首页>>文献首页>>文献正文

求助SPIE会议论文一篇:Signal statistics in x-ray computed tomography

maobl 添加于 2016/5/20 13:38:50  608次阅读 | 0次推荐 | 0个评论

Probability distribution functions (pdfs) of x-ray computed tomography (CT) signals form the basis for statistical reconstruction algorithms and for noise-simulation experiments. The conventional model for pdf's assumes a quanta-counting process obeying a discrete Poisson distribution. In reality, CT scanners employ energy-integrating sensors detecting a polyenergetic X-ray beam, with data quantized for digital reconstructions. A model was developed for the CT signal consisting of an energy spectrum of x-ray quanta (individually obeying Poisson statistics), contributing an incremental signal, proportional to their energy, to an analog-to-digital converter. Using a moment generating function approach, the pdf is shown to be a Compound Poisson process that is functionally dependent on the x-ray energy spectrum, flux level, and quantization step size. Pdfs were computed numerically by a Fourier transform of the characteristic function and compared to experimental pdfs collected from phantom scans. For exposures encountered in normal clinical usage, the pdf is similar to the conventional Gaussian approximation, with rescaling for quantization and polyenergetic spectra. For low intensities, the deviation from the conventional photon-counting (Poisson) model is significant and may have implications for statistical reconstruction algorithms.

作 者:Bruce R. Whiting
期刊名称: Proc. SPIE 4682, Medical Imaging 2002: Physics of Medical Imaging, 53 (May 2, 2002);
期卷页: 第卷 第期 页
学科领域:信息科学 » 光学和光电子学 » 生物、医学光子学
添加人是否为作者:
原文链接:http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=879147
DOI: doi:10.1117/12.465601
ISBN:
关键词:
备 注:
来自论坛的回复:
文献笔记

   
导出选项:

评论 (0 个评论)

Page 1 of 1
<<<[1]>>>
发表评论:
验证码  
 

举报 | Archiver | 科学网( 京ICP备07017567 )

GMT+8, 2011-2-15 11:31

Powered by ScienceNet.cn

Copyright © 2007-2011 科学时报社