نتایج جستجو برای: intercrystal scatter

تعداد نتایج: 12386  

Journal: :Journal of radiological protection : official journal of the Society for Radiological Protection 2014
David John Platten

Existing data used to calculate the barrier transmission of scattered radiation from computed tomography (CT) are based on primary beam CT energy spectra. This study uses the EGSnrc Monte Carlo system and Epp user code to determine the energy spectra of CT scatter from four different primary CT beams passing through an ICRP 110 male reference phantom. Each scatter spectrum was used as a broad-b...

2007
Lynn Sheehan Mark Kozlowski Frank Rainer

The Laser Damage and Conditioning Group at LLNL is evaluating diagnostics which will help make damage testing more efficient and reduce the risk of damage during laser conditioning. The work to date has focused on photoacoustic and scattered light measurements on 1064-nm wavelength Hf@/Si02 multilayer mirror and polarizer coatings. Both the acoustic and scatter diagnostics have resolved 10 pm d...

2011
Angelica Svalkvist Gustaf Ullman Markus Håkansson David Dance Michael Sandborg Gudrun Alm Carlsson Magnus Båth

The primary aim of the present work was to analyze the effects of varying scatter-to-primary ratios on the appearance of simulated nodules in chest tomosynthesis section images. Monte Carlo simulations of the chest tomosynthesis system GE Definium 8000 VolumeRAD (GE Healthcare, Chalfont St. Giles, UK) were used to investigate the variation of scatter-to-primary ratios between different angular ...

Journal: :Nihon Hoshasen Gijutsu Gakkai zasshi 2006
Hideki Kato

The anti-scatter grid is generally used as a way of eliminating scattered radiation from X-ray photographs. This does not change even if the detector system changes from an analogue system to a digital system such as the flat-panel detector. We developed a new method that uses software to eliminate scatter components from digital X-ray images taken without the use of an anti-scatter grid. With ...

Journal: :Medical physics 1997
M S Westmore A Fenster I A Cunningham

A new special-purpose computed tomographic (CT) imaging system is described which produces images based on measurements of the low-angle (0-10 degrees) x-ray diffraction properties of an object. Low-angle scatter in the diagnostic x-ray energy range is dominated by coherent scatter, and the system uses first-generation CT geometry to acquire a diffraction pattern for each pencil beam. The patte...

2011
Fredrik Kjolstad Torsten Hoefler Marc Snir

Many high performance applications spend considerable timepacking data into contiguous communication buffers. Datatypesprovide an alternative by describing the layout of the communi-cated data. This empowers the runtime system to retrieve non-contiguous elements directly from application data structures.However, programmers find complex datatypes hard to use andare reluc...

Journal: :European Journal of Operational Research 2006
Francisco Herrera Manuel Lozano Daniel Molina

Scatter search is an evolutionary method that shares with genetic algorithms, a well-known evolutionary approach, the employment of a combination method that combines the features of two parent vectors to form several offspring. Furthermore, it uses improvement strategies to efficiently produce the local tuning of the solutions. An important aspect concerning scatter search is the trade-off bet...

Journal: :Annals of nuclear medicine 2005
Jingming Bai Jun Hashimoto Koichi Ogawa Atsushi Kubo Atsushi Fukunaga Satoshi Onozuka Koichi Uchida

OBJECTIVE The aim of this study was to evaluate the effect of scatter and attenuation correction in region of interest (ROI) analysis in brain perfusion single-photon emission tomography (SPECT) and to assess the influence of selecting the reference area on semi-quantification. METHODS Ten normal subjects were enrolled and injected with 123I-iodoamphetamine to undergo simultaneous emission an...

2016
Dongcai Hu Hao Chen Yuan Wang Yunbin Chen Zhou Xu

In the flat panel detector-based cone beam CT system, the scatter photons which reach the flat panel detector increase the detected signal, produce the image cupping artifact and reduce the image contrast. To conquer the X-Ray scatter problem, this study proposes the beam attenuation grid -based scatter correction algorithm that needs to add a beam attenuation grid (BAG) between the X-Ray sourc...

2012
Yuantao CHEN Weihong XU Jiaying WU Guiping ZHANG

In this paper, a reformative scatter difference discriminant criterion (SDDC) with fuzzy set theory is studied. The scatter difference between between-class and within-class as discriminant criterion is effective to overcome the singularity problem of the within-class scatter matrix due to small sample size problem occurred in classical Fisher discriminant analysis. However, the conventional SD...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید