BACKGROUND: This study focuses on quantitative reconstruction of dynamic cardiac SPECT. MATERIAL AND METHODS: The Karhunen-Loeve (KL) transform is first applied to gated frames or sinogram data to de-correlate the dynamic information along the time direction. Then the Poisson noise is treated by a penalized weighted least-squares minimization, followed by an analytical inversion of the treated...

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4D computed tomography (4D-CT) is an important modality in medical imaging due to its ability to resolve patient anatomy motion in each respiratory phase. Conventionally 4D-CT is accomplished by performing the reconstruction for each phase independently as in a CT reconstruction problem. We propose a new 4D-CT reconstruction algorithm that explicitly takes into account the temporal regularizati...

Introduction: In radiation therapy of lung tumors, respiratory motion causes target moving, so a larger margin is needed to cover the clinical target volume (CTV). With the margin increasing, a larger volume of normal tissue will be exposed to high-dose.  In this study, dosimetric parameters of normal lung tissue were compared between gated and conventional radiotherapy (RT), u...

In PET/CT thoracic imaging, respiratory motion reduces image quality. A solution consists in performing respiratory gated PET acquisitions. The aim of this study was to generate clinically realistic Monte-Carlo respiratory PET data, obtained using the 4D-NCAT numerical phantom and the GATE simulation tool, to assess the impact of respiratory motion and respiratory-motion compensation in PET on ...

Purpose: To develop and validate an automatic algorithm for the detection and functional assessment of lung tumors on three-dimensional respiratory gated PET/CT images. Method and Materials: First the algorithm will automatically segment lung regions in CT images, then identify and localize focal increases of activity in lung regions of PET images at each gated bin. Once the tumor voxels have b...

An efficient postprocessing method to compensate for the scattering and blurring effects in inhomogeneous medium in SPECT is proposed. A two-dimensional point spread function (2D-PSF) was estimated in the image domain to model the combination of these two physical effects. This 2D-PSF in the inhomogeneous medium is fitted with an asymmetric Gaussian function based on Monte Carlo simulation resu...

introduction: the main goal of spect imaging is to determine activity distribution inside the organs of the body. however, due to photon attenuation, it is almost impossible to do a quantitative study. in this paper, we suggest a mathematical relationship between activity distribution and its corresponding projections using a transfer matrix. monte carlo simulation was used to find a precise tr...

An effective workforce performing within the context of a positive cultural environment is central to a healthcare organization's ability to achieve quality outcomes. The Nursing Culture Assessment Tool (NCAT) provides nurses with a valid and reliable tool that captures the general aspects of nursing culture. This study extends earlier work confirming the tool's construct validity and dimension...