A5041887510- Advanced Radiotherapy Techniques
- Medical Imaging Techniques and Applications
- Advanced MRI Techniques and Applications
- Radiation Therapy and Dosimetry
- MRI in cancer diagnosis
- Radiomics and Machine Learning in Medical Imaging
- Semiconductor Quantum Structures and Devices
- Quantum and electron transport phenomena
- Tendon Structure and Treatment
- Porphyrin and Phthalocyanine Chemistry
- Sports injuries and prevention
- Acoustic Wave Resonator Technologies
- Radiation Detection and Scintillator Technologies
- Bone and Joint Diseases
- Osteoarthritis Treatment and Mechanisms
- Physics of Superconductivity and Magnetism
- Photosynthetic Processes and Mechanisms
- Morphological variations and asymmetry
- Cardiac Imaging and Diagnostics
- Advanced Neuroimaging Techniques and Applications
- Magnetism in coordination complexes
- Terahertz technology and applications
- Nuclear Physics and Applications
- Lanthanide and Transition Metal Complexes
- Nanowire Synthesis and Applications
Medical University of Vienna
2012-2024
Charité - Universitätsmedizin Berlin
2022
Lantmäteriet
2018
FH Campus Wien
2018
Hebrew University of Jerusalem
2006-2016
Lund University
2014-2016
Technion – Israel Institute of Technology
2008-2016
Freie Universität Berlin
2016
Centre Interdisciplinaire de Nanoscience de Marseille
2010
Centre National de la Recherche Scientifique
2010
We determined the nuclear-spin-lattice relaxation rate in vicinity of two-dimensional electrons GaAs heterostructures at liquid-helium temperatures magnetic-field range 4B8.5 T. The occurring magnetoquantum oscillations are, by a model calculation, proved to be due interaction between nuclear and 2D-electronic spins (Korringa relaxation), give new information on electronic density states.
Objectives: To (1) determine whether magnetic resonance (MR) image interpolation at the pixel or k-space level can improve results of texture-based pattern classification, and (2) compare effects on texture features different categories, with regard to their ability distinguish between patterns. Materials Methods: We obtained T2-weighted, multislice multiecho MR images 2 sets each 3 polystyrene spheres agar gel (PSAG) phantoms nodular patterns (sphere diameter: PSAG-1, 0.8-1.25 mm; PSAG-2,...
The photon induced radical-initiated polymerization in polymer gels can be used for high-resolution tissue equivalent dosimeters quality control of radiation therapy. dose (D) distribution therapy measured as a change the physical measurement parameter T2 using T2-weighted magnetic resonance imaging. detection by is relying on local molecular mobility due to initiated radicals generated ionizing radiation. dosimetric signals R2 = 1/T2 many current are dose-rate dependent, which reduces...
Magnetic resonance (MR)‐based polymer gel dosimetry using normoxic gels, represents a new dosimetric method specially suited for high‐resolution three‐dimensional problems. The aim of this study was to investigate the dose response with regard stability, accuracy, reproducibility, and rate dependence. Tetrakis‐hydroxy‐methyl‐phosphonium chloride (THPC) is used as an oxygen scavenger, methacrylic acid monomer. Accuracy, resolution were determined MR protocols at low spatial (typical clinical...
Microbeam Radiation Therapy (MRT) uses highly collimated, quasi‐parallel arrays of X‐ray microbeams 50–600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in U.S., European Facility (ESRF) France, respectively. High dose rates are necessary to deliver therapeutic doses microscopic volumes, avoid spreading cardiosynchronous movement tissues. A small beam divergence a filtered white spectrum energy range between 30 250 keV...
High dose variations across small spatial distances, as present in brachytherapeutic applications or radiosurgery and especially γ‐knife therapy, are difficult to quantify by standard dosimetry. We demonstrate the possibility obtain planar resolutions for imaging at pixel sizes below 200 μm within multislice parameter selective MR on polymer gels. The sensitivity of transversal longitudinal relaxation time well diffusivity is shown. resolution achieved microimaging gels a high‐field (3 T)...
The aims of this study were to obtain clinical measures intraocular pressure (IOP) and central corneal thickness (CCT) during waking hours further assess both the nature diurnal changes, reproducibility any possible association between two measures.Fifteen white (Norwegian) healthy young adult subjects aged 20-29 years had IOP CCT made, using a non-contact specular microscope tonometry (NCT), every hour over period 16 h, starting at 06.30 hours. experiment was repeated on successive days.The...
We apply terahertz (THz) time-domain spectroscopy for monitoring the curing process of three different light-curing dental composites. Exact knowledge sample thickness is required a precise determination THz dielectric parameters, as materials exhibit shrinkage when they are cured. find very small but significant changes refractive index and absorption coefficient during stepwise light exposure. The in correlated with density materials. Furthermore, found to give most reliable result
Three-dimensional (3D) reconstruction of buildings is an active research area with applications in e.g. city planning, environmental simulations, and navigation. Automatic 3D building methods based on point clouds from laser scanning or high resolution dense photogrammetric are common the literature. In where large land areas need to be covered regularly it not practical use acquire images image overlaps. these reconstructed cloud has low less details. We present a method most roof types...
Abstract We propose a method called spatial autocorrelation analysis (SACA) to determine the anisotropy of trabecular bone in order investigate osteoporosis. For demonstrating potential SACA we first evaluate on rectangular, simulated test patterns as simple model for anisotropic pore structure bone. As next step towards biomedical application, photographic reference images human vertebral were investigated by SACA. Osteoporotic could be clearly differentiated from non‐osteoporotic sample...
To establish whether it is possible to quantitatively characterize the degenerative changes in cartilage that typify arthritis on a sub-150-microm resolution scale using 3.0 T whole body MR-scanner with reasonable measurement time.This problem addressed through diffusion-microimaging investigations an model based enzymatic destruction of proteoglycans specimen. A 35-mm birdcage resonator made high spatial possible, and diffusion-micro-imaging was achieved use strong gradient...
We combined femtosecond (fs) VIS pump–IR probe spectroscopy with fs pump–supercontinuum to characterize the photoreaction of hexacoordinated Al(tpfc-Br8)(py)2 in a comprehensive way. Upon excitation at ∼400 nm Soret band, energy relaxes time constant (250 ± 80) S2 and S1 electronic excited states. This is evident from rise stimulated emission signal visible spectral range. On same scale, narrowing broad infrared signals C=C stretching region around 1500 cm−1 observed. Energy redistribution...
Precise methods of modem radiation therapy such as intensity modulated radiotherapy (IMRT), brachytherapy (BT) and high LET irradiation allow for dose localization in volumes a few mm3. However, most dosimetry methods-ionization chambers, TLD arrangements or silicon detectors, example-are not capable detecting sub-mm variations do simple imaging. Magnetic resonance based polymer (MRPD) appears to be well suited three-dimensional resolution relative but the spatial on systematic modulation...
The verification of dose distributions with high gradients as appearing in brachytherapy or stereotactic radiotherapy for example, calls dosimetric methods sufficiently spatial resolution. Polymer gels combination a MR optical scanner readout device have the potential performing three‐dimensional distribution within single measurement. purpose this work is to investigate resolution achievable MR‐based polymer gel dosimetry. authors show that dosimetry on very small scale (voxel size: ) can...
Recent developments in radiation therapy aimed at more precise dose delivery along with higher gradients (dose painting) and efficient rates e.g. flattening filter free (FFF) irradiation.
Purpose To evaluate: (1) the feasibility of MR microscopy T 2 * mapping by performing a zonal analysis spatially matched maps and histological images using microscopic in‐plane pixel resolution; (2) orientational dependence relaxation meniscus; (3) decay characteristics meniscus statistically evaluating quality mono‐ biexponential model. Methods Ultrahigh resolution was performed with ultrashort echo time 7 Tesla system. Measurement one at three orientations to main magnetic field (0, 55,...
Background T 2 * anisotropy affects the clinical assessment of tendons (magic‐angle artifact) and may be a source *‐misinterpretation. Purpose To analyze *‐anisotropy *‐decay Achilles patellar in vitro at microscopic resolution using variable‐echo‐time (vTE) sequence. Study Type Prospective. Specimen Four human four tendons. Field Strength/Sequence A 7 MR‐microscopy; 3D‐vTE spoiled‐gradient‐echo‐sequence (T *‐mapping). Assessment All were measured 0° 55° relative to B 0 . Additional angles...
Quality assurance (QA) in magnetic resonance imaging (MRI) requires test objects. ‘Phantoms’ provided by MR manufacturers are homogeneously filled spheres or cylinders, and commercially available products often too small for abdominal imaging, particularly enlarged polycystic kidneys. Here we present the design, manufacturing testing of a dedicated, yet versatile, MRI phantom, that can be reproduced with relatively low costs. The phantom mimics human abdomen size shape comprises seven...
We investigated whether it is possible to investigate degenerative changes in human tissue on a sub-100-microm resolution scale not only special high-field small-bore MR-microscopy systems but also 3T whole-body MR-scanner.Spin-spin relaxation, proton density, and diffusion microimaging were studying atherosclerotic arteries. Strong weighting high spatial was achieved by means of strong dedicated gradient system small birdcage radiofrequency resonator.Quantitative parameter maps obtained at...
Rationale and Objectives Osteoporosis is characterized by low bone mass inferior structural competence. In this study we introduce the homogeneity factor (BHF) as a quantitative measurement of structure, which could be equally important mineral density. Methods BHF represents an advanced texture analysis tool based on spatial autocorrelation function calculated in 9 different directions. These calculations were performed high-resolution magnetic resonance images calcaneus at 3.0 T compared...
The photoexcited states of two 5,10,15-tris(pentafluorophenyl)corroles (tpfc), hosting Rh(III) in their core, namely Rh(pyr)(PPh 3)(tpfc) and Rh(PPh 3)(tpfc), have been studied by time-resolved electron paramagnetic resonance (TREPR) combined with pulsed laser excitation. Using the transient nutation technique, spin polarized spectra are assigned to triplet states. spectral widths observed for corroles crucially depend on axial ligands at metal ion. In case TREPR found extend over 200 mT,...