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Although of important medical implications, simultaneous dual–tracer positron emission tomography reconstruction remains a challenging problem, primarily because the photon measurements from dual tracers are overlapped. In this paper, we propose a simultaneous dynamic dual–tracer reconstruction of tissue activity maps based on guidance from tracer kinetics. The dual–tracer reconstruction problem is...
Respiratory motion degrades PET image quality and is unavoidable. Respiratory gating and/or motion correction are usually performed to reduce the effect of respiratory motion. However, these methods generally require motion information from external devices. Several groups have proposed data-driven motion extraction methods by analyzing variation of counts, or center-of-mass in reconstructed dynamic...
Statistical reconstruction produces bias in images reconstructed with low counts, such as short-duration frames in dynamic PET studies. While the bias is usually considered to be the consequence of the positivity constraint in MLEM reconstruction, there is no evidence of comparable bias observed with list-mode OSEM reconstruction (MOLAR). Simulation studies were performed of a human brain scan for...
Penalized likelihood reconstruction provides the possibility to produce images with desirable features. However, in some dynamic applications where system sensitivity and emission distribution are spatially and temporally variant, simple quadratic regularization does not produce uniform resolution over space and time for multi-frame reconstructions. In this study, we extended the spatially-invariant...
In expectation-maximization (EM) reconstruction, uniform spatial resolution in the field of view (FOV) is difficult to achieve as the iterations are typically stopped prematurely. Maximum-a-posterior (MAP) reconstruction is known to accelerate convergence by applying desirable constraints on the estimated parameters. However, object-dependent spatial resolution is still present using traditional penalty...
Motion correction for PET brain imaging of awake non-human primates (NHP) is critical if head fixation is not used. We have previously implemented a multi-acquisition frame (MAF) method, in which the list-mode data were divided into sub-frames for reconstruction, based on thresholds for intra-frame motion and minimum frame duration. In this method, residual intra-frame motion is present and scan data...
The probability density function (PDF) is a new concept of modeling the spatial dependence of the system response. In iterative reconstruction algorithms, the PDF plays the same important role as the point spread function in recovering images of high resolution. For the HRRT with a large number of lines of response, Monte Carlo simulation, along with an effective parameterization strategy, provides...
Pulse pile-up at high count rates is one factor that degrades spatial resolution of PET images. Most PET scanners with block detector designs suffer misidentification of event position, moving events from the edge to block center at high count rates. For the HRRT with LSO-LYSO phoswich detectors, there is an extra dimension of pile-up, i.e., inter-layer pile-up, which tends to push events to the LYSO...
The primary goal of dynamic positron emission tomography (PET) is to quantify the physiological and biological processes through tracer kinetics analysis. However, accurate quantification of such functional processes with PET is difficult to achieve because of the fundamental difficulties related to uncertainties in the imaging system and the measurement data. We introduce a novel and efficient strategy...
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