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https://www.readbyqxmd.com/read/29788726/dynamics-of-high-risk-clinical-target-volume-reduction-during-brachytherapy-and-impact-on-its-coverage-in-patients-with-inoperable-cervical-cancer
#1
M Pobijakova, D Scepanovic, M Paluga, M Fekete, J Mardiak
Cervical cancer is the third most common cancer in women worldwide. Standard of care for patients with node positive or locally advanced tumors >4 cm is definitive radiotherapy and concurrent chemotherapy. Brachytherapy is an integral part of definitive radiotherapy for cervical cancer. The aim of the study was to show a dynamics of High Risk Clinical Target Volume (HR-CTV) reduction during Brachytherapy (BT) as a part of definitive treatment (External Beam Radiotherapy /EBRT/ +/- Chemotherapy /ChT/) depending on the initial Gross Tumor Volume (GTV) and its impact on HR-CTV coverage in patients with inoperable cervical cancer...
March 14, 2018: Neoplasma
https://www.readbyqxmd.com/read/29778320/simultaneously-avoiding-the-hippocampus-and-hypothalamic-pituitary-axis-during-whole-brain-radiotherapy-a-planning-study
#2
Xing-Wen Fan, Juan-Qi Wang, Jun-Lan Wu, Hong-Bing Wang, Kai-Liang Wu
Whole brain radiotherapy (WBRT) is the preferred treatment for multiple brain metastases, and patients with limited-stage small cell lung cancer undergo prophylactic cranial irradiation after complete remission. However, neurotoxicity remains a complication. In addition to protecting the hippocampus from irradiation to preserve cognitive function, it is also critical to avoid irradiating the hypothalamic-pituitary axis to preserve endocrine and immune function. This study aimed to evaluate the feasibility of delivering WBRT while protecting the hippocampus and hypothalamic-pituitary axis...
May 16, 2018: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/29776418/the-impact-of-contour-variation-on-tumour-control-probability-in-anal-cancer
#3
Michael P Jones, Jarad Martin, Kerwyn Foo, Patrick Estoesta, Lois Holloway, Michael Jameson
BACKGROUND: While intensity modulated radiotherapy (IMRT) has been widely adopted for the treatment of anal cancer (AC), the added contour complexity poses potential risks. This study investigates the impact of contour variation on tumour control probability (TCP) when using IMRT for AC. METHODS: Nine Australian centres contoured a single computed tomography dataset of a patient with AC. The same optimised template-based IMRT planning protocol was applied to each contour set to generate nine representative treatment plans and their corresponding dose volume histograms...
May 18, 2018: Radiation Oncology
https://www.readbyqxmd.com/read/29773331/novel-use-of-viewray-mri-guidance-for-high-dose-rate-brachytherapy-in-the-treatment-of-cervical-cancer
#4
Huaising C Ko, Jessie Y Huang, Jessica R Miller, Rupak K Das, Charles R Wallace, Anna-Maria A De Costa, David M Francis, Margaret R Straub, Bethany M Anderson, Kristin A Bradley
PURPOSE: To characterize image quality and feasibility of using ViewRay MRI (VR)-guided brachytherapy planning for cervical cancer. METHODS AND MATERIALS: Cervical cancer patients receiving intracavitary brachytherapy with tandem and ovoids, planned using 0.35T VR MRI at our institution, were included in this series. The high-risk clinical target volume (HR-CTV), visible gross tumor volume, bladder, sigmoid, bowel, and rectum contours for each fraction of brachytherapy were evaluated for dosimetric parameters...
May 14, 2018: Brachytherapy
https://www.readbyqxmd.com/read/29772077/a-feature-alignment-score-for-online-cone-beam-ct-based-image-guided-radiotherapy-for-prostate-cancer
#5
Catriona Hargrave, Timothy Deegan, Michael Poulsen, Tomasz Bednarz, Fiona Harden, Kerrie Mengersen
PURPOSE: To develop a method for scoring online cone-beam CT (CBCT)-to-planning CT image feature alignment to inform prostate image-guided radiotherapy (IGRT) decision-making. The feasibility of incorporating volume variation metric thresholds, predictive of delivering planned dose into weighted functions, was investigated. METHODS: Radiation therapists and radiation oncologists participated in workshops where they reviewed prostate CBCT-IGRT case examples and completed a paper-based survey of image feature matching practices...
May 17, 2018: Medical Physics
https://www.readbyqxmd.com/read/29772061/an-image-guided-radiotherapy-decision-support-framework-incorporating-a-bayesian-network-and-visualization-tool
#6
Catriona Hargrave, Timothy Deegan, Tomasz Bednarz, Michael Poulsen, Fiona Harden, Kerrie Mengersen
PURPOSE: To describe a Bayesian network (BN) and complementary visualization tool, that aim to support decision-making during online cone-beam computed tomography (CBCT)-based image guide radiotherapy (IGRT) for prostate cancer patients. METHODS: The BN was created to represent relationships between observed prostate, proximal seminal vesicle (PSV), bladder and rectum volume variations, an image feature alignment score (FASTV _ OAR ), delivered dose and treatment plan compliance (TPC)...
May 17, 2018: Medical Physics
https://www.readbyqxmd.com/read/29771683/an-individualized-strategy-to-estimate-the-effect-of-deformable-registration-uncertainty-on-accumulated-dose-in-the-upper-abdomen
#7
Yibing Wang, Steven F Petit, Eliana Vasquez Osorio, Vikas Gupta, Alejandra Méndez Romero, Ben J M Heijmen
In the abdomen, it is challenging to assess the accuracy of deformable image registration (DIR) for individual patients, due to the lack of clear anatomical landmarks, which can hamper clinical applications that require high accuracy DIR, such as adaptive radiotherapy. In this study, we propose and evaluate a methodology for estimating the impact of uncertainties in DIR on calculated accumulated dose in the upper abdomen, in order to aid decision making in adaptive treatment approaches. 
 Sixteen liver metastasis patients treated with SBRT were evaluated...
May 17, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29761663/a-prospective-pilot-study-on-early-toxicity-from-a-simultaneously-integrated-boost-technique-for-canine-sinonasal-tumours-using-image-guided-intensity-modulated-radiation-therapy
#8
A Soukup, V Meier, S Pot, K Voelter, C Rohrer Bley
In order to overcome the common local treatment failure of canine sinonasal tumours, integrated boost techniques were tried in the cobalt/orthovoltage era, but dismissed because of unacceptable early (acute) toxicity. Intriguingly, a recent calculation study of a simultaneously integrated boost (SIB) technique for sinonasal irradiation using intensity-modulated radiation therapy (IMRT) predicted theoretical feasibility. In this prospective pilot study we applied a commonly used protocol of 10 × 4.2 Gy to the planning target volume (PTV) with a 20%-SIB dose to the gross tumour volume (GTV)...
May 14, 2018: Veterinary and Comparative Oncology
https://www.readbyqxmd.com/read/29747904/optimization-by-monte-carlo-method-of-photon-fluence-from-the-x-ray-beam-spectrum-in-a-bimodal-tomographic-system
#9
H Olaya Davila, S A Martínez-Ovalle, H F Castro Serrato, H R Vega-Carrillo
A bimodal tomographic system with a RTW MCBM 65B-50Mo X-ray tube and a XPAD3s semiconductor camera that contains 8 bars, each one with 67,200 hybrid pixels are modeled in GEANT4 simulation code. Several conical X-ray spectra were simulated, particularly a spectrum with a peak energy of 17.4 keV used in tomography on small animals. Three phantoms located in the tomographic center were added to the simulation to evaluate the image quality and its magnification based on the simulation of different photon fluences and the rotation effect of the tomographic system with an average angular velocity of 360o per minute...
April 28, 2018: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/29747873/assessment-of-image-quality-of-a-radiotherapy-specific-hardware-solution-for-pet-mri-in-head-and-neck-cancer-patients
#10
René M Winter, Sara Leibfarth, Holger Schmidt, Kerstin Zwirner, David Mönnich, Stefan Welz, Nina F Schwenzer, Christian la Fougère, Konstantin Nikolaou, Sergios Gatidis, Daniel Zips, Daniela Thorwarth
BACKGROUND AND PURPOSE: Functional PET/MRI has great potential to improve radiotherapy planning (RTP). However, data integration requires imaging with radiotherapy-specific patient positioning. Here, we investigated the feasibility and image quality of radiotherapy-customized PET/MRI in head-and-neck cancer (HNC) patients using a dedicated hardware setup. MATERIAL AND METHODS: Ten HNC patients were examined with simultaneous PET/MRI before treatment, with radiotherapy and diagnostic scan setup, respectively...
May 7, 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29740097/impact-of-18-f-fet-pet-on-target-volume-definition-and-tumor-progression-of-recurrent-high-grade-glioma-treated-with-carbon-ion-radiotherapy
#11
Charlotte Debus, Maria Waltenberger, Ralf Floca, Ali Afshar-Oromieh, Nina Bougatf, Sebastian Adeberg, Sabine Heiland, Martin Bendszus, Wolfgang Wick, Stefan Rieken, Uwe Haberkorn, Jürgen Debus, Maximilian Knoll, Amir Abdollahi
High-precision radiotherapy (HPR) of recurrent high grade glioma (HGG) requires accurate spatial allocation of these infiltrative tumors. We investigated the impact of 18 F-FET PET on tumor delineation and progression of recurrent HGG after HPR with carbon ions. T1 contrast enhanced MRI and 18 F-FET-PET scans of 26 HGG patients were fused with radiotherapy planning volumes. PET-positive (PET+) tumor volumes using different isocontours (I%) were systematically investigated and compared with MRI-derived gross tumor volumes (GTV)...
May 8, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29733238/dose-response-relationships-of-the-sigmoid-for-urgency-syndrome-after-gynecological-radiotherapy
#12
Eleftheria Alevronta, Viktor Skokic, Ulrica Wilderäng, Gail Dunberger, Fei Sjöberg, Cecilia Bull, Karin Bergmark, Rebecka Jörnsten, Gunnar Steineck
PURPOSE: To find out what organs and doses are most relevant for 'radiation-induced urgency syndrome' in order to derive the corresponding dose-response relationships as an aid for avoiding the syndrome in the future. MATERIAL AND METHODS: From a larger group of gynecological cancer survivors followed-up 2-14 years, we identified 98 whom had undergone external beam radiation therapy but not brachytherapy and not having a stoma. Of those survivors, 24 developed urgency syndrome...
May 7, 2018: Acta Oncologica
https://www.readbyqxmd.com/read/29731160/contouring-of-prostate-tumors-on-multiparametric-mri-evaluation-of-clinical-delineations-in-a-multicenter-radiotherapy-trial
#13
Marcel A van Schie, Cuong V Dinh, Petra J van Houdt, Floris J Pos, Stijn W T J P Heijmink, Linda G W Kerkmeijer, Alexis N T J Kotte, Raymond Oyen, Karin Haustermans, Uulke A van der Heide
PURPOSE: To date no guidelines are available for contouring prostate cancer inside the gland, as visible on multiparametric (mp-) MRI. We assessed inter-institutional differences in interpretation of mp-MRI in the multicenter phase III FLAME trial. METHODS: We analyzed clinical delineations on mp-MRI and clinical characteristics from 260 patients across three institutes. We performed a logistic regression analysis to examine each institute's weighting of T2w, ADC and Ktrans intensity maps in the delineation of the cancer...
May 3, 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29714086/a-dosimetric-evaluation-on-applying-rtog-based-and-ct-mri-based-delineation-methods-to-brachial-plexus-in-radiotherapy-of-nasopharyngeal-carcinoma-treated-with-helical-tomotherapy
#14
Chi-Him Li, Vincent Wc Wu, George Chiu
OBJECTIVE: In radiotherapy of nasopharyngeal carcinoma (NPC) patients, the brachial plexus (BP) situating at both sides of the neck are often irradiated to high dose. This study was to evaluate different BP delineation methods and analyse the dosimetric consequences when applying BP dose constraints in radiotherapy planning of NPC. METHODS: 15 NPC cases treated radically with helical tomotherapy were recruited. Apart from the original treatment plan (Plan A), two new plans (Plan B & C) with additional BP dose constraints were computed using the same planning computed tomography (CT) images, structures and planning parameters...
May 1, 2018: British Journal of Radiology
https://www.readbyqxmd.com/read/29708544/radiation-planning-assistant-a-streamlined-fully-automated-radiotherapy-treatment-planning-system
#15
Laurence E Court, Kelly Kisling, Rachel McCarroll, Lifei Zhang, Jinzhong Yang, Hannah Simonds, Monique du Toit, Chris Trauernicht, Hester Burger, Jeannette Parkes, Mike Mejia, Maureen Bojador, Peter Balter, Daniela Branco, Angela Steinmann, Garrett Baltz, Skylar Gay, Brian Anderson, Carlos Cardenas, Anuja Jhingran, Simona Shaitelman, Oliver Bogler, Kathleen Schmeller, David Followill, Rebecca Howell, Christopher Nelson, Christine Peterson, Beth Beadle
The Radiation Planning Assistant (RPA) is a system developed for the fully automated creation of radiotherapy treatment plans, including volume-modulated arc therapy (VMAT) plans for patients with head/neck cancer and 4-field box plans for patients with cervical cancer. It is a combination of specially developed in-house software that uses an application programming interface to communicate with a commercial radiotherapy treatment planning system. It also interfaces with a commercial secondary dose verification software...
April 11, 2018: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29703501/heart-volume-reduction-during-radiotherapy-involving-the-thoracic-region-in-children-an-unexplained-phenomenon
#16
Irma W E M van Dijk, Jorrit Visser, Jan Wiersma, Jessica R van Boggelen, Brian V Balgobind, Elizabeth A M Lieke Feijen, Sophie C Huijskens, Wouter E M Kok, Leontien C M Kremer, Coen R N Rasch, Arjan Bel
BACKGROUND AND PURPOSE: Radiotherapy involving the thoracic region is associated with cardiotoxicity in long-term childhood cancer survivors. We quantified heart volume changes during radiotherapy in children (<18 years) and investigated correlations with patient and treatment related characteristics. MATERIAL AND METHODS: Between 2010 and 2016, 34 children received radiotherapy involving the thoracic region. We delineated heart contours and measured heart volumes on 114 CBCTs...
April 24, 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29681771/dosimetry-of-the-left-anterior-descending-coronary-artery-in-left-breast-cancer-patients-treated-with-postoperative-external-radiotherapy
#17
Adela Poitevin-Chacón, Jessica Chávez-Nogueda, Rubí Ramos Prudencio, Alejandro Calvo Fernández, Alejandro Rodríguez Laguna, Jesús Linares, Julio César Martínez
Aim: To evaluate the dose distribution to the left anterior descending (LAD) coronary artery in patients treated with postoperative three-dimensional conformal radiotherapy (3DCRT). Background: Postoperative radiotherapy may increase the risk of heart disease, particularly in patients with left-sided breast cancer. Clinical data on doses to the LAD are limited. Materials and methods: Retrospective study of 14 patients who underwent postoperative 3DCRT for left breast cancer in 2014...
March 2018: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/29663419/accelerated-3d-bssfp-imaging-for-treatment-planning-on-an-mri-guided-radiotherapy-system
#18
Yu Gao, Ziwu Zhou, Fei Han, Minsong Cao, Narek Shaverdian, John V Hegde, Biraj B Bista, Michael Steinberg, Percy Lee, Ann Raldow, Daniel A Low, Yingli Yang, Peng Hu
PURPOSE: To introduce a compressed sensing and parallel imaging combined technique to reduce the acquisition time of planning MRI for MR-guided radiotherapy (MRgRT) systems. METHODS AND MATERIALS: A variable-density Poisson-Disk (VDPD) under-sampling acquisition along with compressed sensing reconstruction technique was developed and compared with the current planning MR protocol, which uses an optimized balanced-steady-state-free-precession sequence with 7.5-fold (7...
April 16, 2018: Medical Physics
https://www.readbyqxmd.com/read/29663417/technical-note-a-deep-learning-based-auto-segmentation-of-rectal-tumors-in-mr-images
#19
Jiazhou Wang, Jiayu Lu, Gan Qin, Lijun Shen, Yiqun Sun, Hongmei Ying, Zhen Zhang, Weigang Hu
PURPOSE: Manual contouring of gross tumor volumes (GTV) is a crucial and time-consuming process in rectum cancer radiotherapy. This study aims to develop a simple deep learning based auto segmentation algorithm to segment rectal tumors on T2 weighted MR images. MATERIAL AND METHODS: MRI scans (3T, T2-weighted) of 93 patients with locally advanced (cT3-4 and/or cN1-2) rectal cancer treated with neoadjuvant chemoradiotherapy followed by surgery were enrolled in this study...
April 16, 2018: Medical Physics
https://www.readbyqxmd.com/read/29659977/quantification-of-variation-in-dose-volume-parameters-for-the-heart-pericardium-and-left-ventricular-myocardium-during-thoracic-tumor-radiotherapy
#20
Ying Tong, Yong Yin, Pinjing Cheng, Jie Lu, Tonghai Liu, Jinhu Chen, Guanzhong Gong
Cardiac activity can induce dose-volume evaluation errors for cardiac structures. The purpose of this study was to quantify the variation in dose-volume parameters for the heart, pericardium and left ventricular myocardium (LVM) throughout the cardiac circle. The heart, pericardium and LVM of 22 patients were contoured on 20 phases of electrocardiography-gated 4D computed tomography (4DCT) images acquired during breath-hold. Radiotherapy plans were designed on 0% phase of the 4DCT images, and the dose distributions of the plans were imported into MIM Maestro and deformed to each phase to generate distributions for all phases...
April 5, 2018: Journal of Radiation Research
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