scholarly journals Interpolation-Based Reconstruction Methods for Tomographic Imaging in 3D Positron Emission Tomography

2008 ◽  
Vol 18 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Yingbo Li ◽  
Anton Kummert ◽  
Fritz Boschen ◽  
Hans Herzog
Keyword(s):  
Positron Emission Tomography ◽  
Imaging Techniques ◽  
Tomographic Imaging ◽  
Emission Tomography ◽  
Projection Data ◽  
Valuable Insight ◽  
Two Dimensional ◽  
Reconstruction Procedure ◽  
Reconstruction Methods ◽  
Positron Emission

Interpolation-Based Reconstruction Methods for Tomographic Imaging in 3D Positron Emission TomographyPositron Emission Tomography (PET) is considered a key diagnostic tool in neuroscience, by means of which valuable insight into the metabolism functionin vivomay be gained. Due to the underlying physical nature of PET, 3D imaging techniques in terms of a 3D measuring mode are intrinsically demanded to assure satisfying resolutions of the reconstructed images. However, incorporating additional cross-plane measurements, which are specific for the 3D measuring mode, usually imposes an excessive amount of projection data and significantly complicates the reconstruction procedure. For this reason, interpolation-based reconstruction methods deserve a thorough investigation, whose crucial parts are the interpolating processes in the 3D frequency domain. The benefit of such approaches is apparently short reconstruction duration, which can, however, only be achieved at the expense of accepting the inaccuracies associated with the interpolating process. In the present paper, two distinct approaches to the realization of the interpolating procedure are proposed and analyzed. The first one refers to a direct approach based on linear averaging (inverse distance weighting), and the second one refers to an indirect approach based on two-dimensional convolution (gridding method). In particular, attention is paid to two aspects of the gridding method. The first aspect is the choice of the two-dimensional convolution function applied, and the second one is the correct discretization of the underlying continuous convolution. In this respect, the geometrical structure named the Voronoi diagram and its computational construction are considered. At the end, results of performed simulation studies are presented and discussed.

Basics of Imaging Techniques in Evaluation of Soft Tissue Tumors

2017 ◽  
Author(s):  
Emily Alanna Aherne ◽  
Sinchun Hwang
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Soft Tissue ◽  
Imaging Techniques ◽  
Soft Tissue Tumors ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Positron Emission

Medical imaging plays a pivotal role in the detection, diagnosis, and clinical management of primary soft tissue tumors. Various imaging modalities have been used, and each modality offers unique advantages in the workup of soft tissue tumors by localizing the lesions in different compartments of the body and characterizing macroscopic tissue composition of the lesions in a noninvasive and safe manner. We review the clinical role and technical aspects of the frequently used imaging modalities, including magnetic resonance imaging (MRI), computed tomography, ultrasonography, positron emission tomography, and plain radiography with an emphasis on MRI as a mainstay imaging modality and a brief discussion of advanced techniques. We also review imaging features of common soft tissue tumors that can be detected and characterized using current imaging techniques. This review contains 54 figures, 1 table and 37 references.   Key words: computed tomography, diffusion-weighted imaging, imaging, magnetic resonance imaging, positron emission tomography, soft tissue, technique, tumor, ultrasonography

scholarly journals Neurological update: neuroimaging in dementia

2020 ◽  
Vol 267 (11) ◽  
pp. 3429-3435
Author(s):  
Timothy Rittman
Keyword(s):  
Artificial Intelligence ◽  
Positron Emission Tomography ◽  
Clinical Practice ◽  
Imaging Techniques ◽  
Emission Tomography ◽  
Structural Imaging ◽  
Regulatory Issues ◽  
Positron Emission ◽  
Remarkable Progress

Abstract Neuroimaging for dementia has made remarkable progress in recent years, shedding light on diagnostic subtypes of dementia, predicting prognosis and monitoring pathology. This review covers some updates in the understanding of dementia using structural imaging, positron emission tomography (PET), structural and functional connectivity, and using big data and artificial intelligence. Progress with neuroimaging methods allows neuropathology to be examined in vivo, providing a suite of biomarkers for understanding neurodegeneration and for application in clinical trials. In addition, we highlight quantitative susceptibility imaging as an exciting new technique that may prove to be a sensitive biomarker for a range of neurodegenerative diseases. There are challenges in translating novel imaging techniques to clinical practice, particularly in developing standard methodologies and overcoming regulatory issues. It is likely that clinicians will need to lead the way if these obstacles are to be overcome. Continued efforts applying neuroimaging to understand mechanisms of neurodegeneration and translating them to clinical practice will complete a revolution in neuroimaging.

scholarly journals Analytic time-of-flight positron emission tomography reconstruction: two-dimensional case

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Gengsheng L. Zeng ◽  
Ya Li ◽  
Qiu Huang
Keyword(s):  
Positron Emission Tomography ◽  
Image Reconstruction ◽  
Iterative Algorithm ◽  
Emission Tomography ◽  
Two Dimensional ◽  
Profile Function ◽  
Positron Emission ◽  
Pet Image Reconstruction ◽  
2D Filter ◽  
Tof Pet

AbstractIn a positron emission tomography (PET) scanner, the time-of-flight (TOF) information gives us rough event position along the line-of-response (LOR). Using the TOF information for PET image reconstruction is able to reduce image noise. The state-of-the-art TOF PET image reconstruction uses iterative algorithms. Analytical image reconstruction algorithm exits for TOF PET which emulates the iterative Landweber algorithm. This paper introduces such an algorithm, focusing on two-dimensional (2D) reconstruction. The proposed algorithm is in the form of backprojection filtering, in which the backprojection is performed first, and then a 2D filter is applied to the backprojected image. For the list-mode data, the backprojection is carried out in the event-by-event fashion, and a profile function may be used along the projection LOR. The 2D filter depends on the TOF timing resolution as well as the backprojection profile function. In order to emulate the iterative algorithm effects, a Fourier-domain window function is suggested. This window function has a parameter, k, which corresponds to the iteration number in an iterative algorithm.

scholarly journals Preclinical dosimetry models and the prediction of clinical doses of novel positron emission tomography radiotracers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adam A. Garrow ◽  
Jack P. M. Andrews ◽  
Zaniah N. Gonzalez ◽  
Carlos A. Corral ◽  
Christophe Portal ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Human Studies ◽  
Emission Tomography ◽  
Whole Body ◽  
Preclinical Model ◽  
Reconstruction Method ◽  
Preclinical Research ◽  
Reconstruction Methods ◽  
Positron Emission ◽  
Pet Radiotracers

Abstract Dosimetry models using preclinical positron emission tomography (PET) data are commonly employed to predict the clinical radiological safety of novel radiotracers. However, unbiased clinical safety profiling remains difficult during the translational exercise from preclinical research to first-in-human studies for novel PET radiotracers. In this study, we assessed PET dosimetry data of six 18F-labelled radiotracers using preclinical dosimetry models, different reconstruction methods and quantified the biases of these predictions relative to measured clinical doses to ease translation of new PET radiotracers to first-in-human studies. Whole-body PET images were taken from rats over 240 min after intravenous radiotracer bolus injection. Four existing and two novel PET radiotracers were investigated: [18F]FDG, [18F]AlF-NOTA-RGDfK, [18F]AlF-NOTA-octreotide ([18F]AlF-NOTA-OC), [18F]AlF-NOTA-NOC, [18F]ENC2015 and [18F]ENC2018. Filtered-back projection (FBP) and iterative methods were used for reconstruction of PET data. Predicted and true clinical absorbed doses for [18F]FDG and [18F]AlF-NOTA-OC were then used to quantify bias of preclinical model predictions versus clinical measurements. Our results show that most dosimetry models were biased in their predicted clinical dosimetry compared to empirical values. Therefore, normalization of rat:human organ sizes and correction for reconstruction method biases are required to achieve higher precision of dosimetry estimates.

scholarly journals F18-fluorodeoxyglucose positron emission tomography in the context of other imaging techniques and prognostic factors in multiple myeloma

Blood ◽  
2009 ◽  
Vol 114 (10) ◽  
pp. 2068-2076 ◽  
Author(s):  
Twyla B. Bartel ◽  
Jeff Haessler ◽  
Tracy L. Y. Brown ◽  
John D. Shaughnessy ◽  
Frits van Rhee ◽  
...  
Keyword(s):  
Gene Expression ◽  
Positron Emission Tomography ◽  
Multiple Myeloma ◽  
High Risk ◽  
Expression Profiling ◽  
Imaging Techniques ◽  
Emission Tomography ◽  
Fluorodeoxyglucose Positron Emission Tomography ◽  
Positron Emission ◽  
Fluorodeoxyglucose Positron Emission

Abstract F18-fluorodeoxyglucose positron emission tomography (FDG-PET) is a powerful tool to investigate the role of tumor metabolic activity and its suppression by therapy for cancer survival. As part of Total Therapy 3 for newly diagnosed multiple myeloma, metastatic bone survey, magnetic resonance imaging, and FDG-PET scanning were evaluated in 239 untreated patients. All 3 imaging techniques showed correlations with prognostically relevant baseline parameters: the number of focal lesions (FLs), especially when FDG-avid by PET-computed tomography, was positively linked to high levels of β-2-microglobulin, C-reactive protein, and lactate dehydrogenase; among gene expression profiling parameters, high-risk and proliferation-related parameters were positively and low-bone-disease molecular subtype inversely correlated with FL. The presence of more than 3 FDG-avid FLs, related to fundamental features of myeloma biology and genomics, was the leading independent parameter associated with inferior overall and event-free survival. Complete FDG suppression in FL before first transplantation conferred significantly better outcomes and was only opposed by gene expression profiling-defined high-risk status, which together accounted for approximately 50% of survival variability (R2 test). Our results provide a rationale for testing the hypothesis that myeloma survival can be improved by altering treatment in patients in whom FDG suppression cannot be achieved after induction therapy.

Brain Imaging in Functional Mental Disorders

1986 ◽  
Vol 31 (7) ◽  
pp. 675-680 ◽  
Author(s):  
Trevor Young ◽  
Peter Williamson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Brain Imaging ◽  
Computerized Tomography ◽  
Imaging Techniques ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Positron Emission ◽  
Eeg Topography

The application of brain imaging techniques to psychiatry is reviewed with respect to computerized tomography (CT), EEG topography, positron emission tomography (PET), and magnetic resonance imaging (MRI). While early computerized tomography studies have suggested structural abnormalities in schizophrenia, more recent studies have shown that most schizophrenics and patients with other disorders have normal CT scans. EEG topography and positron emission tomography have not been evaluated as fully as computerized tomography. However, preliminary studies indicate some functional abnormalities in schizophrenia and affective disorders compared to normal controls. Magnetic resonance imaging shows promise but has had only a limited application to date in psychiatry.

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