Browsing by Author "Faishal Ansari"

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Analysis of nonlinear heat transfer model in multi-layered tissues containing a liver tumor during magnetic fluid hyperthermia
(Springer Science and Business Media B.V., 2025) Faishal Ansari; Jitendra Singh
Magnetic fluid hyperthermia (MFH) is a very effective and less invasive treatment method for healing various tumors. Due to the intense heterogeneity and complexity of living tissue, we have considered blood perfusion and thermal conductivity as temperature-dependent. This study examines the behavior of temperature patterns in sphere-shaped living tissues during MFH treatment by using the nonlinear bioheat model that accounts the influence of key variables on heating behavior. Because of its nonlinearity, this problem is simulated using a combination of bvp4c and finite difference methods. This numerical technique is validated by comparing its findings with an analytical solution in a particular case, and it is seen that the outcomes generated from both methods showed a significant level of resemblance. Further, we conducted a comparison between the outcomes of our model and the experimental results, which confirms the reliability of the present nonlinear model. The findings of our study indicate that the temperature-dependent blood perfusion rate and thermal conductivity significantly influence the temperature within tumor area, but have minimal impact on the temperature in the surrounding region during MFH therapy. Further analysis reveals that the influence of quadratically temperature-dependent thermal conductivity is more significant compared to the linearly temperature-dependent forms of thermal conductivity. Additionally, the radius of nanoparticles and magnetic field intensity play a critical role in attaining hyperthermia temperature within the tumor area. © Akadémiai Kiadó Zrt 2025.
Bioheat transfer analysis inside multi-layered breast tissue during magnetic hyperthermia: Incorporating sweating and surface heat sources
(Elsevier Ltd, 2025) Faishal Ansari; Jitendra Singh
Magnetic hyperthermia has emerged as a promising non-invasive technique for cancer treatment, aiming to induce tumor temperature to 42−45 °C while preserving surrounding healthy tissue during the therapy. This article elucidates the thermal behavior governed by the bioheat equation within multi-layered breast tissue, incorporating temperature-dependent thermal conductivity, blood perfusion rate, and metabolism during magnetic hyperthermia. The sweating term has also been incorporated into the present model to precisely forecast the thermal behavior. The aforementioned assumptions render the problem increasingly difficult and nonlinear, resulting in a complicated solution. Therefore, the finite element Runge–Kutta (4,5) scheme, which combines the finite difference with Runge–Kutta (4,5) approaches, has been utilized to address the present problem. Upon meticulous observation, it is determined that the elevated values of nonlinear coefficients (α, β) decline the heating profile, while increasing δ elevates it. It has also been noted that an increase in sweat velocity diminishes the heating profile. The outer surface temperature (θw) significantly impacts the therapy of malignant cells. Because an elevation in θw markedly improves the thermal profile throughout the entire region during the therapy. The study found that a constant surface temperature (θw) is more efficient than homogeneous and sinusoidal heat fluxes. © 2025 Elsevier Ltd
Numerical simulation of burn injuries with temperature-dependent thermal conductivity and metabolism under different surface heat sources
(Elsevier Ltd, 2023) Faishal Ansari; Rajneesh Kumar Chaudhary; Jitendra Singh
In the present paper, the phenomena of heat transport inside human forearm tissue are studied through a one-dimensional nonlinear bioheat transfer model under the influence of various boundary and interface conditions. In this study, we considered temperature-dependent thermal conductivity and metabolic heat to predict temperature distribution inside the forearm tissue. We have studied the temperature distribution inside inner tissue and bone because it has been found that burn injuries are mostly affected by layer thickness. The temperature distribution inside human forearm tissue is analyzed using the finite difference and bvp4c numerical techniques. To examine the accuracy of present numerical code, we compare the obtained numerical result with the exact analytical result in a specific case and find an excellent agreement with the exact results. We also validated our present numerical code with a hybrid scheme based on Runge-Kutta (4,5) and finite difference technique and found it in good compliance. From the obtained results, we observed that the homogeneous heat flux has a greater impact on the temperature at the outer surface of the skin, but the sinusoidal heat flux has a greater impact on the temperature of the subcutaneous layer and inner tissue. It is found that there is no burn injury in the first type of heat source (Tw=44°C), but it may occur in the second and third types of heat sources. It has been observed that by raising the blood perfusion rate and reducing the values of reference metabolic heat, coefficient of thermal conductivity, and heat fluxes, we can manage and reduce burn injuries and achieve hyperthermia temperature. © 2023 Elsevier Ltd
Numerical study of a dual-phase-lag bioheat transfer model via finite element Runge-Kutta (4,5) in spherical tissue with temperature-dependent blood perfusion during magnetic hyperthermia
(Taylor and Francis Ltd., 2025) Faishal Ansari; Rajneesh Kumar Chaudhary; Jitendra Singh
The present article involves a dual-phase-lag nonlinear bioheat model for living spherical tissue during magnetic hyperthermia. In this study, we considered temperature-dependent blood perfusion to forecast accurate hyperthermia temperature for the treatment of tumor cells. Due to the nonlinearity, this problem is handled by a finite element Runge-Kutta (4,5) technique, which is a combination of Runge-Kutta (4,5) and finite difference approaches. In this technique, we discretize the partial derivatives of space variables by using the central difference scheme. After the discretization, the current problem turns out as a system of second-order ODEs with initial conditions. Again, we convert the system of second-order ODEs into the system of first-order coupled ODEs. Then, we employed the RK (4,5) scheme to resolve the problem completely for time interval. The result obtained by the present numerical scheme is validated through an exact analytical result in a special situation, and it is noticed that both results are very close to each other. After analyzing the results, we found that when tumor cells are treated by magnetic hyperthermia, temperature-dependent blood perfusion significantly affects the hyperthermia temperature. It is seen that the impact of quadratically temperature-dependent blood perfusion is more effective than the linearly temperature-dependent types of blood perfusion. The convection effect due to the quadratically temperature-dependent term in the blood perfusion is greater than the other terms. The magnetic heat source is crucial in regulating the temperature inside the living tissue for determining hyperthermia temperature. By rising the ratio of lagging time due to heat flux ((Formula presented.)) and temperature gradient ((Formula presented.)), the temperature profile drops, and these effects are observed initially for a few seconds. © 2025 Taylor & Francis Group, LLC.