Blood Perfusion Rate Research Articles

Numerical analysis of thermal response on a non-linear model of multi-layer skin under heating and cooling processes

Based on the non-linear model of multi-layer skin, the present study is performed under heating and cooling processes with linear and non-linear generalized boundary conditions. The numerical outcome is obtained utilizing Runge Kutta (4,5) along with the finite difference scheme and the accuracy of this scheme is shown graphically by comparing it with an accurate analytical outcome in a special case. When the value of γ increases, the skin temperature is gradually higher in the case of a linear boundary condition and gradually lower in the case of a non-linear boundary condition with respect to linear boundary condition at epidermis-dermis (ED) interface. During cooling, the heat effect has slightly quick vanished in a non-linear boundary condition than in a linear boundary condition. The effect of a non-linear boundary condition gradually decreases as the value of heat transfer coefficient rises, then it reflecting the nature of the first kind of linear boundary condition. The exponential blood perfusion rate has a slightly quick vanishes of heat effect in comparison to constant and linear blood perfusion rate. To investigate the conduct of the temperature distribution in multi-layer skin, all the impacts are depicted graphically.

A Computational Model for Temperature Monitoring During Human Liver Treatment by Nd:YaG Laser Interstitial Thermal Therapy (LITT)

Describing heat transfer in biological organs is absolutely challenging because it is involved with many complex phenomena. Therefore, understanding the optical and thermal properties of living system during external irradiation sources such as laser interstitial thermal therapy (LITT) are too important for therapeutic purposes, especially for hyperthermia treatments. The purpose of this study was to determine a proper laser power and irradiation time for LITT applicator to irradiate liver tissue during hyperthermia treatment. For this aim, bioheat equation in one-dimensional spherical coordinate is solved by Green function method to simulate temperature distribution and rate of damage around irradiated target and how thermal and optical properties such as laser power, laser exposure time, and blood perfusion rate affect the rate of temperature distribution. Guiding equations according to the suggested boundary conditions are written and solved by MATLAB software. The outcomes show that increasing laser exposure time and power increase the temperature, especially at the nearest distance from the center of diffusion. Accordingly, a decrease in blood perfusion rate leads to decrease temperature distribution. The findings show that the model is useful to help the physicians to monitor the amount of heat diffusion by laser power during the treatment to protect healthy cells.

Soluble epoxide hydrolase inhibitor, t-AUCB, improves salivary gland function by ameliorating endothelial injury

AimsInhibitor of soluble epoxide hydrolase (t-AUCB) has been used in the experimental therapy of hypertension. This study aimed to investigate whether the secretion of submandibular glands (SMGs) altered in renal hypertensive rats, and to explore whether t-AUCB could improve the salivary secretion. Main methods2-kidney 1-clip Sprague-Dawley rats were used as renal hypertensive animals. t-AUCB treatment was given for 1 week after 8 weeks modeling. Blood pressure, blood perfusion and the secretion of SMGs, and endothelium-dependent relaxation of external maxillary artery were measured to investigate the effects of t-AUCB on the vascular tone and the secretion of SMGs in renal hypertensive rats. SMGs were collected for histological evaluation and the internal arteries were dissected for primary endothelial cells culture. Key findingsThe blood perfusion and flow rate of SMGs in the renal hypertensive rats were significantly lower than those in the controls. Endothelium-dependent relaxation of the external maxillary artery and AMPK/Akt/eNOS signaling was impaired in hypertensive rats. The glandular morphology and the concentration of salivary ions did not change obviously. t-AUCB treatment ameliorated the secretion of SMGs, the blood perfusion, and the dysfunction of endothelium-dependent relaxation of the external maxillary artery by activating the AMPK/Akt/eNOS pathway in hypertensive rats. Significancet-AUCB increases the blood perfusion through ameliorating dysfunction of endothelium-dependent relaxation of SMGs arteries and thus improves the hyposecretion of SMGs in hypertensive rats.

Numerical simulation of the skin tissue subjected to hyperthermia treatment using a nonlinear DPL model

This article deals with the study of simulation-based mathematical modeling of tissue using the non-linear dual-phase-lag bioheat transfer (DPLBHT) model for hyperthermia treatment of tumor or cancer cells with Gaussian distribution type heat source. The metabolic heat source as an exponential variation, blood perfusion rate as a linear variation and thermal conductivity as a linear variation are considered to be temperature-dependent, resulted in a more accurate prediction of the non-linear DPLBHT model. At initial time, τq is more effective than τt in the targeted region. When the infected or cancerous cells increases in width then for effective treatment the value of the antenna constant could be decreased and the value of probe region can be changed according to the tumor location in the skin tissue. When the value of γ, Wbo, a1 and a2 increases, the temperature profile in the target region decreases. The numerical solution is obtained by hybrid scheme using Runge Kutta (4,5) and finite difference technique. This technique is compared for accuracy with an exact analytical result in a particular case as shown in figures and table and found in good compliance. The effect of lagging, metabolic heat source, blood perfusion rate, coefficient of thermal conductivity, external heat source parameter and the other associated parameter are studied in detail and the results are presented graphically.

Targeting pulmonary vascular endothelial cells for the treatment of respiratory diseases.

Pulmonary vascular endothelial cells (VECs) are the main damaged cells in the pathogenesis of various respiratory diseases and they mediate the development and regulation of the diseases. Effective intervention targeting pulmonary VECs is of great significance for the treatment of respiratory diseases. A variety of cell markers are expressed on the surface of VECs, some of which can be specifically combined with the drugs or carriers modified by corresponding ligands such as ICAM-1, PECAM-1, and P-selectin, to achieve effective delivery of drugs in lung tissues. In addition, the great endothelial surface area of the pulmonary vessels, the “first pass effect” of venous blood in lung tissues, and the high volume and relatively slow blood perfusion rate of pulmonary capillaries further promote the drug distribution in lung tissues. This review summarizes the representative markers at the onset of respiratory diseases, drug delivery systems designed to target these markers and their therapeutic effects.

Thermoelastic analysis of biological tissue during hyperthermia treatment for moving laser heating using fractional dual-phase-lag bioheat conduction

In this paper, a time-fractional dual-phase-lag (DPL) bio-thermoelastic model is presented to solve the thermoelastic response of a biological tissue during hyperthermia treatment by a moving laser heating. To improve the elimination rate of diseased tissue and reduce the side effects to surrounding normal tissue in hyperthermia, it is necessary to study the thermoelastic response of biological tissues under high-speed and high-intensity laser heating. The laser heating process causes a large instantaneous temperature difference and heat flow in the tissue, which leads to abnormal diffusion of heat conduction. The classical Fourier heat conduction model cannot describe this anomalous diffusion phenomenon due to infinite heat propagation velocity. In order to describe anomalous diffusion in tissue, the fractional derivative is introduced into the DPL heat conduction model. In order to solve the elastic deformation of tissue under heating, the biological fractional thermoelastic theory is established by combining the fractional DPL model with one-dimensional thermoelastic theory. The physical significance of the phase lags and fractional order is elucidated. The thermoelastic responses are compared with those based on existing models. Finally, the effects of blood perfusion rate and laser velocity on temperature distribution and thermal stress response during percutaneous laser thermal ablation are analyzed.

Stromal Vascular Fraction Promotes Viability of Co-grafted Axial Skin Flaps in Rats Model.

Stromal vascular fraction (SVF) has been proved in promoting the vascularization of fascial flap through cell differentiation and paracrine effect and can be autologous transplanted without culture after isolation in vitro. We intend to establish a novel co-grafted flap model of rats to investigate the efficacy and mechanism of SVF on flaps and skinsin facilitating angiogenesis and immune regulation. 60 female Sprague Dawley rats were divided into the SVF group and the control group. A pedicled fascial flap combined with a free skin model was established, and 4×106 CM-DIl labeled SVF cells were transplanted into the fascia flap; the rats were executed on days 1, 2, 3, 7, 10 postoperatively (n=6). Flow cytometry was carried out to determine the cell proportion and surface marker of SVFs. The therapeutic effects of SVF were evaluated via Doppler blood perfusion imager, flap survival rates, histology, immunohistochemistry and immunofluorescence. The bioinformatic mechanism analysis was achieved by high-throughput RNAseq of mRNA and LncRNA. Flow cytometry confirmed SVF contains heterogeneous cellular composition, especially hematopoietic cells. Doppler blood perfusion imager showed SVF significantly improved flap survival with higher blood perfusion and survival rates. Immunohistochemistry of CD31 displayed higher level of angiogenesis in SVF-treated group, and CM-DIL-labeled SVF cells could survive and participate in revascularization, and RNA sequencing results revealed SVF promoted wound healing by facilitating intercellular adhesion, cell migration and positive immune response. SVF could reduce skin flap necrosis and activated neovascularization in rats by facilitating intercellular adhesion, cell migration and regulate positive immune response. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Development and characterization of a chick embryo chorioallantoic membrane (CAM) based platform for evaluation of vasoactive medications.

Among various anti-cancer therapies, tumor vascular disrupting agents (VDAs) play a crucial role, for which their off-targeting effects on normal vessels need also to be investigated. The purpose of this study was to set up an in-ovo platform that combines a laser speckle contrast imaging (LSCI) modality with chick embryo chorioallantoic membrane (CAM) to real-time monitor vascular diameters and perfusion without and with intravascular injection. Two eggshell windows for both observation or measurement and injection were opened. Dynamic blood perfusion images and corresponding statistic graphs were acquired by using a LSCI unit on CAMs from embryo date (ED) 9 to ED15. A dedicated fine needle catheter was made for slow intravascular administration over 30min with simultaneous LSCI acquisition. To verify the connectivity between CAM vessels and the embryonic circulations in the egg, contrast-enhanced 3D micro computed tomography (μCT), 2D angiography and histology were executed. This platform was successfully established to acquire, quantify and demonstrate vascular and hemodynamic information from the CAM. Chick embryos even with air cell opened remained alive from ED9 to ED15. Through collecting LSCI derived CAM vascular diameter and perfusion parameters, ED12 was determined as the best time window for vasoactive drug studies. A reverse correlation between CAM vessel diameter and blood perfusion rate was found (p<0.002). Intravascular infusion and simultaneous LSCI acquisition for 30min in ovo proved feasible. Contrast-enhanced angiography and histomorphology could characterize the connectivity between CAM vasculature and embryonic circulation. This LSCI-CAM platform was proved effective for investigating the in-ovo hemodynamics, which paves the road for further preclinical research on vasoactive medications including VDAs.

Effect of Blood Perfusion on Temperature Distribution in the Multilayer of the Human Body with Interstitial Hyperthermia Treatment for Tumour Therapy

Blood perfusion is defined as the volume of blood flowing through units of tissue volume per second. In thermoregulation, blood perfusion is a factor that affects heat transfer in the body, the greater the rate of blood perfusion will complicate the distribution of temperature throughout the body. In the study of bioheat transfer, heat transfer in the human body can be used as a therapy. At therapeutic temperatures (above 40°C), cells will die and stop their growth or commonly called hyperthermia therapy. It can allow thermonecrosis in body tissues and can be useful for tumour tissue. Of the various types of hyperthermia therapy, interstitial hyperthermia therapy is considered more effective because heat is directly delivered to tumour tissue to minimize other tissues exposed to therapeutic temperatures. Currently, there are no studies that study the effect of blood perfusion on the treatment of interstitial hyperthermia, even though blood perfusion greatly affects the temperature distribution in the human body/ In this study, heat transfer analysis will be performed on five layers of the human body, namely the epidermis, dermis, fat, muscle, and bones with interstitial application of hyperthermia therapy and affected by blood perfusion with a value of (8x10-4; 4x10-4; 2x10-4; 1x10-3; and 2x10-3)/s completed using finite element method with unsteady conditions in two axial dimensions. The part of the tumour studied is a tumour in the arm (forearm) in the span of 600s. This study shows that blood perfusion affects the value of temperature distribution in five layers of the body in unsteady conditions. The greater the value of blood perfusion flowing in the body, the more difficult the temperature will be to transmit because the blood distributes heat throughout the body faster, the difference between blood perfusion values is quite significant.

Numerical estimation of temperature response with step heating of a multi-layer skin under the generalized boundary condition

In this article, we discussed a one-dimensional bioheat transfer mathematical model that describes the process of temperature distribution in tissue for the multi-layer skin under the step heating generalized boundary condition. The finite difference scheme is used to estimate the temperature profile along with time and distance. We discussed the stability of the numerical scheme and also validated the accuracy of the numerical code by comparing the present results with the previous reference results. To remove heat from the skin is considered by the surface temperature, heat flux, and ambient temperature to be zero with the help of the unit step like function. Then, we observed that the skin temperature in the second kind boundary condition was slowly decreasing over time as compared to the first and third kind boundary conditions. The temperature or heat flux at the skin surface is assumed to be high then there is negligible effect of the blood perfusion rate on the temperature response over a short time period and the effect of blood perfusion rate is visible when the time duration is long. Effect of blood perfusion rate, heating and after removal of heating, water diffusion, and generalized boundary condition for the analysis of the behavior of temperature response in multi-layer skin are discussed in detail and the results obtained are presented graphically.

Effect of bio-tissue deformation behavior due to intratumoral injection on magnetic hyperthermia

Thermal damage of malignant tissue is generally determined not only by the characteristics of bio-tissues and nanoparticles but also the nanofluid concentration distributions due to different injection methods during magnetic hyperthermia. The latter has more advantages in improving the therapeutic effect with respect to the former since it is a determining factor for the uniformity of nanofluid concentration distribution inside the tumor region. This study investigates the effect of bio-tissue deformation due to intratumoral injection on the thermal damage behavior and treatment temperature distribution during magnetic hyperthermia, in which both the bio-tissue deformation due to nanofluid injection and the mass diffusion after injection behavior are taken into consideration. The nanofluid flow behavior is illustrated by two different theoretical models in this study, which are Navier–Stokes equation inside syringe needle and modified Darcy’s law inside bio-tissue. The diffusion behavior after nanofluid injection is expressed by a modified convection–diffusion equation. A proposed three-dimensional liver model based on the angiographic data is set to be the research object in this study, in which all bio-tissues are assumed to be deformable porous media. Simulation results demonstrate that the injection point for syringe needle can generally achieve the maximum value in the tissue pressure, deformation degree, and interstitial flow velocity during the injection process, all of which then drop sharply with the distance away from the injection center. In addition to the bio-tissue deformation due to injection behavior, the treatment temperature is also highly relevant to determine both the diffusion duration and blood perfusion rate due to the thermal damage during the therapy.

Review of Thermal and Physiological Properties of Human Breast Tissue.

Electromagnetic thermal therapies for cancer treatment, such as microwave hyperthermia, aim to heat up a targeted tumour site to temperatures within 40 and 44 °C. Computational simulations used to investigate such heating systems employ the Pennes’ bioheat equation to model the heat exchange within the tissue, which accounts for several tissue properties: density, specific heat capacity, thermal conductivity, metabolic heat generation rate, and blood perfusion rate. We present a review of these thermal and physiological properties relevant for hyperthermia treatments of breast including fibroglandular breast, fatty breast, and breast tumours. The data included in this review were obtained from both experimental measurement studies and estimated properties of human breast tissues. The latter were used in computational studies of breast thermal treatments. The measurement methods, where available, are discussed together with the estimations and approximations considered for values where measurements were unavailable. The review concludes that measurement data for the thermal and physiological properties of breast and tumour tissue are limited. Fibroglandular and fatty breast tissue properties are often approximated from those of generic muscle or fat tissue. Tumour tissue properties are mostly obtained from approximating equations or assumed to be the same as those of glandular tissue. We also present a set of reliable data, which can be used for more accurate modelling and simulation studies to better treat breast cancer using thermal therapies.

Surface temperature analysis and thermophysical property estimation for breast cancer by deep learning

The breast cancer will affect the skin surface temperature profile, whose thermophysical properties are very important for the diagnose of the disease. The temperature on the skin surface is analyzed by a 3-D layered breast model with variable metabolic heat generations and blood perfusion rates. The thermophysical properties of the breast are estimated by deep learning. The relationship between the temperature profiles and the thermophysical properties of the cancer is revealed. The research shows that infrared thermography with deep learning is a useful diagnostic tool for the breast cancer.

Thermoelastic response of skin using time-fractional dual-phase-lag bioheat heat transfer equation

In this paper, a time-fractional dual-phase-lag (DPL) bioheat heat conduction model is presented to treat thermoelastic response of skin subjected to sudden temperature shock. The skin tissue is treated as a monolayered thermoelastic material. A modified Pennes bioheat transfer equation with non-Fourier effect is introduced to capture the influence of blood perfusion rate in the skin tissue on temperature distribution. The transient response of the temperature field of skin tissue is derived analytically and calculated numerically. The mechanical response is considered and the elastic displacement induced by temperature change is evaluated. The effects of two relaxation times and fractional orders of heat flux and temperature gradient together with blood flow on the temperature distribution in the skin tissue are analyzed.

The blood heat exchanger in intra-arterial selective cooling infusion for acute ischemic stroke: A computational fluid-thermodynamics performance, experimental assessment and evaluation on the brain temperature

Intra-arterial selective cooling infusion with the autologous blood (IA-SCAI) is a promising therapeutic hypothermia induction method for conferring neuroprotection to acute ischemic stroke (AIS) patients. The blood heat exchanger (BHE) plays a crucial role in IA-SCAI's cooling capacity. However, there are no BHEs currently available that are specifically designed for the IA-SCAI, which requires a low blood flow to be compatible with cerebral hemodynamics. In an effort to develop a BHE for AIS patients, a prototype of a commercial BHE, Medtronic MYOtherm XP®, was mathematically modeled; specifically, computational fluid dynamics (CFD) was used to analyze its hemo- and thermo-dynamic characteristics under low blood flow including temperature distribution, velocity field and shear stress.Our numerical model predicted the hemolysis index to be 0.0041%–0.0581% inside the BHE with blood flows rates of 10 ml min−1–50 ml min−1. The in vitro heat transfer experiment showed that the BHE efficiently cooled the simulated blood from the initial 37 °C–5.8 °C within 150 s by using cold water (200 ml·min-1, 0 °C). The cooled simulated blood was able to cool the simulated blood in the middle cerebral artery of an artificial circulating system from 37 °C to 16.8 °C–33.7 °C depending on the blood perfusion rate (10–50 ml/min). A biological heat transfer mathematical model showed that brain tissue could be cooled by 2 °C within the initial 1min of infusion. This study verified the feasibility of using a commercial BHE for IA-SCAI and provided insights into its cooling capacity for therapeutic hypothermia.

Cerebral Blood Flow Disorder in Acute Subdural Hematoma and Acute Intraoperative Brain Bulge.

ContextAcute subdural hematoma (ASDH) has a high incidence and high mortality. During surgery for ASDH, brain tissue sometimes rapidly swells and protrudes into the bone window during or after removal of the hematoma. This phenomenon, known as acute intraoperative brain bulge, progresses rapidly and can cause ischemic necrosis of brain tissue or even mortality. The mechanism of this phenomenon remains unclear.ObjectiveTo investigate the changes in cerebral surface blood flow during ASDH and acute intraoperative brain bulge in rats.MethodsAdult male Sprague–Dawley rats were selected to establish an ASDH model, and acute intraoperative brain bulge was induced by late-onset intracranial hematoma. The changes in cerebral surface blood flow during ASDH and acute intraoperative brain bulge were observed with a laser speckle imaging system, and intracranial pressure (ICP) was monitored.ResultsICP in rats increased significantly after ASDH (P < 0.05). The blood perfusion rate (BPR) values of the superior sagittal sinus, collateral vein and artery decreased significantly in rats with subdural hematomas (P < 0.05). There was no significant difference between the preoperative and 90-min postoperative BPR values of rats. ICP was significantly increased in rats with acute intraoperative brain bulge (P < 0.05) and decreased significantly after the removal of delayed hematomas (P < 0.05). The BPR of the superior sagittal sinus, collateral vein and artery decreased significantly during brain bulge (P < 0.05). After the removal of delayed hematomas, BPR increased significantly, but it remained significantly different from the values measured before brain bulge (P < 0.05).ConclusionASDH may cause not only high intracranial pressure but also cerebral blood circulation disorders. Brain bulge resulting from late-onset intracranial hematoma may aggravate these circulation disorders. If the cause of brain bulge in a given patient is late-onset intracranial hematoma, clinicians should promptly perform surgery to remove the hematoma and relieve circulation disorders, thus preventing more serious complications.

APPLICATION OF STOCHASTIC PARTICLE SWARM OPTIMIZATION ALGORITHM FOR NONINVASIVE DETERMINATION OF TEMPERATURE-DEPENDENT THERMAL PROPERTIES OF BIOLOGICAL TISSUE

The knowledge of thermal properties of biological tissue is of great importance to medical diagnosis and thermotherapy. In this study, an inverse model based on stochastic particle swarm optimization (SPSO) algorithm and sensitivity analysis is developed to determine the temperature-dependent thermal properties of one-dimensional biological tissue. The noninvasive determination task is formulated as an inverse problem which is solved by the SPSO algorithm from the knowledge of surface temperature measurements. A logistic mapping strategy is introduced to improve the quality of the initial particle swarm. Retrieval results demonstrate that the developed inverse technique is robust to determine the temperature-dependent thermal conductivity, specific heat and blood perfusion rate of biological tissue. The maximum relative error of the simultaneous determination results is less than 0.8%. The maximum determination error is 1.15% when a 3% random deviation is considered. Meanwhile, the present SPSO algorithm is proved to be more efficient and accurate than other intelligent algorithms. Considering the convergence accuracy and computational time, the population size of the SPSO algorithm is suggested to be M = 80.

Simultaneous quantification of anthraquinone glycosides, aglycones, and glucuronic acid metabolites in rat plasma and tissues after oral administration of raw and steamed rhubarb in blood stasis rats by UHPLC-MS/MS.

Rhubarb is a widely used herbal medicine. To achieve different effects, rhubarb is usually steamed with rice wine (steamed rhubarb). This steaming treatment increases the blood-activating and stasis-removing effects of rhubarb. A specific and accurate ultra high performance liquid chromatography with tandem mass spectrometry method was established for simultaneous determination of anthraquinone glycosides, aglycones, and glucuronic acid metabolites in plasma and tissues after administration of raw rhubarb and steamed rhubarb in blood stasis rats. Chromatographic separation was performed on ACQUITY UPLC BEH Shield RP 18 column using the mobile phase consisting of water and acetonitrile both containing 0.1% formic acid. Satisfactory linearity, precision, accuracy, extraction recovery, and matrix effect have been achieved. From pharmacokinetic study, it showed that glucuronic acid metabolites were found abundantly in plasma as bioactive components. The lower area under concentration-time curve, maximum concentration, and higher apparent volume of distribution (P<0.01), body clearance (P<0.01) values in steamed rhubarb showed that most components of steamed rhubarb have lower bioavailability in plasma compared with raw rhubarb. But it found these components were mainly distributed in spleen and liver with large blood flow and perfusion rates. The pharmacokinetics and tissue distribution studies of anthraquinone components will provide helpful information for clinical application of steamed rhubarb and raw rhubarb.

Theoretical evaluation of bio-thermal response in human tissue subjected to pulse-laser induced hyperthermia therapy for cancer treatment

This paper aims to develop a theoretical estimation of thermal response in human tissues appearing in a hyperthermia treatment under the influence of laser-induced external heat sources. In general, to develop a theoretical investigation on bioheat transfer, the fundamental aspect is to adopt an appropriate thermal model for predicting the correct thermal response. Among the existing bioheat models, the two-temperature model is considered to be the most feasible one, as it takes into account the arterio-vascular architectural interaction in the analysis. This model is established based on the local thermal non-equilibrium (LTNE) approach. The exact solution of the two-temperature bioheat model has been established by the implementation of the combined scheme of Duhamel's theorem and the Finite integral transform method. A pulse laser heating applied externally as a therapeutic heat source is introduced newly in the area of the LTNE bioheat modelling whereas the existing research works were developed by utilizing scattering laser heat sources. The thermal response of the tissue is analyzed for different laser variables such as laser intensity, optical penetration depth, pulse laser time, and laser irradiation radius. A parametric study has been made to set a theoretical treatment protocol for hyperthermia therapy and correspondingly, the thermal field has been developed within the prescribed peak temperature spectrum for the hyperthermia treatment. The thermal field has also been investigated for various biological parameters, viz. blood perfusion rate, porosity, and pore diameter of the blood vessel. The present research outcome depicts that the hyperthermia temperature can be achieved at the optical penetration depth of 0.0005 m with the laser irradiation radius in the range of 0.004 m–0.008 m. From the present work, it can be highlighted that the health monitoring of infected tissues or the organ of the human body is necessary before processing therapeutic heating as the thermal field depends on the porosity of tissue significantly. A qualitative investigation between pulse heating and scattering laser heating depicts that pulse laser heating is a better option to choose for the thermal therapy for the curtailment of the possibility of thermally induced damage of healthy tissues. A successful verification and authentication study has been carried out between the present work and the published experimental and theoretical works.

An optimization method for magnetic hyperthermia considering Nelder-Mead algorithm

Magnetic hyperthermia destroys malignant cells by absorbing the heat generated by magnetic nanoparticles (MNPs) under an external AC magnetic field. One of the most influencing factors for such therapy is to control the heat generation within MNPs, which is highly relevant to applied AC magnetic field and used MNPs during treatment. This paper optimizes the intensity of magnetic field acting on MNPs by considering an optimum power dissipation of MNPs, which is obtained by using Nelder-Mead algorithm for a proposed objective function during the optimization procedure. The aim of the proposed objective function is to minimize the difference between the maximum treatment temperature and its upper safety value as much as possible. The optimization results can be used to investigate the injury degree for the proposed model by Arrhenius thermal damage model, and also to optimize the performance for the magnetic field strength on MNPs by the implicit function due to Rosensweig’s theory in this study. Simulation results demonstrate that the power dissipation of MNPs can quickly converge to an optimum value after less iterations during the optimization process, which can also result in an ideal treatment temperature profile and can further obtain the injury degree for different malignant cells, when a temperature-dependent blood perfusion rate is considered for the simulation. The magnetic field or the MNPs can also be optimized before the therapy under this optimal power dissipation for MNPs at this time. In addition, this study also reveals the evolution of treatment temperature due to two blood perfusion rates, namely temperature-dependent and constant models.