نتایج جستجو برای: absorbed ratio
تعداد نتایج: 521179 فیلتر نتایج به سال:
Background: For preclinical evaluations of radiopharmaceuticals, most studies are carried out on mice. Values of electron specific absorbed fractions (SAF) have had vital role in the assessment of absorbed dose. In past studies, electron specific absorbed fractions were given for limited source target pairs using older reports of human organ compositions.Objective: Electron specific absorbed fr...
Introduction In this study, we aimed to calculate dose enhancement factor (DEF) for gold (Au) and iron (Fe) nanoparticles (NPs) in brachytherapy and teletherapy, using Monte Carlo (MC) method. Materials and Methods In this study, a new algorithm was introduced to calculate dose enhancement by AuNPs and FeNPs for Iridium-192 (Ir-192) brachytherapy and Cobalt-60 (Co-60) teletherapy sources, using...
The identification and concentration of heavy metals, which may be so harmful for the body, is determined by the method of calibration-free laser-induced breakdown spectroscopy using a special strategy. First, the plasma temperature is obtained using the Boltzmann plot. Then, a line with an inappreciable self-absorption is considered for each element as the reference. The modified intensities o...
Synchrotron self-Compton (SSC) scattering is an important emission mechanism in many astronomical sources, such as gamma-ray bursts (GRBs) and active galactic nuclei. We give a complete presentation of the analytical approximations for the Compton scattering of synchrotron emission with both weak and strong synchrotron self-absorption. All possible orders of the characteristic synchrotron spect...
The complexities of the interactions between long- and short-wave radiation fluxes and the human body make it inherently difficult to estimate precisely the total radiation absorbed (R) by a human in an outdoor environment. The purpose of this project was to assess and compare three methods to estimate the radiation absorbed by a human in an outdoor environment, and to compare the impact of app...
background: radiotherapy plays an important role in the management of most malignant and many benign primary central nervous system (cns) tumors. radiotherapy affects both tumor cells and uninvolved normal cells; so, it is important to estimate absorbed dose to organs at risk in this kind of treatment. the aim of this study was to determine the absorbed dose to chiasma, lens, optic nerve, retin...
BACKGROUND Patient navigation (PN) can improve breast cancer care among disadvantaged women. We evaluated the impact of a PN program on follow-up after an abnormal mammogram. METHODS Between 2007 and 2010, disadvantaged women with an abnormal mammogram (Breast Imaging-Reporting and Data System [BI-RADS] codes 0, 3, 4, 5) cared for in a community health center (CHC) with PN were compared to th...
OBJECTIVE To determine the positive predictive value (PPV) and likelihood ratio for magnetic resonance imaging (MRI) characteristics of category 4 lesions, as described in the Breast Imaging Reporting and Data System (BI-RADS(®)) lexicon, as well as to test the predictive performance of the descriptors using multivariate analysis and the area under the curve derived from a receiver operating ch...
OBJECTIVES To assess whether strain histograms are equal to strain ratios in predicting breast tumour malignancy and to see if either could be used to upgrade Breast Imaging Reporting and Data System (BI-RADS) 3 tumours for immediate biopsy. METHODS Ninety-nine breast tumours were examined using B-mode BI-RADS scorings and strain elastography. Strain histograms and ratios were assessed, and a...
A study was made on the loss of the reproductive capacity of HeLa S3 cells irradiated in vitro under both oxygenated and anoxic conditions with D-T neutrons (14 Mev) at 1, 20, 30, 150 and 400 rads/minute at 25•Ž and 37•Ž and with 180 kvp X-rays at 100 rads/minute at 37•Ž. 1) RBE of neutrons measured at a range of 2 to 10% survival was 2.67-2.62 under oxygenated conditions and 3.83.4.61 under an...
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