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https://www.readbyqxmd.com/read/29777595/a-ring-based-compensator-imrt-system-optimized-for-low-and-middle-income-countries-design-and-treatment-planning-study
#1
Jonathon Van Schelt, Daniel Smith, Nicholas Fong, Dolla Toomeh, Patricia A Sponseller, Derek W Brown, Meghan W Macomber, Nina A Mayr, Shilpen Patel, Adam Shulman, G V Subrahmanyam, K Govindarajan, Eric C Ford
PURPOSE: We propose a novel compensator-based IMRT system designed to provide a simple, reliable, and cost-effective adjunct technology, with the goal of expanding global access to advanced radiotherapy techniques. The system would employ easily-reusable tungsten bead compensators that operate independent of a gantry (e.g. mounted in a ring around the patient). Thereby the system can be retrofitted to existing linac and cobalt teletherapy units. This study explores the quality of treatment plans from the proposed system and the dependence on associated design parameters...
May 19, 2018: Medical Physics
https://www.readbyqxmd.com/read/29777007/development-of-64-cu-nota-trastuzumab-for-her2-targeting-radiopharmaceutical-with-improved-pharmacokinetics-for-human-study
#2
Sang-Keun Woo, Su Jin Jang, Min-Jung Seo, Ju Hui Park, Byoung Soo Kim, Eun Jung Kim, Yong Jin Lee, Tae Sup Lee, Gwang Il An, In Ho Song, Youngho Seo, Kwang Il Kim, Joo Hyun Kang
Purpose The purpose of this study was to develop 64 Cu-labeled trastuzumab with improved pharmacokinetics for human epidermal growth factor receptor 2. Methods Trastuzumab was conjugated with SCN-Bn-NOTA and radiolabeled with 64 Cu. Serum stability and immunoreactivity of 64 Cu-NOTA-trastuzumab were tested. Small animal PET imaging and biodistribution study were performed in HER2-positive breast cancer xenograft model (BT-474). Internal dosimetry of experimental animals was performed using the image-based approach with the Monte Carlo N-Particle Code...
May 18, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/29776831/3d-brachytherapy-for-cervical-cancer-new-optimization-ways
#3
I Fumagalli, C Haie-Méder, C Chargari
Brachytherapy has known major improvements in recent decades. It represents an essential component of local treatment of cervix cancers. One major breakthrough was the advent of 3D imaging for image-guided brachytherapy. Doses could be prescribed to volumes. This allows better delineation and coverage of target volumes, as well as organs at risk (bladder, rectum, sigmoid) protection. Local recurrences have been consequently reduced and survival has been improved. In addition, improvement and development of new applicators have facilitated the delivery of interstitial treatments...
May 15, 2018: Cancer Radiothérapie: Journal de la Société Française de Radiothérapie Oncologique
https://www.readbyqxmd.com/read/29776740/development-of-a-deformable-phantom-for-experimental-verification-of-4d-monte-carlo-simulations-in-a-deforming-anatomy
#4
Sara Gholampourkashi, Joanna E Cygler, Bernie Lavigne, Emily Heath
PURPOSE: To verify the accuracy of 4D Monte Carlo (MC) simulations, using the 4DdefDOSXYZnrc user code, in a deforming anatomy. We developed a tissue-equivalent and reproducible deformable lung phantom and evaluated 4D simulations of delivered dose to the phantom by comparing calculations against measurements. METHODS: A novel deformable phantom consisting of flexible foam, emulating lung tissue, inside a Lucite external body was constructed. A removable plug, containing an elastic tumor that can hold film and other dosimeters, was inserted in the phantom...
May 15, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/29772064/impact-of-inter-patient-variability-on-organ-dose-estimates-according-to-mird-schema-uncertainty-and-variance-based-sensitivity-analysis
#5
Alexandra Zvereva, Florian Kamp, Helmut Schlattl, Maria Zankl, Katia Parodi
PURPOSE: Variance-based sensitivity analysis (SA) is described and applied to the radiation dosimetry model proposed by the Committee on Medical Internal Radiation Dose (MIRD) for the organ-level absorbed dose calculations in nuclear medicine. The uncertainties in the dose coefficients thus calculated are also evaluated. METHODS: A Monte Carlo approach was used to compute first-order and total-effect SA indices, which rank the input factors according to their influence on the uncertainty in the output organ doses...
May 17, 2018: Medical Physics
https://www.readbyqxmd.com/read/29766354/image-based-spect-calibration-based-on-the-evaluation-of-the-fraction-of-activity-in-the-field-of-view
#6
Adrien Halty, Jean-Noël Badel, Olga Kochebina, David Sarrut
BACKGROUND: SPECT quantification is important for dosimetry in targeted radionuclide therapy (TRT) and the calibration of SPECT images is a crucial stage for image quantification. The current standardized calibration protocol (MIRD 23) uses phantom acquisitions to derive a global calibration factor in specific conditions. It thus requires specific acquisitions for every clinical protocols. We proposed an alternative and complementary image-based calibration method that allows to determine a calibration factor adapted to each patient, radionuclide, and acquisition protocol and that may also be used as an additional independent calibration...
May 16, 2018: EJNMMI Physics
https://www.readbyqxmd.com/read/29763446/detector-specific-correction-factors-in-radiosurgery-beams-and-their-impact-on-dose-distribution-calculations
#7
Olivia A García-Garduño, Manuel A Rodríguez-Ávila, José M Lárraga-Gutiérrez
Silicon-diode-based detectors are commonly used for the dosimetry of small radiotherapy beams due to their relatively small volumes and high sensitivity to ionizing radiation. Nevertheless, silicon-diode-based detectors tend to over-respond in small fields because of their high density relative to water. For that reason, detector-specific beam correction factors ([Formula: see text]) have been recommended not only to correct the total scatter factors but also to correct the tissue maximum and off-axis ratios...
2018: PloS One
https://www.readbyqxmd.com/read/29762130/ionization-chamber-correction-factors-for-mr-linacs
#8
Stefan Pojtinger, Oliver Steffen Dohm, Ralf-Peter Kapsch, Daniela Thorwarth

 Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor kB.
 The purpose of this study is to systematically investigate kB for a typical reference setup for commercially available ionization chambers with different magnetic field strengths.
 
 Material and Methods:
 The Monte Carlo simulation tool EGSnrc was used to simulate eight commercially available ionization chambers in magnetic fields whose magnetic flux density was in the range of 0 to 2...
May 15, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29760597/application-of-an-incident-taxonomy-for-radiation-therapy-analysis-of-five-years-of-data-from-three-integrated-cancer-centres
#9
Stuart Greenham, Stephen Manley, Kirsty Turnbull, Matthew Hoffmann, Amara Fonseca, Justin Westhuyzen, Andrew Last, Noel J Aherne, Thomas P Shakespeare
Aim: To develop and apply a clinical incident taxonomy for radiation therapy. Background: Capturing clinical incident information that focuses on near-miss events is critical for achieving higher levels of safety and reliability. Methods and materials: A clinical incident taxonomy for radiation therapy was established; coding categories were prescription, consent, simulation, voluming, dosimetry, treatment, bolus, shielding, imaging, quality assurance and coordination of care...
May 2018: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/29760594/uncertainty-in-positioning-ion-chamber-at-reference-depth-for-various-water-phantoms
#10
Naoki Kinoshita, Hiroshi Oguchi, Toshiki Adachi, Hiroki Shioura, Hirohiko Kimura
Background: Uncertainty in the calibration of high-energy radiation sources is dependent on user and equipment type. Aim: We evaluated the uncertainty in the positioning of a cylindrical chamber at a reference depth for reference dosimetry of high-energy photon beams and the resulting uncertainty in the chamber readings for 6- and 10-MV photon beams. The aim was to investigate major contributions to the positioning uncertainty to reduce the uncertainty in calibration for external photon beam radiotherapy...
May 2018: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/29759887/very-sensitive-%C3%AE-al-2-o-3-c-polycrystals-for-thermoluminescent-dosimetry
#11
Críssia Carem Paiva Fontainha, Neriene Alves, Wilmar Barbosa Ferraz, Luiz Oliveira de Faria
New materials have been widely investigated for ionizing radiation dosimetry for medical procedures. Carbon-doped alumina (α-Al2 O3 :C) have been reported to be excellent thermoluminescent (TL) and optically stimulated luminescence (OSL) radiation dosimeters. In the present study, we have synthetized nano and micro-sized α-Al2 O3 :C polycrystals, doped with different percentages of carbon atoms aiming to compare their efficiency as TL dosimeters. The dosimetric characteristics for X ray and gamma fields were investigated...
May 7, 2018: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/29759328/a-novel-applicator-design-for-intracavitary-brachytherapy-of-the-nasopharynx-simulated-reconstruction-image-guided-adaptive-brachytherapy-planning-and-dosimetry
#12
Warren R Bacorro, Ryan Anthony F Agas, Stellar Marie R Cabrera, Maureen R Bojador, Paolo G Sogono, Michael Benedict A Mejia, Teresa T Sy Ortin
PURPOSE: In nasopharyngeal cancer, brachytherapy is given as boost in primary treatment or as salvage for recurrent or persistent disease. The Rotterdam nasopharyngeal applicator (RNA) allows for suboptimal reduction of soft palate radiation dose, based on image-guided brachytherapy plans. Building on the RNA, we propose a novel design, the Benavides nasopharyngeal applicator (BNA). METHODS AND MATERIALS: The virtual BNA was reconstructed on two cases (one T1, one T2) previously treated with intracavitary brachytherapy using the RNA...
May 11, 2018: Brachytherapy
https://www.readbyqxmd.com/read/29753335/external-beam-planning-module-of-eclipse-for-external-beam-radiation-therapy
#13
REVIEW
Cheng B Saw, SiCong Li, Frank Battin, Janice McKeague, Christopher A Peters
Eclipse is a 3-dimensional (3D) treatment planning system for radiation therapy offered by Varian Medical Systems, Inc. The system has the network connectivity for the electronic transfer of image datasets and digital data communication among different equipment. The scope of this project for this special issue of Medical Dosimetry on 3D treatment planning systems is the assessment of planning tools in the external beam planning module of Eclipse to generate optimized treatment plans for patients undergoing external beam radiation therapy...
July 2018: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/29753334/3d-treatment-planning-system-varian-eclipse-for-proton-therapy-planning
#14
REVIEW
Narayan Sahoo, Falk Poenisch, Xiaodong Zhang, Yupeng Li, MingFu Lii, Heng Li, Archana S Gautam, Richard Wu, Michael Gillin, Xiaorong R Zhu
The capabilities of the Eclipse treatment planning system (TPS) (Varian Medical Systems, Palo Alto, CA) for proton therapy treatment planning are described. Various steps involved in the planning process to produce a 3-dimensional (3D) dose distribution both for the passive scattering and pencil beam scanning proton beam therapy are outlined. Mitigation of range and setup uncertainties through robust optimization is discussed. Use of verification plans for patient treatment field dosimetry quality assurance (QA) is presented...
July 2018: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/29747035/microscale-radiosynthesis-preclinical-imaging-and-dosimetry-study-of-18-f-ambf-3-tate-a-potential-pet-tracer-for-clinical-imaging-of-somatostatin-receptors
#15
Ksenia Lisova, Maxim Sergeev, Susan Evans-Axelsson, Andreea D Stuparu, Seval Beykan, Jeffrey Collins, Jason Jones, Michael Lassmann, Ken Herrmann, David Perrin, Jason T Lee, Roger Slavik, R Michael van Dam
BACKGROUND: Peptides labeled with positron-emitting isotopes are emerging as a versatile class of compounds for the development of highly specific, targeted imaging agents for diagnostic imaging via positron-emission tomography (PET) and for precision medicine via theranostic applications. Despite the success of peptides labeled with gallium-68 (for imaging) or lutetium-177 (for therapy) in the clinical management of patients with neuroendocrine tumors or prostate cancer, there are significant advantages of using fluorine-18 for imaging...
April 20, 2018: Nuclear Medicine and Biology
https://www.readbyqxmd.com/read/29746482/implementation-of-a-voluntary-deep-inspiration-breath-hold-technique-vdibh-using-brainlab-exactrac-infrared-optical-tracking-system
#16
Edy Ippolito, Michele Fiore, Alessia Di Donato, Sonia Silipigni, Carla Rinaldi, Patrizia Cornacchione, Erminia Infusino, Cristina Di Venanzio, Carlo Greco, Lucio Trodella, Sara Ramella, Rolando Maria D'Angelillo
BACKGROUND: Voluntary deep inspiration breath hold technique (vDIBH) is considered as the key to achieving the widest cardiac sparing in whole breast irradiation. Several techniques have been implemented to achieve a reproducible, fast and friendly treatment. The aim of the present study is to implement vDIBH using the ExacTrac (BrainLAB AG, Germany) monitoring system. METHODS: Women with left-sided breast cancer, younger than 50 years or with cardiac disease, underwent whole breast RT with vDIBH using the ExacTrac (BrainLAB AG, Germany) monitoring system...
2018: PloS One
https://www.readbyqxmd.com/read/29746014/dosimetric-and-geometric-characteristics-of-a-small-animal-image-guided-irradiator-using-3d-dosimetry-optical-ct-scanner
#17
Yong Hum Na, Yi-Fang Wang, Paul J Black, Christian Velten, Xin Qian, Shih-Chi Lin, John Adamovics, Cheng-Shie Wuu
PURPOSE: The precise dosimetric and geometric characteristics of small animal irradiators are essential to achieving reproducible dose delivery, especially in cases where image-guidance is utilized. Currently, radiochromic film is the established measurement tool used to evaluate beam characteristics for these systems. However, only 2D information can be acquired with film. This study characterized both the dosimetric and geometric properties of the small animal research radiation platform (SARRP, Xstrahl) for commissioning purposes using a 3D radiochromic dosimetry system with a sub-millimeter resolution optical computed tomography (OCT) scanner...
May 10, 2018: Medical Physics
https://www.readbyqxmd.com/read/29745011/comp-report-cpqr-technical-quality-control-guidelines-for-major-dosimetry-equipment
#18
Gérard Lagmago Kamta
The Canadian Organization of Medical Physicists (COMP), in close partnership with the Canadian Partnership for Quality Radiotherapy (CPQR) has developed a series of Technical Quality Control (TQC) guidelines for radiation treatment equipment. These guidelines outline the performance objectives that equipment should meet to ensure an acceptable level of radiation treatment quality. The TQC guidelines have been rigorously reviewed and field tested in a variety of Canadian radiation treatment facilities. The development process enables rapid review and update to keep the guidelines current with changes in technology (the most update version of this guideline can be found on the CPQR website)...
May 9, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29738914/g4dari-geant4-gate-based-monte-carlo-simulation-interface-for-dosimetry-calculation-in-radiotherapy
#19
Faiçal A A Slimani, Mahdjoub Hamdi, M'hamed Bentourkia
Monte Carlo (MC) simulation is widely recognized as an important technique to study the physics of particle interactions in nuclear medicine and radiation therapy. There are different codes dedicated to dosimetry applications and widely used today in research or in clinical application, such as MCNP, EGSnrc and Geant4. However, such codes made the physics easier but the programming remains a tedious task even for physicists familiar with computer programming. In this paper we report the development of a new interface GEANT4 Dose And Radiation Interactions (G4DARI) based on GEANT4 for absorbed dose calculation and for particle tracking in humans, small animals and complex phantoms...
May 1, 2018: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
https://www.readbyqxmd.com/read/29738812/dosimetry-of-inhaled-elongate-mineral-particles-in-the-respiratory-tract-the-impact-of-shape-factor
#20
Bahman Asgharian, T Price Owen, Eileen D Kuempel, Annie M Jarabek
Inhalation exposure to some types of fibers (e.g., asbestos) is well known to be associated with respiratory diseases and conditions such as pleural plaques, fibrosis, asbestosis, lung cancer, and mesothelioma. In recent years, attention has expanded to other types of elongate mineral particles (EMPs) that may share similar geometry with asbestos fibers but which may differ in mineralogy. Inhalability, dimensions and orientation, and density are major determinants of the aerodynamic behavior for fibers and other EMPs; and the resultant internal dose is recognized as being the critical link between exposure and pathogenesis...
May 5, 2018: Toxicology and Applied Pharmacology
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