| 1. |
- Fhager, Andreas, et al.
(författare)
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Microwave Imaging for Mammography using an Iterative Time-Domain Reconstruction Algorithm; Initial Experiments
- 2005
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Ingår i: Proceedings of the 16th International Zurich Symposium on Electromagnetic Compatibility; Topical Meetings. - Zürich : Laboratory for Electromagnetic Fields and Microwave Electronics, Swiss Federal Institute of Technology. ; , s. 65-70
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Using the microwave imaging technique for mammographic imaging is an interesting application and a growing research field. Compared to X-ray mammography there is potentially a significant benefit in using microwaves in the diagnosis of breast cancer tumours due to the high contrast in the dielectric properties between tumour and surrounding tissue.In this paper a tomographic microwave imaging ex- periment using transient time domain field data for the reconstruction process. A 2D iterative gradient based al- gorithm based on the FDTD-method (Finite Difference Time Domain-method), is used for the image reconstruction. The reconstructions have been performed using air as the background medium. To simulate more tissue like conditions the antennas have also been immersed in water and different objects immersed in the water have been imaged. Two different antenna models in the computations have also been tested. The results are promising and encourages further research on this method
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| 2. |
- Hashemzadeh, Parham, et al.
(författare)
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Imaging of metal prostheses in the human body : experiments and simulations
- 2005
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Ingår i: Proc. RVK 05, Radiovetenskap och kommunikation, Linköping, Sweden, June 14-16 2005. - : Svenska Nationalkommittén för radiovetenskap (SNRV). ; , s. 67-70
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper with present the experimental results of imaging a 12mm copper rod immersed in water with a relative permittivity of ε = 78 , σ = 0.2. A copper rod is a simpler object to analyze for these first series of investigations than a hip prostesis. One should note that it has a relative permeability μ = μ0. The prosteses is also manufactured using titanium and it posseses a similiar permeability to that of copper. The setup used is very similiar to that proposed for the detection of breast cancer tumors [1],[2].The metalic rod is immeresed in water and is surrounded by an array of transceivers. The multi static data matrix is recorded as a function of frequency on the boundary of the medium under test. The multi static data matrix is a square complex symmetrix matrix. The elements consist of the received relative amplitude and phase between each sensor element as a function of frequency. A vector network analyzer and a switching matrix is used as the transceiver module. The mulitstatic data matrix is fourier transformed to time domain in order to be used in the FDTD based algorithm. The imaging algorithm used is similiar but a modified version to that proposed by Tanaka, Takenaka, He[3] and Gustafsson,He [4].The results of these first attempts to image metalic object are very promising and one can potentially use the proposed setup in various fields of medical imaging.
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| 3. |
- Kaestner, Anders P., et al.
(författare)
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Microwave polarimetry tomography of wood
- 2005
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Ingår i: IEEE Sensors Journal. - New York : IEEE Sensors Council. - 1530-437X .- 1558-1748. ; 5:2, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a new microwave-based method to make images of fiber structure, e.g., to locate knots in wood. Evaluation of Maxwell's equations for an electromagnetic wave propagating in an anisotropic media (wood) shows that the polarization of the wave depends on the local fiber orientation in the sample. Experiments support the theoretical evaluation showing that knots can be followed in images of polarimetric parameters, reconstructed from multiple monostatic measurements. The equipment works at low intensity and is, therefore, virtually harmless to human beings; furthermore, it can be made portable and be operated by a single person.
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| 4. |
- Malmberg, Donald, et al.
(författare)
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Preliminary microwave measurements on liquid stags
- 2005
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Ingår i: Ironmaking & steelmaking. - London : Maney Publishing. - 0301-9233 .- 1743-2812. ; 32:1, s. 61-67
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Tidskriftsartikel (refereegranskat)abstract
- Microwave technology has for decades been a tool for astronomers in their work to map and understand the complexities of the universe in terms of composition and extent but it is also used at laboratory scale by spectroscopists to examine the properties of atomic and molecular compounds. This paper discusses the use of microwave technology for the investigation of liquid slag structures. Preliminary results indicate that alteration of slag composition could be correlated to the measured microwave refractive index. Investigations have been performed on Al2 O3 -CaO-SiO2.
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