نتایج جستجو برای: dose rate and radiation source
تعداد نتایج: 17000624 فیلتر نتایج به سال:
the research questions were as follows: 1. is there any relationship between the students concious awareness of the form and implications of the conjuncations and their improvement in using appropriate conjunctions? 2. does students knowledge of the from and the implications of the conjunctions help them to produce more coherent writings. 3. does a comparison between english conjunctions and th...
Determination of the total body absorbed dose consists of two parts: Beta radiation absorbed dose and gamma radiation absorbed dose. The first part is generally determined by clinical data, while the second part has a parameter called absorbed ratio and is determined by computational methods. The Monte-Carlo computational methods have been shown to be the most suita...
All building materials contain various amounts of natural radioactive nuclides. Materials derived from rock and soil contain mainly natural radionuclides of the uranium (238U) and thorium (232Th) series, and the radioactive isotope of potassium (40K). Radiation exposure due to building materials can be divided into external and internal exposure. The external exposure is caused by direct gamma ...
Background: Medical X-rays are the largest man-made source of public exposure to ionizing radiation. While the benefits of Computed Tomography (CT) are well known in accurate diagnosis, those benefits are not risk-free. CT is a device with higher patient dose in comparison with other conventional radiation procedures. Objective: This study is aimed at evaluating radiation dose to patients from ...
Introduction: All of the people worldwide are exposed to low levels of radiation. Cancer induction and genetic disorders are among the hazards of low level exposure. In some cases, radiation close to hot springs is higher than normal areas due to a high concentration and the decay products of Ra-226. Given the use of hot springs by the general public because of their therapeutic p...
In this study, the effects of gamma and electron radiation on reflectivity of silver mirrors coated by TiO2 and Ta2O5, in the wavelength range 250 to 1100 (nm) has been investigated. The coatings are considered for space applications in LEO orbit at 500 (km) from the earth surface for three-year mission in space. Electron and gamma dose absorbed within the three-year are respectively about 7.5 ...
Introduction: Internal radiation dosimetry is important from a radiation protection point of view and can help to optimize the radiation dose delivered to the workers, public, and patients. It has a rather simple protocol but needs a large amount of data. Therefore, it is difficult to do on a routine basis. The use of computer programs makes internal radiation dosimetry simpler...
background: dose calculation algorithms play a very important role in predicting the explicit dose distribution. we evaluated the percent depth dose (pdd), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. materials and methods: the homogeneous and inhomogeneous virtual slab phantoms used in th...
ABSTRACTBackground: Radioprotective effects of famotidine, an antagonist of H2 receptor clinically used for peptic ulcer treatment, was previously shown on radiation-induced micronuclei and chromosomal aberration in human peripheral blood lymphocytes and mouse bone marrow cells. This study was conducted to investigate radioprotective property of famotidine against radiation induced apoptosis i...
Introduction: In radiation therapy, knowing the dose rates to healthy organs and tumors is beneficial, and thermoluminescent dosimeter (TLD) allows for this possibility. This study was aimed at determining the dose-response differences of TLDs in various types of radiation, energy levels, and dose rate calibrated with other types of radiation beams and energy and dose levels. Materials and Meth...
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