In dynamic PET studies, the changing activity of the radiotracer is measured through multiple consecutive time frames. Subsequently, the radioactivity distribution for each frame is obtained by a method known as reconstruction. Then, the distribution of the physiological parameter of interest is estimated by applying an appropriate pharmacokinetic model. Thus, the kinetic parameters are obtaine...

Iterative algorithms such as MLEM are rapidly becoming the standard for reconstruction in emission computed tomography. However, such algorithms require arbitrary stopping criteria, are sensitive to noise artifacts, and require accelerated implementations that may not work well for all imaging situations. We have investigated several new iterative algorithms with likelihood-based objective func...

We propose an algorithm, E-COSEM (enhanced complete-data ordered subsets expectation-maximization), for fast maximum likelihood (ML) reconstruction in emission tomography. E-COSEM is founded on an incremental EM approach. Unlike the familiar OSEM (ordered subsets EM) algorithm which is not convergent, we show that E-COSEM converges to the ML solution. Alternatives to the OSEM include RAMLA, and...

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The aim of this study is to optimise the acquisition and reconstruction for SPECT with 111 In-pentetrotide with the iterative reconstruction software OSEMS. For 111 In-pentetrotide SPECT, the uptake in the tumour is usually high compared to uptake in normal tissue. It may, however, be difficult to detect small tumours with the SPECT method because of high noise levels and the low spatial resolu...

BACKGROUND Positron emission tomography (PET) studies using 15O-labeled CO2, O2, and CO have been used in humans to evaluate cerebral blood flow (CBF), the cerebral oxygen extraction fraction (OEF), and the cerebral metabolic rate of oxygen (CMRO2) and cerebral blood volume (CBV), respectively. In preclinical studies, however, PET studies using 15O-labeled gases are not widely performed because...

We experimentally investigated the SPECT recovery of I-131 activity in multiple spheres located simultaneously at different locations within a cylindrical phantom that had an elliptical cross section. The sphere volumes ranged from 209 cc down to 4.2 cc. A Prism 3000 camera and two types of parallel-hexagonal-hole collimation were employed: high energy (HE) and ultra high energy (UHE). Using ap...

BACKGROUND Our aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in 82Rb PET/CT quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Rest and stress list-mode dynamic 82Rb PET acquisition data from 10 patients without ...