نتایج جستجو برای: background dose
تعداد نتایج: 1101593 فیلتر نتایج به سال:
introduction the purpose of this study was to estimate organ and effective doses in patients undergoing some common x-ray examinations in sabzevar, iran. the effective dose is one of the best parameters for describing the amount of radiation dose received by a patient undergoing any diagnostic x-ray examination. the public dose from x-ray examinations depends on various factors, and its contrib...
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...
background: a study has been conducted to assess two useful radiation protection indices, the annual per-capita effective dose equivalent (aed) and the genetically significant dose (gsd), from conventional diagnostic radiography in 10 counties with more than 1,886,000 inhabitants in khorasan province in iran. materials and methods: the health centre authorities of khorasan province were asked t...
background: radiation dose knowledge through xray examinations and their distribution in iran provides useful guidance on patient dose reduction. the results of the entrance skin dose (esds) of five common radiographies in all radiology centers in yazd province were reported in our previous study (2003). in the present study we have evaluated the collective effective dose of conventional x-ray ...
background: with the introduction of computed tomography in diagnostic radiology a new and fundamentally different imaging modality has become available. meanwhile, it is clear that the absorbed doses by the patients during ct were relatively high in comparison with those of other diagnostic radiology techniques. the aim of this survey was to determine the average absorbed dose in yazd province...
background: for an effective treatment planning in brachytherapy, it is necessary to know the accurate source dosimetric information such as air kerma strength, exposure rate constant, dose rate constant and redial dose distribution. the usual method to determine these factors is thermo luminescent dosimeter (tld) dosimetry. nowadays, another more accurate method is known to be the monte carlo ...
background: the rejected films in radiography may be responsible for an unnecessary increase in the radiation dose to the population. the effective dose to population is a very important factor in estimation of stochastic risk in radiology. the main goal of this study was to determine the effective dose to members of the public due to rejected films in diagnostic radiology departments in the no...
background: the assessment of rbe quantity in the treatment of cancer tumors with proton beams in treatment planning systems (tps) is of high significance. given the significance of the issue and the studies conducted in the literature, this quantity is fixed and is taken as equal to 1.1. objective: the main objective of this study was to assess rbe quantity of proton beams and their variations...
Backgrounds and Objectives: Due to importance of ionizing radiation on human health, many studies have been performed to measure the background gamma radiation all around the world as well as some cities in lran. According to this fact that everybody spends almost 80% of his time in indoor areas, this study was carried out to measure the amount of background gamma radiation in indoor areas in Z...
introduction intensity-modulated radiotherapy (imrt) is becoming an increasingly routine treatment method. imrt can be delivered by use of conventional multileaf collimators (mlcs) and/or physical compensators. one of the most important factors in selecting an appropriate imrt technique is integral dose. integral dose is equal to the mean energy deposited in the total irradiated volume of the p...
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