Implementation of a fast simulation tool for the analysis of contrast mechanisms in HMMDI and enhancement of the SNR in the experimental set-up

İrgin, Ümit
Clinical method for breast tumor detection is Mammography (X-rays), which have limitations and may yield inaccurate results. Alternative novel techniques are required to characterize the breast tissues and extract accurate information for identification of malignancies in the tissue. Harmonic Motion Microwave Doppler Imaging (HMMDI), which enhances hybridizing microwave signals and ultrasound techniques, has been recently proposed for detection of tumors in the tissue. In HMMDI method, the data is a combination of dielectric, elastic and acoustic properties of the focused volume. The contrast levels in the dielectric and elastic properties of the malignant and normal breast tissues enable the detection of the tumorous tissues. However, the level of the received Doppler signal is not a linear function of the contrast levels, especially for the mechanical properties. In this study, the effect of contrast in the dielectric and elastic properties between a 3 mm sized inclusion and the surrounding breast as functions of position of the inclusion and vibration frequency (in 10 Hz to 95 Hz range) is analyzed. To solve the forward problem of HMMDI, a Discrete Dipole Approximation (DDA) based simulation method is developed. DDA solver decreased the simulation time by a factor of 146 compared to the Finite Difference Time Domain method. Increasing the dielectric constant by a factor of 3.2 increased the received signal by 5.1 dB in the whole vibration frequency range. On the other hand, increasing the Young’s modulus by a factor of 3.3 resulted in 1 dB and 2.5 dB decrease in Doppler signal level for vibration frequencies of 40 Hz and 95 Hz, respectively. When the focus was moved away from the inclusion, dielectric and\or elastic contrast variation did not change the relative received signal level significantly. The simulation results showed that the received signal level behavior as a function of vibration frequency can provide useful information on the elastic properties of the inclusion. In the HMMDI experimental set-up there are two main limitations on the sensitivity of the method: i) the phase noise of the transmitter source and ii) the coupling between transmitting and receiving antennas. In this study, a signal cancellation circuit is designed to suppress the coupled signal and to increase the signal to noise ratio (SNR) of the Doppler component. The transmit signal coupled to the receiving antenna was decreased more than 30 dB, enhancing the SNR about 17 dB. Hard inclusions inside a fat phantom were resolved using the HMMDI system with the proposed signal cancellation circuit.


Comparison of GST Isoenzyme Expression in Normal and Neoplastic Breast Tissue: Correlation with Clinical and Prognostic Factors
OĞUZTÜZÜN, SERPİL; İşcan, Mesude; ÖZHAVZALI, MÜZEYYEN; Sak, Serpil Dizbay (2009-01-01)
Glutathione S-transferases in breast tissue play an important role in the susceptibility to the mutagenic effects of chemical carcinogens and in the response of breast tumors to chemotherapy. In this study the immunohistochemical staining characteristics of glutathione S-transferase isoenzymes (alpha, mu, pi, and theta) were investigated in invasive duct carcinomas and in normal breast tissue of 43 patients. The relationships between the expression of the GST isoenzymes and some clinicopathological features...
Using Deep Learning for Mammography Classification
Hepsag, Pinar Uskaner; ÖZEL, SELMA AYŞE; Yazıcı, Adnan (2017-10-08)
Breast biopsies based on the results of mammography and ultrasound have been diagnosed as benign at a rate of approximately 40 to 60 percent. Negative biopsy results have negative impacts on many aspects such as unnecessary operations, fear, pain, and cost. Therefore, there is a need for a more reliable technique to reduce the number of unnecessary biopsies in the diagnosis of breast cancer. So, computer-aided diagnostic methods are very important for doctors to make more accurate decisions and to avoid unn...
Arylamine N-acetyltransferase activities in human breast cancer tissues
Geylan, YS; Sak, SD; Güray, Nülüfer Tülün (2001-01-01)
N-Acetyltransferase activities were determined in tumor (12 malignant and 6 benign) and control (non-cancerous) breast tissues from 18 female patients. The activities of matched 12 malignant tumor and control tissue cytosols showed 6 rapid, 4 intermediate and 2 slow acetylators based on p-aminobenzoic acid (NAT1) and sulfamethazine (NAT2) as substrates, Compared to the activities of slow acetylators, the rapid acetylators exhibited mean apparent V-max values about 5- and 50-fold greater for p-aminobenzoic a...
Harmonic motion microwave doppler imaging method
Top, Can Barış; Gençer, Nevzat Güneri; Department of Electrical and Electronics Engineering (2013)
Conventional method for breast tumor detection, mammography, has a number of drawbacks such as X-ray exposure, patient discomfort and loss of reliability especially for dense breast tissue. Therefore, it is a hot research topic to develop new alternative non-invasive, reliable, safe and patient friendly breast imaging methods. In this thesis, we propose a novel hybrid mechanical and electromagnetic imaging method to identify cancerous regions particularly inside dense glandular breast tissue at the early st...
Development and investigation of etoposide resistance in MCF-7 Breast cancer cell line
Kaplan, Esra; Gündüz, Ufuk; Department of Biology (2010)
Failure of chemotherapy in cancer patients because of development of drug resistance is a major problem. Alterations of DNA repair mechanisms and drug targets are among the important resistance mechanisms which are developed against topoisomerase II inhibitors etoposide and doxorubicin. Modifications in the expression levels of mismatch repair (MMR) genes due to resistance to topoisomerase II inhibitors are involved in breast cancer. In this study, etoposide resistant sublines were developed from MCF7 breas...
Citation Formats
Ü. İrgin, “Implementation of a fast simulation tool for the analysis of contrast mechanisms in HMMDI and enhancement of the SNR in the experimental set-up,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.