Download or read book Comparison of Protocols with Respiratory gated 4D Motion Compensation in PET CT Open source Package for Quantification of Phantom Image Quality written by Andrea Martinez-Movilla and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Background Patient's breathing affects the quality of chest images acquired with positron emission tomography/computed tomography (PET/CT) studies. Movement correction is required to optimize PET quantification in clinical settings. We present a reproducible methodology to compare the impact of different movement compensation protocols on PET image quality. Static phantom images were set as reference values, and recovery coefficients (RCs) were calculated from motion compensated images for the phantoms in respiratory movement. Image quality was evaluated in terms of: (1) volume accuracy (VA) with the NEMA phantom; (2) concentration accuracy (CA) by six refillable inserts within the electron density CIRS phantom; and (3) spatial resolution (R) with the Jaszczak phantom. Three different respiratory patterns were applied to the phantoms. We developed an open-source package to automatically analyze VA, CA and R. We compared 10 different movement compensation protocols available in the Philips Gemini TF-64 PET/CT (4-, 6-, 8- and 10-time bins, 20%-, 30%-, 40%-window width in Inhale and Exhale). Results The homemade package provided RC values for VA, CA and R of 102 PET images in less than 5 min. Results of the comparison of the 10 different protocols demonstrated the feasibility of the proposed method for quantifying the variations observed qualitatively. Overall, prospective protocols showed better motion compensation than retrospective. The best performance was obtained for the protocol Exhale 30% (0.3 s after maximum Exhale position and window width of 30%) with RCVA=1.6±1.3 , RCCA=0.90±0.09 and RCR=0.6±0.4 . Among retrospective protocols, 8 Phase protocol showed the best performance. Conclusion We provided an open-source package able to automatically evaluate the impact of motion compensation methods on PET image quality. A setup based on commonly available experimental phantoms is recommended. Its application for the comparison of 10 time-based approaches showed that Exhale 30% protocol had the best performance. The proposed framework is not specific to the phantoms and protocols presented on this study

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 Motion Compensation for 4D PET CT written by and published by . This book was released on 2014 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Respiratory Motion Correction in PET CT Imaging written by Paul Schleyer and published by . This book was released on 2012 with total page 0 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 4D Image Verification written by Christian Schaller and published by GRIN Verlag. This book was released on 2009-05 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diploma Thesis from the year 2007 in the subject Computer Science - Applied, grade: 1,0, Friedrich-Alexander University Erlangen-Nuremberg (Lehrstuhl für Mustererkennung), language: English, abstract: Far reaching developments and technical advances took place within the field of radiotherapy in the last years. Radiotherapy within the chest and abdomen area is especially important in the field of radiotherapy. Within this regions, organ and tumor positions are significantly affected by patient respiration. The tumor motion, caused due to respiration is compensated by extending the treated area. This extension covers all possible positions of the tumor and therefore also includes healthy tissue. Several clinical studies provide evidence of a survival advantage for higher dose levels. To spare a maximum of healthy tissue physicians use 'gated radiotherapy'. Common recent approaches for gated radiotherapy are based on the observation of a surrogate. This either can be an implanted fiducial marker or an external signal, which is trying to capture the patients' respiration. Within this thesis principles and methods of 'gated radiotherapy' are described. Additionally an overview of recent patents and products related to radiotherapy are presented and advantages and disadvantages of both common approaches are discussed. This discussion leads to a new developed method, which is introduced. The method joins advantages of both known methods but disregards their disadvantages. The developed algorithm is using image guided methods and methods of medical image processing. A mapping between a 4D-CT planning volume and a most recent acquired fluoroscopic sequence of the same patient is calculated before treatment. Using this mapping and an external breathing signal the physician can define gating intervals and treat the patient in certain breathing phases. The developed algorithm is included in an existing prototype developed by Siemens Corporate Research (SCR) in Princeton, NJ

Download or read book 4D Modeling and Estimation of Respiratory Motion for Radiation Therapy written by Jan Ehrhardt and published by Springer. This book was released on 2015-07-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Respiratory motion causes an important uncertainty in radiotherapy planning of the thorax and upper abdomen. The main objective of radiation therapy is to eradicate or shrink tumor cells without damaging the surrounding tissue by delivering a high radiation dose to the tumor region and a dose as low as possible to healthy organ tissues. Meeting this demand remains a challenge especially in case of lung tumors due to breathing-induced tumor and organ motion where motion amplitudes can measure up to several centimeters. Therefore, modeling of respiratory motion has become increasingly important in radiation therapy. With 4D imaging techniques spatiotemporal image sequences can be acquired to investigate dynamic processes in the patient’s body. Furthermore, image registration enables the estimation of the breathing-induced motion and the description of the temporal change in position and shape of the structures of interest by establishing the correspondence between images acquired at different phases of the breathing cycle. In radiation therapy these motion estimations are used to define accurate treatment margins, e.g. to calculate dose distributions and to develop prediction models for gated or robotic radiotherapy. In this book, the increasing role of image registration and motion estimation algorithms for the interpretation of complex 4D medical image sequences is illustrated. Different 4D CT image acquisition techniques and conceptually different motion estimation algorithms are presented. The clinical relevance is demonstrated by means of example applications which are related to the radiation therapy of thoracic and abdominal tumors. The state of the art and perspectives are shown by an insight into the current field of research. The book is addressed to biomedical engineers, medical physicists, researchers and physicians working in the fields of medical image analysis, radiology and radiation therapy.

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 gated PET CT Protocols and Recontructions Optimization written by Joël Daouk and published by . This book was released on 2009 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les mouvements respiratoires sont la cause d'une dégradation importante des images TEP. En effet, les fixations des organes en mouvement apparaissent étalées et leur intensité diminuée, ce qui peut conduire à des conclusions erronées lors de l'interprétation des images. L'objectif du travail de thèse présenté dans ce rapport est de proposer des solutions pratiques pour s'affranchir de cette problématique. Dans un premier temps, nous avons privilégié le développement d'une approche directement applicable au sein d'un service de médecine nucléaire. Nous proposons une technique qui repose sur le concept de compensation des mouvements respiratoires. Cette méthode, baptisée CT-based, est basée sur une acquisition synchronisée des données TEP suivie par une TDM en apnée de fin d'expiration. Un traitement a posteriori permet de ne sélectionner que les évènements TEP ayant été enregistrés autour de la position respiratoire enregistrée lors de la séquence TDM. La méthode CT-based a été implémentée en routine et a montré son efficacité. La seconde méthode proposée consiste à introduire l'information de déplacement dans un algorithme de reconstruction itératif afin de générer un volume corrigé du mouvement en utilisant la totalité de la statistique acquise. Pour cela un algorithme de reconstruction, appelé MOSEM, a été proposé. Une des perspectives de cette thèse est la validation clinique de cet algorithme.

Download or read book Development Validation and Translation of a Respiratory Motion Model based 4DCT Technique for Use as a Clinical Protocol for Radiation Therapy Treatment Planning written by Dylan O'Connell and published by . This book was released on 2018 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Breathing motion in radiotherapy is commonly managed with four-dimensional computed tomography (4DCT). 4DCT datasets consist of multiple breathing-gated images that display motion of the subject's anatomy over a breathing period. Commercial 4DCT protocols are susceptible to image artifacts when the subject breathes irregularly. Unlike commercial protocols, model-based 4DCT techniques describe a correspondence between tissue motion and an external signal used as a surrogate for respiratory phase. One such technique, termed '5DCT,' uses free-breathing fast helical acquisition and characterizes lung tissue motion as function of five degrees of freedom: x,y, and z position in a reference geometry, breathing amplitude, and breathing rate. The overarching goal of this dissertation is to develop the 5DCT technique for clinical use. A validation study was conducted involving comparing 5DCT images to commercial 4DCT using an animal model. Reproducible and periodic breathing patterns were achieved through mechanical ventilation and image similarity was quantified using landmark displacement. Differences in measured tumor motion between 5DCT and commercial 4DCT were examined in a cohort of 20 lung cancer patients. Solutions for the unique challenges of using model model-based techniques clinically, such as appropriate amplitude interval selection and presentation of a quantitative error map, were developed. A quality management program was developed to ensure the safety of the protocol using risk analysis methods such as process mapping and failure modes and effects analysis. In addition, safety of the in-house software required to implement the technique was managed through use cases and quantitative, testable safety requirements. The physiological significance of the 5D model parameters was investigated, particularly their dependence on breathing rate during acquisition. It was shown that the model parameter relating tissue motion to breathing amplitude was largely invariant with breathing rate during acquisition. A prospective scanning method was developed to reduce the number of fast helical scans, and associated imaging dose, necessary to perform 5DCT while maintaining motion modeling accuracy. A simulation study was conducted using patient breathing traces, and the results demonstrated that adequate sampling of the respiratory cycle could be achieved using six scans, compared to the previously published protocol that employs twenty-five.

Download or read book Quantitative Nuclear Medicine Imaging written by International Atomic Energy Agency and published by . This book was released on 2014 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication reviews the current state of the art of image quantification and provides a solid background of tools and methods to medical physicists and other related professionals who are faced with quantification of radionuclide distribution in clinical practice. It describes and analyses the physical effects that degrade image quality and affect the accuracy of quantification, and describes methods to compensate for them in planar, single-photon emission computed tomography (SPECT) and positron emission tomography (PET) images.

Download or read book La Meute silencieuse Le film complet cin roman written by and published by . This book was released on 1931 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book FAIR written by Jan Modersitzki and published by SIAM. This book was released on 2009-01-01 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whenever images taken at different times, from different viewpoints, and/or by different sensors need to be compared, merged, or integrated, image registration is required. Registration, also known as alignment, fusion, or warping, is the process of transforming data into a common reference frame. This book provides an overview of state-of-the-art registration techniques from theory to practice, numerous exercises, and via a supplementary Web page, free access to FAIR.m, a package that is based on the MATLAB software environment.

Download or read book Emission Tomography written by Miles N. Wernick and published by Elsevier. This book was released on 2004-12-07 with total page 597 pages. Available in PDF, EPUB and Kindle. Book excerpt: PET and SPECT are two of today’s most important medical-imaging methods, providing images that reveal subtle information about physiological processes in humans and animals. Emission Tomography: The Fundamentals of PET and SPECT explains the physics and engineering principles of these important functional-imaging methods. The technology of emission tomography is covered in detail, including historical origins, scientific and mathematical foundations, imaging systems and their components, image reconstruction and analysis, simulation techniques, and clinical and laboratory applications. The book describes the state of the art of emission tomography, including all facets of conventional SPECT and PET, as well as contemporary topics such as iterative image reconstruction, small-animal imaging, and PET/CT systems. This book is intended as a textbook and reference resource for graduate students, researchers, medical physicists, biomedical engineers, and professional engineers and physicists in the medical-imaging industry. Thorough tutorials of fundamental and advanced topics are presented by dozens of the leading researchers in PET and SPECT. SPECT has long been a mainstay of clinical imaging, and PET is now one of the world’s fastest growing medical imaging techniques, owing to its dramatic contributions to cancer imaging and other applications. Emission Tomography: The Fundamentals of PET and SPECT is an essential resource for understanding the technology of SPECT and PET, the most widely used forms of molecular imaging. *Contains thorough tutorial treatments, coupled with coverage of advanced topics *Three of the four holders of the prestigious Institute of Electrical and Electronics Engineers Medical Imaging Scientist Award are chapter contributors *Include color artwork

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 Clinical PET and PET CT written by H. Jadvar and published by Springer Science & Business Media. This book was released on 2006-01-20 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: A practical manual covering the full spectrum of PET and PET/CT imaging, now in common clinical practice, this book includes images of normal variants, artifacts, and pathologic conditions. Indications for and the relative clinical value of PET in the armamentarium of diagnostic medical imaging are reviewed. The information in the book is organized to be brief, concise, easy-to-understand and readily accessed. This book is intended for all health practitioners who need a concise reference and review of PET imaging indications, protocols and clinical applications. It will be useful to radiologists, nuclear medicine physicians, and clinicians who refer their patients to PET Centers for diagnostic imaging, including neurologists, neurosurgeons, psychiatrists, cardiologists, internists, and oncologists. Radiologic and nuclear medicine technologists, and physicians in training will also benefit from this work.

Download or read book Comparison of Signal Transduction Latency with Different Types of Respiratory Sensor in Respiratory Gating System to Gate Scanning Proton Beam written by Yi-Ren Chen and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Purposeuff1a Our proton therapy system is equipped with Anzai respiratory gating system. There are two types of respiratory sensor, a patient contact type (Load Cell Sensor) and a patient non-contact type (Laser Sensor) , in this gating system. Since temporal accuracy of interlocking from sensing respiratory motion to gating scanning proton beam on or off is very important in proton therapy, this study aimed to compare the signal transduction latency with different types of respiratory sensor.Methods and Materialsuff1at We used CIRS Dynamic Thorax Phantom to simulate respiratory motion. Five minutes of one respiratory cycle and 30 mm of respiratory motion were set. We acquired images and waveform data of respiratory motion by 4D computed tomography and Anzai respiratory gating system with different types of respiratory sensor. We adopted Level to Level Mode to gate scanning proton beam, and allowed beam on during threshold waveform level. We recorded the signal transduction latency from sensing respiratory motion to gating beam on or off with different types of respiratory sensor to compare the temporal accuracy of interlocking.Results:With Load Cell Sensor, the signal transduction latency from sensing respiratory motion to gate beam on or off was around 10 milliseconds (ms). On the other hand, the signal transduction latency with Laser sensor was around 20 ms. Both types of respiratory sensor fulfilled the requirement (

Download or read book Cardiac SPECT Imaging written by E. Gordon DePuey and published by Lippincott Williams & Wilkins. This book was released on 2001 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cardiac SPECT Imaging, Second Edition offers the best of all possible worlds--a critical topic, internationally recognized authors and cutting-edge coverage. It guides you through all aspects of the modality--from basic principles (acquiring and processing images, quality control)...and clinical applications (evaluating myocardial infarction and coronary artery disease)...to the very latest equipment. It even compares SPECT with other modalities (PET, CT, MRI, and echocardiography) to ensure smart, cost-effective decisions by both the cardiologist and nuclear medicine physician.Look for new chapters on attenuation correction, gated perfusion SPECT, radiopharmaceuticals, and myocardial perfusion SPECT, as well as the very latest on myocardial perfusion SPECT in conjunction with exercise and pharmacologic stress, assessment of perfusion/viability with Tc-99m agents, how SPECT compares with other advanced cardiac imaging modalities, and more!