A5057507577- Medical Imaging Techniques and Applications
- Advanced X-ray and CT Imaging
- Advanced MRI Techniques and Applications
- Radiation Dose and Imaging
- Web Data Mining and Analysis
- Topic Modeling
- Information Retrieval and Search Behavior
- Advanced Radiotherapy Techniques
- Scientific Computing and Data Management
- Radiomics and Machine Learning in Medical Imaging
- Data Management and Algorithms
- Advanced Image and Video Retrieval Techniques
- Radiopharmaceutical Chemistry and Applications
- Graph Theory and Algorithms
- Data Quality and Management
- Thyroid Disorders and Treatments
- Veterinary Practice and Education Studies
- DNA and Biological Computing
- Machine Learning in Materials Science
- Medical Image Segmentation Techniques
- IPv6, Mobility, Handover, Networks, Security
- Recommender Systems and Techniques
- Mobile Agent-Based Network Management
- Cerebrospinal fluid and hydrocephalus
- Fault Detection and Control Systems
Radboud University Nijmegen
2019-2023
University Medical Center Utrecht
2020-2023
Utrecht University
1996-2003
Heidelberg University
2001
University Hospital Heidelberg
2001
Iterative maximum likelihood (ML) transmission computed tomography algorithms have distinct advantages over Fourier-based reconstruction, but unfortunately require increased computation time. The convex algorithm is a relatively fast iterative ML it nevertheless too slow for many applications. Therefore, an acceleration of this by using ordered subsets projections proposed [ordered (OSC)]. OSC applies the sequentially to projections, was compared with simulated and physical thorax phantom...
Nanoparticles are ultrafine particulate matter having considerable potential for treatment of central nervous system (CNS) disorders. Despite their tiny size, the blood-brain barrier (BBB) restricts access to CNS. Their direct cerebrospinal fluid (CSF) administration bypasses BBB endothelium, but still fails give adequate brain uptake. We present a novel approach efficient CNS delivery 111In-radiolabelled gold nanoparticles (AuNPs; 10-15 nm) via intra-cisterna magna administration, with...
Statistical methods for image reconstruction such as the maximum likelihood expectation maximization are more robust and flexible than analytical inversion allow accurate modelling of counting statistics photon transport during acquisition projection data. is prohibitively slow when applied to clinical x-ray CT due large data sets high number iterations required reconstructing high-resolution images. Recently, however, powerful accelerating statistical have been proposed which, instead...
Effects of different scatter compensation methods incorporated in fully 3D iterative reconstruction are investigated. The are: (i) the inclusion an `ideal estimate' (ISE); (ii) like but with a noiseless estimate (ISE-NF); (iii) incorporation point spread function during (`ideal model', ISM); (iv) no (NSC); (v) ideal rejection (ISR), as can be approximated by using camera perfect energy resolution. method used was ordered subset expectation maximization (OS-EM) algorithm. A cylinder...
The quality and quantitative accuracy of iteratively reconstructed SPECT images improves when better point spread function (PSF) models the gamma camera are used during reconstruction. Here, inclusion in PSF model photon crosstalk between different slices caused by limited resolution scatter is examined. A three-dimensional (3-D) projector back-projector (proback) has been developed which both distance dependent detector object shape-dependent single emission computed tomography (SPECT)....
There exists a natural tension between encouraging diverse ecosystem of open-source search engines and supporting fair, replicable comparisons across those systems. To balance these two goals, we examine approaches to providing interoperability the inverted indexes several The first takes advantage internal abstractions around index structures building wrappers that allow one system directly read another. second involves sharing systems via data exchange specification have developed, called...
For SPECT reconstruction, iterative Maximum Likelihood Expectation Maximization (ML-EM) estimation has a huge computational burden. The objective of this paper is to compare images obtained by ML-EM and an EM algorithm acting on Ordered Subsets projections (OS-EM). Two digital phantoms, cylinder with two cold spots ellipsoid several hot one spot were reconstructed from 120 simulated noisy projections. 1D (/spl delta/-like point source response), 2D (single slice response) fully 3D...
Despite improvements in small animal PET instruments, many tracers cannot be imaged at sufficiently high resolutions due to positron range, while multi-tracer is hampered by the fact that all annihilation photons have equal energies. Here we realize multi-isotope and sub-mm resolution of isotopes with several mm range utilizing prompt gamma are commonly neglected. A PET-SPECT-CT scanner (VECTor/CT, MILabs, The Netherlands) equipped a high-energy cluster-pinhole collimator was used image 124I...
Pinhole collimation is widely recognized for offering superior resolution-sensitivity trade-off in SPECT imaging of small subjects. The newly developed EXIRAD-3D autoradiography technique (MILabs B.V.) based on a highly focusing multi-pinhole collimator achieves micron-resolution cryo-cooled tissue samples. For such high resolutions, the choice pinhole material may have significant impact images. Therefore, this paper aims to compare performance with lead, tungsten, gold, and depleted...
Cone-beam (CB) collimators lead to higher sensitivity and resolution in SPECT brain images than parallel beam (PB) collimators. Point sources can be placed the focal points of CB order obtain additional transmission CT projection data. In design a dual-head system with opposing detectors (Opposing Heads System, OHS), it is not possible position point without truncating patient's head projections, even when large crystals are used. Space for created by positioning cameras at right angle...
A triangular phantom is proposed which enables the determination and parameterization of depth dependent scatter response function (SRF) in uniformly attenuating objects for single photon emission computed tomography (SPECT) by means a line source measurement. This approach replaces tedious measurement series with sources at various depths slab phantoms. The method evaluated /sup 99m/Tc. Monte Carlo simulations SRFs scatter-to-primary ratios (SPRs) are compared those slabs. It found that...
Today, versatile emission computed tomography (VECTor) technology using dedicated high-energy collimation enables simultaneous positron (PET) and single photon (SPECT) down to 0.6 mm 0.4 resolution in mice, respectively. We recently showed that for optimal quantitative accuracy of PET images the long tails 511 keV point spread functions (PSFs) need be fully modelled during image reconstruction. This, however, leads very time consuming reconstructions thus significant acceleration...
MMEAD, or MS MARCO Entity Annotations and Disambiguations, is a resource for entity links the datasets. We specify format to store share both document passage collections of MARCO. Following this specification, we release Wikipedia documents passages in (v1 v2). have been produced by REL BLINK systems. MMEAD an easy-to-install Python package, allowing users load link data embeddings effortlessly. Using takes only few lines code. Finally, show how can be used IR research that uses...
This study assesses the influence of collimator hole dimensions on accuracy brain SPECT. To this end, four low energy, parallel (PH) collimators and half cone beam (CB) with different were simulated. The simulated projection data representative Ultra High Resolution (UHR), (HR), Medium (MR), General Purpose (GP) collimators. Reconstruction was performed Ordered Subsets Expectation Maximization (OS-FM) algorithm without correction for camera response (CRC NCRC, respectively)....
In SPECT reconstruction, iterative Maximum Likelihood Expectation Maximization (ML-EM) estimation has a huge computational burden. The objective of this paper is to investigate how large reduction in computation time can be obtained by using an algorithm acting on Ordered Subsets projections (OS-EM). authors validated OS-EM for high number subsets (which correlates with acceleration factor). Two phantoms, cylinder two cold spots and ellipsoid several hot one spot were reconstructed from 120...