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Cardiac Motion artifacts in PET are a well known problem. The heart undergoes two types of motion, the motion due to respiratory displacement and the motion due to cardiac contraction. These movements lead to blurring of data and to inaccuracies in the quantification. In this study a continuity equation based optical flow method is presented and results on(More)
Motion is a source of degradation in positron emission tomography (PET)/computed tomography (CT) images. As the PET images represent the sum of information over the whole respiratory cycle, attenuation correction with the help of CT images may lead to false staging or quantification of the radioactive uptake especially in the case of small tumors. We(More)
The problem of motion is well known in positron emission tomography (PET) studies. The PET images are formed over an elongated period of time. As the patients cannot hold breath during the PET acquisition, spatial blurring and motion artifacts are the natural result. These may lead to wrong quantification of the radioactive uptake. We present a solution to(More)
Respiratory gating is used for reducing the effects of breathing motion in a wide range of applications from radiotherapy treatment to diagnostical imaging. Different methods are feasible for respiratory gating. In this study seven gating methods were developed and tested on positron emission tomography (PET) listmode data. The results of seven patient(More)
UNLABELLED Gating methods acquiring biosignals (such as electrocardiography [ECG] and respiration) during PET enable one to reduce motion effects that potentially lead to image blurring and artifacts. This study evaluated different cardiac and respiratory gating methods: one based on ECG signals for cardiac gating and video signals for respiratory gating; 2(More)
Parkinson's disease is a slowly progressing neurodegenerative disorder caused by loss of dopaminergic neurons in the substantia nigra (SN), leading to severe impairment in motor and non-motor functions. Endogenous subventricular zone (SVZ) neural stem cells constantly give birth to new cells that might serve as a possible source for regeneration in the(More)
The motion of lung tumors with respiration causes difficulties in the imaging with computed tomography (CT) and positronemitted tomography (PET). Since an accurate knowledge of the position of the tumor and the surrounding tissues is needed for radiation treatment planning, it is important to improve CT/PET image acquisition. The purpose of this study was(More)
BACKGROUND Coronary endothelial function and vasomotion are impaired in smokers without coronary disease, and this is thought to be due to increased oxidative stress. METHODS AND RESULTS We used positron emission tomography to measure the coronary flow reserve, an integrated measure of coronary flow, through both the large epicardial coronary arteries and(More)
—PET measurements of tracers with a lower dose rate or short radioactive half life suffer from extremely low SNRs. In these cases standard reconstruction methods (OSEM, EM, filtered backprojection) deliver unsatisfactory and noisy results. Here, we propose to introduce nonlinear variational methods into the reconstruction process to make an efficient use of(More)
Respiratory and cardiac motion leads to image degradation in positron emission tomography (PET) studies of the human heart. In this paper we present a novel approach to motion correction based on dual gating and mass-preserving hyperelastic image registration. Thereby, we account for intensity modulations caused by the highly nonrigid cardiac motion. This(More)