نتایج جستجو برای: megavoltage x ray
تعداد نتایج: 665089 فیلتر نتایج به سال:
introduction: the aim of this study was to compare the chemical compounds of white proroot mineral trioxide aggregate (wmta) hydrated at different ph environments. methods and materials: mixed samples of wmta were kept in acidic (ph=5.4), neutral (ph=7.4) and alkaline (ph=9.4) environments for 48 h. then, x-ray diffraction (xrd) analysis was performed for both hydrated and powder forms of wmta....
background: proper placement of central venous catheter (cvc) tip could reduce early and late catheter-related complications.although the live fluoroscopy is standard of care for placement of the catheter, it is not available in many centers. therefore, the present study evaluated the sensitivity and specificity of bedside chest x-ray (cxr) for proper positioning of the catheter tip. materials ...
conclusions this is the first case report of a vanishing tumor in the right pulmonary apex. case presentation such masses have been designated as vanishing tumors of the lung. it is extremely rare that a vanishing tumor occurs in the apex of the lung. introduction in patients with acute heart failure, pleural fluid localized in an inter-pleural fissure produces a mass on chest x-ray, which mimi...
oxide nanoparticles can exhibit unique physical and chemical properties due to their limited size and a high density of corner or edge surface sites. in this study, mgo nanoparticle was synthesized using mg(ch3coo)2 and hexamethylenetetramine as starting materials. the structure and optical properties of these particles are investigated by using x-ray diffraction (xrd), scanning electron micros...
the magnetite (fe3o4) – agar nanocomposite was prepared by co-precipitation of fe (iii) and fe (ii) ions for the first time. the obtained samples were characterized by x-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. ft-ir results confirm the formation of fe3o4 nanoparticles in agar matrix. the xrd results revealed th...
conclusion the cv value correlated more closely with low lvef and more accurately indicated an enlarged heart than ca or ctr. this may be due to the fact that an anteroposterior measurement of heart size is included in the former but not the latter two measurements. these study results may help quantify left heart enlargement with greater accuracy than may be obtained from standard cxr. backgro...
introduction quality control (qc) techniques are used in monitoring and maintenance of the components of an x-ray system. qc of radiology devices plays a significant role in reduction of medication dose and optimization of image quality. this study aimed to conduct qc tests on randomly selected radiology devices, installed in diagnostic imaging departments of iran. materials and methods in tota...
osteoma is a benign, slow-growing osteogenic tumor that sometimes arises from the craniomaxillofacial region, such as the sinus, temporal or jaw bones. osteoma consists of compact or cancellous bone that may be peripheral, central or extraskeletal type. peripheral osteoma arises from the periosteum and is commonly a unilateral, pedunculated mushroom-like mass. peripheral osteoma of the mandible...
introduction in radiography, dose and image quality are dependent on radiographic parameters. the problem is caused from incorrect use of radiography equipment and from the radiation exposure to patients much more than required. therefore, the aim of this study was to implement a quality-control program to detect changes in exposure parameters, which may affect diagnosis or patient radiation do...
Introduction: Megavoltage X-ray beams are used to treat cervix cancer due to their skin-sparing effect. Preferably, the radiation surface doses should be negligible; however, it increases due to electron contamination produced by various field parameters. Therefore, it is essential to provide proper knowledge about the effect of different field parameters on radiation doses. This study sought t...
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