with the arrival of increasingly higher resolution pet systems, small amounts of motion can cause significant blurring in the images, compared to the intrinsic resolutions of the scanners. in this work, we have reviewed advanced correction methods for the three cases of (i) unwanted patient motion, as well as motions due to (ii) cardiac and (iii) respiratory cycles. for the first type of motion...

objective(s): in positron emission tomography (pet) studies, thoracic movement under free-breathing conditions is a cause of image degradation. respiratory gating (rg) is commonly used to solve this problem. two different methods, i.e., phase-gating (pg) and amplitude-gating (ag) pet, are available for respiratory gating. it is important to know the strengths and weaknesses of both methods when...

Respiratory motion is an important problem in magnetic resonance imaging (MRI) of the thorax and upper abdomen. This study assessed several approaches for practical respiratory gating. Methods of acquiring respiratory signals, gated sequencing methods, duration of examination, strategies for reducing examination time, diagnostic quality of gated images, and the influence of respiratory gating o...

background: in radiation treatment of moving targets located in thorax region of patient body, the delivered dose does not match with the planned treatment, resulting in some over and under dosage in the tumor volume, as a function of motion magnitude and frequency. several efforts have been done to investigate the target motion effects on dose distribution in the target and surrounding normal ...

Objective(s): In positron emission tomography (PET) studies, thoracic movement under free-breathing conditions is a cause of image degradation. Respiratory gating (RG) is commonly used to solve this problem. Two different methods, i.e., phase-gating (PG) and amplitude-gating (AG) PET, are available for respiratory gating. It is important to know the strengths and weaknesses of both methods when...

Background: in radiation treatment of moving targets located in thorax region of patient body, the delivered dose does not match with the planned treatment, resulting in some over and under dosage in the tumor volume, as a function of motion magnitude and frequency. Several efforts have been done to investigate the target motion effects on dose distribution in the target and surrounding normal ...

(a,e) Images reconstructed using 55 spokes/time frame without any constraints. (b,f) Corresponding STCR reconstructions without respiratory self-gating and (c,g) with respiratory self-gating. The arrows indicate the locations of the lesions. (d,h) Comparison of mean intensity time curves for the tumor ROIs. Constrained Reconstruction of Dynamic Contrast Enhanced Tumor MR Data with Respiratory S...

Background Displacement Encoding with Stimulated Echoes (DENSE) directly measures tissue displacements and can be used to quantify cardiac mechanics. Multi-dimensional DENSE results in lengthy scans that require respiratory gating, acquiring data only while the diaphragm is within a prespecified “acceptance window.” Because it is not possible to perform respiratory gating during data acquisitio...

Respiratory sensory gating is evidenced by decreased amplitudes of the respiratory-related evoked potentials (RREP) N1 peak for the second (S2) compared to the first occlusion (S1) when two paired occlusions are presented with a 500-millisecond (ms) inter-stimulus-interval during one inspiration. Because anxiety is prevalent in respiratory diseases and associated with altered respiratory percep...

The perception of respiratory sensations can be of significant importance to individuals for survival and greatly impact quality of life. Respiratory sensory gating, similar to somatosensory gating with exteroceptive stimuli, is indicative of brain cortices filtering out repetitive respiratory stimuli and has been investigated in adults with and without diseases. Respiratory gating can be teste...