Dr. Borislav Gueorguiev Tomov Profile

Dr. Borislav Gueorguiev Tomov

Assistant Professor at Technical Univ of Denmark

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Publications (8)

Proceedings Article | 4 April 2022 Presentation + Paper

Fast super resolution ultrasound imaging using the erythrocytes

Jørgen Arendt Jensen, Mikkel Schou, Sofie Bech Andersen, Stinne Byrholdt Søgaard, Charlotte Mehlin Sørensen, Michael Bachmann Nielsen, Carsten Gundlach, Hans Martin Kjer, Anders Bjorholm Dahl, Matthias Bo Stuart, Borislav Gueorguiev Tomov

Proceedings Volume 12038, 120380E (2022) https://doi.org/10.1117/12.2612245

KEYWORDS: Ultrasonography, Image resolution, Kidney, Super resolution, Tissues, Data acquisition, Scanners, Visualization, Point spread functions, Heart

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Proceedings Article | 20 March 2014 Paper

Rapid measurements of intensities for safety assessment of advanced imaging sequences

Jørgen Arendt Jensen, Morten Fischer Rasmussen, Matthias Bo Stuart, Borislav Tomov

Proceedings Volume 9040, 90400Z (2014) https://doi.org/10.1117/12.2043688

KEYWORDS: Scanners, Transducers, Imaging systems, Calibration, Safety, Ultrasonography, Acoustics, Data storage, Multichannel imaging systems, Time metrology

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FDA requires that intensity and safety parameters are measured for all imaging schemes for clinical imaging. This is often cumbersome, since the scan sequence has to broken apart, measurements conducted for the individually emitted beams, and the final intensity levels calculated by combining the intensities from the individual beams. This paper suggests a fast measurement scheme using the multi-line sampling capability of modern scanners and research systems. The hydrophone is connected to one sampling channel in the research system, and the intensity is measured for all imaging lines in one emission sequence. This makes it possible to map out the pressure field and hence intensity level for all imaging lines in a single measurement. The approach has several advantages: the scanner does not have to be re-programmed and can use the scan sequence without modification. The measurements are orders of magnitude faster (minutes rather than hours) and the final intensity level calculation can be made generic and reused for any kind of scan sequence by just knowing the number of imaging lines and the pulse repetition time. The scheme has been implemented on the Acoustic Intensity Measurement System AIMS III (Onda, Sunnyvale, California, USA). The research scanner SARUS is used for the experiments, where one of the channels is used for the hydrophone signal. A 3 MHz BK 8820e (BK Medical, Herlev, Denmark) convex array with 192 elements is used along with an Onda HFL-0400 hydrophone connected to a AH-2010 pre-amplifier (Onda Corporation, Sunnyvale, USA). A single emission sequence is employed for testing and calibrating the approach. The measurements using the AIMS III and SARUS systems after calibration agree within a relative standard deviation of 0.24%. A duplex B-mode and flow sequence is also investigated. The complex intensity map is measured and the time averaged spatial peak intensity is found. A single point measurement takes 3.43 seconds and the whole sequence can be characterized on the acoustical axis in around 6 minutes.

Proceedings Article | 20 March 2014 Paper

Real-time GPU implementation of transverse oscillation vector velocity flow imaging

David Pierson Bradway, Michael Johannes Pihl, Andreas Krebs, Borislav Gueorguiev Tomov, Carsten Straso Kjær, Svetoslav Ivanov Nikolov, Jørgen Arendt Jensen

Proceedings Volume 9040, 90401Y (2014) https://doi.org/10.1117/12.2043582

KEYWORDS: Ultrasonography, Scanners, MATLAB, Visualization, Data acquisition, Signal processing, Data processing, Algorithm development, Quantization, Diagnostics

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Proceedings Article | 29 March 2013 Paper

Preliminary examples of 3D vector flow imaging

Michael Pihl, Matthias Stuart, Borislav Tomov, Jens Hansen, Morten Rasmussen, Jørgen Jensen

Proceedings Volume 8675, 86750H (2013) https://doi.org/10.1117/12.2006845

KEYWORDS: 3D image processing, 3D acquisition, Data acquisition, Visualization, 3D metrology, Ultrasonography, Transducers, Magnetic resonance imaging, Stereoscopy, Motion measurement

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This paper presents 3D vector flow images obtained using the 3D Transverse Oscillation (TO) method. The method employs a 2D transducer and estimates the three velocity components simultaneously, which is important for visualizing complex flow patterns. Data are acquired using the experimental ultrasound scanner SARUS on a flow-rig system with steady flow. The vessel of the flow-rig is centered at a depth of 30 mm, and the flow has an expected 2D circular-symmetric parabolic profile with a peak velocity of 1 m/s. Ten frames of 3D vector flow images are acquired in a cross-sectional plane orthogonal to the center axis of the vessel, which coincides with the y-axis and the flow direction. Hence, only out-of-plane motion is expected. This motion cannot be measured by typical commercial scanners employing 1D arrays. Each frame consists of 16 flow lines steered from -15 to 15 degrees in steps of 2 degrees in the ZX-plane. For the center line, 3200 M-mode lines are acquired yielding 100 velocity profiles. At the center of the vessel, the mean and standard deviation of the estimated velocity vectors are (v_x, v_y, v_z) = (-0.026, 95, 1.0)±(8.8, 6.2, 0.84) cm/s compared to the expected (0.0, 96, 0.0) cm/s. Relative to the velocity magnitude this yields standard deviations of (9.1, 6.4, 0.88) %, respectively. Volumetric flow rates were estimated for all ten frames yielding 57.9±2.0 mL/s in comparison with 56.2 mL/s measured by a commercial magnetic flow meter. One frame of the obtained 3D vector flow data is presented and visualized using three alternative approaches. Practically no in-plane motion (v_x and v_z) is measured, whereas the out-of-plane motion (v_y) and the velocity magnitude exhibit the expected 2D circular-symmetric parabolic shape. It shown that the ultrasound method is suitable for real-time data acquisition as opposed to magnetic resonance imaging (MRI). The results demonstrate that the 3D TO method is capable of performing 3D vector flow imaging.

Proceedings Article | 29 March 2013 Paper

A delta-sigma beamformer with integrated apodization

Borislav Tomov, Matthias Stuart, Martin Hemmsen, Jørgen Jensen

Proceedings Volume 8675, 86750R (2013) https://doi.org/10.1117/12.2006731

KEYWORDS: Phased arrays, Apodization, Signal to noise ratio, Ultrasonography, Modulators, Analog electronics, Interference (communication), Scanners, Image filtering, Filtering (signal processing)

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Proceedings Article | 16 March 2006 Paper

Recursive delay calculation unit for parametric beamformer

Svetoslav Nikolov, Jørgen Jensen, Borislav Tomov

Proceedings Volume 6147, 61470D (2006) https://doi.org/10.1117/12.653573

KEYWORDS: Phased arrays, Field programmable gate arrays, Point spread functions, Transducers, Clocks, Imaging arrays, Synthetic aperture imaging, Error analysis, Image quality, Image transmission

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Proceedings Article | 28 April 2004 Paper

Compact implementation of dynamic receive apodization in ultrasound scanners

Borislav Tomov, Jørgen Jensen

Proceedings Volume 5373, (2004) https://doi.org/10.1117/12.532957

KEYWORDS: Apodization, Point spread functions, Phased arrays, Ultrasonography, Transducers, Logic, Scanners, Optical simulations, Field programmable gate arrays, Image quality

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Proceedings Article | 23 May 2003 Paper

Delay generation methods with reduced memory requirements

Borislav Tomov, Jorgen Jensen

Proceedings Volume 5035, (2003) https://doi.org/10.1117/12.479957

KEYWORDS: Phased arrays, Ultrasonography, Transducers, Clocks, Algorithm development, Logic, Imaging arrays, Detection and tracking algorithms, Field programmable gate arrays, Surgery

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Showing 5 of 8 publications

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