نتایج جستجو برای: diagnostic radiation fields
تعداد نتایج: 751516 فیلتر نتایج به سال:
Introduction An understanding of radiation transport (RT) through The goal of this experiment is to simulate radiation clouds is fundamental to studies of the earth’s radiation budget and climate dynamics. The transmission through horizontally homogeneous clouds has been studied thoroughly using accurate, discreet ordinates radiative transfer models. However, the applicability of these results ...
Introduction: Most of people are exposed to ionizing radiation sources during their lifetime including background, cosmic or man-made beams like radiation used in nuclear medicine and radiology. Due to unavoidable use of ionizing radiation in diagnosis and treatment of diseases, designing and correct implementation of radiation protection principles in order to reducing its har...
The origin of ultra-high energy cosmic rays is discussed in light of the latest observational results from the Pierre Auger Observatory, highlighting potential astrophysical sources such as active galactic nuclei, gamma-ray bursts, and clusters of galaxies. Key issues include their energy budget, the acceleration and escape of protons and nuclei, and their propagation in extragalactic radiation...
conclusions at present, no single diagnostic procedure is able to cause damage to the embryo or fetus. there are possible harmful effects for doses above 0.2 - 0.25 gy (20-25 rad). context many women of reproductive age and pregnant women require diagnostic tests involving ionizing radiation. fetal exposure to radiation worries both the patient and the obstetricians and could lead to inappropri...
The definition of a precise illumination region is essential in many applications where the electromagnetic field should be confined in some specific volume. By using conventional structures, it is difficult to achieve an adequate confinement distance (or volume) with negligible levels of radiation leakage beyond it. Although metamaterial structures and metasurfaces are well-known to provide hi...
The electric field profiles of broad-bandwidth coherent terahertz (THz) pulses, emitted by laser-wakefield-accelerated electron bunches, are studied. The near-single-cycle THz pulses are measured with two single-shot techniques in the temporal and spatial domains. Spectra of 0-6 THz and peak fields up to approximately or = 0.4 MV cm(-1) are observed. The measured field substructure demonstrates...
introduction: nowadays ionizing radiation has a considerable contribution in medical diagnostic and treatment. using ionizing radiation is increasing rapidly, so biological effects of ionizing radiation should be considered more. x-rays in the range of diagnostic radiology have hazardous effects and risks that are defined as random effects. these effects obey the lnt hypothesis that occur at lo...
Cancer treatment and treatment options are quite limited in circumstances such as when the tumor is inoperable, in brain cancers when the drugs cannot penetrate the blood-brain-barrier, or when there is no tumor-specific target for generation of effective therapeutic antibodies. Despite the fact that electromagnetic fields (EMF) in medicine have been used for therapeutic or diagnostic purposes,...
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 ...
Mapping magnetic fields via heavy ion beam spectral imaging relies upon establishing a high quality ion beam, identifying beam emission at wavelengths favorable for imaging, and designing an appropriate imaging configuration. Identifying emission lines suitable for imaging is difficult due to intense, broadband radiation of the target reversed field pinch plasma. To compensate, we have worked t...
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