PURPOSE Respiratory gating is a commercially available technology for reducing the deleterious effects of motion during imaging and treatment. The efficacy of gating is dependent on the reproducibility within and between respiratory cycles during imaging and treatment. The aim of this study was to determine whether audio-visual biofeedback can improve respiratory reproducibility by decreasing r...

Respiratory perception can be altered by changes in emotional or psychological states. This may be due to affective (i.e., anxiety) modulation of respiratory sensory gating. Nicotine withdrawal induces elevated anxiety and decreased somatosensory gating. Respiratory sensory gating is evidenced by decreased amplitude of the respiratory-related evoked potentials (RREP) N(1) peak for the second oc...

Introduction: Two-dimensional (2D) breath-hold and ECG-triggered cine MRI is frequently used to assess cardiac function. However this technique requires cooperation from the patient, and the MR acquisition has to be synchronized with the cardiac cycle using ECG. To control respiratory motion, the subject has to perform breath-holds or the position of the diaphragm has to be tracked using a resp...

PURPOSE The purpose of this work was to assess the impact of respiratory motion and to compare methods for suppression of respiratory motion artifacts in 4D Flow MRI. METHODS A numerical 3D aorta phantom was designed based on an aorta velocity field obtained by computational fluid mechanics. Motion-distorted 4D Flow MRI measurements were simulated and several different motion-suppression tech...

Respiratory and cardiac motion artefacts degrade image quality in positron emission tomography (PET) imaging and may significantly affect the qualitative and quantitative evaluation of images. At worst, misguided interpretation may lead to wrong diagnosis and inadequate or unnecessary treatment. The aim of this thesis was to study the feasibility of the bioimpedancebased measurement technique f...

During stereotactic body radiotherapy, high radiation dose (~60 Gy) is delivered to the tumour in small fractionation regime. In this study, the dosimetric characteristics were studied using radiochromic film during respiratory-gated and non-gated lung stereotactic body radiotherapy (SBRT). Specifically, the effect of respiratory cycle and amplitude, as well as gating window on the dosimetry we...

Gating The breathing cycle was divided into eight parts by using a respiratory signal. This signal was acquired by laying a belt around the patient's waist with a black disc containing a white spot in the center. The position of this spot was tracked with the help of a video camera. A light emitting diode (LED) was used for synchronizing the respiratory signal with the listmode PET data. The PE...

Gating The PET was divided into six respiratory and six cardiac phases. The respiratory signal was acquired by tracking the position of a white spot on a black disc placed on the abdomen of the patient with a video camera. A LED diode was used for synchronizing the respiratory signal with the listmode PET data. The ECG signal was acquired using the ECG port of the scanner. The PET data was then...

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 others based on measured inherent lis...

INTRODUCTION: Navigator gating is a proven approach to reduce respiratory motion artifacts in free-breathing 3D MRI. Moreover, self-gating techniques to avoid steady state interruption [1, 2], and automatic navigator window selection of the most common respiratory phase [3], have been proposed. However, the most common respiratory position does not necessarily give the best image quality, as ha...