نتایج جستجو برای: scatter system

تعداد نتایج: 2240877  

Journal: :Medical physics 2006
J H Siewerdsen M J Daly B Bakhtiar D J Moseley S Richard H Keller D A Jaffray

X-ray scatter poses a significant limitation to image quality in cone-beam CT (CBCT), resulting in contrast reduction, image artifacts, and lack of CT number accuracy. We report the performance of a simple scatter correction method in which scatter fluence is estimated directly in each projection from pixel values near the edge of the detector behind the collimator leaves. The algorithm operate...

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 ...

2008
Venkataramanan Krishnaswamy P. Jack Hoopes Kimberley S. Samkoe Brian W. Pogue

It has been shown that locally resolved reflectance measurements can directly quantify scatter changes in tissues without the need for computationally expensive model-based reconstruction schemes. Imaging systems exploiting non-model based reconstruction schemes are faster compared to the conventional model based schemes and thus have the potential for imaging tissue pathologies in real-time. I...

2006
Robert Saunders

Scattered radiation plays a significant role in mammographic imaging, with scatter fractions over 50% for larger, denser breasts. For screen-film systems, scatter primarily affects the image contrast, reducing the conspicuity of subtle lesions. While digital systems can overcome contrast degradation, they remain susceptible to scatter’s impact on the image resolution and noise. To better unders...

Journal: :Physics in medicine and biology 2010
J L Ducote S Molloi

X-ray scatter is a major cause of nonlinearity in densitometry measurements using digital mammography. Previous scatter correction techniques have primarily used a single scatter point spread function to estimate x-ray scatter. In this study, a new algorithm to correct x-ray scatter based on image convolution was implemented using a spatially variant scatter point spread function which is energ...

Journal: :IEEE Transactions on Radiation and Plasma Medical Sciences 2020

Journal: :International journal of advanced smart convergence 2013

Hadi Taleshi Mohsen Saffar Peter Knoll, Shabnam Oloomi

Introduction: Scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. Accurate estimation of scatter in projection data of SPECT is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. Methods: The objective of this paper is to develop and validate a scatter correction technique ...

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