نتایج جستجو برای: scatter data

تعداد نتایج: 2418087  

Journal: :Medical physics 2009
Lei Zhu Yaoqin Xie Jing Wang Lei Xing

Cone-beam CT (CBCT) is being increasingly used in modern radiation therapy for patient setup and adaptive replanning. However, due to the large volume of x-ray illumination, scatter becomes a rather serious problem and is considered as one of the fundamental limitations of CBCT image quality. Many scatter correction algorithms have been proposed in literature, while a standard practical solutio...

2017
Cong Zhao Xi Chen Luo Ouyang Jing Wang Mingwu Jin

Scatter contamination is one of the main sources of decreasing the image quality in cone-beam computed tomography (CBCT). The moving blocker method is economic and effective for scatter correction (SC), which can simultaneously estimate scatter and reconstruct the complete volume within the field of view (FOV) from a single CBCT scan. However, at the regions with large intensity transition in t...

Journal: :Annual review of biomedical engineering 2010
Nada N Boustany Stephen A Boppart Vadim Backman

Optical contrast based on elastic scattering interactions between light and matter can be used to probe cellular structure, cellular dynamics, and image tissue architecture. The quantitative nature and high sensitivity of light scattering signals to subtle alterations in tissue morphology, as well as the ability to visualize unstained tissue in vivo, has recently generated significant interest ...

2017
Mathieu Cliche David Rosenberg Dhruv Madeka Connie Yee

Charts are an excellent way to convey patterns and trends in data, but they do not facilitate further modeling of the data or close inspection of individual data points. We present a fully automated system for extracting the numerical values of data points from images of scatter plots. We use deep learning techniques to identify the key components of the chart, and optical character recognition...

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...

2010
M. Toohey K. Strong P. F. Bernath C. D. Boone K. A. Walker A. I. Jonsson T. G. Shepherd

[1] In order to validate the reported precision of space‐based atmospheric composition measurements, validation studies often focus on measurements in the tropical stratosphere, where natural variability is weak. The scatter in tropical measurements can then be used as an upper limit on single‐profile measurement precision. Here we introduce a method of quantifying the scatter of tropical measu...

2016
Masanobu Ibaraki Keisuke Matsubara Kaoru Sato Tetsuro Mizuta Toshibumi Kinoshita

OBJECTIVE Positron emission tomography (PET) enables quantitative measurements of various biological functions. Accuracy in data acquisition and processing schemes is a prerequisite for this. The correction of scatter is especially important when a 3D PET scanner is used. The aim of this study was to validate the use of a simplified calculation-based scatter correction method for 15O studies in...

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...

2006
Joel Sommers Paul Barford Walter Willinger

Visualizations provide a natural means for organizing large complex data sets and mining them for characteristics of interest. In this paper, we describe SPLAT, a scatter and phase plot animation tool. SPLAT offers a broad set of capabilities for investigating Internet measurement data sets based on scatter and phase plots—two well-known techniques for exploratory data analysis. An important fe...

Journal: :Physics in medicine and biology 1998
D J Kadrmas E C Frey S S Karimi B M Tsui

Accurate scatter compensation in SPECT can be performed by modelling the scatter response function during the reconstruction process. This method is called reconstruction-based scatter compensation (RBSC). It has been shown that RBSC has a number of advantages over other methods of compensating for scatter, but using RBSC for fully 3D compensation has resulted in prohibitively long reconstructi...

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