Searched for: author%3A%22Van+Dongen%2C+K.W.A.%22
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Ramirez, Ana B. (author), Abreo, Sergio A. (author), van Dongen, K.W.A. (author)
With full waveform inversion (FWI) all available information enclosed in the recorded wavefield - including multiple scattering, dispersion, and diffraction - is used to obtain accurate images showing quantitative information of the tissue parameters. These non-linear inversion methods are implemented either in the time or in the frequency...
conference paper 2022
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Scherders, Eva M.L. (author), Verschuur, D.J. (author), van Dongen, K.W.A. (author)
Imaging by inversion of acoustic or electromagnetic wave fields have applications in a wide variety of areas, such as non-destructive testing, biomedical applications, and geophysical exploration. Unfortunately, each modality suffers from its own application-specific limitations, typically being difficulties in distinguishing different...
conference paper 2022
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Taskin, U. (author), Suzuki, Atsuro (author), Terada, Takahide (author), Tsubota, Yushi (author), van Dongen, K.W.A. (author)
Quantitative images showing the speed of sound proffle of the breast may be obtained by employing full-waveform inversion (FWI) methods on the measured data. These reconstruction methods work well for both dense and normal breasts. Contrast source inversion (CSI) is a frequency domain FWI method. In literature, many examples of successful...
conference paper 2022
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Hoogerbrugge, L.A. (author), van Dongen, K.W.A. (author), Verschuur, D.J. (author)
Conventional Full Wavefield Migration (FWM) is a full-wavefield inversion method based on recursively applying one-way convolutional propagation and reflection operators in the space-frequency domain at every depth level. Therefore, it struggles to model diving waves and image steep reflectors accurately. In this paper, the Interface Contrast...
conference paper 2022
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Zhao, Wenzhao (author), Wang, Hongjian (author), Gemmeke, Hartmut (author), van Dongen, K.W.A. (author), Hopp, Torsten (author), Hesser, Jürgen (author)
Image reconstruction of ultrasound computed tomography based on the wave equation is able to show much more structural details than simpler ray-based image reconstruction methods. However, to invert the wave-based forward model is computationally demanding. To address this problem, we develop an efficient fully learned image reconstruction...
journal article 2020
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Taskin, U. (author), Solberg Eikrem, Kjersti (author), Naevdal, Geir (author), Jakobsen, Morten (author), Verschuur, D.J. (author), van Dongen, K.W.A. (author)
Transcranial ultrasound has been used to image the brain since 1942. Currently, it is regaining interest and full-waveform inversion (FWI) methods are now employed to reconstruct speed-of-sound profiles of the brain. Many of these methods require a good starting model. Here, we test the applicability of contrast source inversion (CSI) as a...
conference paper 2020
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Ouyang, B. (author), Li, Yanlu (author), Kruidhof, Marten (author), Horsten, R.C. (author), Baets, Roel (author), van Dongen, K.W.A. (author), Caro-Schuurman, J. (author)
We report a highly sensitive ultrasound sensor based on an integrated photonics silicon Mach-Zehnder interferometer (MZI). One arm of the MZI is located on a thin membrane, acting as the sensing part of the device. Ultrasound waves excite the membrane's vibrational mode, thus inducing modulation of the MZI transmission. The measured sensor...
conference paper 2020
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Taskin, U. (author), van der Neut, J.R. (author), Gemmeke, Hartmut (author), van Dongen, K.W.A. (author)
Whole breast ultrasound scanning systems are used to screen a women’s breast for suspicious lesions. Typically, the transducers are located at fixed positions at relatively large distances from the breast to avoid any contact with the breast. Unfortunately, these large distances give rise to large spatial domains to be imaged. These large...
journal article 2020
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Taskin, U. (author), van Dongen, K.W.A. (author)
Multi-parameter inversion for medical ultrasound leads to an improved tissue classification. In general, simultaneous reconstruction of volume density of mass and compressibility would require knowledge of the particle velocity field along with the pressure field. However, in practice the particle velocity field is not measured. Here, the...
journal article 2020
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Meles, G.A. (author), van der Neut, J.R. (author), van Dongen, K.W.A. (author), Wapenaar, C.P.A. (author)
Wavefield focusing can be achieved by Time-Reversal Mirrors, which involve in- and output signals that are infinite in time and waves propagating through the entire medium. Here, an alternative solution for wavefield focusing is presented. This solution is based on a new integral representation where in- and output signals are finite in time,...
conference paper 2019
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van Dongen, K.W.A. (author), de Blécourt, A.J. (author), Lens, E. (author), Schaart, D.R. (author), Vos, F.M. (author)
In proton therapy high energy protons are used to irradiate a tumor. Ideally, the delivered proton dose distribution is measured during treatment to ensure patient safety and treatment effectiveness. Here we investigate if we can use the ionoacoustic wave field to monitor the actual proton dose distribution for the two most commonly used proton...
journal article 2019
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van der Neut, J.R. (author), Fokkema, J.T. (author), van den Berg, P.M. (author), Zapf, Michael (author), Ruiter, Nicole V. (author), Taskin, U. (author), van Dongen, K.W.A. (author)
Synthetic-aperture (SA) imaging is a popular method to visualize the reflectivity of an object from ultrasonic reflections. The method yields an image of the (volume) contrast in acoustic impedance with respect to the embedding. Typically, constant mass density is assumed in the underlying derivation. Due to the band-limited nature of the...
journal article 2019
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Meles, G.A. (author), van der Neut, J.R. (author), van Dongen, K.W.A. (author), Wapenaar, C.P.A. (author)
Wavefield focusing is often achieved by time-reversal mirrors, where wavefields emitted by a source located at the focal point are evaluated at a closed boundary and sent back, after time-reversal, into the medium from that boundary. Mathematically, time-reversal mirrors are derived from closed-boundary integral representations of reciprocity...
journal article 2019
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Zapf, M. (author), Hohlfeld, Kai (author), Pfistner, Patrick (author), Imbracio Liberman, C. (author), van Dongen, K.W.A. (author), Gemmeke, Hartmut (author), Ruiter, Nicole V (author), Michaelis, Alexander (author), Gebhardt, S (author)
At the Karlsruhe Institue of Technology (KIT), a 3D-Ultrasound Computer Tomography (3D-USCT) medical imaging system for early breast cancer detection is currently developed. With the next generation of 3D-USCT 2.5, the current region of interest (ROI) of 10 x 10 x 10 cm³ shall be increased to 20 x 20 x 20 cm³ to allow reliable imaging results...
conference paper 2018
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Ozdemir, Ozgur (author), Oncu, Ahmet (author), van Dongen, K.W.A. (author)
Ultrasound and microwave scanners are developed to scan the breast on the presence of cancer. Typically, these modalities are used independently. Here we investigate if we can achieve an improved resolution if we merge both modalities into a single device. In particular, we test if we can improve the resolution of the resulting images by...
conference paper 2018
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van Dongen, K.W.A. (author), de Blécourt, Anne (author), Lens, E. (author), Schaart, D.R. (author), Vos, F.M. (author)
In proton therapy, cancer patients are irradiated with high energy protons. For a successful treatment it is important that the location with the highest energy deposition, the so-called Bragg-peak, is located inside the tumor and not in the healthy surrounding tissue. Here, we investigate if the iono-acoustic wave field generated by the protons...
conference paper 2018
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Taskin, U. (author), Ozmen, Neslihan (author), Gemmeke, Hartmut (author), van Dongen, K.W.A. (author)
To design breast ultrasound scanning systems or to test new imaging methods, various computer models are used to simulate the acoustic wave field propagation through a breast. The computer models vary in complexity depending on the applied approximations. The objective of this paper is to investigate how the applied approximations affect the...
journal article 2018
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Ruiter, Nicole V (author), Zapf, M. (author), Hopp, Torsten (author), Gemmeke, Hartmut (author), van Dongen, K.W.A. (author)
In the past years we have perceived within the USCT research community a demand for freely available USCT data sets. Inspired by the idea of Open Science, this collection of data sets could stimulate the collaboration and the exchange of ideas and experiences between USCT researchers. In addition, it may lead to comprehensive comparison of...
conference paper 2017
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Ramirez, Ana B (author), van Dongen, K.W.A. (author)
The design of ultrasound scanning systems for applications such as breast cancer detection is a challenging task, especially when the number of sources and receivers increases and they become spread over a large surface. In order to determine the number of transducers and above all their position, several approaches could be followed. A simple...
conference paper 2016
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Sarkalkan, N. (author), Loeve, A.J. (author), Van Dongen, K.W.A. (author), Tuijthof, G.J.M. (author), Zadpoor, A.A. (author)
(Osteo)chondral defects (OCDs) in the ankle are currently diagnosed with modalities that are not convenient to use in long-term follow-ups. Ultrasound (US) imaging, which is a cost-effective and non-invasive alternative, has limited ability to discriminate OCDs. We aim to develop a new diagnostic technique based on US wave propagation through...
journal article 2015
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