Design and realization of a hybrid medical imaging system: harmonic motion microwave doppler imaging

Tafreshi, Azadeh Kamali
Harmonic Motion Microwave Doppler Imaging (HMMDI) is a novel imaging modality to image electrical and mechanical properties of body tissues. This modality is recently proposed by the researchers in the METU EEE department for early-stage diagnosis of cancerous tissues. The main goal of this thesis study is to contribute various stages of the HMMDI's development processes. Speci cally, phantom development, dielectric and elastic characterization of the phantoms, experimental system realization, phantom experiments, and system performance evaluation, are in the scope of this thesis study. In the earlier stages, di effrent phantoms that mimic the mechanical and electrical properties of the body tissues are developed and characterized. In parallel to the phantom studies, experimental system design and realization studies are performed and the performance of the designed system is tested using phantom materials. The developed phantoms are scanned using the HMMDI method and the extracted information is used to generate HMMDI data profi les of the phantoms. The potential of detecting different tissues phantoms from the generated data pro files is explored. Eff ect of different vibration frequencies in HMMDI is discussed. In the acquired 2-D HMMDI data profi les, the potential of this imaging method in detecting 1) 5 mm tumor inside the fat, 2) 14 mm tumor phantom inside 25 mm fibro-glandular phantom in the middle of the fat phantom, 14 mm fi bro-glandular phantom inside the fat phantom, and 14 mm tumor inside the fat phantom, at the depth of 20 mm depths are observed. The experimental system limitations are clarif ed and the possible solutions to improve the system are presented.


Experimental studies for LFEIT with magnetic field measurements
Tetik, Ahmet Önder; Gençer, Nevzat Güneri; Department of Electrical and Electronics Engineering (2018)
Lorentz Force Electrical Impedance Tomography based on magnetic field measurements (LFEIT) is a hybrid imaging modality to image the electrical impedance of body tissues. In this modality, ultrasound pressure waves applied to the body tissues under static magnetic fields induce Lorentz currents. Magnetic flux density due to these currents is measured using receiver coils. The main aim of this thesis is to develop an experimental setup and a data acquisition system to obtain LFEIT sig nals from phantoms. Mor...
An Improved Receiver for Harmonic Motion Microwave Doppler Imaging
Soydan, Damla Alptekin; Irgin, Umit; Top, Can Baris; Gençer, Nevzat Güneri (2020-03-01)
© 2020 EurAAP.Harmonic motion microwave Doppler imaging is a novel imaging modality that combines focused ultrasound and radar techniques to obtain data based on mechanical and electrical properties of the tissue. In previous experimental studies, the Doppler component of the scattered signal is sensed and used to create 2D images of a tumor inside a homogeneous fat phantom. Due to the drawbacks of the receiver configuration, scanning time was high, the signal-to-noise ratio was low, and the multi-frequency...
Data Acquisition System for Harmonic Motion Microwave Doppler Imaging
Tafreshi, Azadeh Kamali; Karadas, Muersel; Top, Can Baris; Gençer, Nevzat Güneri (2014-08-30)
Harmonic Motion Microwave Doppler Imaging (HMMDI) is a hybrid method proposed for breast tumor detection, which images the coupled dielectric and elastic properties of the tissue. In this paper, the performance of a data acquisition system for HMMDI method is evaluated on breast phantom materials. A breast fat phantom including fibro-glandular and tumor phantom regions is produced. The phantom is excited using a focused ultrasound probe and a microwave transmitter. The received microwave signal level is mea...
Analysis of reconstruction performance of magnetic resonance conductivity tensor imaging (MRCTI) using simulated measurements
DEĞİRMENCİ, EVREN; Eyüboğlu, Behçet Murat (2017-01-01)
Magnetic resonance conductivity tensor imaging (MRCTI) was proposed recently to produce electrical conductivity images of anisotropic tissues. Similar to magnetic resonance electrical impedance tomography (MREIT), MRCTI uses magnetic field and boundary potential measurements obtained utilizing magnetic resonance imaging techniques. MRCTI reconstructs tensor images of anisotropic conductivity whereas MREIT reconstructs isotropic conductivity images. In this study, spatial resolution and linearity of five rec...
Electrical impedance tomography using lorentz fields
Zengin, Reyhan; Gençer, Nevzat Güneri; Department of Electrical and Electronics Engineering (2012)
In this thesis, a novel approach is proposed to image the electrical conductivity properties of biological tissues. This technique is based on electrical current induction using ultrasound together with and applied static magnetic field. Acoustic vibrations are generated via piezoelectric transducers located on the surface of a biological body. To simulate the new technique multiphysics solution is required which couples pressure and electromagnetic equations. The feasibility of the proposed approach is inv...
Citation Formats
A. K. Tafreshi, “Design and realization of a hybrid medical imaging system: harmonic motion microwave doppler imaging,” Ph.D. - Doctoral Program, Middle East Technical University, 2016.