نتایج جستجو برای: dose x

تعداد نتایج: 911113  

Journal: :iranian journal of medical physics 0
mohammad taghi bahreyni toossi medical physics department, medical physics research center, mashhad university of medical sciences, mashhad, iran.

introduction the present work describes a study in which, based on patient dose measurements, thermoluminescent dosimeters were used to obtain the diagnostic reference level arising from panoramic radiography. materials and methods ten panoramic units and a sample of 15 patients per x-ray unit were studied. two thermoluminescent dosimeter chips were placed on the skin surface of selected organs...

 ABSTRACTBackground: An electron beam generated X-ray spectrum consists of characteristic X-ray and continuous bermsstrahlung. The aim of this research is calculating and comparing X-ray spectra for different target filter of mammograms. Materials and Methods: Monte Carlo is a very powerful tool to simulate a series of different target-filter assembly in order to calculate the X-ray spectra. MC...

Journal: :American Journal of Roentgenology 1971

Journal: :Journal of the Korean Society of Radiology 2017

Journal: :Journal of computer assisted tomography 2009
Deepak Bharkhada Hengyong Yu Robert Dixon Yuchuan Wei J Jeffrey Carr J Daniel Bourland Ryan Best Richard Hogan Ge Wang

With continuing developments in computed tomography (CT) technology and its increasing use of CT imaging, the ionizing radiation dose from CT is becoming a major public concern particularly for high-dose applications such as cardiac imaging. We recently proposed a novel interior tomography approach for x-ray dose reduction that is very different from all the previously proposed methods. Our met...

Journal: :iranian journal of medical physics 0
m. t. bahreyni toosi professor, medical physics research center, bu-ali research institute, mashhad university of medical sciences, mashhad, iran. h. saberi ph.d. student in medical physics, mashhad university of medical sciences, mashhad, iran m. momen nezhad ph.d. student in medical physics, mashhad university of medical sciences, mashhad, iran

introduction:  skin  sparing  is  one  of  the  most  desirable  characteristics  of  high  energy  photon  beams. however, the photons emerging from the target of linacs are contaminated by secondary  electrons  as  a  result  of  their  interactions  with  air,  collimators,  flattening  filter  and  any  other  objects in their path. this phenomenon tends to increase the skin dose received b...

Journal: :iranian journal of nuclear medicine 2013
hamid javadi ali mahmoud pashazadeh mehdi mogharrabi isa neshandar asli faraj tabei

introduction: the aim of present study was to estimate effective dose from most common procedures performed in nuclear medicine departments of golestan province. methods: data of nuclear medicine procedures performed in 2 nuclear medicine departments in golestan province were collected during 4 years. effective dose, collective effective dose and effective dose per examination were calculated u...

2004
Shigeru Yokoyama Peter L. Roberson Dale W. Litzenberg Jean M. Moran Benedick A. Fraass

The more complex delivery techniques required for implementation of intensity-modulated radiotherapy (IMRT) based on inverse planning optimization have changed the relationship between dose at depth and dose at buildup regions near the surface. Surface buildup dose is dependent on electron contamination primarily from the unblocked view of the flattening filter and secondarily from air and coll...

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