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Contouring radiotherapy

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https://www.readbyqxmd.com/read/27908181/defining-and-assessing-an-anisotropic-delineation-margin-for-modern-radiotherapy
#1
L R Bell, E M Pogson, P E Metcalfe, L C Holloway
PURPOSE: Uncertainty in target volume delineation for modern radiotherapy impacts dosimetry and patient outcomes. Delineation uncertainty is generally overlooked in practice as a source of error, potentially since historically, other uncertainties have been the main focus. This work defined and assessed an anisotropic delineation margin in both polar and spherical coordinate systems in order to account for the spatially varying nature of this uncertainty using a whole breast radiotherapy cohort as a proof of concept...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27903195/dosimetric-effects-of-onyx-embolization-on-gamma-knife-arteriovenous-malformation-dose-distributions
#2
David J Schlesinger, Håkan Nordström, Anders Lundin, Zhiyuan Xu, Jason P Sheehan
OBJECTIVE Patients with arteriovenous malformations (AVMs) treated with Gamma Knife radiosurgery (GKRS) subsequent to embolization suffer from elevated local failure rates and differences in adverse radiation effects. Onyx is a common embolic material for AVMs. Onyx is formulated with tantalum, a high atomic number (Z = 73) element that has been investigated as a source of dosimetric uncertainty contributing to the less favorable clinical results. However, prior studies have not modeled the complicated anatomical and beam geometries characteristic of GKRS...
December 2016: Journal of Neurosurgery
https://www.readbyqxmd.com/read/27903114/a-quantitative-analysis-of-craniopharyngioma-cyst-expansion-during-and-after-radiation-therapy-and-surgical-implications
#3
Kelly Lamiman, Kenneth K Wong, Benita Tamrazi, Jason D Nosrati, Arthur Olch, Eric L Chang, Erin N Kiehna
OBJECTIVE When complete resection of craniopharyngioma is not achievable or the sequelae are prohibitive, limited surgery and radiation therapy have demonstrated excellent local disease control while minimizing treatment-related sequelae. When residual tissue exists, there is a propensity for further cyst development and expansion during and after radiation therapy. This can result in obstructive hydrocephalus, visual changes, and/or clinical decline. The authors present a quantitative analysis of cyst expansion during and after radiotherapy and examine how it affected subsequent management...
December 2016: Neurosurgical Focus
https://www.readbyqxmd.com/read/27895491/comparison-of-internal-target-volumes-defined-on-3-dimensional-4-dimensonal-and-cone-beam-ct-images-of-non-small-cell-lung-cancer
#4
Fengxiang Li, Jianbin Li, Zhifang Ma, Yingjie Zhang, Jun Xing, Huanpeng Qi, Dongping Shang
PURPOSE: The purpose of this study was to compare the positional and volumetric differences of internal target volumes defined on three-dimensional computed tomography (3DCT), four-dimensional CT (4DCT), and cone-beam CT (CBCT) images of non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: Thirty-one patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during free breathing. The first CBCT was performed and registered to the planning CT using the bony anatomy registration during radiotherapy...
2016: OncoTargets and Therapy
https://www.readbyqxmd.com/read/27893446/stability-of-radiomic-features-in-ct-perfusion-maps
#5
M Bogowicz, O Riesterer, R A Bundschuh, P Veit-Haibach, M Hüllner, G Studer, S Stieb, S Glatz, M Pruschy, M Guckenberger, S Tanadini-Lang
This study aimed to identify a set of stable radiomic parameters in CT perfusion (CTP) maps with respect to CTP calculation factors and image discretization, as an input for future prognostic models for local tumor response to chemo-radiotherapy. Pre-treatment CTP images of eleven patients with oropharyngeal carcinoma and eleven patients with non-small cell lung cancer (NSCLC) were analyzed. 315 radiomic parameters were studied per perfusion map (blood volume, blood flow and mean transit time). Radiomics robustness was investigated regarding the potentially standardizable (image discretization method, Hounsfield unit (HU) threshold, voxel size and temporal resolution) and non-standardizable (artery contouring and noise threshold) perfusion calculation factors using the intraclass correlation (ICC)...
December 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27880733/an-automated-workflow-for-patient-specific-quality-control-of-contour-propagation
#6
William J Beasley, Alan McWilliam, Nicholas J Slevin, Ranald I Mackay, Marcel van Herk
Contour propagation is an essential component of adaptive radiotherapy, but current contour propagation algorithms are not yet sufficiently accurate to be used without manual supervision. Manual review of propagated contours is time-consuming, making routine implementation of real-time adaptive radiotherapy unrealistic. Automated methods of monitoring the performance of contour propagation algorithms are therefore required. We have developed an automated workflow for patient-specific quality control of contour propagation and validated it on a cohort of head and neck patients, on which parotids were outlined by two observers...
December 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27877233/the-impact-of-clinical-stage-on-radiation-doses-to-organs-at-risk-following-intensity-modulated-radiotherapy-in-nasopharyngeal-carcinoma-a-prospective-analysis
#7
Lin Xu, Ji-Jin Yao, Guan-Qun Zhou, Wang-Jian Zhang, Guo-Long Liu, Li-Zhi Liu, Jun Ma, Ying Sun
Background: The development of intensity-modulated radiotherapy (IMRT) has revolutionized the management of nasopharyngeal carcinoma (NPC). The purpose of this study was to investigate the impact of clinical stage on radiation doses to organs at risk (OARs) in NPC. Material and Methods: One hundred and forty-eight patients with newly diagnosed and untreated NPC were prospectively enrolled. Based on the anatomic definition and pathogenesis of radiation induced injury, a total of 28 OARs surrounding the nasopharynx were contoured on axial computed tomography (CT) planning images in each patient...
2016: Journal of Cancer
https://www.readbyqxmd.com/read/27868105/feasibility-of-automated-3-dimensional-magnetic-resonance-imaging-pancreas-segmentation
#8
Shuiping Gou, Percy Lee, Peng Hu, Jean-Claude Rwigema, Ke Sheng
PURPOSE: With the advent of MR guided radiotherapy, internal organ motion can be imaged simultaneously during treatment. In this study, we evaluate the feasibility of pancreas MRI segmentation using state-of-the-art segmentation methods. METHODS AND MATERIAL: T2 weighted HASTE and T1 weighted VIBE images were acquired on 3 patients and 2 healthy volunteers for a total of 12 imaging volumes. A novel dictionary learning (DL) method was used to segment the pancreas and compared to t mean-shift merging (MSM), distance regularized level set (DRLS), graph cuts (GC) and the segmentation results were compared to manual contours using Dice's index (DI), Hausdorff distance and shift of the-center-of-the-organ (SHIFT)...
July 2016: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/27846916/intrafractional-dose-variation-and-beam-configuration-in-carbon-ion-radiotherapy-for-esophageal-cancer
#9
M F Haefner, F Sterzing, D Krug, S A Koerber, O Jaekel, J Debus, M M Haertig
BACKGROUND: In carbon ion radiotherapy (CIR) for esophageal cancer, organ and target motion is a major challenge for treatment planning due to potential range deviations. This study intends to analyze the impact of intrafractional variations on dosimetric parameters and to identify favourable settings for robust treatment plans. METHODS: We contoured esophageal boost volumes in different organ localizations for four patients and calculated CIR-plans with 13 different beam geometries on a free-breathing CT...
November 15, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27846899/contribution-of-submandibular-gland-and-swallowing-structure-sparing-to-post-radiation-therapy-peg-dependence-in-oropharynx-cancer-patients-treated-with-split-neck-imrt-technique
#10
Michael F Gensheimer, Matthew Nyflot, George E Laramore, Jay J Liao, Upendra Parvathaneni
BACKGROUND: Radiation therapy-related dysphagia is worsened by xerostomia. The submandibular glands (SMG) produce saliva rich in lubricating mucins, and sparing the SMG has been shown to reduce xerostomia. The goal of this study was to determine whether SMG sparing IMRT is associated with reduced post-treatment PEG dependence in locally advanced oropharynx cancer patients. METHODS: Patients treated with definitive radiation therapy for oropharynx cancer were included in this retrospective study...
November 15, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27843035/consensus-contouring-guidelines-for-postoperative-stereotactic-body-radiation-therapy-for-metastatic-solid-tumor-malignancies%C3%A2-to-the-spine
#11
Kristin J Redmond, Scott Robertson, Simon S Lo, Scott G Soltys, Samuel Ryu, Todd McNutt, Samuel T Chao, Yoshiya Yamada, Amol Ghia, Eric L Chang, Jason Sheehan, Arjun Sahgal
PURPOSE: To develop consensus contouring guidelines for postoperative stereotactic body radiation therapy (SBRT) for spinal metastases. METHODS AND MATERIALS: Ten spine SBRT specialists representing 10 international centers independently contoured the clinical target volume (CTV), planning target volume (PTV), spinal cord, and spinal cord planning organ at risk volume (PRV) for 10 representative clinical scenarios in postoperative spine SBRT for metastatic solid tumor malignancies...
September 17, 2016: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/27826466/buttock-reconstruction-in-sarcoma-surgery-an-esthetic-sigmoidplasty-closure-for-large-circular-defects-using-double-opposing-skin-flaps
#12
Corné P G Nel, Mahendra Daya
BACKGROUND: Large defects arising from extirpation surgery of buttock sarcomas requiring adjuvant radiotherapy are best closed with flap surgery. The traditional solutions are derived from an approach to pressure sores, which were designed for the ischial, sacral, or trochanteric areas, and have now been adapted for true buttock defects. This invariably destroys the esthetics of the buttock. We describe a novel technique of sigmoidplasty, which preserves most of the esthetic features...
October 2016: Plastic and Reconstructive Surgery. Global Open
https://www.readbyqxmd.com/read/27823640/impact-of-pet-ct-on-radiation-treatment-in-patients-with-esophageal-cancer-a-systematic-review
#13
REVIEW
Jing Lu, Xiang-Dong Sun, Xi Yang, Xin-Yu Tang, Qin Qin, Hong-Cheng Zhu, Hong-Yan Cheng, Xin-Chen Sun
PURPOSE: With the advances in radiotracers, positron emission tomography/computed tomography (PET/CT) is recognized as a useful adjunct to anatomic imaging with CT, MRI and endoscopic ultrasonography (EUS). The objective of this review was to comprehensively analyze the roles of PET/CT for the radiotherapy of esophageal cancer. METHODS: In this review, we focused on issues concerning the application of PET/CT in TNM staging, target volume delineation and response to therapy, both for the primary tumor and regional lymph nodes...
November 2016: Critical Reviews in Oncology/hematology
https://www.readbyqxmd.com/read/27806593/effect-of-atelectasis-changes-on-tissue-mass-and-dose-during-lung-radiotherapy
#14
Christopher L Guy, Elisabeth Weiss, Nuzhat Jan, Leonid B Reshko, Gary E Christensen, Geoffrey D Hugo
PURPOSE: To characterize mass and density changes of lung parenchyma in non-small cell lung cancer (NSCLC) patients following midtreatment resolution of atelectasis and to quantify the impact this large geometric change has on normal tissue dose. METHODS: Baseline and midtreatment CT images and contours were obtained for 18 NSCLC patients with atelectasis. Patients were classified based on atelectasis volume reduction between the two scans as having either full, partial, or no resolution...
November 2016: Medical Physics
https://www.readbyqxmd.com/read/27797223/hippocampal-sparing-whole-brain-radiotherapy-and-integrated-simultaneous-boost-vs-stereotactic-radiosurgery-boost-a-comparative-dosimetric-planning-study
#15
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/27782710/individually-optimized-contrast-enhanced-4d-ct-for-radiotherapy-simulation-in-pancreatic-ductal-adenocarcinoma
#16
Wookjin Choi, Ming Xue, Barton F Lane, Min Kyu Kang, Kruti Patel, William F Regine, Paul Klahr, Jiahui Wang, Shifeng Chen, Warren D'Souza, Wei Lu
PURPOSE: To develop an individually optimized contrast-enhanced (CE) 4D-computed tomography (CT) for radiotherapy simulation in pancreatic ductal adenocarcinomas (PDA). METHODS: Ten PDA patients were enrolled. Each underwent three CT scans: a 4D-CT immediately following a CE 3D-CT and an individually optimized CE 4D-CT using test injection. Three physicians contoured the tumor and pancreatic tissues. Image quality scores, tumor volume, motion, tumor-to-pancreas contrast, and contrast-to-noise ratio (CNR) were compared in the three CTs...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27782691/technical-note-scuda-a-software-platform-for-cumulative-dose-assessment
#17
Seyoun Park, Todd McNutt, William Plishker, Harry Quon, John Wong, Raj Shekhar, Junghoon Lee
PURPOSE: Accurate tracking of anatomical changes and computation of actually delivered dose to the patient are critical for successful adaptive radiation therapy (ART). Additionally, efficient data management and fast processing are practically important for the adoption in clinic as ART involves a large amount of image and treatment data. The purpose of this study was to develop an accurate and efficient Software platform for CUmulative Dose Assessment (scuda) that can be seamlessly integrated into the clinical workflow...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27781491/feasibility-of-offline-head-neck-adaptive-radiotherapy-using-deformed-planning-ct-electron-density-mapping-on-weekly-cone-beam-computed-tomography
#18
Anantharaman Ayyalusamy, Subramani Vellaiyan, Subramanian Shanmugam
OBJECTIVE: The purpose of the study is to use deformable mapping of planning CT electron density values on weekly cone beam computed tomography (CBCT) to quantify the anatomical changes and determine the dose volume relationship in offline adaptive volumetric modulated arc therapy. METHODS: Ten patients treated with RapidArc plans who had weekly CBCTs were selected retrospectively. Planning CT was deformed to weekly CBCTs and the deformed contours were checked for any discrepancies...
October 26, 2016: British Journal of Radiology
https://www.readbyqxmd.com/read/27780693/validation-of-a-magnetic-resonance-imaging-based-auto-contouring-software-tool-for-gross-tumour-delineation-in-head-and-neck-cancer-radiotherapy-planning
#19
T Doshi, C Wilson, C Paterson, C Lamb, A James, K MacKenzie, J Soraghan, L Petropoulakis, G Di Caterina, D Grose
AIMS: To carry out statistical validation of a newly developed magnetic resonance imaging (MRI) auto-contouring software tool for gross tumour volume (GTV) delineation in head and neck tumours to assist in radiotherapy planning. MATERIALS AND METHODS: Axial MRI baseline scans were obtained for 10 oropharyngeal and laryngeal cancer patients. GTV was present on 102 axial slices and auto-contoured using the modified fuzzy c-means clustering integrated with the level set method (FCLSM)...
October 22, 2016: Clinical Oncology: a Journal of the Royal College of Radiologists
https://www.readbyqxmd.com/read/27756417/pancreatic-cancer-adjuvant-radiotherapy-target-volume-design-based-on-the-postoperative-local-recurrence-spatial-location
#20
Wei Yu, Wei Hu, Yongjie Shui, Xiaoyang Zhu, Chao Li, Xiaoqiu Ren, Xueli Bai, Risheng Yu, Li Shen, Tingbo Liang, Lei Zheng, Qichun Wei
OBJECTIVES: To explore the areas at highest risk for postoperative pancreatic cancer local recurrence according to the spatial location of local failures, with the aim to provide a precise target volume for pancreatic cancer adjuvant radiotherapy. METHODS: Patients with pancreatic cancer who had undergone surgery for the primary tumor in pancreas at our institution from January 2010 to August 2015 were retrospectively analyzed. All local recurrences were plotted on the computed tomography (CT) image of a representative patient according to their relative coordinates to superior mesenteric artery (SMA) or celiac axis (CA)...
October 19, 2016: Radiation Oncology
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