نتایج جستجو برای: and shield
تعداد نتایج: 16828870 فیلتر نتایج به سال:
introduction the purpose of this study was to evaluate personal shields in radiation departments of hospitals affiliated to mashhad university of medical sciences. materials and methods first, the information related to 109 personal shields was recorded and evaluated by imaging equipment. afterwards, the equivalent lead thickness (elt) of 62 personal shields was assessed, using dosimeter and st...
Objective (s): Recently, the use of nanoparticles in medicine has increased for radiation protection purpose. So the aim of this study was application of nano Bi2O3 in prepared shield for dose reduction during medical imaging.Materials and Methods: Nano Bi2O3 shield with 90% silicon and 10% nano Bi2O3 was prepared and dosimetry test was down in radiology by PTW DIADOS E dosimeter.Results: The m...
background: monte carlo simulations play a vital role in the calculation of the necessary shielding both for neutrons and photons. advanced and simple shielding materials against neutron and gamma rays were compared by simulation using the mcnb4b monte carlo code. the simulations were carried out for the three common neutron sources, namely the 252cf, the 241am/be and the dd neutron generator w...
for superficial lesions, the electrons may be used for radiation therapy. the high energy photons and electrons are produced by a linear accelerator (linac). many of electron fields need the shielding of normal or critical organs. the electron shields are usually lead slabs with few millimeter thickness which should be placed near the skin, less than 1 centimeter away from skin. in the inspec...
Background: Lead-based radiation shields are widely used in radiology departments to protect both workers and patients from any unnecessary exposure to ionizing radiation. Recently there has been a great deal of concern expressed about the toxicity of lead. Human lead toxicity is well documented. In that light, production of environmentally-friendly lead-free radiation shields with less weight ...
The shield tunnel of the Kunming subway crosses beneath the Kun-Shi Railway. Due to the high requirements of railway track for settlement control, this article proposes the following technical measures for controlling the settlement based on the analysis of risks arising from the shield crossing railway: (1) Reinforcing the stratum of the region crossed by the shield in advance to achieve high ...
The secondary cone crusher's shields at Sarcheshmeh Copper Complex of Iran are made of Hadfield steel with a nominal composition of Fe-1.3 % C-12 % Mn. They have a cut-off in the shape of a cone with an upper end diameter of 80cm and an approximate lower end diameter of 200 cm whose main problem is an unexpected early failure under normal working condition. In this paper, the results of metallo...
normal 0 false false false en-us x-none fa introduction: in radiation therapy centers across iran, protection of normal tissues is usually accomplished by either cerrobend or lead block shielding. in this study, the influence of these two shielding methods on central axis dose distribution of photon beam a cobalt unit was investigated in clinical conditions. materials and methods: all measureme...
Introduction: Ionizing radiation can cause damage to biologically important DNA molecules. Radiation in nuclear medicine radiation exposes people working in from two main positions; administer in gradiopharmaceuticals (the barn and squeezing a generator, procurement, distribution and drug infusion) and patients that receive radiation treatment (patients that are prescribed a ra...
Shield tunneling construction of metro infrastructure will continuously disturb the soils. The ground surface will be subjected to uplift or subsidence due to the deep excavation and the extrusion and consolidation of the soils. Implementation of the simultaneous monitoring with the shield tunnel construction will provide an effective reference in controlling the shield driving, while how to de...
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