Author: Tzu-Cheng Lee Publisher: ISBN: Category : Languages : en Pages : 153
Book Description
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.
Author: Ting Xia Publisher: ISBN: Category : Tomography Languages : en Pages : 212
Book Description
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.
Author: Paul Schleyer Publisher: ISBN: Category : Tomography, Emission Languages : en Pages : 0
Book Description
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.
Author: Habib Zaidi Publisher: Elsevier Health Sciences ISBN: 1455772208 Category : Medical Languages : en Pages : 260
Book Description
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.
Author: Kanhaiyalal Agrawal Publisher: Springer Nature ISBN: 3030754766 Category : Medical Languages : en Pages : 132
Book Description
The aim of this book is to provide concise information and quick reference on the basics and practice of PET/CT for beginners. The chapters are written by Nuclear Medicine experts from different countries with enormous experience in PET/CT practice. Starting with the basics of PET/CT describing physics and the use of radiopharmaceuticals in PET/CT, the book explores the principle of PET/CT in radiotherapy planning. The last five chapters explore normal variation, pitfalls and artefacts commonly seen with various routinely used PET radiotracers. The text is enriched by tables and highlighted clinical cases for better understanding. This book will be of interest mostly to nuclear medicine physicians and radiologists, but it may be appealing also to a wider medical community including oncologists and radiotherapists.
Author: Archi Agrawal Publisher: Springer ISBN: 3319726617 Category : Medical Languages : en Pages : 106
Book Description
This concise, excellently illustrated pocket book provides an up-to-date summary of the science and practice of PET/CT imaging in lung cancer. The coverage encompasses the entire spectrum of lung cancer – pathology, radiological and PET/CT imaging, and management. Readers will also find information on the physics of PET and its use in respiratory gating and radiotherapy planning. The highlights of the book are the exquisite depiction of normal variants, pitfalls, and artifacts and a pictorial atlas of the various types of lung cancer and their manifestations. The contributing authors are well-known and experienced oncologists, pathologists, radiologists, and nuclear physicians. This book has been compiled under the auspices of the British Nuclear Medicine Society. It will be of high value for nuclear physicians, radiologists, referring clinicians and oncologists, and paramedical staff working in these fields
Author: Katalin Nemeth Publisher: ISBN: Category : Languages : en Pages : 117
Book Description
Positron Emission Tomography (PET) is a very commonly used molecular and functional imaging method in the field of oncology for diagnosis, staging, follow-up and radiotherapy planning. Computed Tomography (CT) is used for attenuation correction and adding anatomical information. In this thesis, the basics of PET-CT imaging were explained, and possible artefacts were described and classified as PET-based, CT-based and attenuation correction based artefacts. Respiratory artefacts were discussed in the main part of the thesis. The underlying mechanisms (CT can be performed in a few seconds with respiratory hold technique, PET imaging is performed in 6-30 minutes normally with free breathing) were described. The literature research gave a review over respiratory artefacts and state of the art techniques to avoid or at least reduce them. In general, there are three different approaches: pre-reconstruction methods, motion corrections during reconstruction and post-reconstruction correction techniques. There are numerous technical devices used (e.g. impedance based, temperature based, video based, spirometry based) in the clinical practice, and other authors suggest software based solutions (e.g. gated + algorithm). These different possibilities were described and their advantages and disadvantages were shown. Especially for software based solutions there were only limited clinical data, but for most of the methods described here were existing clinical data (at least preliminary data) showing that reducing respiratory artefacts could result in higher rates of lesion detection (higher sensitivity of PET-CT) without a loss of specificity.*****Positron Emission Tomography (PET) is a very commonly used molecular and functional imaging method in the field of oncology for diagnosis, staging, follow-up and radiotherapy planning. Computed Tomography (CT) is used for attenuation correction and adding anatomical information. In this thesis, the basics of PET-CT imaging were explained, and possible artefacts were described and classified as PET-based, CT-based and attenuation correction based artefacts. Respiratory artefacts were discussed in the main part of the thesis. The underlying mechanisms (CT can be performed in a few seconds with respiratory hold technique, PET imaging is performed in 6-30 minutes normally with free breathing) were described. The literature research gave a review over respiratory artefacts and state of the art techniques to avoid or at least reduce them. In general, there are three different approaches: pre-reconstruction methods, motion corrections during reconstruction and post-reconstruction correction techniques. There are numerous technical devices used (e.g. impedance based, temperature based, video based, spirometry based) in the clinical practice, and other authors suggest software based solutions (e.g. gated + algorithm). These different possibilities were described and their advantages and disadvantages were shown. Especially for software based solutions there were only limited clinical data, but for most of the methods described here were existing clinical data (at least preliminary data) showing that reducing respiratory artefacts could result in higher rates of lesion detection (higher sensitivity of PET-CT) without a loss of specificity.
Author: ICRP, Publisher: SAGE Publications Limited ISBN: 9780702034503 Category : Science Languages : en Pages : 0
Book Description
In this report, the Commission provides biokinetic and dosimetric models for 33 radiopharmaceuticals, as well as recommendations related to breast feeding for mothers who have undergone a nuclear medicine investigation. The report is based on Addenda 3–9 to Publication 53. Addenda 3–7 have been available on the ICRP website (www.icrp.org) as interim reports. The work has been carried out by a Joint Task Group of ICRP Committees 2 and 3. This publication provides biokinetic models, absorbed doses, and effective doses for the following radiopharmaceuticals: C-11-acetate; C-11-amino acids; C-11-brain receptor substances; C-11-methionine; F-18-amino acids; F-18-FET; F-18-FDG; In-111-monoclonal antibodies/fragments; I-123-fatty acids (BMIPP, IPPA); I-123-monoclonal antibodies/fragments; I-131-monoclonal antibodies/fragments; and Tl-201-ion. The publication also provides realistic maximum models for C-11 and F-18 substances, for which no specific models are available.
Author: Jan Bucerius Publisher: Springer Science & Business Media ISBN: 3642042333 Category : Medical Languages : en Pages : 203
Book Description
99mTc-sestamibi is a single-photon emission computed tomography (SPECT) radiotracer that is widely used for the imaging of myocardial perfusion, as well as a variety of malignant and benign diseases. 99mTc-Sestamibi – Clinical Applications provides a detailed and informative overview of almost all the oncologic and non-oncologic applications of 99mTc-sestamibi SPECT, including several relatively rare indications. Different disease-related protocols for 99mTc-sestamibi SPECT are presented, and for each disease a comprehensive summary of the relevant pathology and epidemiology is provided. Throughout, there is a strong emphasis on the practical aspects of use of this popular tracer, including instructions for the preparation of several commercially available tracer kits. Clinical practitioners will find this book to be an invaluable guide to the application and benefits of 99mTc-sestamibi SPECT in both the inpatient and the outpatient setting.
Author: Tzu-Cheng Lee
Author: Ting Xia
Author: Paul Schleyer
Author: Habib Zaidi
Author: Kanhaiyalal Agrawal
Author: Archi Agrawal
Author: 
Author: Katalin Nemeth
Author: ICRP,
Author: Jan Bucerius