نتایج جستجو برای: scatter correction

تعداد نتایج: 176847  

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...

2014
Kyoko Saito Yasuyuki Takahashi Naomi Ogano Hirotaka Shimada Takao Kanzaki Hiroki Okada Kei Yokota Kaori Hatano Yuki Yoshida Tetsuya Higuchi

The acquisition method for planar 67Ga imaging has hardly changed for 30 years. In this study, in order to improve image quality and diagnostic accuracy, we take steps to optimize the acquisition method, and to choose a scatter correction. First, we acquired individual images from the 93 keV, 185 keV, and 300 keV photopeak; then the images were added together and compared to the individual imag...

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...

2011
M Ljungberg

In therapy imaging there is a need to optimize imaging protocols and different correction methods for e.g. photon attenuation, contribution from scatter and other physicsrelated effects that limits the possibility to achieve accurate quantitative results. Physical phantom studies are important but lack flexibility and are often difficult to make patient realistic. A complement is to simulate th...

Journal: :Annals of nuclear medicine 2009
Koichi Okuda Kenichi Nakajima Nobutoku Motomura Masahiro Kubota Noriyasu Yamaki Hisato Maeda Shinro Matsuo Seigo Kinuya

OBJECTIVE Segmentation with scatter and photopeak window data using attenuation correction (SSPAC) method can provide a patient-specific non-uniform attenuation coefficient map only by using photopeak and scatter images without X-ray computed tomography (CT). The purpose of this study is to evaluate the performance of attenuation correction (AC) by the SSPAC method on normal myocardial perfusio...

2013
Shabnam Oloomi Hadi Noori Eskandari Seyed Rasoul Zakavi Peter Knoll Faraz Kalantari Mohsen Hajizadeh Saffar

OBJECTIVE(S) In SPECT, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. Many techniques for attenuation and scatter correction have been proposed. An acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. Here, we propose new Maximum Likelihood Expectation Maximization (MLEM) f...

Journal: :CoRR 2018
Awais Ashfaq Jonas Adler

CBCT images suffer from acute shading artifacts primarily due to scatter. Numerous image-domain correction algorithms have been proposed in the literature that use patient-specific planning CT images to estimate shading contributions in CBCT images. However, in the context of radiosurgery applications such as gamma knife, planning images are often acquired through MRI which impedes the use of p...

Journal: :Medical physics 2011
Xiaofeng Niu Yongyi Yang Mingwu Jin Miles N Wernick Michael A King

PURPOSE In gated cardiac single photon emission computed tomography (SPECT), image reconstruction is often hampered by various degrading factors including depth-dependent spatial blurring, attenuation, scatter, motion blurring, and low data counts. Consequently, there has been significant development in image reconstruction methods for improving the quality of reconstructed images. The goal of ...

Journal: :Japanese Journal of Radiological Technology 1998

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