Andrea Marshall
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Hon Biu Chan
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
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19
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Falcinelli L, Palumbo I, Radicchia V, Arcidiacono F, Lancellotta V, Montesi G, Matrone F, Zucchetti C, Marcantonini M, Bini V, Aristei C. Prostate cancer: contouring target and organs at risk by kilovoltage and megavoltage CT and MRI in patients with and without hip prostheses. Br J Radiol 2015; 88:20150509. [PMID: 26462970 DOI: 10.1259/bjr.20150509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE In radiotherapy treatment, planning target volume and organs at risk are contoured on kilovoltage CT (kVCT) images. Unlike MR images, kVCT does not provide precise information on target volume extension. Since neither kVCT nor MRI may be suitable for contouring in patients with ferrous hip prostheses, this study evaluated whether megavoltage CT (MVCT) reduced interobserver variability. METHODS Two patients without hip prostheses and one patient (Patient 3) with hip prostheses were enrolled. Six radiation oncologists contoured prostate, rectum and bladder on kVCT (Patients 1 and 3), MRI (Patient 2) and MVCT images (Patient 3). MVCT was acquired with fine, normal and coarse modalities. Interobserver variability for each organ was analysed using conformity index (CI) and coefficient of variation (CV). RESULTS In patients without hip prostheses, CIs were higher in prostate contouring with MRI than with kVCT, indicating lower interobserver variability with MRI. Very slight variations were seen in rectum and bladder contouring. In the patient with hip prostheses (Patient 3), contouring on kVCT lowered CI and increased CV in the prostate, bladder and rectum. The differences were more marked in the prostate. Only fine modality MVCT reduced interobserver variability and only for the prostate. CONCLUSION Even though greater noise and less soft-tissue contrast increase contouring variability with MVCT than with kVCT, lack of artefacts on MVCT could provide better image definition by this modality in hip prosthesis patients in whom MRI is precluded. ADVANCES IN KNOWLEDGE We recommend the fine modality MVCT for contouring hip prostheses patients.
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Affiliation(s)
- Lorenzo Falcinelli
- 1 Department of Onco-Haematological and Gastroenterological Science, Radiation Oncology Division, Perugia General Hospital, Perugia, Italy
| | - Isabella Palumbo
- 2 Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy
| | - Valentina Radicchia
- 2 Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy
| | - Fabio Arcidiacono
- 2 Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy
| | - Valentina Lancellotta
- 2 Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy
| | - Giampaolo Montesi
- 2 Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy
| | - Fabio Matrone
- 2 Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy
| | - Claudio Zucchetti
- 3 Department of Imaging and Laboratory Diagnosis, Medical Physics Unit, Perugia General Hospital, Perugia, Italy
| | - Marta Marcantonini
- 3 Department of Imaging and Laboratory Diagnosis, Medical Physics Unit, Perugia General Hospital, Perugia, Italy
| | - Vittorio Bini
- 4 Internal Medicine, Endocrine and Metabolic Sciences Section, Perugia General Hospital, Perugia, Italy
| | - Cynthia Aristei
- 2 Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy
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McNair HA, Harris EJ, Hansen VN, Thomas K, South C, Hafeez S, Huddart R, Dearnaley DP. Magnitude of observer error using cone beam CT for prostate interfraction motion estimation: effect of reducing scan length or increasing exposure. Br J Radiol 2015; 88:20150208. [PMID: 26246041 PMCID: PMC4730970 DOI: 10.1259/bjr.20150208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 07/30/2015] [Accepted: 08/04/2015] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE Cone beam CT (CBCT) enables soft-tissue registration to planning CT for position verification in radiotherapy. The aim of this study was to determine the interobserver error (IOE) in prostate position verification using a standard CBCT protocol, and the effect of reducing CBCT scan length or increasing exposure, compared with standard imaging protocol. METHODS CBCT images were acquired using a novel 7 cm length image with standard exposure (1644 mAs) at Fraction 1 (7), standard 12 cm length image (1644 mAs) at Fraction 2 (12) and a 7 cm length image with higher exposure (2632 mAs) at Fraction 3 (7H) on 31 patients receiving radiotherapy for prostate cancer. Eight observers (two clinicians and six radiographers) registered the images. Guidelines and training were provided. The means of the IOEs were compared using a Kruzkal-Wallis test. Levene's test was used to test for differences in the variances of the IOEs and the independent prostate position. RESULTS No significant difference was found between the IOEs of each image protocol in any direction. Mean absolute IOE was the greatest in the anteroposterior direction. Standard deviation (SD) of the IOE was the least in the left-right direction for each of the three image protocols. The SD of the IOE was significantly less than the independent prostate motion in the anterior-posterior (AP) direction only (1.8 and 3.0 mm, respectively: p = 0.017). IOEs were within 1 SD of the independent prostate motion in 95%, 77% and 96% of the images in the RL, SI and AP direction. CONCLUSION Reducing CBCT scan length and increasing exposure did not have a significant effect on IOEs. To reduce imaging dose, a reduction in CBCT scan length could be considered without increasing the uncertainty in prostate registration. Precision of CBCT verification of prostate radiotherapy is affected by IOE and should be quantified prior to implementation. ADVANCES IN KNOWLEDGE This study shows the importance of quantifying the magnitude of IOEs prior to CBCT implementation.
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Affiliation(s)
- Helen A McNair
- Royal Marsden NHS Foundation Trust, Sutton, UK
- Institute of Cancer Research, Sutton, UK
| | - Emma J Harris
- Royal Marsden NHS Foundation Trust, Sutton, UK
- Institute of Cancer Research, Sutton, UK
| | | | | | - Christopher South
- Department of Physics, St Luke's Cancer Centre, The Royal County Hospital NHS Foundation Trust, Guilford, Surrey
| | - Shaista Hafeez
- Royal Marsden NHS Foundation Trust, Sutton, UK
- Institute of Cancer Research, Sutton, UK
| | - Robert Huddart
- Royal Marsden NHS Foundation Trust, Sutton, UK
- Institute of Cancer Research, Sutton, UK
| | - David P Dearnaley
- Royal Marsden NHS Foundation Trust, Sutton, UK
- Institute of Cancer Research, Sutton, UK
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Li Y, Guo X, Sun X, Wang N, Xie M, Zhang J, Lv Y, Han W, Hu M, Liu H. Characteristics of temporomandibular joint in patients with temporomandibular joint complaint. Int J Clin Exp Med 2015; 8:16057-16063. [PMID: 26629112 PMCID: PMC4659001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
INTRODUCTION This study was to investigate whether there was statistical difference between the bilateral temporomandibular joint (TMJ) in patients with unilateral TMJ pain or joint sounds, using cone beam computed tomography (CBCT). METHODS TMJ CBCT images of 123 cases were used to preliminarily determine the indicators suitable for the measuring method. TMJ CBCT image reconstruction was performed and 19 indicators were measured. Thirty-six cases without TMJ complaint served as controls. The comparison of bilateral TMJs was analyzed by paired t-test to find out the indicators without statistical significance. Twenty-nine patients with unilateral TMJ pain or joint sounds who underwent CBCT at the hospital were enrolled for the comparative study. The measured values were analyzed by paired t-test to determine the indicators with statistical difference. RESULTS In the control group, only radius value of bilateral TMJ was different statistically (P < 0.05). In the TMJ complaint group, the vertical 60° joint space of the bilateral TMJ was statistically different (P < 0.05) and the rest of the measured values showed no statistical difference. CONCLUSIONS In the patients with unilateral TMJ pain or joint sounds, the vertical 60° joint space of the symptomatic side was significantly increased comparing with the asymptomatic side.
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Affiliation(s)
- Yanfeng Li
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
| | - Xiaoqian Guo
- Department of Stomatology, General Hospital of Ningxia Medical UniversityNo. 804 Shengli South Street, Yinchuan 750004, China
| | - Xiaoxue Sun
- Department of Brain, Liaoning Armed Police Force HospitalNo. 3 Heishan Road, Huanggu District, Shenyang 110034, China
| | - Ning Wang
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
| | - Min Xie
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
| | - Jianqiang Zhang
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
| | - Yuan Lv
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
| | - Weili Han
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
| | - Min Hu
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
| | - Hongchen Liu
- Department of Stomatology, The First Affiliated Hospital of Chinese PLA General HospitalNo. 51 Fucheng Road, Haidian District, Beijing 100048, China
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Watson PGF, Mainegra-Hing E, Tomic N, Seuntjens J. Implementation of an efficient Monte Carlo calculation for CBCT scatter correction: phantom study. J Appl Clin Med Phys 2015. [PMID: 26219003 PMCID: PMC5690008 DOI: 10.1120/jacmp.v16i4.5393] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cone-beam computed tomography (CBCT) images suffer from poor image quality, in a large part due to contamination from scattered X-rays. In this work, a Monte Carlo (MC)-based iterative scatter correction algorithm was implemented on measured phantom data acquired from a clinical on-board CBCT scanner. An efficient EGSnrc user code (egs_cbct) was used to transport photons through an uncorrected CBCT scan of a Catphan 600 phantom. From the simulation output, the contribution from primary and scattered photons was estimated in each projection image. From these estimates, an iterative scatter correction was performed on the raw CBCT projection data. The results of the scatter correction were compared with the default vendor reconstruction. The scatter correction was found to reduce the error in CT number for selected regions of interest, while improving contrast-to-noise ratio (CNR) by 18%. These results demonstrate the performance of the proposed scatter correction algorithm in improving image quality for clinical CBCT images.
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Mayyas E, Kim J, Kumar S, Liu C, Wen N, Movsas B, Elshaikh MA, Chetty IJ. A novel approach for evaluation of prostate deformation and associated dosimetric implications in IGRT of the prostate. Med Phys 2015; 41:091709. [PMID: 25186384 DOI: 10.1118/1.4893196] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Prostate deformation is assumed to be a secondary correction and is typically ignored in the planning target volume (PTV) margin calculations. This assumption needs to be tested, especially when planning margins are reduced with daily image-guidance. In this study, deformation characteristics of the prostate and seminal vesicles were determined, and the dosimetric impact on treatment plans with different PTV margins was investigated. METHODS Ten prostate cancer patients were retrospectively selected for the study, each with three fiducial markers implanted in the prostate. Two hundred CBCT images were registered to respective planning CT images using a B-spline-based deformable image registration (DIR) software. A manual bony anatomy-based match was first applied based on the alignment of the pelvic bones and fiducial landmarks. DIR was then performed. For each registration, deformation vector fields (DVFs) of the prostate and seminal vesicles (SVs) were quantified using deformation-volume histograms. In addition, prostate rotation was evaluated and compared with prostate deformation. For a patient demonstrating small and large prostate deformations, target coverage degradation was analyzed in each of three treatment plans with PTV margins of 10 mm (6 mm at the prostate/rectum interface), as well as 5, and 3 mm uniformly. RESULTS Deformation of the prostate was most significant in the anterior direction. Maximum prostate deformation of greater than 10, 5, and 3 mm occurred in 1%, 17%, and 76% of the cases, respectively. Based on DVF-histograms, DVF magnitudes greater than 5 and 3 mm occurred in 2% and 27% of the cases, respectively. Deformation of the SVs was most significant in the posterior direction, and it was greater than 5 and 3 mm in 7.5% and 44.9% of the cases, respectively. Prostate deformation was found to be poorly correlated with rotation. Fifty percent of the cases showed rotation with negligible deformation and 7% of the cases showed significant deformation with minimal rotation (<3°). Average differences in the D95 dose to the prostate+SVs between the planning CT and CBCT images was 0.4%±0.5%, 3.0%±2.8%, and 6.6%±6.1%, respectively, for the plans with 10/6, 5, and 3 mm margins. For the case with both a large degree of prostate deformation (≈10% of the prostate volume) and rotation (≈8°), D95 was reduced by 0.5%±0.1%, 6.8%±0.6%, and 20.9%±1.6% for 10/6, 5, and 3 mm margin plans, respectively. For the case with large prostate deformation but negligible rotation (<1°), D95 was reduced by 0.4±0.3, 3.9±1.0, and 11.5±2.5 for 10/6, 5, and 3 mm margin plans, respectively. CONCLUSIONS Prostate deformation over a course of fractionated prostate radiotherapy may not be insignificant and may need to be accounted for in the planning margin design. A consequence of these results is that use of highly reduced planning margins must be viewed with caution.
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Affiliation(s)
- Essa Mayyas
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
| | - Jinkoo Kim
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
| | - Sanath Kumar
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
| | - Chang Liu
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
| | - Ning Wen
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
| | - Benjamin Movsas
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
| | - Mohamed A Elshaikh
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
| | - Indrin J Chetty
- Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202
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Moores MT, Hargrave CE, Deegan T, Poulsen M, Harden F, Mengersen K. An external field prior for the hidden Potts model with application to cone-beam computed tomography. Comput Stat Data Anal 2015. [DOI: 10.1016/j.csda.2014.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Boydev C, Taleb-Ahmed A, Derraz F, Peyrodie L, Thiran JP, Pasquier D. Development of CBCT-based prostate setup correction strategies and impact of rectal distension. Radiat Oncol 2015; 10:83. [PMID: 25890308 PMCID: PMC4465160 DOI: 10.1186/s13014-015-0386-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 03/20/2015] [Indexed: 12/25/2022] Open
Abstract
Background Cone-beam computed tomography (CBCT) image-guided radiotherapy (IGRT) systems are widely used tools to verify and correct the target position before each fraction, allowing to maximize treatment accuracy and precision. In this study, we evaluate automatic three-dimensional intensity-based rigid registration (RR) methods for prostate setup correction using CBCT scans and study the impact of rectal distension on registration quality. Methods We retrospectively analyzed 115 CBCT scans of 10 prostate patients. CT-to-CBCT registration was performed using (a) global RR, (b) bony RR, or (c) bony RR refined by a local prostate RR using the CT clinical target volume (CTV) expanded with 1-to-20-mm varying margins. After propagation of the manual CT contours, automatic CBCT contours were generated. For evaluation, a radiation oncologist manually delineated the CTV on the CBCT scans. The propagated and manual CBCT contours were compared using the Dice similarity and a measure based on the bidirectional local distance (BLD). We also conducted a blind visual assessment of the quality of the propagated segmentations. Moreover, we automatically quantified rectal distension between the CT and CBCT scans without using the manual CBCT contours and we investigated its correlation with the registration failures. To improve the registration quality, the air in the rectum was replaced with soft tissue using a filter. The results with and without filtering were compared. Results The statistical analysis of the Dice coefficients and the BLD values resulted in highly significant differences (p<10−6) for the 5-mm and 8-mm local RRs vs the global, bony and 1-mm local RRs. The 8-mm local RR provided the best compromise between accuracy and robustness (Dice median of 0.814 and 97% of success with filtering the air in the rectum). We observed that all failures were due to high rectal distension. Moreover, the visual assessment confirmed the superiority of the 8-mm local RR over the bony RR. Conclusion The most successful CT-to-CBCT RR method proved to be the 8-mm local RR. We have shown the correlation between its registration failures and rectal distension. Furthermore, we have provided a simple (easily applicable in routine) and automatic method to quantify rectal distension and to predict registration failure using only the manual CT contours.
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Affiliation(s)
- Christine Boydev
- Signal Processing Laboratory, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland. .,Laboratory of Industrial and Human Automation control, Mechanical engineering and Computer Science, University of Valenciennes and Hainaut-Cambrésis, Valenciennes, France.
| | - Abdelmalik Taleb-Ahmed
- Laboratory of Industrial and Human Automation control, Mechanical engineering and Computer Science, University of Valenciennes and Hainaut-Cambrésis, Valenciennes, France.
| | - Foued Derraz
- Unité de Traitements de Signaux Biomédicaux, Faculté Libre de Médecine, Lille, France.
| | - Laurent Peyrodie
- Unité de Traitements de Signaux Biomédicaux, Hautes Etudes d'Ingénieur, Lille, France.
| | - Jean-Philippe Thiran
- Signal Processing Laboratory, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland. .,Department of Radiology, University Hospital Center (CHUV) and University of Lausanne, Lausanne, Switzerland.
| | - David Pasquier
- Academic Department of Radiation Oncology, Centre Oscar Lambret, Lille, France.
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Sbai A, Thariat J, Tachfouti N, Pan Q, Lagrange JL. [Intraprostatic calcifications as natural fiducial markers in image-guided radiotherapy for prostate cancer]. Cancer Radiother 2014; 18:740-4. [PMID: 25451671 DOI: 10.1016/j.canrad.2014.07.161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 04/07/2014] [Accepted: 07/03/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To establish whether intraprostatic calcifications can serve as natural fiducials for image-guided radiotherapy (IGRT), replacing the implantation of intraprostatic fiducial markers. PATIENTS AND METHODS Patients with prostate cancer, having intraprostatic calcifications visible on CT scan were selected and underwent intensity-modulated radiotherapy/3D conformal radiotherapy with IGRT in the department of radiotherapy of Henri-Mondor Hospital. All cone-beam computed tomographies (CBCT) were repositioned on intraprostatic calcifications. For each acquired image, displacements of intraprostatic calcifications were calculated with reference to position on planning CT in three directions: lateral, longitudinal and vertical. RESULTS Between 2011 and 2013, nine patients had 183 CBCT. For each image, three displacements and space coordinates were calculated using a single reference (intraprostatic calcification). Mean lateral, longitudinal and vertical movements were 0.26±5.7 mm, -1±4.6 mm and 0.42±3.5 mm, respectively. CONCLUSION Studies exploring prostatic movements with fiducial markers as reference and ours with natural fiducials yield similar results. Our data confirm previous studies that have suggested that intraprostatic calcifications can be used as natural fiducials with potential reduction of iatrogenic risks and costs associated with the implantation of fiducial markers.
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Affiliation(s)
- A Sbai
- Centre régional d'oncologie Hassan-II, BP 2013, oued Nachef, Oujda, Maroc.
| | - J Thariat
- Département de radiothérapie, centre Antoine-Lacassagne, 33, avenue Valombrose, 06189 Nice cedex 2, France; Université Nice-Sophia-Antipolis, 33, avenue Valombrose, 06189 Nice cedex 2, France
| | - N Tachfouti
- Laboratoire d'épidémiologie, recherche clinique et de santé communautaire, CHU Hassan-II, Fès, Maroc
| | - Q Pan
- Service de radiothérapie, hôpital Henri-Mondor, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil cedex, France
| | - J-L Lagrange
- Service de radiothérapie, hôpital Henri-Mondor, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil cedex, France; Université Paris Est Créteil, avenue du Général-de-Gaulle, 94010 Créteil cedex, France
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van de Schoot AJAJ, Schooneveldt G, Wognum S, Hoogeman MS, Chai X, Stalpers LJA, Rasch CRN, Bel A. Generic method for automatic bladder segmentation on cone beam CT using a patient-specific bladder shape model. Med Phys 2014; 41:031707. [DOI: 10.1118/1.4865762] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Yan H, Zhen X, Cerviño L, Jiang SB, Jia X. Progressive cone beam CT dose control in image-guided radiation therapy. Med Phys 2014; 40:060701. [PMID: 23718579 DOI: 10.1118/1.4804215] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Cone beam CT (CBCT) in image-guided radiotherapy (IGRT) offers a tremendous advantage for treatment guidance. The associated imaging dose is a clinical concern. One unique feature of CBCT-based IGRT is that the same patient is repeatedly scanned during a treatment course, and the contents of CBCT images at different fractions are similar. The authors propose a progressive dose control (PDC) scheme to utilize this temporal correlation for imaging dose reduction. METHODS A dynamic CBCT scan protocol, as opposed to the static one in the current clinical practice, is proposed to gradually reduce the imaging dose in each treatment fraction. The CBCT image from each fraction is processed by a prior-image based nonlocal means (PINLM) module to enhance its quality. The increasing amount of prior information from previous CBCT images prevents degradation of image quality due to the reduced imaging dose. Two proof-of-principle experiments have been conducted using measured phantom data and Monte Carlo simulated patient data with deformation. RESULTS In the measured phantom case, utilizing a prior image acquired at 0.4 mAs, PINLM is able to improve the image quality of a CBCT acquired at 0.2 mAs by reducing the noise level from 34.95 to 12.45 HU. In the synthetic patient case, acceptable image quality is maintained at four consecutive fractions with gradually decreasing exposure levels of 0.4, 0.1, 0.07, and 0.05 mAs. When compared with the standard low-dose protocol of 0.4 mAs for each fraction, an overall imaging dose reduction of more than 60% is achieved. CONCLUSIONS PINLM-PDC is able to reduce CBCT imaging dose in IGRT utilizing the temporal correlations among the sequence of CBCT images while maintaining the quality.
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Affiliation(s)
- Hao Yan
- Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843, USA
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Boydev C, Pasquier D, Derraz F, Peyrodie L, Taleb-Ahmed A, Thiran JP. Automatic prostate segmentation in cone-beam computed tomography images using rigid registration. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:3993-7. [PMID: 24110607 DOI: 10.1109/embc.2013.6610420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We propose to evaluate automatic three-dimensional gray-value rigid registration (RR) methods for prostate localization on cone-beam computed tomography (CBCT) scans. In total, 103 CBCT scans of 9 prostate patients have been analyzed. Each one was registered to the planning CT scan using different methods: (a) global RR, (b) pelvis bone structure RR, (c) bone RR refined by local soft-tissue RR using the CT clinical target volume (CTV) expanded with a 1, 3, 5, 8, 10, 12, 15 or 20-mm margin. To evaluate results, a radiation oncologist was asked to manually delineate the CTV on the CBCT scans. The Dice coefficients between each automatic CBCT segmentation - derived from the transformation of the manual CT segmentation - and the manual CBCT segmentation were calculated. Global or bone CT/CBCT RR has been shown to yield insufficient results in average. Local RR with an 8-mm margin around the CTV after bone RR was found to be the best candidate for systematically significantly improving prostate localization.
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Nishioka K, Shimizu S, Kinoshita R, Inoue T, Onodera S, Yasuda K, Harada K, Nishikawa Y, Onimaru R, Shirato H. Evaluation of inter-observer variability of bladder boundary delineation on cone-beam CT. Radiat Oncol 2013; 8:185. [PMID: 23879876 PMCID: PMC3726473 DOI: 10.1186/1748-717x-8-185] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 07/21/2013] [Indexed: 11/23/2022] Open
Abstract
Background In-room cone-beam computerized tomography (CBCT) imaging is a promising method to reduce setup errors, especially in organs such as the bladder that often have large intrafractional variations due to organ movement. CBCT image quality is limited by low contrast and imaging artifacts, but few data have been reported about inter-observer variability of bladder boundary delineation on CBCT. The aim of this work was to analyze and evaluate the inter-observer contouring uncertainties of bladder boundary delineation on CBCT images in a prospective fashion. Methods Five radiation oncologists contoured 10 bladders using the CBCT datasets of consecutive 10 patients (including 4 females) who were irradiated to the pelvic region. Prostates were also contoured in male patients. Patients who had had prostatectomy were excluded. The coefficient of variation (COV), conformity index (CIgen), and coordinates of center-of-mass (COM) of the bladder and prostate were calculated for each patient. Results The mean COV for the bladder and prostate was 0.08 and 0.20, respectively. The mean CIgen of the bladder and prostate was 0.81 and 0.66, respectively. The root mean square (RMS) of the inter-observer standard deviation (σ) of the COM displacement in the left-right (LR) and anterior-posterior (AP) direction was 0.79, 0.87 and 0.54 for the bladder and 0.63, 0.99 and 1.72 for the prostate. Regarding the mean COV and CIgen for the bladder, the differences between males and females were not significant. Conclusions Inter-observer variability for bladder delineation on CBCT images was substantially small regardless of gender. We believe that our results support the applicability of CBCT in adaptive radiotherapy for bladder cancer.
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Affiliation(s)
- Kentaro Nishioka
- Department of Radiation Medicine, Hokkaido University School of Medicine, Sapporo, Japan
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Petrič P, Hudej R, Rogelj P, Blas M, Tanderup K, Fidarova E, Kirisits C, Berger D, Dimopoulos JCA, Pötter R, Hellebust TP. Uncertainties of target volume delineation in MRI guided adaptive brachytherapy of cervix cancer: a multi-institutional study. Radiother Oncol 2013; 107:6-12. [PMID: 23453539 DOI: 10.1016/j.radonc.2013.01.014] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 01/16/2013] [Accepted: 01/29/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND AIM We aimed to quantify target volume delineation uncertainties in cervix cancer image guided adaptive brachytherapy (IGABT). MATERIALS AND METHODS Ten radiation oncologists delineated gross tumour volume (GTV), high- and intermediate-risk clinical target volume (HR CTV, IR CTV) in six patients. Their contours were compared with two reference delineations (STAPLE-Simultaneous Truth and Performance Level Estimation and EC- expert consensus) by calculating volumetric and planar conformity index (VCI and PCI) and inter-delineation distances (IDD). RESULTS VCISTAPLE and VCIEC were 0.76 and 0.72 for HR CTV, 0.77 and 0.68 for IR CTV and 0.59 and 0.58 for GTV. Variation was most prominent caudally and cranially in all target volumes and posterolaterally in IR CTV. IDDSTAPLE and IDDEC for HR CTV (3.6±3.5 and 3.8±3.4 mm) were significantly lower than for GTV (4.8±4.2 and 4.2±3.5 mm) and IR CTV (4.7±5.2 and 5.2±5.6 mm) (p<0.05). CONCLUSIONS Due to lower delineation uncertainties when compared to GTV and IR CTV, HR CTV may be considered most robust volume for dose prescription and optimization in cervix cancer IGABT. Adequate imaging, training and use of contouring recommendations are main strategies to minimize delineation uncertainties.
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Affiliation(s)
- Primož Petrič
- Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar.
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Evaluation of 4-dimensional computed tomography to 4-dimensional cone-beam computed tomography deformable image registration for lung cancer adaptive radiation therapy. Int J Radiat Oncol Biol Phys 2013; 86:372-9. [PMID: 23462422 DOI: 10.1016/j.ijrobp.2012.12.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 12/17/2012] [Accepted: 12/26/2012] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate 2 deformable image registration (DIR) algorithms for the purpose of contour mapping to support image-guided adaptive radiation therapy with 4-dimensional cone-beam CT (4DCBCT). METHODS AND MATERIALS One planning 4D fan-beam CT (4DFBCT) and 7 weekly 4DCBCT scans were acquired for 10 locally advanced non-small cell lung cancer patients. The gross tumor volume was delineated by a physician in all 4D images. End-of-inspiration phase planning 4DFBCT was registered to the corresponding phase in weekly 4DCBCT images for day-to-day registrations. For phase-to-phase registration, the end-of-inspiration phase from each 4D image was registered to the end-of-expiration phase. Two DIR algorithms-small deformation inverse consistent linear elastic (SICLE) and Insight Toolkit diffeomorphic demons (DEMONS)-were evaluated. Physician-delineated contours were compared with the warped contours by using the Dice similarity coefficient (DSC), average symmetric distance, and false-positive and false-negative indices. The DIR results are compared with rigid registration of tumor. RESULTS For day-to-day registrations, the mean DSC was 0.75 ± 0.09 with SICLE, 0.70 ± 0.12 with DEMONS, 0.66 ± 0.12 with rigid-tumor registration, and 0.60 ± 0.14 with rigid-bone registration. Results were comparable to intraobserver variability calculated from phase-to-phase registrations as well as measured interobserver variation for 1 patient. SICLE and DEMONS, when compared with rigid-bone (4.1 mm) and rigid-tumor (3.6 mm) registration, respectively reduced the average symmetric distance to 2.6 and 3.3 mm. On average, SICLE and DEMONS increased the DSC to 0.80 and 0.79, respectively, compared with rigid-tumor (0.78) registrations for 4DCBCT phase-to-phase registrations. CONCLUSIONS Deformable image registration achieved comparable accuracy to reported interobserver delineation variability and higher accuracy than rigid-tumor registration. Deformable image registration performance varied with the algorithm and the patient.
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Laursen LV, Elstrøm UV, Vestergaard A, Muren LP, Petersen JB, Lindegaard JC, Grau C, Tanderup K. Residual rotational set-up errors after daily cone-beam CT image guided radiotherapy of locally advanced cervical cancer. Radiother Oncol 2012; 105:220-5. [PMID: 23022176 DOI: 10.1016/j.radonc.2012.08.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 08/13/2012] [Accepted: 08/14/2012] [Indexed: 11/17/2022]
Abstract
PURPOSE Due to the often quite extended treatment fields in cervical cancer radiotherapy, uncorrected rotational set-up errors result in a potential risk of target miss. This study reports on the residual rotational set-up error after using daily cone beam computed tomography (CBCT) to position cervical cancer patients for radiotherapy treatment. METHODS AND MATERIALS Twenty-five patients with locally advanced cervical cancer had daily CBCT scans (650 CBCTs in total) prior to treatment delivery. We retrospectively analyzed the translational shifts made in the clinic prior to each treatment fraction as well as the residual rotational errors remaining after translational correction. RESULTS The CBCT-guided couch movement resulted in a mean translational 3D vector correction of 7.4 mm. Residual rotational error resulted in a target shift exceeding 5 mm in 57 of the 650 treatment fractions. Three patients alone accounted for 30 of these fractions. Nine patients had no shifts exceeding 5 mm and 13 patients had 5 or less treatment fractions with such shifts. CONCLUSION Twenty-two of the 25 patients have none or few treatment fractions with target shifts larger than 5mm due to residual rotational error. However, three patients display a significant number of shifts suggesting a more systematic set-up error.
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Interfractional Positional Variability of Fiducial Markers and Primary Tumors in Locally Advanced Non-Small-Cell Lung Cancer During Audiovisual Biofeedback Radiotherapy. Int J Radiat Oncol Biol Phys 2012; 83:1566-72. [DOI: 10.1016/j.ijrobp.2011.10.051] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 10/18/2011] [Accepted: 10/25/2011] [Indexed: 12/20/2022]
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Feasibility of CBCT-based dose calculation: Comparative analysis of HU adjustment techniques. Radiother Oncol 2012; 104:249-56. [DOI: 10.1016/j.radonc.2012.06.007] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 06/10/2012] [Accepted: 06/17/2012] [Indexed: 11/22/2022]
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Breunig J, Hernandez S, Lin J, Alsager S, Dumstorf C, Price J, Steber J, Garza R, Nagda S, Melian E, Emami B, Roeske JC. A system for continual quality improvement of normal tissue delineation for radiation therapy treatment planning. Int J Radiat Oncol Biol Phys 2012; 83:e703-8. [PMID: 22583604 DOI: 10.1016/j.ijrobp.2012.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 02/03/2012] [Accepted: 02/03/2012] [Indexed: 02/08/2023]
Abstract
PURPOSE To implement the "plan-do-check-act" (PDCA) cycle for the continual quality improvement of normal tissue contours used for radiation therapy treatment planning. METHODS AND MATERIALS The CT scans of patients treated for tumors of the brain, head and neck, thorax, pancreas and prostate were selected for this study. For each scan, a radiation oncologist and a diagnostic radiologist, outlined the normal tissues ("gold" contours) using Radiation Therapy Oncology Group (RTOG) guidelines. A total of 30 organs were delineated. Independently, 5 board-certified dosimetrists and 1 trainee then outlined the same organs. Metrics used to compare the agreement between the dosimetrists' contours and the gold contours included the Dice Similarity Coefficient (DSC), and a penalty function using distance to agreement. Based on these scores, dosimetrists were re-trained on those organs in which they did not receive a passing score, and they were subsequently re-tested. RESULTS Passing scores were achieved on 19 of 30 organs evaluated. These scores were correlated to organ volume. For organ volumes <8 cc, the average DSC was 0.61 vs organ volumes ≥8 cc, for which the average DSC was 0.91 (P=.005). Normal tissues that had the lowest scores included the lenses, optic nerves, chiasm, cochlea, and esophagus. Of the 11 organs that were considered for re-testing, 10 showed improvement in the average score, and statistically significant improvement was noted in more than half of these organs after education and re-assessment. CONCLUSIONS The results of this study indicate the feasibility of applying the PDCA cycle to assess competence in the delineation of individual organs, and to identify areas for improvement. With testing, guidance, and re-evaluation, contouring consistency can be obtained across multiple dosimetrists. Our expectation is that continual quality improvement using the PDCA approach will ensure more accurate treatments and dose assessment in radiotherapy treatment planning and delivery.
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Affiliation(s)
- Jennifer Breunig
- Department of Radiation Oncology, Loyola University Medical Center, Maywood, Illinois, USA
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Cone-Beam CT-Based Delineation of Stereotactic Lung Targets: The Influence of Image Modality and Target Size on Interobserver Variability. Int J Radiat Oncol Biol Phys 2012; 82:e265-72. [DOI: 10.1016/j.ijrobp.2011.03.042] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 02/28/2011] [Accepted: 03/05/2011] [Indexed: 11/19/2022]
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Fotina I, Lütgendorf-Caucig C, Stock M, Pötter R, Georg D. Critical discussion of evaluation parameters for inter-observer variability in target definition for radiation therapy. Strahlenther Onkol 2012; 188:160-7. [PMID: 22281878 DOI: 10.1007/s00066-011-0027-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/20/2011] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND PURPOSE Inter-observer studies represent a valid method for the evaluation of target definition uncertainties and contouring guidelines. However, data from the literature do not yet give clear guidelines for reporting contouring variability. Thus, the purpose of this work was to compare and discuss various methods to determine variability on the basis of clinical cases and a literature review. PATIENTS AND METHODS In this study, 7 prostate and 8 lung cases were contoured on CT images by 8 experienced observers. Analysis of variability included descriptive statistics, calculation of overlap measures, and statistical measures of agreement. Cross tables with ratios and correlations were established for overlap parameters. RESULTS It was shown that the minimal set of parameters to be reported should include at least one of three volume overlap measures (i.e., generalized conformity index, Jaccard coefficient, or conformation number). High correlation between these parameters and scatter of the results was observed. CONCLUSION A combination of descriptive statistics, overlap measure, and statistical measure of agreement or reliability analysis is required to fully report the interrater variability in delineation.
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Affiliation(s)
- I Fotina
- Div. Medical Radiation Physics, Department of Radiotherapy, Medical University Vienna/AKH Vienna, Währinger Gürtel 18-20, Vienna, Austria.
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Harris VA, McDonald FMA, Huddart R. Latest advances in cone-beam CT for bladder radiotherapy. ACTA ACUST UNITED AC 2011. [DOI: 10.2217/iim.11.20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Choi HJ, Kim YS, Lee SH, Lee YS, Park G, Jung JH, Cho BC, Park SH, Ahn H, Kim CS, Yi SY, Ahn SD. Inter- and intra-observer variability in contouring of the prostate gland on planning computed tomography and cone beam computed tomography. Acta Oncol 2011; 50:539-46. [PMID: 21391773 DOI: 10.3109/0284186x.2011.562916] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To investigate inter-/intra-observer variability in defining the prostate by use of planning computed tomography (PCT) and cone beam CT (CBCT) with magnetic resonance image (MRI) as guidance prior to the introduction of an adaptive radiotherapy for prostate cancer. MATERIAL AND METHODS We reviewed PCT and firstly acquired CBCT datasets of each ten patients with prostate cancer. Three physicians independently delineated the prostate based on PCT and CBCT with MRI as guidance, allowing determination of inter-physician variability. Two physicians repeated prostate contouring three times in total to investigate intra-physician variability. We compared delineated prostate volumes in terms of the generalized conformity index (CI(gen)), maximum variation ratio (MVR), and center of mass (COM). RESULTS There were no significant inter-/intra-observer differences in the estimation of prostate volume on both PCT and CBCT. For both inter- and intra-observer variability in contouring the prostate gland, there were no significant differences in MVR between PCT and CBCT. The CI(gen) for inter-observer variability was 0.74 by PCT and 0.69 by CBCT. The CI(gen) for intra-observer variability on PCT and CBCT was 0.84 and 0.81 for observer 2 and 0.76 and 0.73 for observer 3. COM analyses showed that the greatest inter-/intra-observer variability was in the measurement of the prostate apex and base. With respect to CI(gen) and COM analysis for the inter-observer variability, more precise delineation of the prostate was possible on PCT than CBCT. More precise contouring in terms of both CI(gen) and COM was demonstrated by observer 2 than observer 3. CONCLUSIONS Despite some ambiguity in apex and base level, there was a good consistency in delineating the gland on CBCT plus MRI-guided modification both among/within observer(s), without any significant difference from the consistency in defining the prostate on PCT. This study provides a framework for future studies of CBCT imaging of the prostate.
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Affiliation(s)
- Hyuck Jae Choi
- Department of Radiology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea
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Feasibility of CBCT-based target and normal structure delineation in prostate cancer radiotherapy: multi-observer and image multi-modality study. Radiother Oncol 2010; 98:154-61. [PMID: 21176984 DOI: 10.1016/j.radonc.2010.11.016] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 11/28/2010] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND PURPOSE In-room cone-beam CT (CBCT) imaging and adaptive treatment strategies are promising methods to decrease target volumes and to spare organs at risk. The aim of this work was to analyze the inter-observer contouring uncertainties of target volumes and organs at risks (oars) in localized prostate cancer radiotherapy using CBCT images. Furthermore, CBCT contouring was benchmarked against other image modalities (CT, MR) and the influence of subjective image quality perception on inter-observer variability was assessed. METHODS AND MATERIALS Eight prostate cancer patients were selected. Seven radiation oncologists contoured target volumes and oars on CT, MRI and CBCT. Volumes, coefficient of variation (COV), conformity index (cigen), and coordinates of center-of-mass (COM) were calculated for each patient and image modality. Reliability analysis was performed for the support of the reported findings. Subjective perception of image quality was assessed via a ten-scored visual analog scale (VAS). RESULTS The median volume for prostate was larger on CT compared to MRI and CBCT images. The inter-observer variation for prostate was larger on CBCT (CIgen=0.57±0.09, 0.61 reliability) compared to CT (CIgen=0.72±0.07, 0.83 reliability) and MRI (CIgen=0.66±0.12, 0.87 reliability). On all image modalities values of the intra-observer reliability coefficient (0.97 for CT, 0.99 for MR and 0.94 for CBCT) indicated high reproducibility of results. For all patients the root mean square (RMS) of the inter-observer standard deviation (σ) of the COM was largest on CBCT with σ(x)=0.4 mm, σ(y)=1.1 mm, and σ(z)=1.7 mm. The concordance in delineating OARs was much stronger than for target volumes, with average CIgen>0.70 for rectum and CIgen>0.80 for bladder. Positive correlations between CIgen and VAS score of the image quality were observed for the prostate, seminal vesicles and rectum. CONCLUSIONS Inter-observer variability for target volume delineation in prostate cancer is larger for CBCT-based contouring compared to CT and MRI. This factor of influence needs to be considered when defining safety margins for CBCT-based Adaptive Radiotherapy (ART).
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