Download or read book Respiratory Motion Correction in Positron Emission Tomography computerised Tomography Imaging written by Paul Schleyer and published by . This book was released on 2012 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: In dual modality PET-CT imaging, respiratory motion can introduce blurring in PET images and create a spatial mismatch between the PET and CT datasets. Attenuation correction errors can result from this mismatch, which can produce severe artefacts that potentially alter the clinical interpretation of the images. Various approaches of reducing these effects have been developed. Many involve respiratory gated acquisitions which generally require a measure of the respiratory cycle throughout imaging. In this work, a retrospective respiratory gating technique was devel¬oped for both PET and CT which extracts the respiratory cycle from the acquired data itself, removing the requirement for hardware that measures respiration. This data-driven gating method was validated with phantom and patient data, and compared with a hardware based approach of gating. Extensions to the method facilitated the gating of multi-bed position, 3D clinical PET scans. Finally, 60 Ammonia cardiac PET/CT images were used to compare several different ap¬proaches of reducing respiratory induced attenuation correction errors and motion blur. The data-driven respiratory gating method accurately substituted a hardware based approach, and no significant difference was found between images gated with either methods. Gating 11 clinical 3D whole body PET images validated the extended data-driven gating methods and demonstrated successful combination of separate PET bed-positions. All evaluated approaches to reduce respiratory motion artefacts in cardiac imaging demonstrated an average improvement in PET-CT alignment. However, cases were found where alignment worsened and artefacts resulted. Fewer and less severe cases were produced when the 4D attenuation correction data was created from a 3D helical CT and PET derived motion fields. Full motion cor¬rection produced a small effect on average, however in this case no detrimental effects were found.

Download or read book Ultra low dose CT based Attenuation Correction for Respiratory Motion Compensation in PET CT Imaging written by Tzu-Cheng Lee and published by . This book was released on 2017 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron emission tomography (PET) is a commonly used imaging tool in the management of patients with lung cancer and is of considerable interest in quantitative imaging of the thorax. Mismatch of PET data with computed tomography (CT) attenuation correction (CTAC) due to respiratory motion is a known source of errors in PET imaging. In theory, this can be corrected by matching individual PET and CT phases which have been generated by respiratory-correlated PET and CT. However, due to the high variability of patient breathing patterns and the nature of the scanning time differences between PET and CT, current respiratory-gated CTAC protocols for the irregular breather may cause additional bias in the PET image values. A ten-fold extension of the CT scanning time duration helps reduce PET imaging bias, but leads to the higher radiation dose to the patient. Lowering the CT source flux level to reduce dose, however, leads to increased noise and bias. Here we test the possibility of using model based iterative reconstruction algorithms (MBIRs) for generating the sparse-view, ultra-low-dose (i.e. an order lower than current low-dose protocols) CTAC images for both phantom and patient PET data. We also propose a new variance estimation model, which considers statistical changes caused by the non-positivity correction process, for the MBIR algorithms. The model based iterative CT reconstruction approach does generate more accurate CTAC map compared to current approaches. However, since iterative reconstruction algorithms typically assume a normal distribution of the attenuation data, we tested if the assumption is still valid in the ultra-low-dose regime. The simulation and empirical ultra-low-dose CT studies showed a skewed post-log likelihood distribution in certain ranges. The information delineates the estimation limits of model based iterative reconstruction approach on the ultra-low-dose CT imaging, and potentially helps guide scanning protocols customized for a lowest-reasonable radiation dose.

Download or read book Respiratory and Cardiac Gating in PET An Issue of PET Clinics written by Habib Zaidi and published by Elsevier Health Sciences. This book was released on 2013-01-28 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: The complexity of issues associated with gating studies with PET imaging are mostly unknown among practitioners of the field, which is posing a significant danger to those who undergo such studies. This is particularly true for respiratory gating examination. Topics in this issue include both basic and clinical topics, including views from radiation oncology physicians.

Download or read book Motion Correction in Thoracic Positron Emission Tomography written by Fabian Gigengack and published by Springer. This book was released on 2014-09-10 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Respiratory and cardiac motion leads to image degradation in Positron Emission Tomography (PET), which impairs quantification. In this book, the authors present approaches to motion estimation and motion correction in thoracic PET. The approaches for motion estimation are based on dual gating and mass-preserving image registration (VAMPIRE) and mass-preserving optical flow (MPOF). With mass-preservation, image intensity modulations caused by highly non-rigid cardiac motion are accounted for. Within the image registration framework different data terms, different variants of regularization and parametric and non-parametric motion models are examined. Within the optical flow framework, different data terms and further non-quadratic penalization are also discussed. The approaches for motion correction particularly focus on pipelines in dual gated PET. A quantitative evaluation of the proposed approaches is performed on software phantom data with accompanied ground-truth motion information. Further, clinical applicability is shown on patient data. The book concludes with an outlook of recent developments and potential future advances in the field of PET motion correction.

Download or read book Respiratory Motion Modeling for Use in Diagnostic Imaging and Radiation Therapy written by Hadi Fayad and published by . This book was released on 2011 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important parameters reducing the sensitivity and specificity in the thoracic and abdominal areas is respiratory motion and associated deformations which represent today an important challenge in medical imaging. In addition, respiratory motion reduces accuracy in image fusion from combined positron emission tomography computed tomography (PET/CT) systems. Solutions presented to date include respiratory synchronized PET and CT acquisitions. However, differences between acquired 4D PET and corresponding CT image series have been reported due to differences in respiration conditions during PET and CT acquisitions. In addition, the radiation dose burden resulting from a 4D CT acquisition may not be justifiable for every patient. The first objective of this thesis was to generate dynamic CT images from one reference CT image; based on deformation matrices obtained from the elastic registration of 4D non attenuation corrected PET images. Such an approach eliminates, on one hand the need for the acquisition of dynamic CT, while at the same time ensuring the good matching between CT and PET images. The second objective was to develop and evaluate methods of building patient specific respiratory motion models and at as a second step more developed generic respiratory motion models. These models relate the internal motion to the parameters of an external surrogate signal (PET respiratory signal or patient's surface) that can be acquired during data acquisition and treatment delivery. Finally, the two developed models were validated and used in the PET respiratory motion and attenuation correction and in radiation therapy applications.

Download or read book PET CT in Radiotherapy Planning written by Sue Chua and published by Springer. This book was released on 2017-06-16 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: This pocket book offers a succinct but comprehensive overview of the role of PET/CT in radiotherapy planning. Individual chapters are devoted to specific application of the technique to particular tumor types, including non-small cell lung, gastrointestinal, head and neck squamous cell, prostate, gynecological, and pediatric tumors. Helpful information is also presented on the practical implementation of PET/CT in routine oncological practice. Technical and logistical issues are discussed, and guidance provided on potential problems and pitfalls and available solutions. The book will be invaluable in assisting readers to exploit PET/CT’s ability to significantly improve delineation of tumor tissue through the addition of metabolic information to structural imaging data, thereby avoiding unnecessary radiation injury and associated complications while enhancing therapeutic effects and minimizing the risk of marginal recurrences. It is published within the Springer series Clinicians’ Guides to Radionuclide Hybrid Imaging, compiled under the auspices of the British Nuclear Medicine Society.

Download or read book Joint Cardiac and Respiratory Motion Correction and Super resolution in Coronary PET CT written by Sonal Ambwani and published by . This book was released on 2012 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Coronary artery diseases (CAD) such as atherosclerosis is a leading cause of mortality and morbidity in industrialized nations. Such diseases are marked by development of chronic vascular inflammation in coronary arteries, and accurate assessment and characterization of this inflammation through medical imaging methods is an important step towards the treatment of CAD. It has been shown that positron emission tomography (PET) is capable of detecting large vessel inflammation via activated macrophage uptake of a radiotracer such as [ 18 F] - FDG (Fluorine-18 - Fluro deoxyglucose). However, respiratory and cardiac motions during image acquisition lead to severe blurring of the resulting images thereby rendering the spatial resolution inadequate for detection of the coronary arteries. The objective of this research is to develop novel algorithms that facilitate the ability to produce high resolution PET images of the coronary artery inflammation. In this dissertation, we propose novel algorithms for performing motion aware reconstruction in PET which fall under two categories: image domain and projection domain methods. In the image domain category, we describe a novel method for joint cardiac and respiratory motion correction in PET/CT called Cardiac Shape Tracking with Adjustment for Respiration (CSTAR). It uses a sequential cardiac and respiratory motion correction scheme by decoupling the two motions, and also features the use of all acquired data for SNR preservation. CT images are used for cardiac shape tracking through the estimation of cardiac motion. Cardiac motion correction is incorporated in a super-resolution framework, followed by adjustment for the residual respiratory motion blur using blind deconvolution. Later, we extend our previous image-domain approach to a fully integrated, data-domain method that starts from the observed projection data and performs a model-based inversion and motion correction of all the data to create a high-resolution focused cardiac image. We term the new approach Data-domain Cardiac Shape Tracking and Adjustment for Respiration or D-CSTAR. In contrast to existing image domain methods the image reconstruction and motion correction steps are not separated. Unlike current data domain methods both cardiac and respiratory motions are compensated for. In D-CSTAR, cardiac motion parameters are estimated from X-ray CT images acquired in a breath-hold state. This cardiac motion information is incorporated in a unified PET reconstruction functional which jointly estimates and corrects for respiratory motion, compensates for phase aligned cardiac motion, and super-resolves the image. The technique is presented and applied to simulated cardiac PET/CT data corresponding to the XCAT phantom with both cardiac and respiratory cycles. The results show a marked qualitative and quantitative improvement when compared to conventional and existing PET methods.

Download or read book Characterisation and Correction of Respiratory motion Artefacts in Cardiac PET CT written by S. McQuaid and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Respiratory motion during cardiac Positron Emission Tomography (PET) Computed Tomography (CT) imaging results in blurring of the PET data and can induce mismatches between the PET and CT datasets, leading to attenuation-correction artefacts. The aim of this project was to develop a method of motion-correction to overcome both of these problems. The approach implemented was to transform a single CT to match the frames of a gated PET study, to facilitate respiratory-matched attenuation-correction, without the need for a gated CT. This is benecial for lowering the radiation dose to the patient and in reducing PETCT mismatches, which can arise even in gated studies. The heart and diaphragm were identied through phantom studies as the structures responsible for generating attenuation-correction artefacts in the heart and their motions therefore needed to be considered in transforming the CT. Estimating heart motion was straight-forward, due to its high contrast in PET, however the poor diaphragm contrast meant that additional information was required to track its position. Therefore a diaphragm shape model was constructed using segmented diaphragm surfaces, enabling complete diaphragm surfaces to be produced from incomplete and noisy initial estimates. These complete surfaces, in combination with the estimated heart motions were used to transform the CT. The PET frames were then attenuation-corrected with the transformed CT, reconstructed, aligned and summed, to produce motion-free images. It was found that motion-blurring was reduced through alignment, although benets were marginal in the presence of small respiratory motions. Quantitative accuracy was improved from use of the transformed CT for attenuation-correction (compared with no CT transformation), which was attributed to both the heart and the diaphragm transformations. In comparison to a gated CT, a substantial dose saving and a reduced dependence on gating techniques were achieved, indicating the potential value of the technique in routine clinical procedures.

Download or read book Quantification of Respiratory Motion in PET CT and Its Significance in Radiation Therapy written by Chandrani Chakraborty and published by . This book was released on 2008 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Respiratory Motion Correction in Nuclear Medicine Imaging written by Paul Schleyer and published by . This book was released on 2003 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lesion Quantification in Respiratory Motion Compensated Positron Emission Tomography written by Nicole Christine Detorie and published by . This book was released on 2009 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PET MRI in Oncology written by Andrei Iagaru and published by Springer. This book was released on 2018-01-23 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, experts from premier institutions across the world with extensive experience in the field clearly and succinctly describe the current and anticipated uses of PET/MRI in oncology. The book also includes detailed presentations of the MRI and PET technologies as they apply to the combined PET/MRI scanners. The applications of PET/MRI in a wide range of oncological settings are well documented, highlighting characteristic findings, advantages of this dual-modality technique, and pitfalls. Whole-body PET/MRI applications and pediatric oncology are discussed separately. In addition, information is provided on PET technology designs and MR hardware for PET/MRI, MR pulse sequences and contrast agents, attenuation and motion correction, the reliability of standardized uptake value measurements, and safety considerations. The balanced presentation of clinical topics and technical aspects will ensure that the book is of wide appeal. It will serve as a reference for specialists in nuclear medicine and radiology and oncologists and will also be of interest for residents in these fields and technologists.

Download or read book Reduction of CT Dose for CT based PET Attenuation Correction written by Ting Xia and published by . This book was released on 2012 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: One important goal of quantitative imaging using positron emission tomography (PET) combined with X-ray computed tomography (CT) is to accurately measure a tumor's characteristics both before and during therapy to determine as early as possible the efficacy of the treatment. The transmission CT scans in the dual modality PET/CT are used for attenuation correction of the PET emission data. Two significant challenges for quantitative PET/CT imaging come from respiratory motion in lung cancer imaging and estimation of the attenuation coefficients for high atomic number materials in bone imaging. Longer duration respiratory-gated CT has been proposed for attenuation correction of phase-matched respiratory-gated PET and motion estimation. Dual energy CT (DECT) has been proposed for accurate CT based PET attenuation correction (CTAC) for bone imaging. However, for both methods, the radiation dose from the CT scan is unacceptably high with the current CT techniques. This directly limits the clinical application of the quantitative PET imaging. Ultra-low dose CT for PET attenuation correction is studied for lung cancer imaging. Selected combinations of dose reduced acquisition and noise suppression methods are investigated by taking advantage of the reduced requirement of CT for PET CTAC. The impact of these methods on PET quantitation is evaluated through simulations on different digital phantoms. When CT is not used for diagnostic and anatomical localization purposes, it is shown that ultra-low dose CT for PET/CT is feasible. The noise and bias propagation from DECT acquisitions to PET or SPECT are studied for bone imaging, and related dose minimization are investigated. It is shown that through appropriate selection of CT techniques, DECT could deliver the same radiation dose as that of a single spectra CT and provide accurate attenuation correction for PET imaging containing high-Z materials. Finally, phantom-based measured experiments are performed to characterize the simulation and provide spectra validation.

Download or read book PET in Oncology written by Stefan Dresel and published by Springer Science & Business Media. This book was released on 2009-04-20 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: At last, here is a comprehensive compilation of the accumulated knowledge on PET and PET/CT in oncology. It covers the entire spectrum from solidly documented indications, such as staging and monitoring of lung and colorectal cancer, to the application of PET/CT in head and neck surgery, gynecology, radiation therapy, urology, pediatrics and others. The chapters are supplemented by an introduction into the underlying techniques of both imaging devices and radiopharmacy.

Download or read book PET MRI Advances in Instrumentation and Quantitative Procedures An Issue of PET Clinics E Book written by Habib Zaidi and published by Elsevier Health Sciences. This book was released on 2016-04-05 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue of PET Clinics focuses on PET/MRI: Advances in Instrumentation and Quantitative Procedures. Articles will include: Advances in clinical PET/MRI instrumentation; Magnetic resonance imaging-guided attenuation correction of positron emission tomography data in PET/MRI; Magnetic resonance imaging-guided partial volume correction of positron emission tomography data in PET/MRI; Magnetic resonance imaging-guided derivation of the input function for PET kinetic modeling; Innovations in small-animal PET/MRI instrumentation; Dual-modal PET/MRI molecular imaging probes; Magnetic resonance imaging-guided motion compensation of positron emission tomography data in PET/MRI; Attenuation correction for MR coils in combined PET/MR imaging; and more!

Download or read book Respiratory Motion Correction in PET written by Paul Schleyer and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference NSS MIC written by and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: