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Simulation and Assessment of Millimeter-Wave Reflectometry for Detection of Skin Cancers

Aminzadeh, Reza | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 45722 (55)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Shishegar, Amir Ahmad
  7. Abstract:
  8. The goal of the research presented in this thesis is assessment of millimeter-wave (mm-wave) reflectometry as a potential method for non-invasive detection of skin cancers. The reasons for choosing mm-waves are lower penetration, higher resolution and technology maturity. The main work of this research is numerical simulation of reflection from skin and other media as well as reflection measurement of some skin-equivalent phantoms at mm-wave frequencies. By exposing the skin to mm-waves and studying the characteristics of the reflected wave malignant lesions are differentiated from benign and normal skin tissues. Since Oxygen molecules have strong attenuation peaks around 60 GHz band, this frequency is selected with more focus to study if the same phenomenon occurs in biological tissues due to their high water content nature or not.Several numerical models of human skin and tumors are presented for mm-wave reflectometry of the human skin. The proposed numerical models can be used as a basis for future studies on skin tomography. It will be also useful for other propagation simulation in complicated environments.The dielectric properties of human skin at mm-wave frequencies are limited in the literature because of the need for special and expensive instruments and measurement procedures. On the other hand available dielectric properties of cancerous tissues in the literature are for other tissues rather than skin and are restricted to the frequencies below 20 GHz. To this end the effective medium theory is used to calculate the dielectric properties of several tissues for desired frequencies. Before simulations a contrast and sensitivity analysis is done to get an insight into the difference between the reflection from normal and cancerous tissues. Several simulations were performed iv for proposed theoretical models of normal and cancerous skin by applying the Finite-Difference Time-Domain (FDTD) method. The Results showed a significant contrast between normal and cancerous skin tissues. To perform experimental analysis several tissue-equivalent phantoms were fabricated mimicking similar dielectric properties to normal and cancerous skin tissues. Different compositions for phantoms were considered to achieve the appropriate quantity of materials. The dielectric properties and reflection measurements were performed on each phantom. Qualitative comparison of measurements and simulations shows that mm-wave reflectometry can be used as a potential method for detection of skin cancers
  9. Keywords:
  10. Millimeter Wave ; Effective Medium Approximation ; Dielectric Properties ; Human Skin ; Skin Cancer ; Reflectometry

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