نتایج جستجو برای: gamma absorbed dose
تعداد نتایج: 438914 فیلتر نتایج به سال:
large quantities of radiopharmaceuticals prescribed for treatment and diagnosis are excreted through kidney. therefore, radiation unwanted dose is created in kidney. as a result, exact calculation of prescribed radiopharmaceuticals amount is important. monte carlo method is used for simulation of radiation transport in body due to random nature of radiation. in this research, for the first time...
Irradiation of blood products abrogates the proliferation of lymphocytes present in cellular component, which is currently the only accepted methodology to prevent transfusion-associated graft versus host disease (TA-GVHD). A range of irradiation dose levels between 15 Gy and 50 Gy is being used, but the majority of facilities are employing 15 Gy. It should, however, be recognized that the deli...
Introduction: This study investigated the exposure rates of background radiations in selected locations of Najaf and Dhi Qar cities, Iraq. Materials and Methods: Exposure rates were quantified using a portable Geiger–Müller meter. Frequent readings of gamma dose rates were recorded (82 and 101 nGy h-1). Results: The lowest absorbed doserate was found to be 43.5±17.4 nGyh-1 in Najaf (outdoor e...
ct.scan examinations cause high patient absorbed dose from x-ray ionizing radiation. therefore it is necessary to obtain superficial dose profile in z-line. in this research 11 thermoluminecent dosimeter (tld), after calibration were located on z line perpendicular to slice thickness. ct.scan machines did x-ray exposures. the resultant dose profiles showed gussian shape apperience, which has se...
introduction radioactive materials naturally exist in the world. indeed, approximately 82% of human-absorbed radiation doses, which are out of human control, arise from natural sources of radiation including cosmic, terrestrial, and exposure through inhalation or ingestion. thus, the aim of the present study was to estimate health risk, as well as the effective and organ doses from naturally oc...
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: the exposure of human being to ionize radiation from natural sources is a continuing, inescapable feature of life on earth. direct measurement of absorbed dose rates in air has been carried out in many countries of the world during the last few decades. such investigations can be useful for assessment of public dose rates, the performance of epidemiological studies, and keeping refe...
background: prompt gamma neutron activation analysis (pgnaa) is known as a non-invasive technique capable of measuring elemental concentration in voluminous samples in a short period of time. also it is a valuable diagnostic tool for total body elemental measurements. 252cf and 241am-be sources which are usually used in this method, generate not only neutrons, but also emit high-energy and unwa...
introduction radon is a colorless and tasteless gas which exists in most soils. it is a substance that poses a potential risk for lung cancer in case a person is exposed to high levels over long periods of time. the environmental protection agency (epa) estimates that 90% of lung cancers per year are caused by radon. the aim of this paper is to estimate the absorbed doses of 222rn by mcnpx simu...
Introduction: Stereotactic Gamma Knife radiosurgery has been widely used for treating brain tumors. The scattered radiation outside of treatment field (peripheral dose) can induce the secondary cancer to specific organ. This paper investigated the absorbed dose to eyes, thyroid, heart, lung, breast and colon using a Monte Carlo technique for Mird phantom. We also study the ef...
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