Evaluation of limestone layer’s effect for uwb microwave imaging of breast models using neural network

X-ray mammography is widely used for detection of breast cancer. Besides its popularity, this method did not have the potential of discriminating a tumor covered with limestone from a pure limestone mass. This might cause misdetection of some tumors covered with limestone or unnecessary surgery for a pure limestone mass. In this study, Ultra-Wide Band (UWB) signals are used for the imaging. A feed-forward artificial neural network (FF-ANN) is used to classify the mass in the breast whether it is a tumor or not by using the transmission coefficients obtained from UWB signals. A spherical tumor covered with limestone and pure limestone masses were designed and placed into the fibro-glandular layer of breast model using CST Microwave Studio Software. The radius of the masses for both cases is changed from 1 mm to 10 mm with 1 mm steps. Horn antennas were chosen to send and receive Ultra-Wide Band (UWB) signals between 2 and 18 GHz frequency range. The obtained results show that the proposed method, on the contrary of the mammogram, has the potential of discriminating the tumor covered with limestone from the pure limestone, for the mass sizes of 7, 8 and 10 mm. Consequently, the UWB microwave imaging can be used to distinguish these cases from each other

A preliminary study for early breast cancer detection with microwaves

Breast cancer is the most common type of cancer in female all over the world. Early detection and treatment gives a chance to overcome this cancer. In breast cancer detection, there are many methods such as X-ray mammography, Magnetic Resonance Imaging, and Ultrasound Imaging. However, existing these methods have limitations such as X-rays, disturbing pressure on the breast, and high cost of devices, etc. Because of all the reasons mentioned, microwave breast imaging has the potential to overcome from some of the limitations of conventional breast cancer screening systems. The physical basis breast cancer detection by microwaves depends on the difference between the dielectric properties of normal and malignant breast tissue. Microwave breast cancer imaging is also a noninvasive method and it has low cost. Therefore, microwave imaging technology for breast cancer detection has attracted much attention by many researchers in these days. By using Computer Simulation Technology Microwave Studio and Antenna Magus Software, breast model with tumor and antennas were generated in this study. The presence of the tumor was investigated using a receiver and a transmitting antenna. While the transmitting antenna was stationary, the receiving antenna was moved to different positions. S11 (return loss) results were evaluated. This study is a preliminary study to determine the location and characteristic features of the tumor. Furthermore, this study will show that scanning methods will determine the location and size of the tumor at higher accuracy and the reconstruction of the reflected waves will allow to clearly determining the location of the tumor

The effects of dielectric values, breast and tumor size on the detection of breast tumor

Although breast cancer is the second main cause of female deaths after lung cancer, early diagnosis plays a crucial role to diminish the death rate. Many techniques have been improved to detect the cancerous cells. At different microwave frequencies, the malignant cells indicate different electrical characteristics as compared to the normal cells. According to these frequencies, the breast tissue is more permeable than other tissues such as the brain and muscle. Due to this property of the breast tissue, microwaves can be used for the detection of breast cancer. In this study, the breast prototype was modelled using the CST STUDIO SUITE electromagnetic simulation software with respect to different breast size, tumor size and dielectric values tested at a range of the 0-3.0 GHz frequency. The objective of this paper is to investigate the effects of each factor and the interactions of factors on detecting cancer cells using the factorial analysis. The results indicate that the factors such as fat and skin permittivity, tumor and breast sizes are more effective in the detection of breast tumor. Although the effect of fibro permittivity is not significant alone, there are considerable interaction effects of a large breast size and small tumor size through low-to-high values of fibro permittivity. Furthermore, the combinations of a breast radius smaller than almost 8.5 cm with a high level tumor radius and breast radius larger than 8.5 cm with a low level tumor radius are desirable for lessening the return loss value

Okvirno rješenje za difrakciju ravnog vala impedacijskom trakom: slučaj H-polarizacije

In this study, the diffraction of H-polarized plane wave by an infinitely long strip which has the same impedance on both faces with a width of 2a is investigated by using an analytical-numerical method. The diffracted field is obtained by an integral equation in terms of the electric and magnetic currents induced by the incident field. This integral equation is reduced to two uncoupled integral equations that include only induced electric and magnetic currents separately. Both of the currents are defined as a sum of infinite series of Gegenbauer polynomials with unknown coefficients satisfying the edge conditions. The integral equations are transformed to linear algebraic equations by using analytical methods and the unknown coefficients are determined by solving numerically obtained matrix equations. Numerical examples on the RCS (radar cross section) are presented, and the far field scattering characteristics of the strip are discussed in detail. Some of the obtained results are compared with the other existing method.U ovom radu istražuje se difrakcija H-polariziranog ravnog vala od beskonačno duge trake koja ima jednak otpor na obje strane i širinu 2a korištenjem analitičkog-numeričke metode. Difraktirano polje dobiveno je putem integralne jednadžbe u smislu električnih i magnetskih struja induciranih upadnim poljem. Ova integralna jednadžba svedena je na dvije odvojene integralne jednadžbe koje zasebno uključuju samo inducirane električne i magnetske struje. Obje struje definirane su kao zbroj beskonačnog niza Gegenbauerovih polinoma s nepoznatim koeficijentima koji zadovoljavaju rubne uvjete. Integralne jednadžbe pretvorene su u linearne algebarske jednadžbe pomoću analitičkih metoda i nepoznati su koeficijenti utvrđeni rješavanjem numerički dobivenih matričnih jednadžbi. Predstavljeni su numerički primjeri na PRP-u (površina radarskog presjeka), a karakteristike rasipanja na dalekom polju kod traka detaljno su raspravljeni. Neki od dobivenih rezultata uspoređeni su s drugom postojećom metodom

Reference Breast Phantoms for Low-Cost Microwave Imaging

Microwave imaging provides an alternative method for breast cancer screening and the diagnosis of cerebrovascular accidents. Before a surgical operation, the performance of microwave imaging systems should be evaluated on anatomically detailed anthropomorphic phantoms. This paper puts forward the advances in the development of breast phantoms based on 3D printing structures filled with liquid solutions that mimic biological tissues in terms of complex permittivity in a wide microwave frequency band. In this paper; four different experimental scenarios were created, and measurements were performed, and although there are many vector network analyzers on the market, the miniVNA used in this study has been shown to have potential in many biomedical applications such as portable computer-based breast cancer detection studies. We especially investigated the reproducibility of a particular mixture and the ability of some mixes to mimic various breast tissues. Afterwards, the images similar to the experimentally created scenarios were obtained by implementing the inverse radon transform to the obtained data

Ocjena preciznog dielektičnog modela i izabranih patenta o otkrivanju raka dojke pomoću mikrovalova

Advances in microwave breast cancer detection and imaging during last decade are reported in this review paper. An introduction to breast cancer and detection methods and detailed information about microwave imaging and selected patents are presented. The advantages and disadvantages of the presented patents and also state of breast cancer detection and imaging are discussed. Microwave imaging for breast tumor detection is considered to be promising, as it is believed that there is a significant or detectable contrast in malignant, benign and normal tissues over a broad frequency range. Also, there have been many dielectric models, especially the double Debye model has been used to define the dielectric response of different biological tissues. On the other hand, double Debye model is not accurate for human breast tissue because there are knowledge limitations about the structure, dynamics, and macroscopic behavior of breast tissue. It is vital that, according to frequency, accurate dielectric model should be chosen in detection systems.Ovaj rad govori o naprecima u otkrivanju i snimanju raka dojke pomoću mikrovalova u posljednjem desetljeću. Dan je uvod o raku dojke i metodama otkrivanja te detaljne informacije o snimanju pomoću mikrovalova i izabranim patentima. Raspravljene su prednosti i nedostaci prezentiranih patenata kao i trenutno stanje u detektiranju i snimanju raka dojke. Snimanje mikrovalovima kako bi se otkrio rak dojke metoda je od koje se mnogo očekuje, pošto se smatra kako postoje znatni ili primjetni kontrasti između malignih, benignih i normalnih tkiva kroz široki raspon frekvencija. Također, postoje mnogi dielektrični modeli, posebno se dvostruki Debye model koristio u definiranju dielektričnog odziva raznih bioloških tkiva. S druge strane, dvostruki Debye model nije precizan prilikom korištenja za ljudska tkiva, jer postoje ograničenja u saznanjima oko strukture, dinamike i makroskopskog ponašanja tkiva dojke. Neophodno je, ovisno o frekvenciji, izabrati ispravan dielektrični model u sustavima za detekciju

OCJENA MNOGOSTRUKIH PODRUČJA NA SREDNJESAGITALNIM SLIKAMA MAGNETSKE REZONANCIJE MOZGA U BOLESNIKA S MULTIPLOM SKLEROZOM

The aim of the study was to compare the first and last magnetic resonance images (MRIs) in patients diagnosed with multiple sclerosis (MS) with MRIs of normal subjects. We wanted to investigate the region initially involved in MS patients. In this retrospective study, midsagittal plane was explored on brain MRIs taken at the time when MS diagnosis was established and the last MRI was obtained following treatment for MS. Comparison was done between healthy subjects and patients diagnosed with MS. The measures included the area of corpus callosum, cerebrum, cerebellum, pons, bulbus, fourth ventricle and pituitary gland. As a result, while there was growth in the fourth ventricle area, there was shrinkage in the other areas in MS patients. In women, the tissues involved at the beginning of the disease were pituitary gland, cerebrum and bulbus, and in men corpus callosum and cerebrum. Atrophy was not time-dependent. Assessment of the correlation between the Expanded Disability Status Scale (EDDS) and atrophy revealed an increase in EDDS (disease progression) to be associated with a decrease in the area of cerebrum and corpus callosum in men, and an increase in the fourth ventricular area in women. In conclusion, we demonstrated that pituitary gland atrophy develops in the early stage of MS, especially in women. Additional studies are needed to investigate the phenomenon of early pituitary and bulbus atrophy in women versus late atrophy of these tissues in men.Cilj rada bio je usporediti prve i posljednje slike magnetske rezonancije (MR) u bolesnika s multiplom sklerozom (MS) sa slikama zdravih osoba. Kod bolesnika s MS htjeli smo ispitati najranije zahvaćeno područje. U ovoj studiji se srednjesagitalno područje kod bolesnika s postavljenom dijagnozom MS pregledalo na slikama MR mozga u vrijeme postavljanja dijagnoze i nakon liječenja. Uspoređivalo se zdrave osobe s bolesnicima kojima je dijagnosticirana MS. Mjerenje je uključilo područje korpusa kalozuma, mozga, malog mozga, ponsa, bulbusa, četvrtog ventrikula i hipofi ze. Kod bolesnika s MS došlo je do porasta na području četvrtog ventrikula, a do smanjenja u drugim područjima. Utvrđeno je da su zahvaćena tkiva u žena na početku bolesti bila hipofi za, mozak i bulbus, a kod muškaraca korpus kalozum i mozak. Otkriveno je da atrofi ja ne ovisi o vremenu. Kada se promatralo korelaciju između zbira na Expanded Disability Status Scale (EDDS) i atrofi je, vidjelo se da s povećanjem EDDS (kada bolest napreduje) dolazi do smanjenja područja malog mozga i korpusa kalozuma u muškaraca, a povećanja područja četvrtog ventrikula u žena. Pokazali smo da se atrofi ja hipofi ze razvija u ranoj fazi MS, osobito u žena. Pozornost privlači rana atrofi ja hipofi ze i bulbusa u žena te kasna atrofi ja ovih tkiva u muškaraca

Sturm comparison theorems for some elliptic type equations via Picone-type inequalities

10th Colloquium on the Qualitative Theory of Differential Equations -- JUL 01-04, 2015 -- Szeged, HUNGARYWOS: 000390590900006Sturm theorems have appeared as one of the fundamental subjects in qualitative theory to determine properties of the solutions of differential equations. Motivated by some recent developments for half-linear type elliptic equations, we obtain Picone-type inequalities for two pairs of elliptic type equations with damping and external terms in order to establish Sturmian comparison theorems. Some oscillation results are given as applications

Sturm comparison theorems for some elliptic type equations via Picone-tpye inequalities

Sturm theorems have appeared as one of the fundamental subjects in qualitative theory to determine properties of the solutions of differential equations. Motivated by some recent developments for half-linear type elliptic equations, we obtain Picone-type inequalities for two pairs of elliptic type equations with damping and external terms in order to establish Sturmian comparison theorems. Some oscillation results are given as applications

A meta-analysis of science education studies for students with intellectual and developmental disabilities (IDD)

Teaching science education has remained limited for students with intellectual and developmental disabilities (IDD), which, in turn, has resulted in an ongoing discrepancy between these students and their typically developing peers for decades. Although there is a growing body of research in effective teaching approaches aimed at overcoming this discrepancy, there is still a need to identify evidence-based practices for addressing this academic core content. The purpose of this meta-analysis was to (a) find out the skills taught in science education to students with IDD, (b) define the characteristics of instructional approaches or adaptations of instructional approaches used to teach science content and practices, (c) conduct visual and effect size analysis of science education studies meeting the Council for Exceptional Children (CEC) quality indicators (QIs; Cook et al., 2015), and (d) determine whether there are differences in effect sizes of science education studies meeting CEC QIs based on participant and intervention characteristics. Of 27 studies reviewed, 18 studies met all the CEC QIs. A meta-analysis of these 18 studies resulted in an overall medium effect size of 0.82 CI95 (0.76, 0.87). While all the moderator variables showed a medium effect size in participant characteristics, intervention characteristics showed differences in effect sizes for comprehension-based learning and peer and researcher-implemented interventions