Search results

1 – 10 of 47
Article
Publication date: 6 July 2015

Juan C. Vanegas-Acosta, V. Lancellotti and A.P.M. Zwamborn

Electric fields (EFs) are known to influence cell and tissue activity. This influence can be due to thermal or non-thermal effects. While the non-thermal effects are still matter…

Abstract

Purpose

Electric fields (EFs) are known to influence cell and tissue activity. This influence can be due to thermal or non-thermal effects. While the non-thermal effects are still matter of discussion, thermal effects might be detrimental for cell and tissue viability due to thermal damage, this fact being exploited by applications like hyperthermia and tissue ablation. The paper aims to discuss these issues.

Design/methodology/approach

In this work the authors investigate the influence of thermal damage in the consolidation of bone formation during electrostimulation (ES). The authors introduce a mathematical model describing the migration of osteoprogenitor cells, the thermal variation, the thermal damage accumulation and the formation of new bone matrix in an injury (fracture) site.

Findings

Numerical results are in agreement with experimental data and show that EFs more intense than 7.5 V/cm are detrimental for the viability of osteoprogenitor cells and the formation of new bone.

Originality/value

The model is suitable to conduct dosimetry studies in support of other different ES techniques aimed at improving bone and soft tissues repair.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 April 1992

JAROSLAV MACKERLE

This bibliography is offered as a practical guide to published papers, conference proceedings papers and theses/dissertations on the finite element (FE) and boundary element (BE…

Abstract

This bibliography is offered as a practical guide to published papers, conference proceedings papers and theses/dissertations on the finite element (FE) and boundary element (BE) applications in different fields of biomechanics between 1976 and 1991. The aim of this paper is to help the users of FE and BE techniques to get better value from a large collection of papers on the subjects. Categories in biomechanics included in this survey are: orthopaedic mechanics, dental mechanics, cardiovascular mechanics, soft tissue mechanics, biological flow, impact injury, and other fields of applications. More than 900 references are listed.

Details

Engineering Computations, vol. 9 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 6 July 2015

Tony R. Almeida and Carlos L. Antunes

In this paper a numerical simulation analysis of a modified stent-based electrode is introduced to be used as a bipolar electrode for radio frequency ablation of tumours located…

Abstract

Purpose

In this paper a numerical simulation analysis of a modified stent-based electrode is introduced to be used as a bipolar electrode for radio frequency ablation of tumours located in hollow organs. The purpose of this paper is to study the possibility of achieving a more regular volume of induced lesion with the presented electrode without imperilling the ductal organ where the tumour is located.

Design/methodology/approach

Three types of bipolar electrode configurations were considered, formed by two, three and five tubular segments. Numerical simulations were performed considering a tumour located in the bile duct, where two important blood vessels – the portal vein and the hepatic artery – have a significant impact due to the convective heat transfer caused by the blood flow (heat sink effect) which significantly affects the shape of lesion that is intended to induce in order to destroy the tumour.

Findings

The results obtained show that the five-segment electrode arrangement allows a regular volume for the induced lesion, independently of the different values of applied voltage considered.

Originality/value

The presented work introduces a numerical simulation analysis on a modified based-stent electrode previously studied. In this case, the electrode is configured so it can be used as a bipolar electrode, i.e., active and ground electrode are placed in the same device. Besides the results evinced by the obtained results, this kind of electrode avoids eventual skin burns that might occur due to the need of the return electrodes when monopolar electrodes are used.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 26 June 2020

Atul Babbar, Vivek Jain and Dheeraj Gupta

In present research work, the effects of rotational speed, feed rate and vibration amplitude have been investigated during novel method of ultrasonic-assisted bone grinding…

Abstract

Purpose

In present research work, the effects of rotational speed, feed rate and vibration amplitude have been investigated during novel method of ultrasonic-assisted bone grinding. During dissection of tumors, firstly a bone flap is removed near the target region to create passage for grinding burr. During abrasion, heat is produced, which sometimes increases the temperature to unsafe levels. So, efforts have been made to limit the temperature below the threshold levels of osteonecrosis during bone grinding.

Design/methodology/approach

The temperature produced during osteotomy has been measured using infrared thermography camera during the implementation of L18 Taguchi orthogonal array design. Subsequently, main effect plots and contour plots have been presented to analyze and visualize the effect of grinding parameters on temperature rise during bone grinding. Furthermore, the process parameters have been optimized for optimum results for response characteristics using Taguchi SN ratio-based optimization methodology. For multiobjective optimization, the process parameters are further optimized using grey relational analysis.

Findings

It is revealed that all three process parameters substantially affect the response characteristics. The proposed optimization methodology is successfully applied on the experimental findings and the optimum results for change in temperature are found to be rotational speed = 3,000 rpm, feed rate = 20 mm/min, amplitude = 10 µm and for standard deviation are 5,000 rpm, 60 mm/min, 10 µm.

Research limitations/implications

The present research findings cannot be generalized, and researchers are encouraged to further investigate the proposed rotary ultrasonic-assisted bone grinding at higher rotational speed up to 60k rpm on the skull bone.

Originality/value

The research on osteotomy is still at its initial phase, and continuous research is carried out for making patients’ life comfortable. In this direction, the authors have proposed a novel osteotomy method to limit the temperature below the threshold limit of osteonecrosis. The outcomes of the present study will be beneficial for the neurosurgeons working in this field.

Details

Grey Systems: Theory and Application, vol. 10 no. 4
Type: Research Article
ISSN: 2043-9377

Keywords

Article
Publication date: 31 October 2018

Deepkamal Kaur Gill, Kartikeya Walia, Aditi Rawat, Divya Bajaj, Vipin Kumar Gupta, Anand Gupta, Mamta Juneja, Rakesh Tuli and Prashant Jindal

To relieve intracranial pressure and save patient inflicted with severe head injury, neurosurgeons restore cranial defects. These defects can be caused because of trauma or…

Abstract

Purpose

To relieve intracranial pressure and save patient inflicted with severe head injury, neurosurgeons restore cranial defects. These defects can be caused because of trauma or diseases (Osteomyelitis of bone) which are treated by cranioplasty, using the preserved bone of patient. In case of non-availability of bone, a cranial implant is generated using a biocompatible synthetic material, but this process is less accurate and time-consuming. Hence, this paper aims to present the use of rapid prototyping technology that allows the development of a more accurate patient-specific template and saves the surgery time.

Design/methodology/approach

A five-year-old girl patient having cranial defect was taken up for cranioplasty. CT (computed tomography) scans of the patient were used to generate 3D design of the implant suitable to conceal the defect on the left frontal portion using CAD/CAM (computer-aided design/ computer-aided manufacturing) software. The design was used for 3D printing to manufacture a base template, which was finally used to fabricate the actual implant using Simplex® P bone cement material to conceal the defect.

Findings

Surgery using Simplex® P implant was performed successfully on the patient, giving precise natural curvature to left frontal portion of the patient, decreasing surgery time by about 30 per cent.

Originality/value

The case demonstrates the development of a convenient, time-saving and aesthetically superior digital procedure to treat cranial defect in the absence of preserved bone flap using CT scan as input. 3D modelling and printing were deployed to produce an accurate template which was used to generate an implant using bone cement biocompatible material.

Details

Rapid Prototyping Journal, vol. 25 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 7 March 2016

Anup Paul, Arunn Narasimhan and Sarit Kumar Das

The large blood vessels (LBV) would act as a heat sink and hence play a significant role during photo-thermal therapy. Gold nanoshell was considered as a high-heat absorbing agent…

Abstract

Purpose

The large blood vessels (LBV) would act as a heat sink and hence play a significant role during photo-thermal therapy. Gold nanoshell was considered as a high-heat absorbing agent in photo-thermal heating to reduce the cooling effect of LBV. The heat sink effect of LBV results in insignificant irreversible tissue thermal damage. The paper aims to discuss these issues.

Design/methodology/approach

In this paper, the thermal history of tissue embedded with LBV during photo-thermal heating were calculated using finite element-based simulation technique. A volumetric laser source term based on modified Beer-Lambert law was introduced to model laser heating. The numerically predicted temperature drop was validated against that of previously performed experiments by the authors on tissue mimic embedded with simulated blood vessels. In the later part of the study, Arrhenius equation was coupled with the energy equation to investigate and report the irreversible thermal damage to the bio-tissues.

Findings

The results obtained conclude that tissue with different orientation of blood vessels results in different thermal response at the tissue surface. Gold nanoshells were introduced into the laser irradiated tissue to overcome the cooling effect of LBV during plasmonic photo-thermal heating. The effect of size and concentration of nanoparticles on tissue heating were analyzed. The predicted damage parameter was much lower in case of tissue embedded with blood vessel than that predicted in case of bare tissue, which results in incomplete tissue necrosis. Finally, the effects of laser specification, blood vessel specification and blood perfusion on the tissue thermal damage were examined.

Originality/value

The conjugate energy equations in conjunction with Arrhenius equation were solved numerically to predict the tissue irreversible damage embedded with LBV.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 6 March 2017

Mykola Ostroushko, André Buchau and Wolfgang Rucker

The purpose of this paper is to present the design and the numerical calculation of the electromagnetic heating system for the ablation therapy. Hence, the heating of the tumor…

Abstract

Purpose

The purpose of this paper is to present the design and the numerical calculation of the electromagnetic heating system for the ablation therapy. Hence, the heating of the tumor cells must be processed very carefully to achieve a localized coagulative necrosis and to avoid too high temperatures inside the tissue.

Design/methodology/approach

The non-invasive method of the ablation therapy is implemented due to the inductive power transmission between the generator and implant. The ferromagnetic implant has a small size and can be placed intravenously into tumor cells. High-frequency driving currents are necessary to obtain high induced eddy currents within the ferromagnetic implant.

Findings

Finite element analysis has been used for the design and numerical calculation of the electromagnetic heating system. The electromagnetic analysis is done in the time domain due to the nonlinearity of the ferromagnetic implant. Magnetic fields are computed based on a magnetic vector potential formulation. The thermal analysis is done in the time domain as well. The temperature computation in biological tissue is based on a heat balance equation.

Research limitations/implications

This paper is focused on the design and simulation of the inductive system for the ablation therapy.

Practical implications

The designed system can be practically implemented. It can be used for the clinical study of the immune response by the thermal ablation therapy.

Originality/value

The common method of thermal ablation is combined with an inductive power transmission. It enables a repetitive application of this method to study the immune response.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 6 July 2012

Dagmara M. Dołęga and Jerzy Barglik

The purpose of this paper is to enable the correct selection of the radiofrequency thermal ablation (RFTA) process parameters for an individual patient by applying a computer…

Abstract

Purpose

The purpose of this paper is to enable the correct selection of the radiofrequency thermal ablation (RFTA) process parameters for an individual patient by applying a computer modelling of RFTA.

Design/methodology/approach

The model is based on the X‐ray computer tomography images of the primary and metastatic hepatic tumours. The authors used the professional package of FLUX3D to generate the geometric models, assign materials properties, assign boundary conditions, perform mesh, carry out coupled thermo‐electromagnetic analysis and for post processing. The distribution of temperature and electric potential in the tissues of tumour and liver had been obtained as main results of the calculations.

Findings

The computational results show that the RFTA algorithm is effective in solving this practical problem. The computational results show that the selection of the type of electrodes used in the RFTA process is as important as the correct selection of the process parameters, i.e. voltage and frequency.

Originality/value

The paper presents a method to simulate the RFTA process and to select the process parameters.

Details

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

Keywords

Article
Publication date: 5 October 2010

Cho‐Pei Jiang

The purpose of this paper is to propose a method for fabricating tumor vessel phantom and then investigate the thermal dosage profile caused by high‐intensity‐focused ultrasound…

Abstract

Purpose

The purpose of this paper is to propose a method for fabricating tumor vessel phantom and then investigate the thermal dosage profile caused by high‐intensity‐focused ultrasound (HIFU) surgery.

Design/methodology/approach

In this paper, a thermal sensitive powder has been added to silicon‐based gel as a vessel phantom raw material for displaying the thermal dosage profile caused by HIFU. A fused deposition modeling system was used for fabricating the shell casting mold and the vessel arbor mold. The arbor prototype, made of wax, was solidified in the cavity of vessel arbor mold. The vessel phantom object embedded with the arbor prototype was created in the shell mold casting process. The vessel phantom was obtained by immersing the vessel phantom object into hot water (65°C) for melting the vessel arbor prototype. A HIFU experiment has been conducted for verifying the feasibility of displaying the thermal dosage profile of the fabricated vessel phantom. The HIFU experimental parameters including the driving power of HIFU transducer, ultrasound exposure duration and volume flow rate were used for investigating the thermal dosage variation by the perfusion of vessel phantom.

Findings

The properties of fabricated mimicking phantom agree well with those of human tissue. The experimental results show that the proposed method can fabricate the Y‐type vessel phantom. The proposed method has been proved as a promising fabrication process in fabricating the vessel phantom and it displays the thermal dosage profile in HIFU experiment.

Originality/value

The proposed method and the developed experimental apparatus are helpful for pre‐clinical HIFU surgery.

Details

Rapid Prototyping Journal, vol. 16 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 6 March 2017

Marek Paruch

The purpose of this study is to show that the methods of the numerical simulation can be a very effective tool for a proper choice of control parameters of artificial…

Abstract

Purpose

The purpose of this study is to show that the methods of the numerical simulation can be a very effective tool for a proper choice of control parameters of artificial hyperthermia. An electromagnetic field induced by two external electrodes and a temperature field resulting from electrodes action in a 3D domain of biological tissue is considered. An important problem is the appropriate directing of heat in the region of tumor, so as to avoid damaging healthy cells surrounding the tumor. Recently, to concentrate the heat on the tumor, magnetic nanoparticles, which are introduced into the tumor, were used. The nanoparticles should be made of material that ensures appropriate magnetic properties and has a high biocompatibility with the biological tissue. External electric field causes the heat generation in the tissue domain.

Design/methodology/approach

The distribution of electric potential in the domain considered is described by the Laplace system of equations, while the temperature field is described by the Pennes’ system of equations. These problems are coupled by source function being the additional component in the Pennes’ equation and resulting from the electric field action. The boundary element method is applied to solve the coupled problem connected with the heating of biological tissues.

Findings

The aim of investigations is to determine an electric potential of external electrodes and the number of nanoparticles introduced to a tumor region to obtain the artificial hyperthermia state. The tests performed showed that the proposed tool to solve the inverse problem provides correct results.

Research limitations/implications

In the paper the steady state bioheat transfer problem is considered, so the thermal damage is a function of the temperature only. Therefore, the solution can be considered as the maximum ablation zone of cancer. Additionally, the choice of appropriate parameters will be affected on the position and shape of the tumor and the electrodes.

Originality/value

In the paper the inverse problem has been solved using the evolutionary algorithm, gradient method and hybrid algorithm which is a combination of the two previous.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

1 – 10 of 47