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Microwave ablation is a therapeutic technique that kills tumors by inducing heat generation in biological tissue through microwave emissions. Microwave ablation is a minimally invasive treatment technique, which has the advantage of treating deeply located tumors with less bleeding than traditional surgical techniques. In this study, the therapeutic effect of microwave ablation was analyzed from the perspective of the temperature range where apoptosis and necrosis occur. Through the numerical modelling, the tumor located inside the liver tissue was implemented, and the temperature distribution in the hepatic tissue was calculated by varying value of the microwave frequency, microwave antenna input power, and the insertion depth of the microwave coaxial antenna. Microwave frequencies were selected as 915, and 2450 MHz, and the insertion depth of the microwave coaxial antenna was set at a distance difference between the tumor tip and the slot of 4 to 16 mm. In addition, the microwave antenna input power was set to a range of 0 to 60 W. Based on the obtained temperature distribution, the apoptotic variables, which are parameters specifically defined apoptosis ratios that can quantitatively verify the therapeutic effect, were calculated to derive the microwave ablation treatment condition that maximizes the therapeutic effect for each microwave frequency. Through the quantitative analysis of apoptotic variables, the optimal conditions for maximum therapeutic effect were derived for each microwave frequency analyzed in this study. For frequencies of 915 MHz, the optimal insertion depth of the antenna is 8 mm above the bottom of the tumor, and the optimal microwave input power is 40 W. For 2450 MHz, the optimal insertion depth and input power were found to be 4 mm and 4 W, respectively. Ultimately, it is expected that the results presented in this study will lead to more improved treatment of microwave ablation in practice., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Recent advances in technology have led to an increase in the detection of previously undetected deep-located tumor tissue. As a result, the medical field is using a variety of methods to treat deep-located tumors, and minimally invasive treatment techniques are being explored. In this study, therapeutic effect of microwave ablation (MWA) on tumor generated inside liver tissue was analyzed through numerical analysis. The distribution of electromagnetic fields in biological tissues emitted by microwave coaxial antenna (MCA) was calculated through the wave equation, and the thermal behavior of the tissue was analyzed through the Pennes bioheat equation. Among various treatment conditions constituting MWA, tumor radius and the slot length inside the MCA were changed, and the resulting treatment effect was quantitatively confirmed through three apoptotic variables. As a result, each tumor radius has optimal power condition for MWA, 2.6W, 2.4W, and 3.0W respectively. This study confirmed optimal therapeutic conditions for MWA. Three apoptotic variables were used to quantitatively identify apoptotic temperature maintenance inside tumor tissue and thermal damage to surrounding normal tissue. The findings of this study are expected to serve as a standard for treatment based on actual MWA treatment., (© 2024. International Federation for Medical and Biological Engineering.)

Ultrasound (US) stimulated microbubbles (MB) is a new treatment approach that sensitizes cancer cells to radiation (XRT). The molecular pathways in this response remain unelucidated, however, previous data has supported a role for cell membrane-metabolism related pathways including an up regulation of UDP glycosyltransferase 8 (UGT8), which catalyzes the transfer of galactose to ceramide, a lipid that is associated with the induction of apoptotic signalling. In this study, the role of UGT8 in responses of prostate tumours to ultrasound-stimulated microbubble radiation enhancement therapy is investigated. Experiments were carried out with cells in vitro and tumours in vivo in which UGT8 levels had been up regulated or down regulated. Genetically modified PC3 cells were treated with XRT, US+MB, or a combination of XRT+US+MB. An increase in the immunolabelling of ceramide was observed in cells where UGT8 was down-regulated as opposed to cells where UGT8 was either not regulated or was up-regulated. Clonogenic assays have revealed a decreased level of cellular survival with the down-regulation of UGT8. Xenograft tumours generated from stably transfected PC3 cells were also treated with US+MB, XRT or US+MB+XRT. Histology demonstrated more cellular damage in tumours with down-regulated UGT8 in comparison with control tumours. In contrast, tumours with up-regulated UGT8 had less damage than control tumours. Power Doppler imaging indicated a reduction in the vascular index with UGT8 down-regulation and photoacoustic imaging revealed a reduction in oxygen saturation. This was contrary to when UGT8 was up regulated. The down regulation of UGT8 led to the accumulation of ceramide resulting in more cell death signalling and therefore, a greater enhancement of radiation effect when vascular disruption takes place through the use of ultrasound-stimulated microbubbles.

Antimitotic agents, including Taxol, disrupt microtubule dynamics and cause a protracted mitotic arrest and subsequent cell death. Despite the broad utility of these drugs in breast cancer and other tumor types, clinical response remains variable. Tumor-associated macrophages (TAMs) suppress the duration of Taxol-induced mitotic arrest in breast cancer cells and promote earlier mitotic slippage. This correlates with a decrease in the phosphorylated form of histone H2AX (γH2AX), decreased p53 activation, and reduced cancer cell death in interphase. TAMs promote cancer cell viability following mitotic slippage in a manner sensitive to MAPK/ERK kinase (MEK) inhibition. Acute depletion of major histocompatibility complex class II low (MHCII lo ) TAMs increased Taxol-induced DNA damage and apoptosis in cancer cells, leading to greater efficacy in intervention trials. MEK inhibition blocked the protective capacity of TAMs and phenocopied the effects of TAM depletion on Taxol treatment. TAMs suppress the cytotoxic effects of Taxol, in part through cell non-autonomous modulation of mitotic arrest in cancer cells, and targeting TAM-cancer cell interactions potentiates Taxol efficacy., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to assess the efficacy of quantitative ultrasound imaging in characterizing cancer cell death caused by enhanced radiation treatments. This investigation focused on developing this ultrasound modality as an imaging-based non-invasive method that can be used to monitor therapeutic ultrasound and radiation effects. High-frequency (25 MHz) ultrasound was used to image tumor responses caused by ultrasound-stimulated microbubbles in combination with radiation. Human prostate xenografts grown in severe combined immunodeficiency (SCID) mice were treated using 8, 80, or 1000 µL/kg of microbubbles stimulated with ultrasound at 250, 570, or 750 kPa, and exposed to 0, 2, or 8 Gy of radiation. Tumors were imaged prior to treatment and 24 hours after treatment. Spectral analysis of images acquired from treated tumors revealed overall increases in ultrasound backscatter intensity and the spectral intercept parameter. The increase in backscatter intensity compared to the control ranged from 1.9±1.6 dB for the clinical imaging dose of microbubbles (8 µL/kg, 250 kPa, 2 Gy) to 7.0±4.1 dB for the most extreme treatment condition (1000 µL/kg, 750 kPa, 8 Gy). In parallel, in situ end-labelling (ISEL) staining, ceramide, and cyclophilin A staining demonstrated increases in cell death due to DNA fragmentation, ceramide-mediated apoptosis, and release of cyclophilin A as a result of cell membrane permeabilization, respectively. Quantitative ultrasound results indicated changes that paralleled increases in cell death observed from histology analyses supporting its use for non-invasive monitoring of cancer treatment outcomes.

Background: Dexamethasone is a potent glucocorticoid with anti-inflammatory effects. Dexamethasone can protect ischemic cardiomyocytes from apoptosis. To apply the anti-apoptotic effect of dexamethasone to ischemic disease gene therapy, dexamethasone-conjugated polyethylenimine (PEI-Dexa) was synthesized and evaluated as an anti-apoptotic gene carrier., Methods: PEI-Dexa was synthesized with low molecular weight polyethylenimine (PEI2K, 2 kDa). The transfection efficiency and cytotoxicity of PEI-Dexa were evaluated by luciferase assay and the MTT assay. To evaluate the anti-apoptotic effect, PEI-Dexa/DNA complex was transfected into cells and the cells were treated with H(2)O(2). Cell viability and apoptosis level were measured by the MTT assay and caspase-3 assay, respectively., Results: A transfection assay into H9C2 rat cardiomyocytes showed that PEI-Dexa had the highest transfection efficiency at an 8 : 1 weight ratio (PEI-Dexa/DNA). At this ratio, PEI-Dexa had higher transfection efficiency than high molecular polyethylenimine (PEI25K, 25 kDa) and PEI2K. In addition, the cytotoxicity of PEI-Dexa was lower than that of PEI25K. To evaluate the anti-apoptotic effect, PEI-Dexa/pSV-Luc or PEI2K/pSV-Luc was transfected into H9C2 cells and the cells were treated with H(2)O(2). PEI-Dexa was found to reduce caspase-3 activity and increase cell viability compared to PEI2K. Heme oxygenase-1 (HO-1) can protect ischemic cardiomyocytes from apoptosis. Therefore, pSV-HO-1 was cloned and transfected into H9C2 cells using PEI-Dexa. The cells transfected with PEI-Dexa/pSV-HO-1 complex had lower caspase-3 activity and higher viability than the cells transfected with PEI-Dexa/pSV-Luc complex after the H(2)O(2) treatment., Conclusions: PEI-Dexa is an efficient gene carrier with an anti-apoptotic effect and may be useful for anti-apoptotic gene therapy in combination with pSV-HO-1., ((c) 2009 John Wiley & Sons, Ltd.)

Microwave ablation (MWA) is based on the energy absorbed by biological tissue through microwave emission, which raises the temperature of the tumor to perform the treatment. MWA has the advantage of causing minimal bleeding and treating deep tumors. In this study, MWA for various slot design situations in a microwave coaxial antenna (MCA) was simulated through numerical analysis. For the slot design, the number of slots and the distance between slots were determined by the analysis parameters. A tumor developed inside the liver tissue was implemented, and the temperature distribution of the tumor and surrounding liver tissue was calculated for all cases selected for numerical analysis. The Helmholtz electromagnetic equation was used to calculate the electromagnetic field inside the tissue, and the modified Pennes bioheat equation was used to calculate the temperature change in the tissue due to the emitted microwave. Treatment effects were quantitatively analyzed for each slot design condition through an apoptotic variable based on the calculated temperature distribution. Lastly, conditions that produce optimal treatment effects were derived depending on the number of slots. The analysis showed that as the distance between the slots increased from 0.5 to 3.5 mm, the optimal treatment effect was obtained when the number of slots was 4, 3, 3, and 2, respectively, and the microwave input power at that time was 3.0, 2.8, 2.6, and 3.0 W, respectively. This is expected to allow for more rigorous and more therapeutically effective MWA. [ABSTRACT FROM AUTHOR]

Anticancer treatment is performed in various ways, and photothermal therapy (PTT) is gaining traction from a noninvasive treatment perspective. PTT is a treatment technique based on the photothermal effect that kills tumors by increasing their temperature. In this study, gold nanoparticles (AuNPs), which are photothermal agents, were used in numerical simulations to determine the PTT effect by considering diffusion induced changes in the distribution area of the AuNPs. The treatment effect was confirmed by varying the initial injection radius of AuNPs represented by the injection volume, the elapsed time after injection of AuNPs, and the laser intensity. The degree of maintenance of the apoptotic temperature band in the tumor was quantitatively analyzed by the apoptotic variable. Ultimately, if the initial injection radius of AuNPs is 0.7 mm or less, the optimal time to start treatment is 240 min after injection, and for 1.0 and 1.2 mm, it is optimal to start treatment when the elapsed time after injection is 90 and 30 min, respectively. This study identified the optimal treatment conditions for dosage of AuNPs and treatment start time in PTT using AuNPs, which will serve as a reference point for future PTT studies. [ABSTRACT FROM AUTHOR]

Recently, the incidence of skin cancer has been increasing owing to the development of science and technology and the increase in outdoor activities. Research on photothermal therapy as a treatment technique for similar skin cancer is in progress. Photothermal therapy is a treatment technique that removes tumor tissue by increasing the temperature. It has the advantage of rapid recovery and a low risk of secondary infection. In this study, a numerical investigation of photothermal therapy based on heat transfer is conducted on squamous cell carcinoma present inside the skin layer. Analysis is performed by varying the number of injections of gold nanoparticles, volume fraction of gold nanoparticles in the tumor, and laser intensity. In addition, conditions for maximizing expression of apoptosis in the tumor and minimizing amount of thermal damage to surrounding normal tissues are identified through the variable which is apoptosis retention ratio, thermal hazard value and effective apoptosis retention ratio. It was confirmed that the optimal therapeutic effect was shown when the volume fraction of injected GNPs was 10−3, the number of injections was 6 times, and the irradiated laser intensity was 140 mW for the tumor presented in this study. Ultimately, these results are expected to accelerate the commercialization of photothermal therapy. [ABSTRACT FROM AUTHOR]

Photothermal therapy is a new chemotherapy technique using photothermal effects, a phenomenon in which light energy is converted into thermal energy. Since the treatment technique is performed without surgical incision, it does not cause bleeding and patients are expected to make rapid recoveries, which are significant advantages. In this study, photothermal therapy with direct injection of gold nanoparticles into tumor tissue was simulated through numerical modeling. The treatment effect resulting from changing the intensity of the irradiated laser, volume fraction of the injected gold nanoparticles, and number of gold nanoparticle injections was quantitatively evaluated. The discrete dipole approximation method was applied to calculate the optical properties of the entire medium, and the Monte Carlo method was applied to identify the absorption and scattering behavior of lasers in tissue. In addition, by confirming the temperature distribution of the entire medium through the calculated light absorption distribution, the treatment effect of photothermal therapy was evaluated, and the optimal treatment conditions were suggested. This is expected to accelerate the popularization of photothermal therapy in the future. [ABSTRACT FROM AUTHOR]

Photothermal therapy is a treatment technique that has attracted attention as an alternative to conventional surgical techniques. It is based on the photothermal effect, wherein light energy is converted into thermal energy, and facilitates rapid recovery after treatment. This study employed various laser irradiation conditions and presented conditions with the optimal treatment effects through a numerical analysis based on heat transfer. A skin layer comprising four stages containing squamous cell carcinoma was targeted, and the treatment effect was confirmed by varying the heating conditions of the laser and volume fraction of gold nanoparticles. The therapeutic effect was confirmed through both the apoptosis retention ratio, which quantitatively estimated the degree of maintenance of the apoptosis temperature range within the tumor, and the thermal hazard retention value, which quantitatively calculates the amount of thermal damage to the surrounding normal tissues. Finally, the optimal treatment conditions were determined based on the laser intensity, cooling time ratio, and volume fraction of injected gold nanoparticles through numerical analysis. [ABSTRACT FROM AUTHOR]

The photothermal effect refers to a phenomenon in which light energy is converted into heat energy, and in the medical field, therapeutics based on this phenomenon are used for anticancer treatment. A new treatment technique called photothermal therapy kills tumor tissue through a temperature increase and has the advantages of no bleeding and fast recovery. In this study, the results of photothermal therapy for squamous cell carcinoma in the skin layer were analyzed numerically for different laser profiles, intensities, and radii and various concentrations of gold nanoparticles (AuNPs). According to the heat-transfer theory, the temperature distribution in the tissue was calculated for the conditions under which photothermal therapy was performed, and the therapeutic effect was quantitatively confirmed through three apoptotic variables. In addition, the laser intensity and the volume fraction of AuNPs were optimized, and the results provide useful criteria for optimizing the treatment effects in photothermal therapy. [ABSTRACT FROM AUTHOR]

Nanosized materials are used in various industries, depending on their production form. In the medical field, nanosized particles are used for treatment. Among various treatment techniques, photothermal therapy (PTT) uses nanoparticles as photothermal agents (PTAs). In this study, the effectiveness of PTT using noble-metal PTAs with various materials and radii was analyzed using numerical analysis. For squamous cell carcinoma within the skin layer, the thermal behavior of the medium was analyzed when PTT was performed by varying the material and radius of the noble-metal PTAs, the volume fraction of the injected PTAs, and the intensity of the irradiating laser. The optical properties of the PTAs and tissue and the temperature distribution in the tissue under laser irradiation were calculated using the discrete dipole approximation method, the Dombrovsky relation, and the Pennes bioheat equation. In addition, an apoptotic variable was derived based on the calculated temperature distribution, and the optimal treatment conditions for each PTAs material were analyzed. The results of the study showed that the maximum therapeutic effect was achieved at a volume fraction of 10−6 and laser intensity of 0.16 W when all PTAs were used, and the difference in therapeutic effect was insignificant with respect to the radius of the nanoparticles. Accordingly, an accurate PTT can be performed using each PTAs material if the proposed treatment conditions are applied. • Optimization of treatment conditions for skin cancer photothermal therapy. • Squamous cell carcinoma presented in tumor. • Effective apoptosis retention ratio for optimization of photothermal therapy. • Various noble-metal nanoparticles for photothermal agents. • Numerical analysis based on heat transfer to induce apoptosis in tumor. [ABSTRACT FROM AUTHOR]

The incidence of skin cancer is increasing with the recent increase in UV exposure. The treatment of skin cancer generally proceeds through an excision of the tumor area, which causes bleeding into the affected area and surrounding tissues, and there is a possibility that secondary infection may occur. Photothermal therapy is drawing attention as an alternative treatment to overcome this limitation. In this study, a numerical analysis was performed on skin cancer tumors located between the reticular dermis and the skin surface by applying the Monte Carlo method. The numerical analysis derives a quantitative correlation using an effective apoptosis ratio with respect to the intensity of the laser that produces the optimal photothermal therapy effect and the volume fraction of gold nanorods (GNRs) injected into a tumor. Through this study, it is confirmed that the optimal treatment effect exists for the depth and length of the various tumors, the intensity of the laser, and the volume fraction of GNRs to minimize the thermal damage to the surrounding normal tissues while maximizing the apoptosis in the tumor. It is expected that it can be used as an optimal condition for better treatment while performing photothermal therapy in the future. [ABSTRACT FROM AUTHOR]

• Optimization of treatment conditions for skin cancer photothermal therapy. • Multiple blood vessels presented in tumor by angiogenesis. • Effective apoptosis retention ratio for optimal photothermal therapy was determined. • Numerical analysis based on heat transfer to induce apoptosis was conducted. • Tumor apoptosis and thermal damage to surrounding normal tissue were quantified. In recent years, lasers have gained considerable attention as a potential treatment option in the medical field. Photothermal therapy, in particular, has been investigated as a technique to remove tumor tissue by leveraging photothermal effects. The method involves raising the temperature of the tumor tissue to destroy it and has primarily been studied for skin cancer treatment. This study aimed to simulate a skin layer with squamous cell carcinoma by using numerical modeling and investigate the effect of different numbers of blood vessels on the temperature distribution in the medium under conditions such as varied laser intensity and gold nanoparticle volume fraction. Optical properties of the light absorption enhancer were calculated using the discrete dipole approximation method, and the temperature and velocity distribution were computed using continuity, momentum, and energy equations. Quantitative determination of the apoptotic variable was performed to evaluate the treatment effect for each case, and the treatment condition with the maximum treatment effect was identified. Laser intensity with optimal therapeutic effect was confirmed to be 0.13 W, 0.15 W, 0.18 W, and 0.24 W, depending on the number of vessels, respectively, and the volume fraction of injected GNRs was confirmed to be 10−6 for all vessel numbers. The results of this study can serve as a guide for selecting appropriate treatment conditions when conducting photothermal therapy in the future [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: We show here that ultrasound-stimulated microbubbles can enhance cell death within tumors when combined with radiation. The aim of this study was to investigate how different ultrasound parameters, different microbubble concentrations and different radiation doses interact to enhance cell death. Prostate xenograft tumors (PC-3) in severe combined immunodeficiency mice were subjected to ultrasound treatment at various peak negative pressures (250, 570 and 750 kPa) at a center frequency of 500 kHz, different microbubble concentrations (8, 80 and 1000 μL/kg) and different radiation doses (0, 2 and 8 Gy). Twenty-four hours after treatment, tumors were excised and assessed for cell death. Histologic analyses revealed that increases in radiation dose, microbubble concentration and ultrasound pressure promoted apoptotic cell death and disruption within tumors by as much as 21%, 30% and 43%, respectively. Comparable increases in ceramide, a cell death mediator, were identified using immunohistochemistry. We also show here that even clinically used microbubble concentrations combined with ultrasound can induce significant enhancement of cell death. [Copyright &y& Elsevier]

Due to increased exposure to ultraviolet radiation caused by increased outdoor activities, the incidence of skin cancer is increasing. Incision is the most typical method for treating skin cancer, and various treatments that can minimize the risks of incision surgery are being investigated. Among them, photothermal therapy is garnering attention because it does not cause bleeding and affords rapid recovery. In photothermal therapy, tumor death is induced via temperature increase. In this study, a numerical study based on heat transfer theory was conducted to investigate the death of squamous cell carcinoma located in the skin layer based on various shapes of gold nanoparticles (AuNPs) used in photothermal therapy. The quantitative correlation between the conditions of various AuNPs and the laser intensity that yields the optimal photothermal treatment effect was derived using the effective apoptosis ratio. It was confirmed that optimal conditions exist for maximizing apoptosis within a tumor tissue and minimizing the thermal damage to surrounding normal tissues when using AuNPs under various conditions. Furthermore, it is envisioned that research result will be utilized as a standard for photothermal treatment in the future. [ABSTRACT FROM AUTHOR]

• Numerical analysis based on heat transfer to induce apoptosis. • Determine the tendency of photothermal therapy based on vessel diameter. • Single blood vessels presented in tumor with various diameter. • Intratumoral apoptosis and thermal damage to surrounding normal tissue analysis. Recently, usage of nanoparticles, nanometer sized materials, in several therapeutic techniques including photothermal therapy, which uses elevated temperatures to kill tumor tissue, is on the rise. In this study, implementation of photothermal therapy for blood vessels of various diameters, present in the skin layer of squamous cell carcinoma, is simulated using numerical analysis. The optical properties of the nanoparticles were calculated using the discrete dipole approximation method, and the optical properties of the medium were calculated using the optical coefficients calculation method of a composite medium. The calculated optical properties revealed the temperature distribution in the medium using the energy equation, and the flow rate of blood through various vessel diameters using the continuity and momentum equations. Finally, the calculated temperature distribution was used to quantitatively confirm the therapeutic effect of different photothermal treatment conditions through the apoptotic variable. This is expected to serve as a standard for selecting optimal treatment conditions when performing actual photothermal therapy in the future. [ABSTRACT FROM AUTHOR]

Recently, photothermal therapy has attracted attention as an alternative treatment to conventional surgical techniques because it does not lead to bleeding and patients quickly recover after treatment compared to incisional surgery. Photothermal therapy induces tumor cell death through an increase in the temperature using the photothermal effect, which converts light energy into thermal energy. This study was conducted to perform numerical analysis based on heat transfer to induce apoptosis of tumor tissue under various heating conditions in photothermal therapy. The Monte Carlo method was applied to evaluate a multi-layered skin structure containing squamous cell carcinoma. Tissue-equivalent phantom experiments verified the numerical model. Based on the effective apoptosis retention ratio, the numerical analysis results showed the quantitative correlation for the laser intensity, volume fraction of gold nanorods injected into the tumor, and cooling time. This study reveals optimal conditions for maximizing apoptosis within tumor tissue while minimizing thermal damage to surrounding tissues under various heating conditions. This approach may be useful as a standard treatment when performing photothermal therapy. [ABSTRACT FROM AUTHOR]

Photothermal therapy can serve as an alternative to classic surgery in the treatment of patients with cancer. However, using photothermal therapy can result in local overheating and damage to normal tissues. Therefore, it is important to determine effective heating conditions based on heat transfer. In this study, we analyzed laser–tissue interactions in gold nanoparticle (GNP)-enhanced photothermal therapy based on the theory of heat transfer. The thermal behavior inside tissues during photothermal therapy was analyzed using numerical analysis. The apoptosis ratio was defined by deriving the area having a temperature distribution between 43 °C and 50 °C, which is required for inducing apoptosis. Thermal damage, caused by local heating, was defined using the thermal hazard value. Using this approach, we confirmed that apoptosis can be predicted with respect to tumor size (aspect ratio) and heating conditions (laser intensity and radius) in photothermal therapy with a continuous-wave laser. Finally, we determined the effective apoptosis ratio and thermal hazard value of normal tissue according to tumor size and heating conditions, thereby establishing conditions for inducing maximal levels of cell apoptosis with minimal damage to normal tissue. The optimization conditions proposed in this study can be a gentle and effective treatment option for photothermal therapy. [ABSTRACT FROM AUTHOR]