Objective(s): In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF) measurement by dynamic N-13 ammonia positron emission tomography (PET), we compared various reconstruction and filtering methods with image characteristics. Methods: Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; a...

For characterization and activity distribution of radioisotopes in nuclear waste, Active and Passive Computed Tomography (A&PCT) method can be employed. During the Active CT measurements, an external gamma/X-ray source is used to determine the attenuation map of the object. With this knowledge of the attenuation map, the Passive CT measurements are then carried out to reconstruct the activity o...

This paper investigates the possibility of developing a SPECT system that combines the high spatial resolution of position sensitive photomultiplier tubes (PSPMTs) with the excellent performance of iterative reconstruction algorithms. A small field of view (FOV) camera based on a PSPMT and a pixelized scintillation crystal made of CsI(Tl) have been used for the acquisition of the projections. W...

We present and evaluate the first method known to us that can create rich nonextract-based opinion summaries from general text (e.g. newspaper articles). We first describe two possible representations for opinion summaries and then present our system OASIS, which identifies, and optionally aggregates, fine-grained opinions from the same source on the same topic. We propose new evaluation measur...

The goal of this study was to determine the quantitative accuracy of our OSEM-APDI reconstruction method based on SPECT/CT imaging for Tc-99m, In-111, I-123, and I-131 isotopes. Phantom studies were performed on a SPECT/low-dose multislice CT system (Infinia-Hawkeye-4 slice, GE Healthcare) using clinical acquisition protocols. Two radioactive sources were centrally and peripherally placed insid...

We propose filtering the PET sinograms with a constraint curvature motion diffusion. The edge-stopping function is computed in terms of edge probability under the assumption of contamination by Poisson noise. We show that the Chi-square is the appropriate prior for finding the edge probability in the sinogram noise-free gradient. Since the sinogram noise is uncorrelated and follows a Poisson di...