For transmission computed tomography (TCT) systems using a centered transmission source with a fan-beam collimator, the transmission projection data are truncated. To achieve sufficiently large imaging field of view (FOV), we have designed the combination of an asymmetric fan-beam (AsF) collimator and a small uncollimated sheet-source for TCT, and implemented AsF sampling on a two-head SPECT sy...

An improved soot diagnostics technique based on tomographic reconstruction of flame emission spectra has been developed for an axisymmetric laminar diffusion flame without optically-thin assumption. Emission from the flame is scanned along the horizontal lateral axis of flame at several altitudes above the burner. At each measurement position, the local line-of-sight flame emission spectra is c...

A filtered backprojection reconstruction algorithm was developed for cardiac single photon emission computed tomography with cone-beam geometry. The algorithm reconstructs cone-beam projections collected from ;short scan' acquisitions of a detector traversing a noncircular planar orbit. Since the algorithm does not correct for photon attenuation, it is designed to reconstruct data collected ove...

Soft tissue attenuation artefacts are more likely to occur in patients with high body mass index (BMI) undergoing myocardial perfusion imaging (MPI) and therefore it is routine practice in our department to perform attenuation correction in this group of patients. However, we suspected that attenuation artefacts may also occur in patients with normal BMI. We collected data prospectively on 5...

A method for achieving quantitative single-photon emission computed tomography (SPECT) based upon corrections derived from x-ray computed tomography (CT) data is presented. A CT-derived attenuation map is used to perform transmission-dependent scatter correction (TDSC) in conjunction with non-uniform attenuation correction. The original CT data are also utilized to correct for partial volume ef...

German Cancer Research Center (DKFZ), Heidelberg, Germany Accurate quantification of the activity distribution in positron emission tomography (PET) mandates attenuation correction (AC). Unlike in PET/CT, AC in PET/MR is, however, challenging, since information about the attenuation properties of the patient tissue distribution is not available directly. Standard MR-based AC (MRAC) does not acc...

A three-dimensional reconstruction method for simultaneous compensation of attenuation, scatter and distance-dependent detector response for single photon emission computed tomography is described and tested by experimental studies. The method determines the attenuation factors recursively along each projection ray starting at the intersected source voxel closest to the detector. The method sub...

PET/CT scanners offer a hardware solution for aligning and viewing functional and anatomic images that is immune to many of the errors in strictly software registration techniques. Moreover, PET attenuation-corrected emission scans benefit from the use of the onboard CT for fast, low-noise attenuation correction. Along with the significant improved localization and reduced acquisition time, PET...

Positron Emission Tomography (PET) is a functional imaging modality widely used in neuroscience studies. To obtain meaningful quantitative results from PET images, attenuation correction is necessary during image reconstruction. For PET/MR hybrid systems, PET attenuation is challenging as Magnetic Resonance (MR) images do not reflect attenuation coefficients directly. To address this issue, we ...