نتایج جستجو برای: Absorbed dose
تعداد نتایج: 326013 فیلتر نتایج به سال:
background: changes in body composition may be used for monitoring progression/ regression of a disease. prompt γ-rays in vivo neutron activation analysis (ivnaa) has been widely used for the measurement of body composition in recent years. objective: in this paper, we tried to improve the safety of ivnaa operator. methods: the most important factor for reducing the operator receiving dose is t...
background: the shielding methods in radiotherapy due to delivering an accurate radiation dose to cancer tissues and avoiding unnecessary dose to normal tissues are very important. these methods include lead standard blocks, individual molding and multi leaf collimator (mlc). the mlc method is not still common in iran radiotherapy centers. individual molding is better than the lead block shield...
introduction in computed tomography (ct) technology, an optimal radiation dose can be achieved via changing radiation parameters such as ma, pitch factor, rotation time and tube voltage (kvp) for diagnostic images. materials and methods in this study, the brain, abdomen, and thorax scaning was performed using toshiba 16-slice scannerand standard aapm and ctdi phantoms. aapm phantom was used for...
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...
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...
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...
animals that breed in ground holes can be exposed to higher doses of radiation from natural radioactive isotopes, including radon and its daughters, present in soil air. one of such species is the sand martin riparia riparia. examination of natural burrows in sand mines revealed radon levels of 2.82-1320 bq/m3 in the examined soil horizon where martins dug their burrows. it was shown that adult...
background: this study assessed the clinical usefulness of the solid phantom, which may compensate for the disadvantages of the water phantom, by comparing the radiological doses between the two depending on their depths. materials and methods: the experimental equipment used was a linear accelerator for medical use, water phantom, solid phantom, farmer type ion chamber and electrometer. the di...
background: people who have been administrated radiopharmaceuticals could be a source of radiation to their relatives, medical nurses, and people who are in contact with them. the aim of this work was to estimate radiation dose received by nuclear medicine nurses. materials and methods: in this study, the dose rates at various distances of 5 – 100 cm from 70 patients, who were administered diag...
introduction: in patients with thyroid carcinoma, radiation absorbed doses of the thyroid and surrounding tissues is important to weigh risk and benefit considerations. in nuclear medicine, the accuracy of absorbed dose of internally distributed radionuclides is estimated by different methods such as mird and direct method using tld. the aim of this study is using tld and a phantom to determine...
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