Resolution and covariance predictors have been derived previously for penalized-likelihood estimators. These predictors can provide accurate approximations to the local resolution properties and covariance functions for tomographic systems given a good estimate of the mean measurements. Although these predictors may be evaluated iteratively, circulant approximations are often made for practical computation times. However, when numerous evaluations are made repeatedly (as in penalty design or calculation of variance images), these predictors still require large amounts of computing time. In Stayman and Fessler (2000), we discussed methods for precomputing a large portion of the predictor for shift-invariant system geometries. In this paper, we generalize the efficient procedure discussed in Stayman and Fessler (2000) to shift-variant single photon emission computed tomography (SPECT) systems. This generalization relies on a new attenuation approximation and several observations on the symmetries in SPECT systems. These new general procedures apply to both two-dimensional and fully three-dimensional (3-D) SPECT models, that may be either precomputed and stored, or written in procedural form. We demonstrate the high accuracy of the predictions based on these methods using a simulated anthropomorphic phantom and fully 3-D SPECT system. The evaluation of these predictors requires significantly less computation time than traditional prediction techniques, once the system geometry specific precomputations have been made.
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http://dx.doi.org/10.1109/TMI.2004.837790 | DOI Listing |
Epileptic Disord
December 2024
Department of Neurology, Duke University Hospital, Durham, North Carolina, USA.
Objective: The aim of this paper was to visualize 3-dimensional (3-D) brain and electrode placement data for epilepsy surgery within an augmented reality (AR) environment using a wearable headset, with the ultimate goal of enhancing presurgical planning for epilepsy surgery and understanding the efficiency and utility of such a program in a clinical setting. The evaluation process for surgical intervention in epilepsy cases involves a series of extensive tests, including EEG, MRI, PET, SPECT, and fMRI. A second phase of assessment incorporates the placement of depth electrodes within the brain to record seizure activity.
View Article and Find Full Text PDFLymphology
October 2024
Department of Surgery, University of Arizona College of Medicine-Tucson, Tucson, Arizona USA.
After the introduction of conventional oil contrast lymphography and the founding of the discipline of lymphology, great impetus was given to investigating central lymphatic system and its disorders along with lymphatic involvement and specifically lymphostasis in common diseases of major organs such as the liver (cirrhosis) and heart (heart failure). Gradually interest shifted to more peripheral disorders such as limb lymphedema and its treatment by physical and surgical measures. At the same time, basic lymphology turned to the study of isolate-ed ex vivo and in vitro, including lymphatic endothelial models and more recently, molecular lymphology focusing on lymphatic growth and modulating factors, genes and proteins under-lying primary lymphedema, and more potential biomarkers of lymphatic disease have gained prominence.
View Article and Find Full Text PDFInt Heart J
November 2023
Department of Cardiovascular and Renal Medicine, School of Medicine, Hyogo Medical University.
Bull's eye view for the display of myocardial single-photon emission computed tomography (SPECT) 3-D perfusion maps does not reflect left ventricular (LV) volume, an important parameter. We created and evaluated a myocardial SPECT display method that reflects the LV volume.Using Digital Imaging and Communications in Medicine data, short-axis slices from the apex to the base were reconstructed and interpolated into 0.
View Article and Find Full Text PDFJ Nucl Med
November 2023
Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York
A single-institution prospective pilot clinical trial was performed to demonstrate the feasibility of combining [Lu]Lu-PSMA-617 radiopharmaceutical therapy (RPT) with stereotactic body radiotherapy (SBRT) for the treatment of oligometastatic castration-sensitive prostate cancer. Six patients with 9 prostate-specific membrane antigen (PSMA)-positive oligometastases received 2 cycles of [Lu]Lu-PSMA-617 RPT followed by SBRT. After the first intravenous infusion of [Lu]Lu-PSMA-617 (7.
View Article and Find Full Text PDFFront Med (Lausanne)
June 2023
Department of Engineering Physics, Tsinghua University, Beijing, China.
Purpose: Single-photon emission computed tomography (SPECT) is an important tool for myocardial perfusion imaging (MPI). Mechanical collimators cause the resolution-sensitivity trade-off in the existing cardiac SPECT systems, which hinders fast cardiac scan capability. In this work, we propose a novel collimator-less cardiac SPECT system with interspaced mosaic-patterned scintillators, aiming to significantly improve sensitivity and reduce scan time without trading-off image resolution.
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