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Radiotherapy contouring atlas

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https://www.readbyqxmd.com/read/28611300/consistency-mapping-of-16-lymph-node-stations-in-gastric-cancer-by-ct-based-vessel-guided-delineation-of-255-patients
#1
Shuhang Xu, Lingling Feng, Yongming Chen, Ying Sun, Yao Lu, Shaomin Huang, Yang Fu, Rongqin Zheng, Yujing Zhang, Rong Zhang
In order to refine the location and metastasis-risk density of 16 lymph node stations of gastric cancer for neoadjuvant radiotherapy, we retrospectively reviewed the initial images and pathological reports of 255 gastric cancer patients with lymphatic metastasis. Metastatic lymph nodes identified in the initial computed tomography images were investigated by two radiologists with gastrointestinal specialty. A circle with a diameter of 5 mm was used to identify the central position of each metastatic lymph node, defined as the LNc (the central position of the lymph node)...
June 20, 2017: Oncotarget
https://www.readbyqxmd.com/read/28510808/development-of-a-contouring-guide-in-three-different-head-set-ups-for-hippocampal-sparing-radiotherapy-a-practical-approach
#2
Saide Di Biase, Marianna Trignani, Luciana Caravatta, Paul Ioan Voicu, Clelia Di Carlo, Annamaria Vinciguerra, Antonietta Augurio, Francesca Perrotti, Valentina Panara, Domenico Genovesi
BACKGROUNDS: Irradiation of the hippocampus plays a role in neurocognitive toxicity. Its delineation is complex and in practice different head position can vary hippocampus morphology on axial images; so atlas in a single standard position can result ineffective to describe different hippocampal morphologies in different head set-up. The purpose of our study was to develop a guide based on magnetic resonance imaging for hippocampus delineation in three different head set-ups. MATERIALS AND METHODS: Three patients were selected to elaborate our guide...
May 16, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/28379850/a-novel-geometry-dosimetry-label-fusion-method-in-multi-atlas-segmentation-for-radiotherapy-a-proof-of-concept-study
#3
Jina Chang, Zhen Tian, Weiguo Lu, Xuejun Gu, Mingli Chen, Steve B Jiang
Multi-atlas segmentation (MAS) has been widely used to automate the delineation of organs at risk (OARs) for radiotherapy. Label fusion is a crucial step in MAS to cope with the segmentation variabilities among multiple atlases. However, most existing label fusion methods do not consider the potential dosimetric impact of the segmentation result. In this proof-of-concept study, we propose a novel geometry-dosimetry label fusion method for MAS-based OAR auto-contouring, which evaluates the segmentation performance in terms of both geometric accuracy and the dosimetric impact of the segmentation accuracy on the resulting treatment plan...
April 5, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28376237/use-of-image-registration-and-fusion-algorithms-and-techniques-in-radiotherapy-report-of-the-aapm-radiation-therapy-committee-task-group-no-132
#4
Kristy K Brock, Sasa Mutic, Todd R McNutt, Hua Li, Marc L Kessler
Image registration and fusion algorithms exist in almost every software system that creates or uses images in radiotherapy. Most treatment planning systems support some form of image registration and fusion to allow the use of multimodality and time-series image data and even anatomical atlases to assist in target volume and normal tissue delineation. Treatment delivery systems perform registration and fusion between the planning images and the in-room images acquired during the treatment to assist patient positioning...
July 2017: Medical Physics
https://www.readbyqxmd.com/read/28351523/quality-assessment-of-delineation-and-dose-planning-of-early-breast-cancer-patients-included-in-the-randomized-skagen-trial-1
#5
Giulio Francolini, Mette S Thomsen, Esben S Yates, Carine Kirkove, Ingelise Jensen, Egil S Blix, Claus Kamby, Mette H Nielsen, Mechthild Krause, Martin Berg, Ingvil Mjaaland, Andreas Schreiber, Unn-Miriam Kasti, Kristian Boye, Birgitte V Offersen
BACKGROUND AND PURPOSE: To report on a Quality assessment (QA) of Skagen Trial 1, exploring hypofractionation for breast cancer patients with indication for regional nodal radiotherapy. MATERIAL AND METHODS: Deviations from protocol regarding target volume delineations and dose parameters (Dmin, Dmax, D98%, D95% and D2%) from randomly selected dose plans were assessed. Target volume delineation according to ESTRO guidelines was obtained through atlas based automated segmentation and centrally approved as gold standard (GS)...
May 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28339289/the-role-of-delineation-education-programs-for-improving-interobserver-variability-in-target-volume-delineation-in-gastric-cancer
#6
Cem Onal, Mustafa Cengiz, Ozan C Guler, Yemliha Dolek, Serdar Ozkok
OBJECTIVE: To assess whether delineation courses for radiation oncologists improve interobserver variability in target volume delineation for post-operative gastric cancer radiotherapy planning. METHODS: 29 radiation oncologists delineated target volumes in a gastric cancer patient. An experienced radiation oncologist lectured about delineation based on contouring atlas and delineation recommendations. After the course, the radiation oncologists, blinded to the previous delineation, provided delineation for the same patient...
May 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28296324/the-feasibility-of-atlas-based-automatic-segmentation-of-mri-for-h-n-radiotherapy-planning
#7
Kieran Wardman, Robin J D Prestwich, Mark J Gooding, Richard J Speight
Atlas-based autosegmentation is an established tool for segmenting structures for CT-planned head and neck radiotherapy. MRI is being increasingly integrated into the planning process. The aim of this study is to assess the feasibility of MRI-based, atlas-based autosegmentation for organs at risk (OAR) and lymph node levels, and to compare the segmentation accuracy with CT-based autosegmentation. Fourteen patients with locally advanced head and neck cancer in a prospective imaging study underwent a T1-weighted MRI and a PET-CT (with dedicated contrast-enhanced CT) in an immobilization mask...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28134979/a-multiresolution-prostate-representation-for-automatic-segmentation-in-magnetic-resonance-images
#8
Charlens Alvarez, Fabio Martínez, Eduardo Romero
PURPOSE: Accurate prostate delineation is necessary in radiotherapy processes for concentrating the dose onto the prostate and reducing side effects in neighboring organs. Currently, manual delineation is performed over magnetic resonance imaging (MRI) taking advantage of its high soft tissue contrast property. Nevertheless, as human intervention is a consuming task with high intra- and interobserver variability rates, (semi)-automatic organ delineation tools have emerged to cope with these challenges, reducing the time spent for these tasks...
April 2017: Medical Physics
https://www.readbyqxmd.com/read/28048133/su-f-j-113-multi-atlas-based-automatic-organ-segmentation-for-lung-radiotherapy-planning
#9
J Kim, J Han, S Ailawadi, J Baker, A Hsia, Z Xu, S Ryu
PURPOSE: Normal organ segmentation is one time-consuming and labor-intensive step for lung radiotherapy treatment planning. The aim of this study is to evaluate the performance of a multi-atlas based segmentation approach for automatic organs at risk (OAR) delineation. METHODS: Fifteen Lung stereotactic body radiation therapy patients were randomly selected. Planning CT images and OAR contours of the heart - HT, aorta - AO, vena cava - VC, pulmonary trunk - PT, and esophagus - ES were exported and used as reference and atlas sets...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048041/su-f-j-34-automatic-target-based-patient-positioning-framework-for-image-guided-radiotherapy-in-prostate-cancer-treatment
#10
M Sasahara, H Arimura, Y Shibayama, T Hirose, S Ohga, Y Umezu, H Honda, T Sasaki
PURPOSE: Current image-guided radiotherapy (IGRT) procedure is bonebased patient positioning, followed by subjective manual correction using cone beam computed tomography (CBCT). This procedure might cause the misalignment of the patient positioning. Automatic target-based patient positioning systems achieve the better reproducibility of patient setup. Our aim of this study was to develop an automatic target-based patient positioning framework for IGRT with CBCT images in prostate cancer treatment...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047965/tu-h-campus-jep2-05-can-automatic-delineation-of-cardiac-substructures-on-noncontrast-ct-be-used-for-cardiac-toxicity-analysis
#11
Y Luo, Z Liao, W Jiang, D Gomez, R Williamson, L Court, J Yang
PURPOSE: To evaluate the feasibility of using an automatic segmentation tool to delineate cardiac substructures from computed tomography (CT) images for cardiac toxicity analysis for non-small cell lung cancer (NSCLC) patients after radiotherapy. METHODS: A multi-atlas segmentation tool developed in-house was used to delineate eleven cardiac substructures including the whole heart, four heart chambers, and six greater vessels automatically from the averaged 4DCT planning images for 49 NSCLC patients...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047834/su-c-bra-04-automated-segmentation-of-head-and-neck-ct-images-for-radiotherapy-treatment-planning-via-multi-atlas-machine-learning-maml
#12
X Ren, G Sharp, H Gao
PURPOSE: Accurate image segmentation is a crucial step during image guided radiation therapy. This work proposes multi-atlas machine learning (MAML) algorithm for automated segmentation of head-and-neck CT images. METHODS: As the first step, the algorithm utilizes normalized mutual information as similarity metric, affine registration combined with multiresolution B-Spline registration, and then fuses together using the label fusion strategy via Plastimatch. As the second step, the following feature selection strategy is proposed to extract five feature components from reference or atlas images: intensity (I), distance map (D), box (B), center of gravity (C) and stable point (S)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047301/tu-ab-202-10-how-effective-are-current-atlas-selection-methods-for-atlas-based-auto-contouring-in-radiotherapy-planning
#13
D Peressutti, B Schipaanboord, J van Soest, T Lustberg, W van Elmpt, T Kadir, A Dekker, M Gooding
PURPOSE: To investigate the effectiveness of atlas selection methods for improving atlas-based auto-contouring in radiotherapy planning. METHODS: 275 H&N clinically delineated cases were employed as an atlas database from which atlases would be selected. A further 40 previously contoured cases were used as test patients against which atlas selection could be performed and evaluated. 26 variations of selection methods proposed in the literature and used in commercial systems were investigated...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047055/su-g-jep2-06-dosimetric-and-workflow-evaluation-of-first-commercial-synthetic-ct-software-for-clinical-use-in-pelvis
#14
N Tyagi, J Zhang, L Happersett, M Kadbi, J Mechalakos, J Deasy, M Hunt
PURPOSE: evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy METHODS: Twenty prostate patients underwent CT and MR simulation scans in treatment position on a 3T Philips scanner. The MR protocol consisted of a T2w turbo spin-echo for soft tissue contrast, a 2D balanced-fast field echo (b-FFE) for fiducial identification, a dual-echo 3D FFE B0 map for distortion analysis and a 3D mDIXON FFE sequence to generate syn-CT. Two echoes are acquired during mDIXON scan, allowing water, fat, and in-phase images to be derived using the frequency shift of the fat and water protons...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046433/we-h-202-03-accounting-for-large-geometric-changes-during-radiotherapy
#15
G Hugo
Deformable image registration has now been commercially available for several years, with solid performance in a number of sites and for several applications including contour and dose mapping. However, more complex applications have arisen, such as assessing response to radiation therapy over time, registering images pre- and post-surgery, and auto-segmentation from atlases. These applications require innovative registration algorithms to achieve accurate alignment. The goal of this session is to highlight emerging registration technology and these new applications...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/27992058/an-mri-compatible-patient-rotation-system-design-construction-and-first-organ-deformation-results
#16
Brendan Whelan, Gary P Liney, Jason A Dowling, Robba Rai, Lois Holloway, Leigh McGarvie, Ilana Feain, Michael Barton, Megan Berry, Rob Wilkins, Paul Keall
PURPOSE: Conventionally in radiotherapy, a very heavy beam forming apparatus (gantry) is rotated around a patient. From a mechanical perspective, a more elegant approach is to rotate the patient within a stationary beam. Key obstacles to this approach are patient tolerance and anatomical deformation. Very little information on either aspect is available in the literature. The purpose of this work was therefore to design and test an MRI-compatible patient rotation system such that the feasibility of a patient rotation workflow could be tested...
February 2017: Medical Physics
https://www.readbyqxmd.com/read/27991439/augmenting-atlas-based-liver-segmentation-for-radiotherapy-treatment-planning-by-incorporating-image-features-proximal-to-the-atlas-contours
#17
Dengwang Li, Li Liu, Jinhu Chen, Hongsheng Li, Yong Yin, Bulat Ibragimov, Lei Xing
Atlas-based segmentation utilizes a library of previously delineated contours of similar cases to facilitate automatic segmentation. The problem, however, remains challenging because of limited information carried by the contours in the library. In this studying, we developed a narrow-shell strategy to enhance the information of each contour in the library and to improve the accuracy of the exiting atlas-based approach. This study presented a new concept of atlas based segmentation method. Instead of using the complete volume of the target organs, only information along the organ contours from the atlas images was used for guiding segmentation of the new image...
January 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27797223/hippocampal-sparing-whole-brain-radiotherapy-and-integrated-simultaneous-boost-vs-stereotactic-radiosurgery-boost-a-comparative-dosimetric-planning-study
#18
Soon Keat Cheah, Thomas Matthews, Bin Sing Teh
BACKGROUND: Whole brain radiotherapy (WBRT) and stereotactic radiosurgery were frequently used to palliate patients with brain metastases. It remains controversial which modality or combination of therapy is superior especially in the setting of limited number of brain metastases. The availability of newer medical therapy that improves survival highlighted the importance of reducing long term radiation toxicity associated with WBRT. In this study, we aim to demonstrate the hippocampal sparing technique with whole brain and integrated simultaneous boost Materials and Methods: Planning data from 10 patients with 1-5 brain metastases treated with SRS were identified...
2016: Asian Pacific Journal of Cancer Prevention: APJCP
https://www.readbyqxmd.com/read/27570583/quantitative-assessment-of-target-delineation-variability-for-thymic-cancers-agreement-evaluation-of-a-prospective-segmentation-challenge
#19
Emma Holliday, Clifton D Fuller, Jayashree Kalpathy-Cramer, Daniel Gomez, Andreas Rimner, Ying Li, Suresh Senan, Lynn D Wilson, Jehee Choi, Ritsuko Komaki, Charles R Thomas
OBJECTIVES: We sought to quantitatively determine the inter-observer variability of expert radiotherapy target-volume delineation for thymic cancers, as part of a larger effort to develop an expert-consensus contouring atlas. METHODS: A pilot dataset was created consisting of a standardized case presentation with pre- and post-operative DICOM CT image sets from a single patient with Masaoka-Koga Stage III thymoma. Expert thoracic radiation oncologists delineated tumor targets on the pre- and post-operative scans as they would for a definitive and adjuvant case, respectively...
March 2016: Journal of Radiation Oncology
https://www.readbyqxmd.com/read/27536556/comparison-of-automated-atlas-based-segmentation-software-for-postoperative-prostate-cancer-radiotherapy
#20
Grégory Delpon, Alexandre Escande, Timothée Ruef, Julien Darréon, Jimmy Fontaine, Caroline Noblet, Stéphane Supiot, Thomas Lacornerie, David Pasquier
Automated atlas-based segmentation (ABS) algorithms present the potential to reduce the variability in volume delineation. Several vendors offer software that are mainly used for cranial, head and neck, and prostate cases. The present study will compare the contours produced by a radiation oncologist to the contours computed by different automated ABS algorithms for prostate bed cases, including femoral heads, bladder, and rectum. Contour comparison was evaluated by different metrics such as volume ratio, Dice coefficient, and Hausdorff distance...
2016: Frontiers in Oncology
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