نتایج جستجو برای: scatter correction

تعداد نتایج: 176847  

1999
Habib Zaidi

Accurate scatter correction is one of the major problems facing quantitative 3D PET and many methods have been developed for the purpose of reducing the resultant degradation of image contrast and loss of quantitative accuracy. A new scatter correction method called Statistical Reconstruction-Based Scatter Correction (SRBSC) is proposed in this paper and evaluated using Monte Carlo simulations,...

2013
Jun Li Weiguang Yao Ying Xiao Yan Yu

The study was to explore the feasibility of improving cone-beam CT (CBCT) number (corresponding to the Hounsfield units in computed tomography) consistency using a scatter-correction algorithm, with the aim of using CBCT images for treatment planning with density correction. A scatter correction algorithm was applied to a Varian OBI CBCT and an Elekta XVI CBCT, and was evaluated for improving C...

Journal: :Journal of nuclear medicine technology 2003
Douglass C Vines Masanori Ichise Jeih-San Liow Hiroshi Toyama Robert B Innis

OBJECTIVE Scatter correction is an important factor in quantitative SPECT. In this study, we evaluated 2 methods of scatter correction for brain SPECT. The first is based on thresholding the energy spectrum (ES), and the second is based on a modification of the transmission-dependent convolution subtraction (TDCS) method. METHODS SPECT imaging of a skull striatal phantom was performed using a...

Introduction: The key characteristics of positron emission tomography (PET) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. Therefore, accurate quantification is important. However, it can be sensitive to several physical factors. The aim of this investigation is the assessment of the e...

Journal: :Physics in medicine and biology 2012
Matthias Baer Marc Kachelrieß

The purpose of this study was to develop and evaluate the hybrid scatter correction algorithm (HSC) for CT imaging. Therefore, two established ways to perform scatter correction, i.e. physical scatter correction based on Monte Carlo simulations and a convolution-based scatter correction algorithm, were combined in order to perform an object-dependent, fast and accurate scatter correction. Based...

2015
Peter G.F. Watson Ernesto Mainegra‐Hing Nada Tomic Jan Seuntjens

Cone-beam computed tomography (CBCT) images suffer from poor image quality, in a large part due to contamination from scattered X-rays. In this work, a Monte Carlo (MC)-based iterative scatter correction algorithm was implemented on measured phantom data acquired from a clinical on-board CBCT scanner. An efficient EGSnrc user code (egs_cbct) was used to transport photons through an uncorrected ...

Journal: :iranian journal of medical physics 0
afshin akbarzadeh ph.d. student, department of medical physics and biomedical engineering and research center for science and technology in medicine, tehran university of medical sciences, tehran, iran mohammad rreza ay assistant professor in biomedical engineering, biomedical systems & medical physics dept., tehran university of medical sciences & research center for science and technology in medicine, tehran, iran. hossein ghadiri ph.d. student, department of medical physics and biomedical engineering and research center for science and technology in medicine, tehran university of medical sciences, tehran, iran saied sarkar associate professor in biomedical engineering, biomedical systems & medical physics dept., tehran university of medical sciences & research center for science and technology in medicine, tehran, iran.

introduction: one of the most important parameters in x-ray ct imaging is the noise induced by detected scattered radiation. the detected scattered radiation is completely dependent on the scanner geometry as well as size, shape and material of the scanned object. the magnitude and spatial distribution of the scattered radiation in x-ray ct should be quantified for development of robust scatter...

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...

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

  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 Maximiz...

Journal: :Annals of nuclear medicine 1999
H Ito H Iida T Kinoshita J Hatazawa T Okudera K Uemura

The transmission dependent convolution subtraction method which is one of the methods for scatter correction of SPECT was applied to the assessment of CBF using SPECT and I-123-IMP. The effects of scatter correction on regional distribution of CBF were evaluated on a pixel by pixel basis by means of an anatomic standardization technique. SPECT scan was performed on six healthy men. Image recons...

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