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https://www.readbyqxmd.com/read/29219117/prediction-of-radiation-necrosis-in-a-rodent-model-using-magnetic-resonance-imaging-apparent-transverse-relaxation-r-sub-2-sub-sup-sup
#1
Jean-Guy Belliveau, Michael D Jensen, James M P Stewart, Igor Solovey, Martyn L Klassen, Glenn S Bauman, Ravi S Menon
Radiation necrosis remains an irreversible long-term side-effect following radiotherapy to the brain. The ability to predict areas that could ultimately develop into necrosis could lead to prevention and management of radiation necrosis. Materials and Methods: Fischer 344 rats were irradiated using two platforms (micro-CT irradiator and x-RAD 225 IGRT) with radiation up to 30 Gy for the micro-CT and 40 Gy for the xRAD-224 to half the brain. Animals were subsequently imaged using a 9.4T MRI scanner every 2-4 weeks for up to 28 weeks using a 7-echo gradient echo sequence...
December 8, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29184684/impact-of-sarcopenia-on-outcomes-of-locally-advanced-esophageal-cancer-patients-treated-with-neoadjuvant-chemoradiation-followed-by-surgery
#2
Gilbert Z Murimwa, Puja S Venkat, William Jin, Susan Leuthold, Kujtim Latifi, Khaldoun Almhanna, Jose M Pimiento, Jacques-Pierre Fontaine, Sarah E Hoffe, Jessica M Frakes
Background: Sarcopenia is an independent predictor of clinical outcomes in multiple gastrointestinal cancers. Total psoas area (TPA), as measured on a single cross-sectional CT image at the L4 vertebral body level, has been correlated with sarcopenia. We sought to evaluate whether TPA was predictive of acute grade ≥3 toxicity, pathologic response, and overall survival in patients with locally advanced esophageal cancer receiving tri-modality therapy. Methods: An institutional database of esophageal cancer patients treated with neoadjuvant chemoradiation followed by surgery was queried...
October 2017: Journal of Gastrointestinal Oncology
https://www.readbyqxmd.com/read/29181556/oligometastases-in-prostate-cancer-metabolic-response-in-follow-up-psma-pet-cts-after-hypofractionated-igrt
#3
René Baumann, Mark Koncz, Ulf Luetzen, Fabian Krause, Juergen Dunst
BACKGROUND: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMAPET/CT) is a new and evolving diagnostic method in prostate cancer with special impact on treatment planning in image-guided radiotherapy (IGRT). Initial results of metabolic response in repeated PSMA PET/CTs after hypofractionated IGRT for metastatic lesions are reported here. MATERIALS AND METHODS: Of 280 patients investigated with 68Ga-PSMA PET/CT in the period from 01/2014 through 12/2016 in the authors' department, patients were selected according to the following criteria: oligometastatic disease at initial PSMA PET/CT defined as not more than five metastatic lesions, hypofractionated IGRT to all lesions, no systemic therapy in the last 6 months and during follow-up, and at least one follow-up PSMA PET after radiotherapy...
November 27, 2017: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/29154259/evaluation-of-coefficients-to-derive-organ-and-effective-doses-from-cone-beam-ct-cbct-scans-a-monte-carlo-study
#4
Abdullah Abuhaimed, Colin J Martin
Regular imaging is used throughout image guided radiation therapy (IGRT) to improve treatment delivery. In order for treatment procedures to be optimized, the doses delivered by imaging exposures should be taken into account. CT dosimetry methods based on the CT dose index (CTDI), measured with a 100 mm long pencil ionization chamber (CTDI<sub>100</sub>) in standard phantoms, are not designed for the cone beam CT (CBCT) imaging systems used in radiotherapy, therefore a modified version has been proposed for CBCT by the International Electrotechnical Commission (CTDI<sub>IEC</sub>)...
November 20, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/29136287/quantification-of-mri-visibility-and-artefacts-at-3t-of-liquid-fiducial-marker-in-a-pancreas-tissue-mimicking-phantom
#5
Sergej Schneider, Rasmus Irming Jølck, Esther Gera Cornelia Troost, Aswin Louis Hoffmann
PURPOSE: X-ray based position verification of the target volume in image-guided radiation therapy (IGRT) of patients with pancreatic ductal adenocarcinoma (PDAC) is currently performed on solid fiducial markers that are implanted under endoscopic ultrasonography. A new biodegradable liquid fiducial marker has recently been introduced. To assess its potential use for magnetic resonance imaging (MRI) guided photon or proton radiotherapy of PDAC, the MRI visibility and artefacts of this marker were quantified and compared against solid gold markers...
November 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/29125857/phantom-based-evaluation-of-dose-exposure-of-ultrafast-combined-kv-mv-cbct-towards-clinical-implementation-for-igrt-of-lung-cancer
#6
Anna Arns, Manuel Blessing, Jens Fleckenstein, Dzmitry Stsepankou, Judit Boda-Heggemann, Juergen Hesser, Frank Lohr, Frederik Wenz, Hansjoerg Wertz
PURPOSE: Combined ultrafast 90°+90° kV-MV-CBCT within single breath-hold of 15s has high clinical potential for accelerating imaging for lung cancer patients treated with deep inspiration breath-hold (DIBH). For clinical feasibility of kV-MV-CBCT, dose exposure has to be small compared to prescribed dose. In this study, kV-MV dose output is evaluated and compared to clinically-established kV-CBCT. METHODS: Accurate dose calibration was performed for kV and MV energy; beam quality was determined...
2017: PloS One
https://www.readbyqxmd.com/read/29125035/cone-beam-computed-tomography-cbct-for-adaptive-image-guided-head-and-neck-radiation-therapy
#7
Christian A Hvid, Ulrik V Elstrøm, Kenneth Jensen, Cai Grau
BACKGROUND: Adaptive (ART) and image guided radiation therapy (IGRT) can improve target coverage and reduce unnecessary irradiation of organs at risk (OAR). The purpose of this study is to report the results of using mid-course imaging and a novel workflow with cone-beam computed tomography (CBCT) surveillance of dose to OAR to trigger adaptive replanning in head and neck radiotherapy. MATERIAL AND METHODS: Impact of radiation therapist (RTT) managed match protocol and mid-course imaging was assessed in two cohorts of consecutive patients receiving RT to the head and neck region, using computed tomography (CT) and CBCT-based dose verification respectively...
November 10, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/29122556/effect-of-imaging-frequency-on-ptv-margins-and-geographical-miss-during-image-guided-radiation-therapy-for-prostate-cancer
#8
Meetakshi Gupta, Poonam Gamre, Sadhana Kannan, Ganesh Rokde, Rahul Krishnatry, Vedang Murthy
BACKGROUND: The relationship between frequency of imaging during image guided radiation therapy (IGRT) and planning target volume (PTV) margin remains unclear. This issue is of practical significance given resource and time intensive nature of IGRT. The purpose of this study was to evaluate PTV margins with predefined and commonly used less-than-daily IGRT schedules using data obtained from patients treated with daily IGRT for prostate cancer. METHODS AND MATERIALS: Daily setup error and 3-dimensional daily alignment data for a total of 108 consecutive patients with prostate cancer treated with 2700 fractions of daily image guidance on tomotherapy were retrospectively analyzed...
October 7, 2017: Practical Radiation Oncology
https://www.readbyqxmd.com/read/29114617/two-and-a-half-year-clinical-experience-with-the-world-s-first-magnetic-resonance-image-guided-radiation-therapy-system
#9
Benjamin W Fischer-Valuck, Lauren Henke, Olga Green, Rojano Kashani, Sahaja Acharya, Jeffrey D Bradley, Clifford G Robinson, Maria Thomas, Imran Zoberi, Wade Thorstad, Hiram Gay, Jiayi Huang, Michael Roach, Vivian Rodriguez, Lakshmi Santanam, Harold Li, Hua Li, Jessika Contreras, Thomas Mazur, Dennis Hallahan, Jeffrey R Olsen, Parag Parikh, Sasa Mutic, Jeff Michalski
Purpose: Magnetic resonance image guided radiation therapy (MR-IGRT) has been used at our institution since 2014. We report on more than 2 years of clinical experience in treating patients with the world's first MR-IGRT system. Methods and materials: A clinical service was opened for MR-IGRT in January 2014 with an MR-IGRT system consisting of a split 0.35T magnetic resonance scanner that straddles a ring gantry with 3 multileaf collimator-equipped (60)Co heads...
July 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/29080990/reirradiation-of-skull-base-tumors-with-advanced-highly-conformal-techniques
#10
REVIEW
Jennifer C Ho, Jack Phan
PURPOSE OF REVIEW: Skull base reirradiation is challenging due to complex anatomy, enrichment of treatment-resistant clonogens, and increased risk of severe treatment complications. Without local therapy, early mortality is certain and tumor progression can result in debilitating symptoms. Modern radiotherapy advancements, such as image-guided radiation therapy (IGRT), intensity-modulated radiation therapy (IMRT), particle therapy, and stereotactic radiation therapy (SRT), are attractive for skull base reirradiation...
October 28, 2017: Current Oncology Reports
https://www.readbyqxmd.com/read/29071800/national-survey-on-image-guided-radiotherapy-practice-in-new-zealand
#11
Jerusha Padayachee, Jasmin Loh, Albert Tiong, Louis Lao
INTRODUCTION: This survey aimed to assess the use of image-guided radiotherapy (IGRT) within New Zealand (NZ) and evaluate the quality of IGRT delivery. METHOD: All nine centres in NZ were invited to participate in an online survey in November 2015. Questions were asked on type of IGRT technologies available, IGRT use by tumour site and frequency of imaging. In addition, questions were asked in reference to the American Society for Radiation Oncology (ASTRO) White Paper recommendations on safe practice of IGRT...
October 26, 2017: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/28983664/-radiation-therapy-of-locally-advanced-prostate-cancer
#12
REVIEW
N-S Schmidt-Hegemann, M Li, C Eze, C Belka, U Ganswindt
The risk classification for localized prostate cancer is based on the groups "low", "intermediate", and "high-risk" prostate cancer. Following this established risk group definition, locally advanced prostate cancer (cT3/4N0M0) has to be classified as "high-risk" prostate cancer. Radical prostatectomy or high-dose radiotherapy, which is combined with androgen deprivation, are the only curative standard treatments for locally advanced prostate cancer. Particularly adequate radiation doses, modern radiotherapy techniques like IMRT/IGRT, as well as long-term androgen suppression are essential for an optimal treatment outcome...
November 2017: Der Urologe. Ausg. A
https://www.readbyqxmd.com/read/28965894/intrafraction-monitoring-of-prostate-motion-during-radiotherapy-using-the-clarity-%C3%A2-autoscan-transperineal-ultrasound-tpus-system
#13
A K Richardson, P Jacobs
INTRODUCTION: Implementation of the Clarity(®) Autoscan (Elekta) Transperineal Ultrasound (TPUS) system in Bristol is the first of its kind in the UK and we have already shown its utility in interfractional Image Guided Radiotherapy (IGRT).(14) This study establishes the extent of intrafraction prostate motion as measured by Clarity and explores the potential benefits of TPUS for intrafraction monitoring. METHODS: Monitoring data was analysed for 526 fractions from 20 localised prostate cancer patients...
November 2017: Radiography
https://www.readbyqxmd.com/read/28964533/investigation-of-magnetic-field-effects-on-the-dose-response-of-3d-dosimeters-for-magnetic-resonance-image-guided-radiation-therapy-applications
#14
Hannah J Lee, Yvonne Roed, Sara Venkataraman, Mitchell Carroll, Geoffrey S Ibbott
BACKGROUND AND PURPOSE: The strong magnetic field of integrated magnetic resonance imaging (MRI) and radiation treatment systems influences secondary electrons resulting in changes in dose deposition in three dimensions. To fill the need for volumetric dose quality assurance, we investigated the effects of strong magnetic fields on 3D dosimeters for MR-image-guided radiation therapy (MR-IGRT) applications. MATERIAL AND METHODS: There are currently three main categories of 3D dosimeters, and the following were used in this study: radiochromic plastic (PRESAGE®), radiochromic gel (FOX), and polymer gel (BANG™)...
September 27, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28952463/a-monte-carlo-study-of-organ-and-effective-doses-of-cone-beam-computed-tomography-cbct-scans-in-radiotherapy
#15
Abdullah Abuhaimed, Colin J Martin, Marimuthu Sankaralingam
Cone-beam CT (CBCT) scans utilized for image guided radiation therapy (IGRT) procedures have become an essential part of radiotherapy. The aim of this study was to assess organ and effective doses resulting from new CBCT scan protocols (head, thorax, and pelvis) released with a software upgrade of the kV on-board-imager (OBI) system. Influence of the scan parameters that were changed in the new protocols on the patient dose was also investigated. Organ and effective doses for protocols of the new software (V2...
September 27, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/28924967/postoperative-radiotherapy-for-prostate-cancer-the-sooner-the-better-and-potential-to-reduce-toxicity-even-further
#16
Paolo Borghetti, Luigi Spiazzi, Claudia Cozzaglio, Sara Pedretti, Bruno Caraffini, Luca Triggiani, Diana Greco, Lilia Bardoscia, Fernando Barbera, Michela Buglione, Stefano Maria Magrini
PURPOSE: To evaluate biochemical relapse-free survival (bRFS), overall survival (OS), late rectal and bladder toxicities in a retrospective single institution series, also applying an in-house software for biological dose calculation. METHODS: 258 patients submitted to radiotherapy after prostatectomy were considered. Differences between groups were calculated using the log-rank test and the relevant clinical and therapeutic variables were considered for multivariate analysis...
September 18, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/28916952/air-electron-stream-interactions-during-magnetic-resonance-igrt-skin-irradiation-outside-the-treatment-field-during-accelerated-partial-breast-irradiation
#17
Jong Min Park, Kyung Hwan Shin, Jung-In Kim, So-Yeon Park, Seung Hyuck Jeon, Noorie Choi, Jin Ho Kim, Hong-Gyun Wu
PURPOSE: To investigate and to prevent irradiation outside the treatment field caused by an electron stream in the air generated by the magnetic field during magnetic resonance image-guided accelerated partial breast irradiation (APBI). MATERIALS AND METHODS: In all, 20 patients who received APBI with a magnetic resonance image-guided radiation therapy (MR-IGRT) system were prospectively studied. The prescription dose was 38.5 Gy in 10 fractions of 3.85 Gy and delivered with a tri-cobalt system (the ViewRay system)...
September 15, 2017: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/28895278/contrast-enhancement-for-portal-images-by-combination-of-subtraction-and-reprojection-processes-for-compton-scattering
#18
Masatsugu Hariu, Yuhi Suda, Weishan Chang, Atsushi Myojoyama, Hidetoshi Saitoh
For patient setup of the IGRT technique, various imaging systems are currently available. MV portal imaging is performed in identical geometry with the treatment beam so that the portal image provides accurate geometric information. However, MV imaging suffers from poor image contrast due to larger Compton scatter photons. In this work, an original image processing algorithm is proposed to improve and enhance the image contrast without increasing the imaging dose. Scatter estimation was performed in detail by MC simulation based on patient CT data...
September 12, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28864858/erratum-to-an-igrt-margin-concept-for-pelvic-lymph-nodes-in-high-risk-prostate-cancer
#19
M Groher, P Kopp, M Drerup, H Deutschmann, F Sedlmayer, Frank Wolf
No abstract text is available yet for this article.
October 2017: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/28808749/bioxmark-for-high-precision-radiotherapy-in-an-orthotopic-pancreatic-tumor-mouse-model-experiences-with-a-liquid-fiducial-marker
#20
S Dobiasch, S Kampfer, R Burkhardt, D Schilling, T E Schmid, J J Wilkens, S E Combs
BACKGROUND AND PURPOSE: High-precision radiotherapy (RT) requires precise positioning, particularly with high single doses. Fiducial markers in combination with onboard imaging are excellent tools to support this. The purpose of this study is to establish a pancreatic cancer mouse model for high-precision image-guided RT (IGRT) using the liquid fiducial marker BioXmark (Nanovi, Kongens Lyngby, Denmark). METHODS: In an animal-based cancer model, different volumes of BioXmark (10-50 µl), application forms, and imaging modalities-cone-beam computer tomography (CBCT) incorporated in either the Small Animal Radiation Research Platform (SARRP) or the small-animal micro-CT Scanner (SkyScan; Bruker, Brussels, Belgium)-as well as subsequent RT with the SARRP system were analyzed to derive recommendations for BioXmark...
August 14, 2017: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
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