نتایج جستجو برای: scatter

تعداد نتایج: 12375  

Journal: :Medical physics 2015
G J Bootsma F Verhaegen D A Jaffray

PURPOSE X-ray scatter is a significant impediment to image quality improvements in cone-beam CT (CBCT). The authors present and demonstrate a novel scatter correction algorithm using a scatter estimation method that simultaneously combines multiple Monte Carlo (MC) CBCT simulations through the use of a concurrently evaluated fitting function, referred to as concurrent MC fitting (CMCF). METHO...

Journal: :Journal of biomedical optics 2010
Robert M Pasternack Jing-Yi Zheng Nada N Boustany

We combine optical scatter imaging (OSI) with fluorescence imaging of mitochondria to investigate the spatial relationship between the optical scatter signal and the location and structure of mitochondria within endothelial cells undergoing apoptosis. The OSI data corroborate our previous results showing a decrease in the intensity ratio of wide-to-narrow angle scatter [optical scatter image ra...

2010
Toshiki Hanyu

This paper describes the development of a theoretical framework for quantitatively characterizing sound field diffusion based on scattering coefficient and absorption coefficient of walls. The concepts of equivalent scattering area, equivalent scatter reflection area, average scattering coefficient and average scatter reflection coefficient are introduced in order to express all walls' capabili...

Journal: :Physics in medicine and biology 2008
Sarah E Bohndiek Emily J Cook Costas D Arvanitis Alessandro Olivo Gary J Royle Andy T Clark Mark L Prydderch Renato Turchetta Robert D Speller

X-ray diffraction studies give material-specific information about biological tissue. Ideally, a large area, low noise, wide dynamic range digital x-ray detector is required for laboratory-based x-ray diffraction studies. The goal of this work is to introduce a novel imaging technology, the CMOS active pixel sensor (APS) that has the potential to fulfil all these requirements, and demonstrate i...

2011
Rostislav Khlebnikov Bernhard Kainz Bernhard Roth Judith Muehl Dieter Schmalstieg

We present a novel on-the-fly scatter approximation scheme that can be applied concurrently to multiple volumetric datasets. We use a simplified version of the emission-absorption model, including single scattering and shadowing and guide the scatter sample positions and in-scatter coefficients by local gradients. This allows us to render multiple intersecting volumes with our rendering system ...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2001
Z Lee M Ljungberg R F Muzic M S Berridge

UNLABELLED Planar gamma-scintigraphy is often used to quantify pulmonary deposition patterns from aerosol inhalers. The results are quite different from those obtained using 3-dimensional PET and SPECT. The purpose of this study was to characterize the effects of scatter and tissue attenuation on the distribution of radiolabeled aerosol as measured by planar scintigraphy using Monte Carlo simul...

Journal: :Physics in medicine and biology 2000
I Laurette G L Zeng A Welch P E Christian G T Gullberg

The qualitative and quantitative accuracy of SPECT images is degraded by physical factors of attenuation, Compton scatter and spatially varying collimator geometric response. This paper presents a 3D ray-tracing technique for modelling attenuation, scatter and geometric response for SPECT imaging in an inhomogeneous attenuating medium. The model is incorporated into a three-dimensional projecto...

2004
Yong Liu

From the process of scatter-gather algorithm explained above, we can easily find the essence of the parallel version of this algorithm is the parallel clustering algorithm used in the scatter phase. Frieder, et al. implements a parallel version of the buckshot clustering algorithm [1]. Their work meets the need of the parallel scatter-gather clustering algorithm pretty well, although we can des...

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