Publications by authors named "Hamid R Khosravi"

Dose calculation algorithm is one of the main sources of uncertainty in the radiotherapy sequences. The aim of this study was to compare the accuracy of different inhomogeneity correction algorithms for external photon beam dose calculations. The methodology was based on International Atomic Energy Agency TEC-DOC 1583.

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Objective: To survey procedures and protocols in paediatric computed tomography (CT) in 40 less resourced countries.

Methods: Under a project of the International Atomic Energy Agency, 146 CT facilities in 40 countries of Africa, Asia, Europe and Latin America responded to an electronic survey of CT technology, exposure parameters, CT protocols and doses.

Results: Modern MDCT systems are available in 77 % of the facilities surveyed with dedicated paediatric CT protocols available in 94 %.

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Recognizing the lack of information on image quality and patient doses in most countries in Asia, the International Atomic Energy Agency (IAEA) initiated a project to assess the status of imaging technology, practice in conventional radiography, mammography, computed tomography (CT) and interventional procedures, and to implement optimisation actions. A total of 20 countries participated. Obsolete practices of use of fluoroscopy for positioning, photofluorography, chest fluoroscopy and conventional tomography were reported by 4 out of 7 countries that provided this information.

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The general population, everywhere in the world is exposed to a small dose of ionising radiation from natural sources. Stochastic effects such as cancer and genetic disorders are caused when living creatures are exposed to low doses. In Iran, it is measured in some cities, especially in high-background areas such as Ramsar, but so far there is no measurement in the Hamadan province.

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Objective: The purpose of this study was to assess the frequency of pediatric CT in 40 less-resourced countries and to determine the level of appropriateness in CT use.

Materials And Methods: Data on the increase in the number of CT examinations during 2007 and 2009 and appropriate use of CT examinations were collected, using standard forms, from 146 CT facilities at 126 hospitals.

Results: The lowest frequency of pediatric CT examinations in 2009 was in European facilities (4.

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Purpose: Different types of concretes are used for bunker construction for radiation therapy. As neutron production occurs in high-energy photon beams, the purpose of this study was to investigate the effect of different concretes on photoneutron doses at an isocenter and maze entrance door.

Materials And Methods: The 18-MV photon beam of a Varian 2100 C/D linear accelerator and a radiation therapy bunker were simulated using the MCNPX Monte Carlo code.

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