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https://www.readbyqxmd.com/read/28516046/image-quality-assessment-of-a-1-5t-dedicated-magnetic-resonance-simulator-for-radiotherapy-with-a-flexible-radio-frequency-coil-setting-using-the-standard-american-college-of-radiology-magnetic-resonance-imaging-phantom-test
#1
Oi Lei Wong, Jing Yuan, Siu Ki Yu, Kin Yin Cheung
BACKGROUND: A flexible RF coil setting has to be used on an MR-simulator (MR-sim) in the head and neck simulation scan for radiotherapy (RT) purpose, while the image quality might be compromised due to the sub-optimized flexible coil compared to the normal diagnostic radiological (DR) head coil. In this study, we assessed the image quality of an MR-sim by conducting the standard American College of Radiology (ACR) MRI phantom test on a 1.5T MR-sim under RT-setting and comparing it to DR-setting...
April 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28507702/plasmon-induced-charge-separation-chemistry-and-wide-applications
#2
Tetsu Tatsuma, Hiroyasu Nishi, Takuya Ishida
Recent development of nanoplasmonics has stimulated chemists to utilize plasmonic nanomaterials for efficient and distinctive photochemical applications, and physicists to boldly go inside the "wet" chemistry world. The discovery of plasmon-induced charge separation (PICS) has even accelerated these trends. On the other hand, some confusion is found in discussions about PICS. In this perspective, we focus on differences between PICS and some other phenomena such as co-catalysis effect and plasmonic nanoantenna effect...
May 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28502257/physics-moves-to-the-provinces-the-siberian-physics-community-and-soviet-power-1917-1940
#3
Paul Josephson, Aleksandr Sorokin
The rich tradition of Siberian science and higher education is little known outside Russian academic circles. Using institutional history, this article focuses on the founding and pre-war period of the Siberian Physical Technical Institute, the establishment of its research focus and its first difficult steps to become a leading centre of R & D in Siberia. Based on archival materials, the article describes how local and national physicists justified the institute's creation by demonstrating ties with industry and building on the presence of a cohort of locally trained physicists, whose numbers were augmented by Leningrad specialists...
May 15, 2017: British Journal for the History of Science
https://www.readbyqxmd.com/read/28500759/a-monte-carlo-model-for-mean-glandular-dose-evaluation-in-spot-compression-mammography
#4
Antonio Sarno, David R Dance, Ruben E van Engen, Kenneth C Young, Paolo Russo, Francesca Di Lillo, Giovanni Mettivier, Kristina Bliznakova, Baowei Fei, Ioannis Sechopoulos
PURPOSE: To characterize the dependence of normalized glandular dose (DgN) on various breast model and image acquisition parameters during spot compression mammography and other partial breast irradiation conditions, and evaluate alternative previously-proposed dose-related metrics for this breast imaging modality. METHODS: Using Monte Carlo simulations with both simple homogeneous breast models and patient-specific breasts, three different dose related metrics for spot compression mammography were compared: the standard DgN, the normalized glandular dose to only the directly irradiated portion of the breast (DgNv), and the DgN obtained by the product of the DgN for full field irradiation and the ratio of the mid-height area of the irradiated breast to the entire breast area (DgNM )...
May 13, 2017: Medical Physics
https://www.readbyqxmd.com/read/28499659/-spinal-stereotactic-body-radiotherapy-french-assessment-in-2016
#5
I Pougnet, E Jaegle, R Garcia, F Tessier, J C Faivre, G Louvel, E Gross, L Gonzague, M Benchalal, A Ducteil, S Supiot, D Autret, J B Clavier, X Mirabel, A Bellière, D Wdowczyk, S Heymann, I Barillot, B de La Lande, V Passerat, M P Sunyach, F Lipinski, D Thibouw, F Guichard, B Chauvet, J Thariat, A Arnaud
PURPOSE: Stereotactic body radiotherapy to vertebral column remains uncommon practice and only relevant in selected group of patients. The main objective of the study was to describe the current state of medical practices of stereotactic body radiotherapy to vertebral column in France in 2016 and to assess the diversity of practices to identify areas for improvement and establish a common database set for this technique. MATERIALS AND METHODS: A questionnaire was written with contribution of a medical physicist, a radiation oncologist, an information technologist and a radiotherapy resident...
May 9, 2017: Cancer Radiothérapie: Journal de la Société Française de Radiothérapie Oncologique
https://www.readbyqxmd.com/read/28497529/aapm-medical-physics-practice-guideline-6-a-performance-characteristics-of-radiation-dose-index-monitoring-systems
#6
Dustin A Gress, Renee L Dickinson, William D Erwin, David W Jordan, Robert J Kobistek, Donna M Stevens, Mark P Supanich, Jia Wang, Lynne A Fairobent
The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education and professional practice of medical physics. The AAPM has more than 8,000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States...
May 12, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28496379/self-organization-of-nucleic-acids-in-lipid-constructs
#7
Minjee Kang, Hojun Kim, Cecilia Leal
Lipids and nucleic acids (NAs) can hierarchically self-organize into a variety of nanostructures of increasingly complex geometries such as the 1D lamellar, 2D hexagonal, and 3D bicontinuous cubic phases. The diversity and complexity of those lipid-NA assemblies are interesting from a fundamental perspective as well as being relevant to the performance in gene delivery and gene silencing applications. The finding that not only the chemical make of the lipid-NA constructs, but their actual supramolecular organization, affects their gene transfection and silencing efficiencies has inspired physicists, chemists, and engineers to this field of research...
December 2016: Current Opinion in Colloid & Interface Science
https://www.readbyqxmd.com/read/28492099/-let-the-stars-shine-in-peace-niels-bohr-and-stellar-energy-1929-1934
#8
Helge Kragh
Faced with various anomalies related to nuclear physics in particular, in 1929 Niels Bohr suggested that energy might not be conserved in the atomic nucleus and the processes involving it. By this radical proposal he hoped not only to get rid of the anomalies but also saw a possibility to explain a puzzle in astrophysics, namely the energy generated by stars. Bohr repeated his suggestion of stellar energy arising ex nihilo on several occasions but without ever going into detail. In fact, it is not very clear what he meant or how seriously he took the stellar energy hypothesis...
May 11, 2017: Annals of Science
https://www.readbyqxmd.com/read/28491032/topological-filtering-of-dynamic-functional-brain-networks-unfolds-informative-chronnectomics-a-novel-data-driven-thresholding-scheme-based-on-orthogonal-minimal-spanning-trees-omsts
#9
Stavros I Dimitriadis, Christos Salis, Ioannis Tarnanas, David E Linden
The human brain is a large-scale system of functionally connected brain regions. This system can be modeled as a network, or graph, by dividing the brain into a set of regions, or "nodes," and quantifying the strength of the connections between nodes, or "edges," as the temporal correlation in their patterns of activity. Network analysis, a part of graph theory, provides a set of summary statistics that can be used to describe complex brain networks in a meaningful way. The large-scale organization of the brain has features of complex networks that can be quantified using network measures from graph theory...
2017: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/28490730/multi-pass-transmission-electron-microscopy
#10
Thomas Juffmann, Stewart A Koppell, Brannon B Klopfer, Colin Ophus, Robert M Glaeser, Mark A Kasevich
Feynman once asked physicists to build better electron microscopes to be able to watch biology at work. While electron microscopes can now provide atomic resolution, electron beam induced specimen damage precludes high resolution imaging of sensitive materials, such as single proteins or polymers. Here, we use simulations to show that an electron microscope based on a multi-pass measurement protocol enables imaging of single proteins, without averaging structures over multiple images. While we demonstrate the method for particular imaging targets, the approach is broadly applicable and is expected to improve resolution and sensitivity for a range of electron microscopy imaging modalities, including, for example, scanning and spectroscopic techniques...
May 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28474819/towards-a-standard-for-the-evaluation-of-pet-auto-segmentation-methods-requirements-and-implementation
#11
Beatrice Berthon, Emiliano Spezi, Paulina Galavis, Tony Shepherd, Aditya Apte, Mathieu Hatt, Hadi Fayad, Elisabetta De Bernardi, Chiara Soffientini, Charles R Schmidtlein, Issam El Naqa, Robert Jeraj, Wei Lu, Shiva Das, Habib Zaidi, Osama R Mawlawi, Dimitris Visvikis, John A Lee, Assen S Kirov
PURPOSE: The aim of this paper is to define the requirements and describe the design and implementation of a standard benchmark tool for evaluation and validation of PET-auto-segmentation (PET-AS) algorithms. This work follows the recommendations of Task Group 211 (TG211) appointed by the American Association of Physicists in Medicine (AAPM). METHODS: The recommendations published in the AAPM TG211 report were used to derive a set of required features and to guide the design and structure of a benchmarking software tool...
May 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/28467707/plane-wave-density-functional-theory-meets-molecular-crystals-thermal-ellipsoids-and-intermolecular-interactions
#12
Volker L Deringer, Janine George, Richard Dronskowski, Ulli Englert
Molecular compounds, organic and inorganic, crystallize in diverse and complex structures. They continue to inspire synthetic efforts and "crystal engineering", with implications ranging from fundamental questions to pharmaceutical research. The structural complexity of molecular solids is linked with diverse intermolecular interactions: hydrogen bonding with all its facets, halogen bonding, and other secondary bonding mechanisms of recent interest (and debate). Today, high-resolution diffraction experiments allow unprecedented insight into the structures of molecular crystals...
May 3, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28464490/the-geographic-penetration-of-the-jacmp-and-the-benefits-of-aapm-membership-for-clinical-medical-physicists-worldwide
#13
EDITORIAL
Michael D Mills
No abstract text is available yet for this article.
May 2, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28462894/a-survey-of-residents-experience-with-patient-safety-and-quality-improvement-concepts-in-radiation-oncology
#14
Matthew B Spraker, Matthew Nyflot, Kristi Hendrickson, Eric Ford, Gabrielle Kane, Jing Zeng
PURPOSE: The safety and quality of radiation therapy have recently garnered increased attention in radiation oncology (RO). Although patient safety guidelines expect physicians and physicists to lead clinical safety and quality improvement (QI) programs, trainees' level of exposure to patient safety concepts during training is unknown. METHODS AND MATERIALS: We surveyed active medical and physics RO residents in North America in February 2016. Survey questions involved demographics and program characteristics, exposure to patient safety topics, and residents' attitude regarding their safety education...
December 1, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28455152/defining-a-leader-role-curriculum-for-radiation-oncology-a-global-delphi-consensus-study
#15
Sandra Turner, Matthew Seel, Theresa Trotter, Meredith Giuliani, Kim Benstead, Jesper G Eriksen, Philip Poortmans, Christine Verfaillie, Henrike Westerveld, Shamira Cross, Ming-Ka Chan, Timothy Shaw
BACKGROUND AND PURPOSE: The need for radiation oncologists and other radiation oncology (RO) professionals to lead quality improvement activities and contribute to shaping the future of our specialty is self-evident. Leadership knowledge, skills and behaviours, like other competencies, can be learned (Blumenthal et al., 2012). The objective of this study was to define a globally applicable competency set specific to radiation oncology for the CanMEDS Leader Role (Frank et al., 2015). METHODS: A modified Delphi consensus process delivering two rounds of on-line surveys was used...
May 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28452342/air-kerma-calculation-in-monte-carlo-simulations-for-deriving-normalized-glandular-dose-coefficients-in-mammography
#16
Antonio Sarno, Giovanni Mettivier, Paolo Russo
The estimation of the mean glandular dose in mammography using Monte Carlo simulations requires the calculation of the air kerma incident on the breast surface. In such a calculation, caution should be applied in considering explicitly the presence of the top compression paddle, since Compton scattering in this slab may produce a large angular spread of the incidence angles of x-ray photons on the scoring surface. Then, the calculation of the incident air kerma should contain the "effective" area of the scoring surface, which takes into account the angle of incidence of photons on such a surface...
April 28, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28443654/quantifying-the-self-assembly-behavior-of-anisotropic-nanoparticles-using-liquid-phase-transmission-electron-microscopy
#17
Binbin Luo, John W Smith, Zihao Ou, Qian Chen
For decades, one of the overarching objectives of self-assembly science has been to define the rules necessary to build functional, artificial materials with rich and adaptive phase behavior from the bottom-up. To this end, the computational and experimental efforts of chemists, physicists, materials scientists, and biologists alike have built a body of knowledge that spans both disciplines and length scales. Indeed, today control of self-assembly is extending even to supramolecular and molecular levels, where crystal engineering and design of porous materials are becoming exciting areas of exploration...
April 26, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28435986/asian-consortium-on-radiation-dose-of-pediatric-cardiac-ct-asci-redcard
#18
Peter K T Hui, Hyun Woo Goo, Jing Du, Janice J K Ip, Suzu Kanzaki, Young Jin Kim, Supika Kritsaneepaiboon, Oktavia Lilyasari, Suvipaporn Siripornpitak
BACKGROUND: With incremental utilization of pediatric cardiac CT in congenital heart disease, it is imperative to define its current radiation dose levels in clinical practice in order to help imagers optimize CT protocols, particularly in Asia and other developing countries where CT physicists are not readily available. OBJECTIVE: To evaluate current radiation dose levels and influencing factors in cardiac CT in children with congenital heart disease in Asia by conducting a retrospective multi-center, multi-vendor study...
April 24, 2017: Pediatric Radiology
https://www.readbyqxmd.com/read/28432806/rapid-acceptance-testing-of-modern-linac-using-on-board-mv-and-kv-imaging-systems
#19
Sridhar Yaddanapudi, Bin Cai, Taylor Harry, Steven Dolly, Baozhou Sun, Hua Li, Keith Stinson, Camille Noel, Lakshmi Santanam, Todd Pawlicki, Sasa Mutic, S Murty Goddu
PURPOSE: The purpose of this study was to develop a novel process for using on-board MV and kV Electronic Portal Imaging Devices (EPIDs) to perform linac acceptance testing (AT) for two reasons: 1) to standardize the assessment of new equipment performance, and 2) to reduce the time to clinical use while reducing physicist workload. METHODS AND MATERIALS: In this study, Varian TrueBeam linacs equipped with amorphous silicon based EPID (aS1000) were used. The conventional set of AT tests and tolerances were used as a baseline guide...
April 22, 2017: Medical Physics
https://www.readbyqxmd.com/read/28431680/two-paradigms-for-religious-representation-the-physicist-and-the-playground-a-reply-to-levy
#20
Neil Van Leeuwen
In an earlier issue, I argue (2014) that psychology and epistemology should distinguish religious credence from factual belief. These are distinct cognitive attitudes. Levy (2017) rejects this distinction, arguing that both religious and factual "beliefs" are subject to "shifting" on the basis of fluency and "intuitiveness." Levy's theory, however, (1) is out of keeping with much research in cognitive science of religion and (2) misrepresents the notion of factual belief employed in my theory. So his claims don't undermine my distinction...
July 2017: Cognition
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