A5005183671- Medical Imaging Techniques and Applications
- Advanced MRI Techniques and Applications
- Advanced X-ray and CT Imaging
- Cardiac Imaging and Diagnostics
- Radiomics and Machine Learning in Medical Imaging
- Cardiovascular Function and Risk Factors
- Advanced Radiotherapy Techniques
- Radiation Dose and Imaging
- Advanced X-ray Imaging Techniques
- Elasticity and Material Modeling
- Advanced Neuroimaging Techniques and Applications
- Medical Image Segmentation Techniques
- Radiation Detection and Scintillator Technologies
- NMR spectroscopy and applications
- Atomic and Subatomic Physics Research
- Radiopharmaceutical Chemistry and Applications
- MRI in cancer diagnosis
- Cardiac Structural Anomalies and Repair
- Electrical and Bioimpedance Tomography
- Numerical methods in inverse problems
- Coronary Interventions and Diagnostics
- Functional Brain Connectivity Studies
- Radioactive Decay and Measurement Techniques
- Nuclear Physics and Applications
- Seismic Imaging and Inversion Techniques
Lawrence Berkeley National Laboratory
2015-2025
University of California, San Francisco
2016-2025
University of California, Berkeley
1974-2023
University of California System
2014-2022
Berry (United States)
2017-2018
Good Samaritan Medical Center
2015
Bellingham Technical College
2015
Motion Control (United States)
2013
Johns Hopkins University
2010
University of Utah
1996-2008
The study presents application of methods ascertaining the three-dimensional distribution isotope concentration or density in nuclear medicine, and differs from previous reconstruction efforts astrophysics, electron microscopy, X-ray radiology that statistically poor measurements photon attenuation are taken into account by algorithm. discussed applicable to heavy ion transmission radiography as well emission imaging.
A three-dimensional iterative reconstruction algorithm which incorporates models of the geometric point response in projector-backprojector is presented for parallel, fan, and cone beam geometries. The algorithms have been tested on an IBM 3090-600S supercomputer. EM 50 times longer with photon attenuation than without modeling these physical effects. An improvement image quality projection data collected from a single-photon-emission computed tomography (SPECT) imaging system has observed....
Simultaneous correction of nonuniform attenuation and detector response was implemented in single-photon-emission computed tomography (SPECT) image reconstruction. A ray-driven projector-backprojector that exactly models the reconstructed slice spatially variant developed used iterative maximum-likelihood algorithm for correction. computer-generated heart-lung phantom simulation studies to compare simultaneous method with an intrinsic using a smoothing filter, deconvolution modified Chang...
Computational burden is a major concern when an iterative algorithm used to reconstruct three-dimensional (3-D) image with attenuation, detector response, and scatter corrections. Most of the computation time spent executing projector backprojector algorithm. Usually, are transposed operators each other. The should model imaging geometry physics as accurately possible. Some researchers have backprojectors that computationally less expensive than projectors reduce time. This paper points out...
Computed transverse section emission tomography using 99mTc with the Anger camera is compared to positron annihilation coincident detection a ring of crystals and 68Ga. The single-photon system has line spread function (LSF) 9 mm full width at half maximum (FWHM) collimator gives reconstruction LSF 11 FWHM 144 views. 6 center 7.5 FWHM. Correction for uniformity detector response accurate rotation determination essential in both techniques. signal-to-noise ratio diminished by factor 1.2 x...
Photon attenuation in cardiac single photon emission computed tomography (SPECT) is a major factor contributing to the quantitative inaccuracy and decrease specificity of lesion detection. A measured map distribution was used combination with iterative reconstruction algorithms accurately compensate for variable chest. The transmission data were acquired simultaneously using multidetector, fan-beam collimated SPECT system line source (Tc-99m) precisely aligned at focal opposite one detectors...
A new ray-driven projector-backprojector which can easily be adapted for hardware implementation is described and simulated in software. The discretely models the attenuated Radon transform of a source distributed within an attenuating medium as line integrals discrete pixels, obtained using standard sampling technique averaging emission attenuation distribution over small square regions. Attenuation factors are calculated each pixel during projection backprojection operations instead...
A back projection of filtered (BKFIL) reconstruction algorithm is presented that applicable to single-photon emission computed tomography (ECT) in the presence a constant attenuating medium such as brain. The filters used transmission (TCT)-comprised ramp multiplied by window functions-are modified so ECT filter function attenuation coefficient. give good results with sufficient angular and lateral sampling. With continuous samples BKFIL has point spread Hankel transform function. resolution...
Objective: The human heart is composed of a helical network muscle fibers organized to form sheets that are separated by cleavage planes responsible for the orthotropic mechanical properties cardiac muscle. purpose this study reconstruction and visualization these structures in 3 dimensions. Methods: Anisotropic least square filtering followed fiber sheet tracking techniques were applied diffusion tensor magnetic resonance imaging data excised heart. Fibers reconstructed using first...
An iterative Bayesian reconstruction algorithm based on the total variation (TV) norm constraint is proposed. The motivation for using TV regularization that it extremely effective recovering edges of images. This paper extends minimization to field SPECT image with a Poisson noise model. included in OSL-EM (one step late expectation maximization) algorithm. Unlike many other edge-preserving techniques, method depends one parameter. Reconstructions computer simulations and patient data show...
A novel magnetic resonance flow-imaging technique is presented and its suitability evaluated for both qualitative quantitative imaging of flow. The method derived from a selective saturation-recovery scheme consisting tagging detection pulse followed by bipolar read gradient. detrimental phase effects causing signal loss at fast flow are shown to be greatly reduced because the absence 180 degrees associated section-selection second mechanism intrinsic spin echoes, washout excited spins...
RATIONALE AND OBJECTIVES. Single photon emission computed tomography (SPECT) with a cone–beam collimator improves the trade-off between detection efficiency and spatial resolution for cardiac imaging. However, acquisitions using orbits where focus remains in plane do not provide sufficient data exact reconstruction. In current study authors evaluate clinical utility of planar-orbit SPECT detecting simple myocardial defect. METHODS. Observer performance experiments compared high-resolution...
A method is presented for estimating the geometrical parameters a cone beam detector geometry from coordinates of centroid projected point source sampled over 360°. Nonlinear expressions are derived centroids in terms which include: two‐dimensional projection center rotation onto image plane; focal length; distance to rotation; and spatial itself. Experimental data were obtained using rotating gamma camera with symmetrically converging collimator. The Marquardt algorithm was used estimate...
Analytical expressions exist for the geometric point response functions parallel, fan, and cone beam collimators. The are shown to be shift-invariant these three collimators if distance between source detection plane is constant. For single photon emission computed tomography (SPECT), this property used in projector/backprojector correct distortion using iterative EM reconstruction algorithm. In implementation, system response, crystal intrinsic attenuation were compensated. compensation was...
Geometric response functions are derived for both cone and fan beam collimators the scintillation camera. The formulation is based on an effective function which determined by geometric of a single hole. technique provides accurate description spatial resolution characterising complete includes effects shape orientation collimator holes. theoretical was used to design SPECT imaging shown agree well with experimental results.
The authors present a method for obtaining magnetic resonance (MR) images of intra- and extracranial vessels from thin contiguous transaxial sections. A section-selective gradient refocusing pulse sequence with short repetition time caused flow-related enhancement spins that flowed perpendicular to the signal was further enhanced by means flow compensation gradients rephase any phase shifts resulting moving in presence imaging gradients. Coronal sagittal sections, reformatted multiple are...
Deep convolutional neural networks (DCNN) have demonstrated its capability to convert MR image pseudo CT for PET attenuation correction in PET/MRI. Conventionally, attenuated events are corrected sinogram space using maps derived from or MR-derived CT. Separately, scattered iteratively estimated by a 3D model-based simulation down-sampled and emission sinograms. However, no studies investigated joint of scatter DCNN space. Therefore, we aim develop optimize model (ASC) simultaneously without...
Dedicated cardiac SPECT scanners with cadmium-zinc-telluride cameras have shown capabilities for shortened scan times or reduced radiation doses, as well improved image quality. Since most dedicated do not integrated CT, quantification attenuation correction (AC) is challenging and artifacts are routinely encountered in daily clinical practice. In this work, we demonstrated a direct AC technique using deep learning (DL) myocardial perfusion imaging (MPI). <b>Methods:</b> an institutional...
Single photon emission computed tomography (SPECT) has limited ability to identify multivessel and microvascular coronary artery disease. Gamma cameras with cadmium zinc telluride detectors allow the quantification of absolute myocardial blood flow (MBF) reserve (MFR). However, evidence its accuracy is limited, reproducibility lacking. We aimed validate 99mTc-sestamibi SPECT MBF MFR using standard spline-fitted reconstruction algorithms compared 13N-ammonia positron in a cohort patients...