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| 2. |
- Henriksson, Tommy, et al.
(författare)
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Breast Tumor Detection Ability Using aPlanar 2.45 GHz System
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper deals with the breast tumor detectionability of a planar microwave imaging system. Indeed, microwaveimaging seems to have a significant potential in such a biomedicalapplication. By means of a numerical model based upon electricfield volume integral equations, we investigate the influence ofseveral parameters, such as the respective sizes of the breastand the tumor, the operating frequency and the electromagneticproperties of the different media, on the detection ability. Thelatter is estimated by comparing the scattered fields observed inthe presence and in the absence of tumor and by accounting forthe signal to noise ratio available with the experimental setupdeveloped at the laboratory.
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| 3. |
- Henriksson, Tommy, 1978-
(författare)
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CONTRIBUTION TO QUANTITATIVE MICROWAVE IMAGING TECHNIQUES FOR BIOMEDICAL APPLICATIONS
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation presents a contribution to quantitative microwave imaging for breast tumor detection. The study made in the frame of a joint supervision Ph.D. thesis between University Paris-SUD 11 (France) and Mälardalen University (Sweden), has been conducted through two experimental microwave imaging setups, the existing 2.45 GHz planar camera (France) and the multi-frequency flexible robotic system, (Sweden), under development. In this context a 2D scalar flexible numerical tool based on a Newton-Kantorovich (NK) scheme, has been developed. Quantitative microwave imaging is a three dimensional vectorial nonlinear inverse scattering problem, where the complex permittivity of an object is reconstructed from the measured scattered field, produced by the object. The NK scheme is used in order to deal with the nonlinearity and the ill-posed nature of this problem. A TM polarization and a two dimensional medium configuration have been considered in order to avoid its vectorial aspect. The solution is found iteratively by minimizing the square norm of the error with respect to the scattered field data. Consequently, the convergence of such iterative process requires, at least two conditions. First, an efficient calibration of the experimental system has to be associated to the minimization of model errors. Second, the mean square difference of the scattered field introduced by the presence of the tumor has to be large enough, according to the sensitivity of the imaging system. The existing planar camera associated to a flexible 2D scalar NK code, are considered as an experimental platform for quantitative breast imaging. A preliminary numerical study shows that the multi-view planar system is quite efficient for realistic breast tumor phantoms, according to its characteristics (frequency, planar geometry and water as a coupling medium), as long as realistic noisy data are considered. Furthermore, a multi-incidence planar system, more appropriate in term of antenna-array arrangement, is proposed and its concept is numerically validated. On the other hand, an experimental work which includes a new fluid-mixture for the realization of a narrow band cylindrical breast phantom, a deep investigation in the calibration process and model error minimization, is presented. This conducts to the first quantitative reconstruction of a realistic breast phantom by using multi-view data from the planar camera. Next, both the qualitative and quantitative reconstruction of 3D inclusions into the cylindrical breast phantom, by using data from all the retina, are shown and discussed. Finally, the extended work towards the flexible robotic system is presented.
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| 4. |
- Henriksson, Tommy, 1978-, et al.
(författare)
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Quantitative Imaging Using a 2.45 GHzPlanar Camera
- 2007
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Ingår i: 5th World Congress on Industrial Process Tomography, Bergen, Norway. - Bergen, Norway. - 9780853163213
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Microwave imaging is recognized as an efficient diagnostic modality for no invasively visualizingdielectric contrasts in non metallic bodies. The usefulness of this modality results from the existingcorrelation between dielectric properties and quantities of practical relevance for industrial orbiomedical applications. At the beginning of the 80’s, Supélec developed a 2.45 GHz planarmicrowave camera, in the 90’s the group developed algorithms for quantitative microwave imaging.The purpose of this study is to investigate the capability of these existing materials, or an extendedversion of it, in terms of quantitative imaging of high contrast inhomogeneous object for application ofbreast cancer detection.
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| 5. |
- Henriksson, Tommy, 1978-, et al.
(författare)
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Quantitative Microwave Breast Phantom Imaging Using a Planar 2.45 GHz System
- 2008
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Ingår i: (Supélec), XXIX General Assembly of URSI, International Union of Radio Science, Chicago, MO, USA, August, 2008. - Chicago, Illinois, USA : XXIX General Assembly of the International Union of Radio Science, URSI.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Breast cancer is a global health problem, needing cheep and effective alternative diagnosis methods in order to minimize the mortality. This experimental study is performed in the context of an ongoing collaborative project towards a future planar three-dimensional microwave breast mammography system. Herein the first quantitative image of an inhomogeneous breast tumor phantom, composed by different Triton X-100/water/salt mixtures, is obtained by using the existing planar 2.45 GHz microwave camera.
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| 6. |
- Henriksson, Tommy, 1978-, et al.
(författare)
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Quantitative Microwave Imaging for Breast Cancer Detection Using a Planar 2.45 GHz System
- 2010
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 59:10, s. 2691-2699
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Microwave imaging is recognized as a potentialcandidate for biomedical applications, such as breast tumordetection. In this context a planar microwave camera isinvestigated for quantitative imaging of inhomogeneous objects.Promising simulation results indicates that the planar geometryis suitable for quantitative imaging, as long as the signal to noiseratio is higher than 40 dB. Different calibration techniques arediscussed with several proposed model improvements and thefirst reconstructed quantitative image of an inhomogeneous 2Dobject is obtained by using experimental data from the camera.
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| 7. |
- Johansson, Markus, 1978, et al.
(författare)
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Source Modeling using Phaseless Low-Frequency Near-Field Measurements
- 2012
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Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 54:3, s. 613-624
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Tidskriftsartikel (refereegranskat)abstract
- Field measurements of both amplitude and phase generally are more complicated and require more expensive equipment than amplitude-only measurements. Phase retrieval from measured phaseless field data is, therefore, of interest for source modeling in dosimetry applications, electromagnetic compatibility investigations, near-field to far-field transformations and antenna diagnostics. We here present a phase-retrieval method that uses an optimization algorithm based on the phase angle gradients of a functional. Numerical test cases have shown that the method is working for different initial phase distributions as well as different placements of the source. The method also works well for a test case with measured 50 Hz magnetic flux density from a transformer. The obtained phase angles on a measurement plane in front of the transformer gave calculated field amplitudes on other measurement planes that agree well with measured field. The ratios between the largest amplitude difference and the largest measured amplitude for the three Cartesian magnetic flux density components, for one of the planes, are for example 6.62%, 9.51% and 6.40%.
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