OBJECTIVES The purpose of this study was to evaluate the image quality and diagnostic accuracy of very low-dose, dual-source computed tomography (DSCT) angiography for the evaluation of coronary stents. BACKGROUND Iterative reconstruction (IR) leads to substantial reduction of image noise and hence permits the use of very low-dose data acquisition protocols in coronary computed tomography ang...

On reconstructing a volume, the exact reconstruction algorithm for spiral cone-beam CT accesses the memory many times while all the filtered projection data has to be arrived. This is quite a bottleneck for implementation. Normally, the filtered projection data is transferred frame by frame in serial. In this paper, a new backprojection algorithm is proposed. The algorithm uses data inside the ...

In this paper, a new method for metal artefact reduction in computed tomography is investigated, based on sinusoidal amendment. Each voxel in the scanned object corresponds to a sinusoidal curve in the projection data set. Some of the sinusoidal curves result from metal implant, which can be identified because the attenuation coefficient of the metal is much higher than that of human tissue, an...

We present an explicit formula for spline kernels; these are defined as the convolution of several B-splines of variable widths hi and degrees ni. The spline kernels are useful for continuous signal processing algorithms that involve Bspline inner-products or the convolution of several spline basis functions. We apply our results to the derivation of spline-based algorithms for two classes of p...

Introduction:Low-pass filters eliminate noise, and accordingly improve the quality of filtered back-projection (FBP) in the reconstruction of single photon emission computed tomography (SPECT) images. This study aimed at selection of an optimum low-pass filter for FBP reconstruction of SPECT images of small structures. Material and Methods:Sp...

The strong inter-channel cross correlation between stereo received signals creates a problem of non-unique solutions for stereo echo cancellation. To avoid this problem, the addition of inaudible non-linearly filtered received signals to themselves was proposed. However, the convergence of misalignment is still slow even when the affine projection algorithm is used, since strong inter-channel c...

A new complex, neutron-, gammaand X-ray three-dimensional computer tomography system suitable for experimental and industrial applications has been built at the 10-MW Budapest research reactor site. After the system was installed, a number of objects were investigated and tomographic projections were made. The evaluation relied on two reconstruction approaches. One of these is the classical, fi...

................................................................................................................... 1 SAMMANFATTNING ................................................................................................... 3 LIST OF PAPERS ........................................................................................................... 5 ABBREVIATIONS ..........................

We establish inversion formulas of the so called filtered back-projection type to recover a function supported in the ball in even dimensions from its spherical means over spheres centered on the boundary of the ball. We also find several formulas to recover initial data of the from (f, 0) (or (0, g)) for the free space wave equation in even dimensions from the trace of the solution on the boun...

We show that discrete tomography (DT) is suitable to increase the possible inspection size of single material oblong objects compared to filtered back projection (FBP) in non-destructive testing (NDT) with 2D X-ray computed tomography (CT). For such objects which are in one dimension larger than the maximum detectable material thickness limited view angles occur and FBP is not suitable for reco...