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Radiotherapy contouring atlas

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
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
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
Daniel Andreasen, Koen Van Leemput, Jens M Edmund
PURPOSE: In radiotherapy based only on magnetic resonance imaging (MRI), knowledge about tissue electron densities must be derived from the MRI. This can be achieved by converting the MRI scan to the so-called pseudo-computed tomography (pCT). An obstacle is that the voxel intensities in conventional MRI scans are not uniquely related to electron density. The authors previously demonstrated that a patch-based method could produce accurate pCTs of the brain using conventional T1-weighted MRI scans...
August 2016: Medical Physics
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...
2016: Journal of Applied Clinical Medical Physics
Julia Koeck, Frank Lohr, Daniel Buergy, Karen Büsing, Marcus J Trunk, Frederik Wenz, Sabine Mai
BACKGROUND: While intensity modulated radiotherapy (IMRT) in anal cancer is feasible and improves high-dose conformality, the current RTOG/AGITG contouring atlas and planning guidelines lack specific instructions on how to proceed with external genitalia. Meanwhile, the RTOG-Protocol 0529 explicitly recommends genital sparing on the basis of specific genital dose constraints. Recent pattern-of-relapse studies based on conventional techniques suggest that marginal miss might be a potential consequence of genital sparing...
2016: Radiation Oncology
Jamie A Dean, Liam C Welsh, Dualta McQuaid, Kee H Wong, Aleksandar Aleksic, Emma Dunne, Mohammad R Islam, Anushka Patel, Priyanka Patel, Imran Petkar, Iain Phillips, Jackie Sham, Kate L Newbold, Shreerang A Bhide, Kevin J Harrington, Sarah L Gulliford, Christopher M Nutting
BACKGROUND AND PURPOSE: Current oral mucositis normal tissue complication probability models, based on the dose distribution to the oral cavity volume, have suboptimal predictive power. Improving the delineation of the oral mucosa is likely to improve these models, but is resource intensive. We developed and evaluated fully-automated atlas-based segmentation (ABS) of a novel delineation technique for the oral mucosal surfaces. MATERIAL AND METHODS: An atlas of mucosal surface contours (MSC) consisting of 46 patients was developed...
April 2016: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
Katherine L Chapman, Matthew E Witek, Hongyu Chen, Timothy N Showalter, Voichita Bar-Ad, Amy S Harrison
To compare the roles of intensity-modulated radiation therapy (IMRT) and volumetric- modulated arc therapy (VMAT) therapy as compared to simple and complex 3-dimensional chemoradiotherpy (3DCRT) planning for resectable and borderline resectable pancreatic cancer. In all, 12 patients who received postoperative radiotherapy (8) or neoadjuvant concurrent chemoradiotherapy (4) were evaluated retrospectively. Radiotherapy planning was performed for 4 treatment techniques: simple 4-field box, complex 5-field 3DCRT, 5 to 6-field IMRT, and single-arc VMAT...
2016: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Albert K Hoang Duc, Gemma Eminowicz, Ruheena Mendes, Swee-Ling Wong, Jamie McClelland, Marc Modat, M Jorge Cardoso, Alex F Mendelson, Catarina Veiga, Timor Kadir, Derek D'Souza, Sebastien Ourselin
PURPOSE: The aim of this study was to assess whether clinically acceptable segmentations of organs at risk (OARs) in head and neck cancer can be obtained automatically and efficiently using the novel "similarity and truth estimation for propagated segmentations" (STEPS) compared to the traditional "simultaneous truth and performance level estimation" (STAPLE) algorithm. METHODS: First, 6 OARs were contoured by 2 radiation oncologists in a dataset of 100 patients with head and neck cancer on planning computed tomography images...
September 2015: Medical Physics
Jose Dolz, Anne Laprie, Soléakhéna Ken, Henri-Arthur Leroy, Nicolas Reyns, Laurent Massoptier, Maximilien Vermandel
PURPOSE: To constrain the risk of severe toxicity in radiotherapy and radiosurgery, precise volume delineation of organs at risk is required. This task is still manually performed, which is time-consuming and prone to observer variability. To address these issues, and as alternative to atlas-based segmentation methods, machine learning techniques, such as support vector machines (SVM), have been recently presented to segment subcortical structures on magnetic resonance images (MRI). METHODS: SVM is proposed to segment the brainstem on MRI in multicenter brain cancer context...
January 2016: International Journal of Computer Assisted Radiology and Surgery
Wei Huang, Yong Huang, Jujie Sun, Xibin Liu, Jian Zhang, Tao Zhou, Baijiang Zhang, Baosheng Li
PURPOSE: To construct an anatomical atlas of thoracic lymph node regions of esophageal cancer (EC) based on definitions from The Japan Esophageal Society (JES) and generate a consensus to delineate the nodal clinical target volume (CTVn) for elective nodal radiation (ENI) of esophageal squamous cell carcinoma (ESCC). METHODS AND MATERIALS: An interdisciplinary group including two dedicated radiation oncologists, an experienced radiologist, a pathologist and two thoracic surgeons were gathered to generate a three-dimensional radiological description for the mediastinal lymph node regions of EC on axial CT scans...
July 2015: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
J Yang, P Balter, L Court
PURPOSE: To evaluate the performance of commercially available automatic segmentation tools built into treatment planning systems (TPS) in terms of their segmentation accuracy and flexibility in customization. METHODS: Twelve head-and-neck cancer patients and twelve thoracic cancer patients were retrospectively selected to benchmark the model-based segmentation (MBS) and atlas-based segmentation (ABS) in RayStation TPS and the Smart Probabilistic Image Contouring Engine (SPICE) in Pinnacle TPS...
June 2015: Medical Physics
J Yu, Y Gong, V Bar-Ad, T Giaddui, C Hu, E Gore, M Wheatley, J Witt, C Robinson, F Kong, J Bradley, J Galvin, Y Xiao
PURPOSE: Accurate contour delineation is crucial for radiotherapy. Atlas based automatic segmentation tools can be used to increase the efficiency of contour accuracy evaluation. This study aims to optimize technical parameters utilized in the tool by exploring the impact of library size and atlas number on the accuracy of cardiac contour evaluation. METHODS: Patient CT DICOMs from RTOG 0617 were used for this study. Five experienced physicians delineated the cardiac structures including pericardium, atria and ventricles following an atlas guideline...
June 2015: Medical Physics
Y Chen
PURPOSE: To improve the quality of kV X-ray cone beam CT (CBCT) for use in radiotherapy delivery assessment and re-planning by using penalized likelihood (PL) iterative reconstruction and auto-segmentation accuracy of the resulting CBCTs as an image quality metric. METHODS: Present filtered backprojection (FBP) CBCT reconstructions can be improved upon by PL reconstruction with image formation models and appropriate regularization constraints. We use two constraints: 1) image smoothing via an edge preserving filter, and 2) a constraint minimizing the differences between the reconstruction and a registered prior image...
June 2015: Medical Physics
Dengwang Li, Li Liu, Daniel S Kapp, Lei Xing
PURPOSE: For facilitating the current automatic segmentation, in this work we propose 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. METHODS: In setting up an atlas-based library, we include not only the coordinates of contour points, but also the image features adjacent to the contour. 139 planning CT scans with normal appearing livers obtained during their radiotherapy treatment planning were used to construct the library...
June 2015: Medical Physics
J Yang, L Zhang, Y Zhang, L Dong, P Balter, L Court
PURPOSE: To develop a practical approach for accurate contour deformation when deformable image registration (DIR) is used for atlas-based segmentation or contour propagation in image-guided radiotherapy. METHODS: A contour deformation approach was developed on the basis of 3D mesh operations. The 2D contours represented by a series of points in each slice were first converted to a 3D triangular mesh, which was deformed by the deformation vectors resulting from DIR...
June 2015: Medical Physics
C Brooks, V N Hansen, A Riddell, V A Harris, D M Tait
OBJECTIVE: Intensity-modulated radiotherapy (IMRT) for anal canal carcinoma (ACC) is associated with favourable toxicity outcomes. Side effects include sexual dysfunction, skin desquamation, pain and fibrosis to perineum and genitalia region. The genitalia are situated anterior to the primary ACC between two inguinal regions providing a challenging structure to avoid. Techniques improving outcomes require robust, consistent genitalia contouring to ensure standardization and production of fully optimized IMRT plans...
July 2015: British Journal of Radiology
William J Magnuson, Erich Urban, R Adam Bayliss, Paul M Harari
There is considerable practice variation in treatment of the node negative (N0) contralateral neck in patients with head and neck cancer. In this study, we examined the impact of N0 neck target delineation volume on radiation dose to the contralateral parotid gland. Following institutional review board approval, 12 patients with head and neck cancer were studied. All had indications for treatment of the N0 neck, such as midline base of tongue or soft palate extension or advanced ipsilateral nodal disease. The N0 neck volumes were created using the Radiation Therapy Oncology Group head and neck contouring atlas...
June 2015: Technology in Cancer Research & Treatment
Silvia Scoccianti, Beatrice Detti, Davide Gadda, Daniela Greto, Ilaria Furfaro, Fiammetta Meacci, Gabriele Simontacchi, Lucia Di Brina, Pierluigi Bonomo, Irene Giacomelli, Icro Meattini, Monica Mangoni, Sabrina Cappelli, Sara Cassani, Cinzia Talamonti, Lorenzo Bordi, Lorenzo Livi
PURPOSE: Accurate organs at risk definition is essential for radiation treatment of brain tumors. The aim of this study is to provide a stepwise and simplified contouring guide to delineate the OARs in the brain as it would be done in the everyday practice of planning radiotherapy for brain cancer treatment. METHODS: Anatomical descriptions and neuroimaging atlases of the brain were studied. The dosimetric constraints used in literature were reviewed. RESULTS: A Computed Tomography and Magnetic Resonance Imaging based detailed atlas was developed jointly by radiation oncologists, a neuroradiologist and a neurosurgeon...
February 2015: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
Manuel Conson, Laura Cella, Roberto Pacelli, Marco Comerci, Raffaele Liuzzi, Marco Salvatore, Mario Quarantelli
PURPOSE: To implement and evaluate a magnetic resonance imaging atlas-based automated segmentation (MRI-ABAS) procedure for cortical and sub-cortical grey matter areas definition, suitable for dose-distribution analyses in brain tumor patients undergoing radiotherapy (RT). PATIENTS AND METHODS: 3T-MRI scans performed before RT in ten brain tumor patients were used. The MRI-ABAS procedure consists of grey matter classification and atlas-based regions of interest definition...
September 2014: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
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