Now showing items 31-40 of 204
Low-Dose Dual-Energy Computed Tomography for PET Attenuation Correction with Statistical Sinogram Restoration
(SPIE, 2008-02-18)
Dual-energy (DE) X-ray computed tomography (CT) has been proposed as an useful tool in various applications.
One promising application is DECT with low radiation doses used for attenuation correction in positron ...
Regularized Methods for Topology-Preserving Smooth Nonrigid Image Registration Using B-Spline Basis
(IEEE, 2008-05-14)
B-splines are a convenient tool for nonrigid registration, but ensuring invertibility can be challenge. This paper describes a new penalty method that is devised to enforce a sufficient condition for local invertibility ...
A Penalized-Likelihood Image Reconstruction Method for Emission Tomography, Compared to Postsmoothed Maximum-Likelihood With Matched Spatial Resolution
(IEEE, 2003-09-04)
Regularization is desirable for image reconstruction in emission tomography. A powerful regularization method is the penalized-likelihood (PL) reconstruction algorithm (or equivalently, maximum a posteriori reconstruction), ...
Exploring Breathing Pattern Irregularity with Projection-Based Method
(American Association of Physicists in Medicine, 2006-06-21)
Accurate descriptions of organ motion due to breathing are highly desirable for radiation treatment planning. This paper proposes an index that quantifies the irregularity of a signal related to respiratory motion. The ...
Quadratic Regularization Design for 2-D CT
(IEEE, 2008-10-31)
Statistical methods for tomographic image reconstruction have improved noise and spatial resolution properties that may improve image quality in X-ray computed tomography (CT). Penalized weighted least squares (PWLS) methods ...
Covariance of Kinetic Parameter Estimators Based on Time Activity Curve Reconstructions: Preliminary Study on 1D Dynamic Imaging
(IEEE, 2004-04-15)
We provide approximate expressions for the covariance matrix of kinetic parameter estimators based on time activity curve (TAC) reconstructions when TACs are modeled as a linear combination of temporal basis functions such ...
Quadratic Regularization Design for 3d Cylindrical PET
(IEEE, 2005-10-23)
Statistical methods for tomographic image reconstruction lead to improved spatial resolution and noise properties in PET. Penalized-likelihood (PL) image reconstruction methods involve maximizing an objective function that ...
TOPICAL REVIEW: Microfluidics for flow cytometric analysis of cells and particles
(IOP Publishing Ltd, 2005-06-01)
This review describes recent developments in microfabricated flow cytometers and related microfluidic devices that can detect, analyze, and sort cells or particles. The high-speed analytical capabilities of flow cytometry ...
Dynamic field map estimation using a spiral-in/spiral-out acquisition
(Wiley Subscription Services, Inc., A Wiley Company, 2004-06)
The long readout times of single-shot acquisitions and the high field strengths desired for functional MRI (fMRI) using blood oxygenation level-dependent (BOLD) contrast make functional scans sensitive to magnetic field ...
Estimating 3-D Respiratory Motion From Orbiting Views by Tomographic Image Registration
(IEEE, 2007-01-29)
Respiratory motion remains a significant source of errors in treatment planning for the thorax and upper abdomen. Recently, we proposed a method to estimate two-dimensional (2-D) object motion from a sequence of slowly ...