نتایج جستجو برای: electron contamination

تعداد نتایج: 359689  

Journal: :Micron 2015
D R G Mitchell

Modern scanning transmission electron microscopy (STEM) enables imaging and microanalysis at very high magnification. In the case of aberration-corrected STEM, atomic resolution is readily achieved. However, the electron fluxes used may be up to three orders of magnitude greater than those typically employed in conventional STEM. Since specimen contamination often increases with electron flux, ...

Introduction Accurate estimation of the skin-absorbed dose in external radiation therapy is essential to estimating the probability of secondary carcinogenesis induction Materials and Methods Electron contamination in prostate radiotherapy was investigated using the Monte Carlo (MC) code calculation. In addition, field size dependence of the skin dose was assessed. Excess cancer risk induced by...

ژورنال: سنجش و ایمنی پرتو 2014

During the radiation therapy with electron beam, due to electron interaction and scattering from structures of the head of the medical linear accelerator, unwanted photons are produced. The main contribution of the photon contamination is resulted from the various components of the medical linear accelerator on the way of the high energy electron beam, and few percent is due to the interaction ...

E Akbari, H R Baghani H R Mirzaei K Tanha, M Mousavi, M Robatjazi, N Nafissi, S R Mahdavi,

Background: One of the main problems of dedicated IORT accelerators is to determine dosimetric characteristics of the electron beams. Monte Carlo simulation of IORT accelerator head and produced beam will be useful to improve the accuracy of beam dosimetry.Materials and Methods: Liac accelerator head was modeled using the BEAMnrcMonte Carlo simulation system. Phase-space files were generated at...

Journal: :iranian journal of radiation research 0
a. mesbahi department of medical physics, medical school, tabriz university of medical sciences, tabriz, iran p. mehnati department of medical physics, medical school, tabriz university of medical sciences, tabriz, iran a. keshtkar department of medical physics, medical school, tabriz university of medical sciences, tabriz, iran

background: monte carlo method (mc) has played an important role in design and optimization of medical linacs head and beam modeling. the purpose of this study was to compare photon beam features of two commercial linacs, varian 21ex and elekta sl-25 using mcnp4c mc code. materials and methods: the 6mv photon beams of varian 21ex and elekta sl-25 linacs were simulated based on manufacturers pro...

Hojatollah Shahbazian Jafar Fatahiasl Mansour Zabihzadeh Mohammad Ali Behrooz Mohammad Javad Tahmasebibirgani Nahid Chegeni Reza Maskani

Introduction: Photon contamination is a restriction on treatment with electron that increase dose to healthy tissue below the tumor. The aim of this study is to reduce the photon contamination using a magnet system. Materials and Methods: A mini-applicator equipped with two neodymium boron permanent magnets was designed which make it possible to adjust the d...

ژورنال: طلوع بهداشت یزد 2017

Introduction: Pistachio is  an important export product in some countries, especially Iran.  Pistachios are with the highest risk of aflatoxin contamination between agricultural products. Aflatoxin B1 is the most potent carcinogenic aflatoxins. Aflatoxins have an important role in the etiology of cancer. Undoubtedly, the major problem is, Aspergillus flavus contamination Aflatoxin pr...

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