Wyniki 1-10 spośród 27 dla zapytania: authorDesc:"Arkadiusz MIASKOWSKI"

Finite Difference Time Domain Method for high resolution modeling of low frequency electric induction in humans

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The paper deals with the implementation of low frequency finite difference time domain method (FDTD) algorithm in the investigation of induced electric field in the human body model with digitally implanted cardiac pacemaker. In order to investigate if the basic restrictions could be exceeded according to international standards, the induced electric fields at both the input port of cardiac pace[...]

Modelling of Magnetotherapy in the Healing of Knee Joint

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The paper presents the method of establishing a computer model of the electromagnetic therapy connected with some knee joint problems. Two cases were considered: the arthritis of the knee and the fracture of bone. In both cases the analysis of eddy current distribution in the knee were made. It gave results which can be helpful in the planning of treatment. The paper presents the exemplary results of eddy current distribution inside a bone. A short discussion on the safety aspect of magnetotherapy has been carried out. Streszczenie. W artykule przedstawiono numeryczna aplikacje niskoczęstotliwościowego algorytmu FDTD do symulacji prądów wirowych w modelu kolana ludzkiego. Analiza efektywności magnetoterapii zrealizowana została poprzez porównanie rozkładu pola magnetycznego i prądów w[...]

Two-Step Inverse Problem Algorithm for Ground Penetrating Radar Technique

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The aim of the article is to present the new method of GPR data interpretation. The presented methodology allows to determine the depths and diameters of hidden objects. To generate the data and to solve the forward problem the Finite-Difference Time-Domain method was used. In order to solve the inverse problem of rebar diameter estimation the author’s two-step algorithm was constructed. The algorithm was based on edges detection methods mixed with neural networks. Streszczenie: W artykule przedstawiono metodę interpretacji danych uzyskanych z geo-radaru. Zaprezentowana metodologia pozwala na wyznaczanie głębokości oraz średnicy ukrytych obiektów. Do generacji danych użyto metody różnic skończonych w dziedzinie czasu, zaś w celu rozwiązania zagadnienia odwrotnego posłużono się autorskim algorytmem opartym na metodach detekcji krawędzi oraz sieciach neuronowych. . (Dwustopniowy algorytm do rozwiązywania zagadnienia odwrotnego w georadarach). Keywords: GPR, inverse problem, FDTD, neural networks. Słowa kluczowe: georadar, zagadninie odwrotne, FDTD, sieci neuronowe. Introduction Ground penetrating radar (GPR) is a non-destructive technique for investigating hidden objects. It detects changes in the electromagnetic properties of materials, principally their permittivity, and is capable of producing cross-sectional representations of what is beneath surfaces [1]. That idea can be seen in Fig. 1 where GPR antenna transmits a signal to the ground, and then scattered signals are collected in a storage unit via control one. Fig.1. The idea of GPG technique. In th[...]

Magnetic Fluid Hyperthermia for Cancer Therapy

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The aim of the paper is to show basic ideas of magnetic fluid hyperthermia treatment with regard to power losses which occur during heating with alternating magnetic field. A special attention has been paid to dielectric, hysteresis and relaxation mechanism losses and their contribution to total power losses. A numerical analysis has been done with regard to a simplified female breast phantom and its dielectric parameters. Streszczenie. W artykule przedstawiono fizyczne podstawy hipertermii cieczy magnetycznej ze szczególnym uwzględnieniem strat mocy, jakie zachodzą podczas grzania zmiennym polem magnetycznym tkanek ludzkich połączonych z cieczą magnetyczną. I tak, zaprezentowano straty wiroprądowe, histerezowe i relaksacyjne, a następnie dokonano numerycznej analizy rozkładu gęstości mocy w zastosowaniu do parametrów dielektrycznych tkanek gruczołu piersiowego. (Zastosowanie hipertermii cieczy magnetycznej w terapii antynowotworowej). Keywords: magnetic fluid hyperthermia, Finite Element Method, computer simulation. Słowa kluczowe: hipertermia cieczy magnetycznej, metoda elementów skończonych, symulacja komputerowa. Introduction Hyperthermia is a method of treating cancer by preferentially heating the tumor. Generally speaking, it involves reaching and maintaining for several minutes a temperature of 42 to 48 0C in the tissues [1]. There are three main approaches to hyperthermia treatments i.e. whole-body hyperthermia, regional and localized hyperthermia. The whole-body hyperthermia raises the temperature of the entire body to nearly 420C, and it is often uncomfortable for the patients due to high temperature gradients. Besides, the tumors may not reach sufficiently high temperatures. Regional hyperthermia attempts to heat moderately large volumes, such as thorax or pelvis including the cancerous region as well as surrounding healthy tissues. The remainder of the body is kept as close to normal temperature as possible. Localized h[...]

Numerical model of magnetic fluid hyperthermia

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The article presents the computer model of magnetic fluid hyperthermia (MFH), which is new, promising cancer treatment. Special attention was focused on the complete mapping of physical and biological phenomenon, such as a realistic model of magnetic field excitement, blood perfusion, metabolic heat and convective heat exchange with the environment. The described model was implemented using the finite element method. Streszczenie. Artyku. prezentuje metodyk.e numerycznego modelowania hipertermii p.ynu magnetycznego (ang. MFH), ktora jest nowa., obiecuja.ca. technika. leczenia nowotworow. Specjalna uwaga zosta.a zwrocona na pe.ne odwzorowanie zjawisk fizycznych i biologicznych, takich jak: realistyczny model wymuszenia magnetycznego, zjawisko perfuzji krwi, metaboliczne ?Lzrod.a ciep.a oraz zjawisko konwekcyjnej wymiany ciep.a z otoczeniem. Opisany model zosta. zaimplenemtowany przy wykorzystaniu metody elementow skonczonych. Numeryczny model hipertermii p.ynu magnetycznego Keywords: Magnetic Fluid Hyperthermia, computational bioelectromagnetics, superparamagnetic heat S.owa kluczowe: Hipertermia p.ynu magnetycznego, bioelektromagnetyzm obliczeniowy, grzanie superparamagnetyczne Introduction According to the reports made by National Cancer Registry and Polish Committee for Fighting Cancer, cancer is the second after circulatory system diseases cause of death in Poland. Among different types of cancer, the most frequent malignant tumor observed in active women in age between 40 and 60 is the breast cancer. Breast cancer diagnosed early enough, i.e. the diameter of cancer is lower than 2 cm, can be treated successfully in 90 percent of cases. That implicates the possibility of a minimalinvasive treatment without deformation of the morphological structure of the organ is of special interest for the patient?fs emotional and physical welfare. One of such methods, being developed nowadays, is hyperthermia. Human cells are very sensitive to [...]

SAR optimization for multi-dipole antenna array with regard to local hyperthermia DOI:10.15199/48.2019.01.05

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Hyperthermia (HT) is defined as the phenomenon of natural or artificial increase in temperature of whole body or its specific parts such as tissues or organs [1]. A natural HT results from the impairment of the body's thermoregulatory system, which leads to defect the heat dissipation mechanism and, as a result, to heat accumulation in dysfunctional tissue. An artificial HT involves increasing the temperature in the target area to values 40-45°C [2] or even higher (socalled thermal ablation) [3], under the influence of external heat sources (eg. hot water or wax baths) or different EMF applicators including various-type solenoids, coils, antennas or their multi-element arrays [1, 2]. The main task of artificial HT is thermal damage of malignant cells that are more sensitive to high temperature than normal cells. The main reason for this is the fact that the cancer tissue is highly vascularized but the tumor vessels are unable to growth their cross-sections during heating and remove excess heat as in the case of healthy tissues. Therefore, the tumor heats up much faster than the surrounding tissues with the same power of RF or MV applicators [1]. The challenge of modern hyperthermia is to design such HT systems that selectively heat only cancerous tissue, keeping intact healthy tissues [4]. Developing research connected with the EM energy usage results in the emergence of novel radiating elements [5] that allow for constant and controlled EMF exposure conditions [6, 8]. Importantly, the use of high frequencies limits the area of tissue penetration [1]. Simultaneously, the combination of several probes in the antenna matrix allows to increase the EM energy accumulation in the target volume [9]. By utilizing several EMF sources with the appropriate power, amplitude and phase control of the power supply signals, the required heat focusing within the deep-seated tumors can be achieved [10, 11]. For better targeting the EM energy[...]

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