Iterative PET image reconstructions can improve quantitation accuracy by explicitly modeling photon-limited nature and physical effects of coincident photons. Geometric model in iterative reconstructions defines the mapping between image and sinogram domains based on scanners geometry, which affects the accuracy of image results and the convergence rate of reconstruction algorithms. This paper ...

X-ray grating interferometer can simultaneously retrieve attenuation, refraction, and scattering signals of the imaged sample, which shows its great potential in biomedical imaging. However, fast scan gratings high centrifugal forces during rotating grating-based cone-beam computed tomography (CBCT) system may lead to phase-stepping (PS) errors position fluctuations, cause reconstruction failur...

background: photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of spect images and results to errors in accuracy of quantitative measurements. this can be corrected via different physical or mathematical approaches. as the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘piece wise line...

At the experimental heavy ion therapy facility at the GSI Darmstadt an in-beam PET scanner is operated for quality assurance monitoring simultaneously to the therapeutic irradiation. A fully 3D maximum likelihood expectation maximization (MLEM) reconstruction algorithm has been developed and adapted to the special conditions of in-beam PET [1]. The system response function (system matrix) for t...

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...

Abstract Digital rock is an emerging area of physics, which involves scanning reservoir rocks using X-ray micro computed tomography (XCT) scanners and it for various petrophysical computations evaluations. The acquired CT projections are used to reconstruct the attenuation maps rock. image reconstruction problem can be solved by utilization analytical (such as Feldkamp–Davis–Kress (FDK) algorit...

Limited-angle positron emission tomography systems can be placed next to the anatomical area of interest, improving their spatial resolution and diagnostic sensitivity. However, the incomplete angular sampling makes the reconstruction process susceptible to image artifacts and anisotropic spatial resolution. In this work, I show that combining total variation (TV) minimization with the maximum ...

Background: Photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of SPECT images and results to errors in accuracy of quantitative measurements. This can be corrected via different physical or mathematical approaches. As the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘Piece ...