We calibrated a scintillation camera for the counts-to-activity conversion factor, CF, by measuring a phantom consisting of a sphere containing a known 131-I activity placed within an elliptical cylinder. Within a 3D OSEM reconstruction algorithm, we employed a depth-dependent detector-response model based on smooth fits to the pointsource-response function. Using the ultra-high-energy (UHE) co...

Abstrcwt-We have developed a new projector model speciflcally tailored for fast list-mode tomographic reconstructions in Positrón emission tomography (PET) scanners with parallel planar detectors. The model provides an accurate estimation of the probability distribution of coincidence events defined by pairs of scintillating crystals. This distribution is parameterized with 2D elliptical Gaussi...

OBJECTIVES SPECT/slow-rotation low-output CT systems can produce streak artifacts in filtered backprojection (FBP) attenuation maps, impacting attenuation correction (AC) in myocardial perfusion imaging. This paper presents an adaptive Bayesian iterative transmission reconstruction (ABITR) algorithm for more accurate AC. METHODS In each iteration, ABITR calculated a three-dimensional prior co...

A fully 3D iterative image reconstruction algorithm has been developed for high-resolution PET cameras composed of pixelated scintillator crystal arrays and rotating planar detectors, based on the ordered subsets approach. The associated system matrix is precalculated with Monte Carlo methods that incorporate physical effects not included in analytical models, such as positron range effects and...

Introduction A system matrix with high accuracy is essential when applying iterative reconstruction algorithms like MLEM and OSEM in PET imaging. However, using Monte Carlo simulations may not always be feasible, as they take a considerable amount of time. The detector response function (DRF) model has proven to be a good alternative [1]. Further accelerating the execution of this model is bene...

In this paper we present four different parallel implementations of the popular LM OSEM medical image reconstruction algorithm. While two of them use libraries such as MPI, OpenMP, or Threading Building Blocks (TBB) directly, the other two implementations use algorithmic skeletons of the Münster Skeleton Library Muesli to hide the parallelism. We compare the implementations w.r.t. runtime, effi...

The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated solid-state technology for nuclear medicine applications. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). For Compton camera, especially with a large numbe...

A penalized-likelihood (PL) SPECT reconstruction method using a modified regularizer that accounts for anatomical boundary side information was implemented to achieve accurate estimates of both the total target activity and the activity distribution within targets. In both simulations and experimental I-131 phantom studies, reconstructions from (1) penalized likelihood employing CT-side informa...

The purpose of this study was to analyze the behavior of a contouring algorithm for PET images based on adaptive thresholding depending on lesions size and target-to-background (TB) ratio under different conditions of image reconstruction parameters. Based on this analysis, the image reconstruction scheme able to maximize the goodness of fit of the thresholding algorithm has been selected. A ph...

The Fourier Rebinning (FORE), which sorts 3D data into 2D data, requires that the 3D sinogram is previously corrected for non-quantitative physical effects. So, 2D sinograms are no longer Poisson distributed, an assumption behind OSEM (Ordered Subsets Expectation Maximization). This means that whenever data are corrected and OSEM is the reconstruction algorithm, the need to restore the Poisson ...