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Article
Publication date: 6 July 2012

Arkadiusz Miaskowski, Bartosz Sawicki and Andrzej Krawczyk

The purpose of this paper is to present the basic ideas of magnetic nanoparticles' usage in the breast cancer treatment, which is called magnetic fluid hyperthermia. The proposed…

357

Abstract

Purpose

The purpose of this paper is to present the basic ideas of magnetic nanoparticles' usage in the breast cancer treatment, which is called magnetic fluid hyperthermia. The proposed approach offers a relatively simple methodology of energy deposition, allowing an adequate temperature control at the target tissue, in this case a cancerous one. By means of a numerical method the authors aim to investigate two heating effects caused by varying magnetic fields, i.e. to compare the power density heating effects of eddy currents and magnetic nanoparticles.

Design/methodology/approach

In order to numerically investigate the combination of the overheating effect of magnetic nanoparticles and eddy currents, the Finite Element Method solver based on FEniCS project has been prepared. To include the magnetic fluid in the model it has been assumed that power losses in the magnetic nanoparticles are completely converted into heat, according to experimentally developed formula. That formula can be interpreted as the hysteresis losses with regard to the volume of magnetic fluid. Finally, the total power density has been calculated as the product of the sum of power density from eddy currents and hysteresis losses. That methodology has been applied to calculate the effectiveness of magnetic fluid hyperthermia with regard to the female breast phantom.

Findings

The paper presents the methodology which can be used in magnetic fluid hyperthermia therapy planning and Computer Aid Diagnosis (CAD). Furthermore, it is shown how to overcome one of the most serious engineering challenges connected with hyperthermia, i.e. achieving adequate temperature in deep tumors without overheating the body surface.

Practical implications

The obtained results connected with the assessment of eddy currents effect suggest that during hyperthermia treatment the configuration which consists of an exciting coil and human body, plays a curial role. Moreover, the authors believe that these results will help to predict the skin surface overheating that accompanies deep heating. The presented methodology can be used by engineers in the development of Computer Aid Diagnosis systems.

Originality/value

In a given patient's situation a number of choices must be made to determine the parameters of the hyperthermia treatment. These include the need of multiple‐point temperature measurements for accurate and thorough monitoring. Treatment planning will require accurate characterization of the applicator deposition pattern and the tissue parameters, as well as the numerical techniques to predict the resultant heating pattern. The presented paper shows how to overcome these problems from the numerical point of view at least.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 September 2012

Arkadiusz Miaskowski, Andrzej Krawczyk and Yoshiyuki Ishihara

The purpose of this paper is to use numerical methods and modelling to estimate the effect of a passive, metallic (conducting) implant on eddy currents distribution in a human…

197

Abstract

Purpose

The purpose of this paper is to use numerical methods and modelling to estimate the effect of a passive, metallic (conducting) implant on eddy currents distribution in a human knee model. There exists a concern among wearers of such implants that they alter electromagnetic field (eddy currents) significantly and there is a need for standardization of that problem.

Design/methodology/approach

The numerical model of a human knee has been built on the base of Visual Human Project and electromagnetic field calculations were carried out using Meep FDTD engine. In total, two scenarios have been considered: the knee model with and without a metallic implant. The knee implant model has been prepared as the knee model with overestimated electrical parameters of bone tissues by titanium metal. Alternating eddy current distribution has then been evaluated for both models using FDTD low frequency algorithm.

Findings

The highest values of eddy currents occurred on the interface between skin and muscle tissues when the model without an implant is considered. However, when the bone tissues have been replaced with titanium metal, the highest values have occurred in the implant (about 100 times higher than the previous one). This means that an implant can be heated by external electromagnetic fields and that the location of the highest values of eddy currents can be shifted to the proximity of the implant. Moreover, one should realize that in this model the implant is like a knee bone with all anatomical details. It has emerged from this that the implant's shape and size are essential when evaluating its effect on eddy currents distribution.

Practical implications

The interaction of electromagnetic field with implants should be generally further investigated, at least for the presumable worst cases. Such investigation has already been done by some researches but they have been devoted to radio frequencies. The authors believe that the presented research will be helpful in the standardization process, when talking about low frequency electromagnetic field.

Originality/value

The presented methodology can be used in the development of computer aid diagnosis systems. Overestimation of electrical parameters of some parts of the model allows us to predict the distribution of electromagnetic field in the model under investigation very quickly. The results presented in the paper can be used during the standardization process.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 13 July 2010

Arkadiusz Miaskowski, Andrzej Krawczyk and Yoshiyuki Ishihara

The paper aims to clarify the method/methodology of establishing a computer model of the electromagnetic therapy connected with some knee joint problems. Two cases are considered…

322

Abstract

Purpose

The paper aims to clarify the method/methodology of establishing a computer model of the electromagnetic therapy connected with some knee joint problems. Two cases are considered: the arthritis of the knee and the fracture of bone. In both cases the analysis of eddy current distribution in the knee is made. It gives 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.

Design/methodology/approach

In order to calculate the eddy current distribution in human knee joint the low frequency finite‐difference time‐domain algorithm has been applied. The numerical model of the leg was based on US Air Force Research Laboratory data and the electrical properties of tissues were modeled using 4‐Cole‐Cole approximation with parameters taken from Gabriels.

Findings

The paper presents the general methodology which can be used in magnetotherapy to estimate a magnetic flux density of stimulators and value of current density inside the knee joint. Both factors mentioned above can be helpful in therapeutical processes, i.e. in magnetoteraphy.

Research limitations/implications

The eddy current distribution is limited to the presented model and it is obvious it can be different for another one as it is shown in the paper but it is also shown that the biggest value of eddy current density is just in the vicinity of the joint, so it can help in a therapeutical process.

Practical implications

The methodology of estimating the values of current density and magnetic flux density can be used by physiologists and doctors to determine the value of current density which gives therapeutical effect.

Originality/value

The efficient application of low frequency finite‐difference time‐domain algorithm to the electromagnetic therapy connected with some knee joint problems has been shown and the general methodology has been conducted.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 11 July 2008

Arkadiusz Miaskowski, Andrzej Krawczyk and Andrzej Wac‐Wlodarczyk

The aim of this paper is to investigate the coupling model which describes the relationship between the electromagnetic (EM) field emitted by a field source, in this case the…

611

Abstract

Purpose

The aim of this paper is to investigate the coupling model which describes the relationship between the electromagnetic (EM) field emitted by a field source, in this case the mobile phone, and the interfering voltage at a cardiac pacemaker which is digitally implanted into the human body model.

Design/methodology/approach

The research was carried out using two kinds of numerical phantoms with various configurations, i.e. the mobile placed in front of a trunk and the mobile placed near the human ear (totally 12 configurations). Moreover, the simplified homogeneous human model with numerically implanted cardiac pacemaker is considered (two configurations). The simulations are carried out using the finite difference time domain method according to international standards.

Findings

From the investigation it was found that the interfering voltage at the cardiac pacemaker (for each of the considered models) was much smaller than the one proposed by IEC standard. A practical conclusion that can be drawn is that the highest interfering voltages occur when the mobile is in a vertical position.

Research limitations/implications

The analysis was limited to the cardiac pacemaker with a unipolar electrode and could be carried out for other types of pacemakers.

Practical implications

The evaluations such as those presented should be useful in the development of protection standards of human exposure to EM field with respect to humans with implants such as cardiac pacemakers. Furthermore, such a modeling allows for the evaluation of potential EM interference prior to an implantation of implants.

Originality/value

Such a detailed analysis of a coupling model considering various configurations of mobile phone position to a human model has so far never been carried out.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 4
Type: Research Article
ISSN: 0332-1649

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