نتایج جستجو برای: photon attenuation

تعداد نتایج: 118713  

Introduction: Integration of single photon emission computed tomography (SPECT) and computed tomography (CT) scanners into SPECT/CT hybrid systems permit detection of coronary artery disease in myocardial perfusion imaging (MPI). Misregistration between CT and emission data can produce some errors in uptake value of SPECT images. The aim of this study was evaluate the influence...

Journal: :IEEE transactions on radiation and plasma medical sciences 2021

Attenuation correction (AC) is essential for the generation of artifact-free and quantitatively accurate positron emission tomography (PET) images. PET AC based on computed (CT) frequently results in artifacts attenuation-corrected images, these mainly originate from CT PET-CT mismatches. The combined with a magnetic resonance imaging (MRI) scanner (PET/MRI) more complex than PET/CT, given that...

2011
Ákos Szlávecz Gábor Hesz Tamás Bükki Balázs Benyó

Parallel projection based Single Photon Emission Computed Tomography (SPECT) is one of the most widely used nuclear imaging technique even nowadays. Serious artefacts are produced in the reconstructed images due to the non-homogeneous attenuation medium and the distance dependent spatial resolution (DDSR) of the parallel imaging. Effective non-uniform attenuation correction and DDSR reduction p...

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 ...

Introduction: This study aimed to evaluate the efficacy of a synthesized bolus in the reduction of damage to body tissues and the protection of the organ at risk (OAR) in radiotherapy application. Several properties of the synthesized bolus, including density, transmission factor, and effective mass attenuation coefficient, were investigated. Material and ...

N. Demir, O. Gurler, U. Akar Tarim,

Background: In radiation therapy, water is the phantom material of choice, both for reference and for relative dosimetry measurements. Solid phantoms, however, are more useful for routine measurements because they tend to be more robust and easier to set up than water phantoms. Materials and Methods: FLUKA input data cards have been arranged in sequential order. A simple cylindrical geometry wi...

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