نتایج جستجو برای: Bismuth Shielding
تعداد نتایج: 15800 فیلتر نتایج به سال:
BACKGROUND AND PURPOSE The lens of the eye is sensitive to radiation. Children undergoing CT of the head and patients undergoing repeated CT scanning of the head are vulnerable to this complication. The purpose of this study was to test the ability of a heavy metal, bismuth, in reducing radiation to the lens of the eye during routine cranial CT. METHODS Both phantom and human studies were don...
PURPOSE To compare the dose and image quality of three methods for reducing the radiation dose to the eye at head computed tomography (CT): bismuth shielding, organ-based tube current modulation (TCM), and global reduction of the tube current. MATERIALS AND METHODS An anthropomorphic head phantom was scanned under six conditions: (a) without any dose reduction techniques (reference scanning);...
The object of this study was to compare organ dose and image quality effects of using bismuth and barium vinyl in-plane shields with standard and low tube current thoracic CT protocols. A RANDO phantom was scanned using a 64-slice CT scanner and three different thoracic protocols. Thermoluminescent dosemeters were positioned in six locations to record surface and absorbed breast and lung doses....
Background: Polymer composites when reinforced with heavy metals in the form of micro/nano particles are efficient gamma- and X-ray shielding materials providing such advantageous features as cost-effectiveness, light-weight factor, flexibility, non-toxicity, conformability over conventional shields. Materials and Methods: In this paper the influence of weight percentages and particle sizes of ...
BACKGROUND Coronary computed tomographic angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding offers the potential to significantly reduce dose to the breasts and nearby organs, but the magnitude of this reduction and its impact on image quality and radiation dose have not been evaluated. METHODS Radiation doses from CCTA to critical organs...
OBJECTIVE Several studies have been published regarding the use of bismuth shielding to protect the breast in computed tomography (CT) scans and, up to the writing of this article, only one publication about barium shielding was found. The present study was aimed at characterizing, for the first time, a lead breast shielding. MATERIALS AND METHODS The percentage dose reduction and the influen...
The primary purpose of this report is to review the general principles of shielding during computed tomography (CT) and to summarize the latest published information on shielding efficacy. Currently, there are discordant opinions within the literature regarding the appropriateness of shielding, particularly with regard to in-plane bismuth. Understanding that the decision to implement use of a p...
The increased use of computed tomography (CT) and its high radiation dose have led to great concerns about its potential for radiation induced cancer risks. Breast is a radiosensitive tissue based on tissue weighting factors assigned by the International Commission on Radiological Protection (ICRP). Moreover, the dose is maximal on the surface of the patient. Therefore, strategies should be tak...
Background: Epidemiological studies show that computed tomography (CT) is one of the main sources of ionizing radiations. Shielding of radiosensitive organs is one of the dose reduction methods. This study aimed to assess the eye lens dose reduction and image quality resulting from the use of radio-protective bismuth shield in brain CT imaging. Methods: Bismut...
By use of silicon rubber as polymeric matrix and bismuth oxide as fillers, composite materials were fabricated up to 70 wt% and their gamma ray attenuation was studied. Due to the fair solubility of bismuth oxide particles in polymer matrix, the solution intercalation method is used for nanocomposite fabrication. The applied source for radiation attenuation test was 241Am with photon energies 5...
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