نتایج جستجو برای: radiation shielding

تعداد نتایج: 245445  

Introduction: Development of higher energy modalities such as positron emission tomography/computed tomography (PET/CT), has led to more complex shielding problems. This is due to several factors, such as the radiopharmaceutical relatively high-administered activity, high patient throughput, and high energies of 511 kilo-electron volt (keV) positron annihilation photon...

ژورنال: سلامت کار ایران 2016

Background and aims: X-band with 8-12.5 frequencies range has various applications such as air control traffic, navy communication and etc. Uncontrolled exposure with microwave can lead to adverse effect on workers. Application of the shielding is superior control for prevention of microwave exposure, now. This study investigated the effect of dispersion on shielding effectiveness improvement a...

2003
Daniel Proga

We summarize recent developments in modeling of mass outflows from accretion disks in AGN. We illustrate how the hydrodynamical and magnetohydrodynamical wind structures revealed in numerical simulations relate to observations. Important results from the numerical simulations include: no shielding from X-rays is needed to radiatively launch a wind from the inner disk; shielding is needed to acc...

2001
M.-H. Y. Kim S. A. Thibeault R. L. Kiefer J. W. Wilson R. C. Singleterry H. Huff

The development of Mars for human activity will require the utilization of Martian materials in building habitats and working structures. One approach is to use polymer binders with regolith to form structural elements. Not only can useful composite materials be produced in this way but the radiation protection properties are also increased. This is important since only modest protection from s...

Journal: :Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics 2001
J W Wilson F A Cucinotta M H Kim W Schimmerling

Future deep space mission and International Space Station exposures will be dominated by the high-charge and -energy (HZE) ions of the Galactic Cosmic Rays (GCR). A few mammalian systems have been extensively tested over a broad range of ion types and energies. For example, C3H10T1/2 cells, V79 cells, and Harderian gland tumors have been described by various track-structure dependent response m...

2001
G. D. Qualls J. W. Wilson C. Sandridge F. A. Cucinotta J. H. Heinbockel W. Atwell

The projected radiation levels within the International Space Station (ISS) have been criticized by the Aerospace Safety Advisory Panel in their report to the NASA Administrator. Methods for optimal reconfiguration and augmentation of the ISS shielding are now being developed. The initial steps are to develop reconfigurable and realistic radiation shield models of the ISS modules, develop compu...

2012
Kosuke Matsubara Mai Sugai Asami Toyoda Haruka Koshida Keita Sakuta Tadanori Takata Kichiro Koshida Hiroji Iida Osamu Matsui

Recently, specific computed tomography (CT) scanners have been equipped with organ-based tube current modulation (TCM) technology. It is possible that organ-based TCM will replace the conventional dose-reduction technique of reducing the effective milliampere-second. The aim of this study was to determine if organ-based TCM could reduce radiation exposure to the breasts without compromising the...

Journal: :Health physics 2003
K R Kase W R Nelson A Fasso J C Liu X Mao T M Jenkins J H Kleck

Optimum shielding of the radiation from particle accelerators requires knowledge of the attenuation characteristics of the shielding material. The most common material for shielding this radiation is concrete, which can be made using various materials of different densities as aggregates. These different concrete mixes can have very different attenuation characteristics. Information about the a...

2008

diation and radiobiological researches and radiation protection. The first two lines are included in the Topical Plan for Scientific Research of JINR and were concentrated on: • neutron spectrometry and radiometry, radiation monitoring; • investigation of radiation fields around thick targets; • physical support of radiobiological experiments; • shielding calculations and design; • investigatio...

2009
Mario Ciocca Guido Pedroli Roberto Orecchia Andrea Guido Federica Cattani Raffaella Cambria Umberto Veronesi

The aim of this study was to perform a detailed analysis of the air kerma values around a Liac mobile linear accelerator working in a conventional operating room (OR) for IORT. The Liac delivers electron beams at 4, 6, 8 and 10 MeV. A radiation survey to determine photon leakage and scatter consisted of air kerma measurements on a spherical surface of 1.5 m radius, centered on the titanium exit...

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