نتایج جستجو برای: scattered radiation

تعداد نتایج: 258284  

2011
Maï K. Nguyen Tuong T. Truong Marcela Morvidone Habib Zaidi

Imaging processes built on the Compton scattering effect have been under continuing investigation since it was first suggested in the 50s. However, despite many innovative contributions, there are still formidable theoretical and technical challenges to overcome. In this paper, we review the state-of-the-art principles of the so-called scattered radiation emission imaging. Basically, it consist...

Journal: :Аналитика и контроль 2013

2012
Philipp Schuetz Alice Miceli Alexander Flisch Iwan Jerjen Jürgen Hofmann Urs Sennhauser

Absorption computed tomography (CT) relies on the imaging of X-ray radiation transmitted through a specimen in different orientations. For photon energies exceeding 100 keV, a significant fraction of the X-ray radiation is scattered by the object and the environment (components of the instrument, detector, radiation protection, etc.). As the scattered radiation blurs the transmission images, th...

Journal: :iranian journal of nuclear medicine 2004
nasrollah jabbari hossein rajabi hassan firoozabadi fereidoon rastgoo nahid yaghoobi

introduction: scatter radiation is one of the major sources of error in nuclear medicine data processing. different methods of scatter correction have been introduced in order to improve the quality of data. however the best method is to avoid recording of scatter photons in acquisition. the only difference between scattered and non-scattered photons is the energy. pulse height analyzer is the ...

Journal: :Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics 1999
A P Potylitsyn

This paper considers the process of Thomson scattering of coherent diffraction radiation (CDR) produced by the preceding electron bunch in the accelerator onto one of the subsequent bunches. It is shown that the yield of scattered hard photons is proportional to N(3)(e), where N(e) is the number of electrons per bunch. A geometry is chosen for the CDR generation and an expression is obtained fo...

2002
Charles D. Dermer Reinhard Schlickeiser

We treat transformation properties of external radiation fields in the proper frame of a plasma moving with constant speed. The specific spectral energy densities of external isotropic and accretion-disk radiation fields are derived in the comoving frame of relativistic outflows, such as those thought to be found near black-hole jet and gammaray burst sources. Nonthermal electrons and positrons...

Journal: :Physics in medicine and biology 2009
Wayne D Newhauser Jonas D Fontenot Anita Mahajan David Kornguth Marilyn Stovall Yuanshui Zheng Phillip J Taddei Dragan Mirkovic Radhe Mohan James D Cox Shiao Woo

The purpose of this work was to compare the risk of developing a second cancer after craniospinal irradiation using photon versus proton radiotherapy by means of simulation studies designed to account for the effects of neutron exposures. Craniospinal irradiation of a male phantom was calculated for passively-scattered and scanned-beam proton treatment units. Organ doses were estimated from tre...

Background & Aims: Spatial resolution is one of the important features of evaluating the function of nuclear medicine imaging systems. The aim of this study was evaluating the capability of the spatial resolution in images of nuclear medicine planar by calculating the modulation transfer function (MTF). Materials & Methods: Nuclear medicine imaging of capillary tube with activity 1 mCi was per...

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