A class of photoacoustic acquisition geometries in n is considered such that the spherical mean transform admits an exact filtered back projection reconstruction formula. The reconstruction is interpreted as a time reversion mirror that reproduces exactly an arbitrary source distribution in the cavity. A series of examples of non-uniqueness of the inverse potential problem is constructed based ...

BACKGROUND AND PURPOSE Acute intracranial hemorrhage represents a severe and time critical pathology that requires precise and quick diagnosis, mainly by performing a CT scan. The purpose of this study was to compare image quality and intracranial hemorrhage conspicuity in brain CT with sinogram-affirmed iterative reconstruction and filtered back-projection reconstruction techniques at standard...

The iterative reconstruction (IR) algorithms are able to generate CT images with higher quality compared with the filtered backprojection method when the projection data is noisy or the radiation dose is low. IR can also be used when the data is incomplete. The major disadvantage of the IR is its high demand on computation and slow reconstruction. To improve the time performance of the IR we pa...

Introduction: We have investigated cardiac SPECT with slant hole collimator in which the holes are slanted towards the target organ, to provide greater sensitivity over the parallel hole collimator. In addition, parallel hole collimator was used to obtain a comparison in FWHM, sensitivity, Compton and photoelectric area values in the simulations. Materials and Methods...

Volume rendering techniques are conventionally classified into two categories represented by direct and indirect methods. Indirect methods require to transform the initial volumetric model into an intermediate geometrical model in order to efficiently visualize it. In contrast, direct volume-rendering (DVR) methods can directly process the volumetric data. Modern 3D scanning technologies, like ...

We report on a method for tomographic phase contrast imaging of centimeter sized objects. As opposed to existing techniques, our approach can be used with low-brilliance, lab based x-ray sources and thus is of interest for a wide range of applications in medicine, biology, and nondestructive testing. The work is based on the recent development of a hard x-ray grating interferometer, which has b...

We have analysed the formation of streak artefacts in the reconstruction based on the filtered back projection algorithm in electron tomography (ET) and accordingly applied an adaptive interpolation technique to artefact reduction. In the adaptive interpolation to recover the missing information, the edge positions in a projection curve were tracked to reduce the interpolation error. A simulati...