Elektrik Elektronik Fakültesi

Bu topluluk için Kalıcı Uri

http://hdl.handle.net/11527/18000

Gözat

Yazar "Aydınalp, Cemanur" ile Elektrik Elektronik Fakültesi'a göz atma
  • Öge
    In vitro dielectric properties of rat skin tissue for microwave skin cancer detection
    (IEEE, 2019) Aydınalp, Cemanur ; joof, Sulayman ; Yılmaz, Tuba ; Pastacı Özsobacı, Nural ; Ateş Alkan, Fatma ; Akduman, İbrahim ; Elektronik ve Haberleşme Mühendisliği ; Electronics and Communication Engineering
    Dermal tissue characterization based on dielectric properties can be utilized as a non-invasive method for diagnosis of skin cancers. To enable such technology, there is a need to develop techniques that can rapidly and accurately collect the dielectric properties of the skin tissues. Therefore, the current measurement techniques and tools has to be optimized for skin cancer detection. To this end, this study presents dielectric property measurements with open-ended coaxial probes having small apertures customized for detection of skin cancer. Relative permittivity and conductivity of rat skin tissue is characterized with open-ended coaxial probes with outer diameters of 0.9mm and 0.5mm between 0.5GHz6GHz and the measurement results are compared with the traditional probes having diameter of 2.2mm. The results agree well with the reported literature data.
  • Öge
    Microwave dielectric properties of osteosarcoma cell line (SAOS-2) suspensions
    (İstanbul Teknik Üniversitesi, 2019) Macit, Zeynep ; Aydınalp, Cemanur ; Yılmaz, Tuba ; Elektronik ve Haberleşme Mühendisliği ; Electronics and Communication Engineering
    Dielectric properties of biological tissues have been limited to some in vivo animal and mostly ex vivo animal and human tissue measurements. Recent studies showed that factors changing after the excision of tissue such as temperature, heterogeneity, hydration can significantly alter the dielectric properties. However, due to the challenging nature of performing dielectric properties on living tissues, the underlying factors of dielectric property discrepancy between diseased and healthy tissues remains an open question. As building blocks of tissues, cells can serve as an alternative sample to living tissue to explore the fundamental dielectric property discrepancy between normal and diseased tissues. With this motivation, we are reporting two different concentrations of Osteosarcoma Cell Line (SAOS-2) suspended in Dulbecco’s Modified Eagle Medium (DMEM) dielectric property measurements. Dielectric property measurements are performed with the open-ended coaxial probe technique between 500 MHz to 18 GHz. A very small decrease (0.5 units) is observed between the relative permittivity of pure DMEM and cell suspension. Similarly, the difference between dielectric properties of 12,500,000 SAOS-2 cell suspensions and 22,500,000 SAOS-2 cell suspensions is found to be small and inconsistent at frequencies between 500 MHz to 18 GHz.
  • Öge
    Microwave dielectric property based classification of renal calculi: Application of a kNN algorithm
    (Elsevier, 2019) Saçlı, Banu ; Aydınalp, Cemanur ; Cansız, Gökhan ; joof, Sulayman ; Yılmaz, Tuba ; Çayören, Mehmet ; Önal, Bülent ; Akduman, İbrahim ; Elektronik ve Haberleşme Mühendisliği ; Electronics and Communication Engineering
    The proper management of renal lithiasis presents a challenge, with the recur- rence rate of the disease being as high as 46%. To prevent recurrence, the first step is the accurate categorization of the discarded renal calculi. Currently, the discarded renal calculi type is determined with the X-ray powder diffraction method which requires a cumbersome sample preparation. This work presents a new approach that can enable fast and accurate classification of discarded renal calculi with minimal sample preparation requirements. To do so, first, the measurements of the dielectric properties of naturally formed renal calculi are collected with the open-ended contact probe technique between 500 MHz to 6 GHz with 100 MHz intervals. Cole–Cole parameters are fitted to the measured dielectric properties with the generalized Newton–Raphson method. The re- nal calculi types are classified based on their Cole–Cole parameters as calcium oxalate, cystine, or struvite. The classification is performed using nearest neigh- bors (kNN) machine learning algorithm with the 10 nearest neighbors, where accuracy as high as 98.17% is achieved.
  • Öge
    Microwave dielectric spectroscopy of renal calculi: A large scale study on dielectric properties from 500 MHz to 18 GHz
    (IEEE, 2019) Yılmaz, Tuba ; Saçlı, Banu ; Cansız, Gökhan ; joof, Sulayman ; Aydınalp, Cemanur ; Çayören, Mehmet ; Akduman, İbrahim ; Önal, Bülent ; Elektronik ve Haberleşme Mühendisliği ; Electronics and Communication Engineering
    Inherent dielectric property discrepancy between biological anomalies and healthy tissue enables the microwave diagnostic and therapeutic technologies. To reveal this discrepancy, microwave dielectric properties of many different biological tissues are tabulated. Although the dielectric properties of biological tissues are well documented in the literature, the knowledge on microwave dielectric property behavior of the renal calculi is limited. This work presents ultra wideband dielectric properties of three renal calculi types between 500 MHz to 18 GHz to pave the way for possible application of microwave technologies for diagnosis, treatment, and prevention of urolithiasis. Microwave dielectric spectroscopy is performed on a total of 66 natural stone samples with open-ended coaxial probe technique. The samples belong to three commonly diagnosed renal calculi categories, namely calcium oxalate, cystine, struvite. Analysis of variance (ANOVA) test is performed on fitted Cole-Cole parameters and it was concluded that there is a statistically significant difference between the dielectric properties of the renal calculi types. A patient-to-patient statistical test is also performed and it was concluded that there is no statistical difference between the samples belonging to the same renal calculi category. To this end, based on the relative permittivity discrepancy between the renal calculi types, the category of renal calculi can be identified by measuring the dielectric properties of renal calculi with open-ended coaxial probe technique.
  • Öge
    Sensing depth analysis of open-ended coaxial probe for skin cancer detection
    (İstanbul Teknik Üniversitesi, 2019) Aydınalp, Cemanur ; joof, Sulayman ; Yılmaz, Tuba ; Elektronik ve Haberleşme Mühendisliği ; Electronics and Communication Engineering
    Inherent dielectric properties discrepancy between different tissues have long been of interest to researchers in order to improve medical diagnostic approaches and therapeutic technologies. Hence, determination of the dielectric properties for biological tissues is keystone to develop an innovative medical system. Widely, the dielectric properties of biological tissues have been determined by utilizing slim form open-ended probes. Although, the method is superior to other dielectric property measurement techniques in several aspects, the mea- surement procedure suffers from equipment-related and tissue- related errors. Sensing depth, which is one of the confounders can be associated with both equipment- and tissue-related errors. In this work, we performed the preparation of skin mimicking phantom and conducted a series of experiments on a two-layer configuration consisting of the prepared phantom and a liquid (olive oil). Furthermore, the sensing depth of the 2.2mm aperture open-ended coaxial probe was analyzed at five different frequencies. The results obtained show that the sensing depth of biological tissues strongly depends on the operation frequency. We also observed that the sensing depth decreases at higher frequencies and this is a property can be utilized in tackling thin multi-layered structures problem such as skin cancer detection.
  • Öge
    Sensitivity and sensing depth analysis of open-ended contact probes for cancer diagnosis
    (İstanbul Teknik Üniversitesi, 2019) Aydınalp, Cemanur ; joof, Sulayman ; Akduman, İbrahim ; Yılmaz, Tuba ; Elektronik ve Haberleşme Mühendisliği ; Electronics and Communication Engineering
    Open-ended contact probes have been widely utilized in laboratory environment to quantify the dielectric properties of high permittivity and lossy materials such as biological tissues and other lossy liquids. At microwave frequencies, the dielectric properties of biologi- cal tissues have been quantified with open-ended contact probes method with the motivation of building microwave diagnostic and therapeutic technologies. The method is preferred to other microwave dielectric property measurement techniques due to broadband measurement capabil- ities and minimal sample preparation requirements. However, the measurement procedure is cumbersome and the measurements tend to be error-prone. The commercial probes can have error rates as high as 5% and it can increase with the cable movements, calibration degradation, and probe wear-off. Although the technique is powerful and able to measure the inherent dielec- tric property discrepancy between different tissues the applications are confined to laboratory use. To explore the true potential of this technique and enable the transition of this technique to a diagnostic technology, there is a need to improve the technique and analyze the performance in a layered heterogeneous medium. In this work, we performed simulations and measurements with open-ended contact probes having different aperture diameters. The probes are built with copper and Teflon sandwiched between inner and outer conductors. Measurements with open- ended coaxial probes are performed on layered medium emulating the dielectric properties of the biological tissues to analyze the sensing depth and sensitivity of four in-house fabricated open- ended coaxial probes. An in-house algorithm is utilized to retrieve the dielectric properties of the mediums utilized during this study.