The influence of microwave ablation parameters on the positioning of trocar in different cancerous tissues: a numerical study.

The present study analyzed the microwave ablation of cancerous tumors located in six major cancer-prone organs and estimated the significance of input power and treatment time parameters in the apt positioning of the trocar into the tissue during microwave ablation. The present study has considered a three-dimensional two-compartment tumour-embedded tissue model. FEA based COMSOL Multiphysics software with inbuilt bioheat transfer, electromagnetic waves, heat transfer in solids and fluids, and laminar flow physics has been used to obtain the numerical results. Based on the mortality rates caused by cancer, the present study has considered six major organs affected by cancer, viz. lung, breast, stomach/gastric, liver, liver (with colon metastasis), and kidney for MWA analysis. The input power (100 W) and ablation times (4 minutes) with apt and inapt positioning of the trocar have been considered to compare the ablation volume of various cancerous tissues. The present study addresses one of the major problems clinicians face, i.e. the proper placement of the trocar due to poor imaging techniques and human error, resulting in incomplete tumor ablation and increased surgical procedures. The highest values of the ablation region have been observed for the liver, colon metastatic liver and breast cancerous tissues compared with other organs at the same operating conditions.

The present study has investigated the application of microwave ablation for cancer treatment in six major organs, specifically emphasizing the evaluation of ablation volume during the procedure. Using COMSOL-Multiphysics software, the study has investigated MWA of tumor embedded organs in the lung, breast, stomach, liver, and kidney. The positioning of the trocar, a crucial element in the treatment process, has been examined to address challenges in effectively ablating tumors.From the results, it has been revealed that liver, colon metastatic liver, and breast cancer tissues exhibited the largest areas of ablation volume compared with other organs.Organs like the breast and hepatic glands, characterized by lower heat capacity and density, have shown larger ablation zones. Trocar positioning significantly influenced the stomach, liver, and kidney, where improper placement led to notable increases in ablation volume, posing a risk of unintended damage to healthy tissue.Further, the study has concluded that precise trocar positioning plays a crucial role in optimizing microwave ablation. This precision has the potential to enhance the effectiveness of cancer treatments while minimizing harm to healthy tissue. The insights gained from this research offer valuable information for clinicians looking to enhance the precision of cancer therapies, ultimately aiming for improved outcomes for patients.

Advances and challenges in organ-on-chip technology: toward mimicking human physiology and disease in vitro.

Organs-on-chips have been tissues or three-dimensional (3D) mini-organs that comprise numerous cell types and have been produced on microfluidic chips to imitate the complicated structures and interactions of diverse cell types and organs under controlled circumstances. Several morphological and physiological distinctions exist between traditional 2D cultures, animal models, and the growing popular 3D cultures. On the other hand, animal models might not accurately simulate human toxicity because of physiological variations and interspecies metabolic capability. The on-chip technique allows for observing and understanding the process and alterations occurring in metastases. The present study aimed to briefly overview single and multi-organ-on-chip techniques. The current study addresses each platform's essential benefits and characteristics and highlights recent developments in developing and utilizing technologies for single and multi-organs-on-chips. The study also discusses the drawbacks and constraints associated with these models, which include the requirement for standardized procedures and the difficulties of adding immune cells and other intricate biological elements. Finally, a comprehensive review demonstrated that the organs-on-chips approach has a potential way of investigating organ function and disease. The advancements in single and multi-organ-on-chip structures can potentially increase drug discovery and minimize dependency on animal models, resulting in improved therapies for human diseases.

In-Silico Analysis of Optimal Configurations for Rotational Bioinspired Bone Marrow Biopsy Needle Designs: An ANN Approach.

Medical needle innovations have utilized rotating motion to enhance tissue-cutting capabilities, reducing cutting force and improving clinical outcomes. This study analyzes the effects of six essential factors on insertion and extraction forces during bone marrow biopsy (BMB) procedures. The study uses Taguchi's L32 orthogonal array and numerically simulates the BMB process using the Lagrangian surface-based method on a three-dimensional (3D) heterogeneous Finite Element (FE) model of the human iliac crest. The study evaluates cutting forces in needle insertion and extraction using uni-directional (360° rotation) and bidirectional (180° clock and anti-clock rotation) bioinspired BMB needles. This work aims to create an AI tool that assists researchers and clinicians in selecting the most suitable and safe design parameters for a bio-inspired barbed biopsy needle. An efficient Graphical User Interface (GUI) has been developed for easy use and seamless interaction with the AI tool. With a remarkable accuracy rate exceeding 98%, the tool's predictions hold significant value in facilitating the development of environmentally conscious biopsy needles. The tool demonstrates significantly higher efficiency compared to Abaqus, rendering it a valuable asset for researchers and clinicians engaged in bio-inspired biopsy needle development.

Honeybee stinger-based biopsy needle and influence of the barbs on needle forces during insertion/extraction into the iliac crest: A multilayer finite element approach.

Bone marrow biopsy (BMB) needles are frequently used in medical procedures, including extracting biological tissue to identify specific lesions or abnormalities discovered during a medical examination or a radiological scan. The forces applied by the needle during the cutting operation significantly impact the sample quality. Excessive needle insertion force and possible deflection might cause tissue damage, compromising the integrity of the biopsy specimen. The present study aims at proposing a revolutionary bioinspired needle design that will be utilized during the BMB procedure. A non-linear finite element method (FEM) has been used to analyze the insertion/extraction mechanisms of the honeybee-inspired biopsy needle with barbs into/from the human skin-bone domain (i.e., iliac crest model). It can be seen from the results of the FEM analysis that stresses are concentrated around the bioinspired biopsy needle tip and barbs during the needle insertion process. Also, these needles reduce the insertion force and reduce the tip deflection. The insertion force in the current study has been reduced by 8.6% for bone tissue and 22.66% for skin tissue layers. Similarly, the extraction force has been reduced by an average of 57.54%. Additionally, it has been observed that the needle-tip deflection got reduced from 10.44 mm for a plain bevel needle to 6.3 mm for a barbed biopsy bevel needle. According to the research findings, the proposed bioinspired barbed biopsy needle design could be utilized to create and produce novel biopsy needles for successful and minimally invasive piercing operations.

Safety and efficacy of intracavitary microwave ablation in hepatic gland tumours: Numerical and in vitro studies.

The microwave ablation (MWA) of large hepatic gland tumour using multiple trocars operated at 2.45/6 GHz frequencies has been analysed. The ablation region (in vitro) obtained using parallel and non-parallel insertion of multiple trocars into the tissue has been analysed and compared with the numerical studies. The present study has considered a typical triangular-shaped hepatic gland model for experimental and numerical analysis. COMSOL Multiphysics software with inbuilt bioheat transfer, electromagnetic waves, heat transfer in solids and fluids and laminar flow physics has been used to obtain the numerical results. Experimental analysis has been conducted on egg white using a market-available microwave ablation device. It has been found from the present study that MWA operated at 2.45/6 GHz with the non-parallel position of multiple trocars into the tissue leads to a considerable increase in the ablation region as compared to the parallel insertion of trocars. Hence, non-parallel insertion of trocars is suitable to treat irregular-shaped large cancerous tumours (>3 cm). The non-parallel simultaneous insertion of trocars can overcome the healthy tissue ablation issue as well as the problem associated with indentation. Further, reasonable accuracy (with the difference being nearly ±0.1 cm in ablation diameter) has been achieved in comparing the ablation region and temperature variation between experimental and numerical studies. The present study may create a new path in the ablation of large size tumours (>3 cm) with multiple trocars of all shapes by sparing the healthy tissue.

A prospective survey on trephine biopsy of bone and bone marrow: an experience with 274 Indian patients' biopsies.

Trephine bone marrow biopsy is an effective technique for diagnosing hematological malignancies in patients of different ages. During trephine biopsy, bone marrow cores are obtained for detailed morphological evaluation to look for any abnormality and arrive at a diagnosis. The primary goal of this work is to perform a survey on Indian patients of various ages for the trephine bone marrow biopsy process. In the present study, data related to 274 trephine biopsy samples from 300 patients were acquired at the Post Graduate Institute of Medical Education and Research (PGIMER) in Chandigarh, India. Pain was found to be the sole major procedure-related complication, and patients reported no/less pain in 41 BMB (14.96%) patients, moderate pain in 82 (29.92%) cases, and unbearable pain in 151 (55.1%) BMB cases. In addition, the patients were evaluated by the authors and hematologist as non-anxious for the procedure in 34 (12.4%), anxious in 92 (33.57%), and very/highly anxious in 148 (56%) cases. The bone texture of the patients significantly affected the needle bending, number of repetitions required, and size of the bone marrow sample. This demonstrates the need for improvement in the biopsy procedure. To this end, a survey was conducted to assess the numerous difficulties and diagnostic outcomes throughout the trephine biopsy process.

Simulating radiofrequency ablation of hepatocellular carcinomas proximal to bare area of liver.

PURPOSE: To numerically assess the significance of dextrose 5% in water (D5W) thermo-protection during radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) located near the 'bare area of liver'. MATERIAL AND METHODS: This study utilises quasi-anatomical structures extracted from CT images. A multi-tine electrode, deployed inside the extracted organs and operated under temperature-controlled mode was used as the source of ablation. Geometrically, D5W was modelled around the 'bare area' and sandwiched between the liver and diaphragm. RFA at different sites relative to the 'bare area' was simulated to answer when to consider modelling D5W. RESULTS: For targets near the edge of 'bare area' and at 0.5 mm gap (between the electrode and the 'bare area'), ignoring D5W and using ground conditions could result in underestimation of ablation volume by almost 25%. The importance of D5W becomes negligible for ablations near the centre of the 'bare area'. CONCLUSIONS: Consideration of D5W during RFA of HCCs proximal to the 'bare area' can significantly influence the ablation outcome, especially when ablation is performed near the edge of the 'bare area'.

Microwave ablation trocar for ablating cancerous tumors: a numerical analysis.

Microwave ablation (MWA) is a newly developing minimally invasive thermal therapies technology. The ablation region obtained during MWA mainly depends on the type and efficiency of the trocar as well as the energy transfer from the generator to the biological tissue. In the present article, a novel trocar for MWA therapies has been proposed. A 3-dimensional tumor-embedded hepatic gland ablated with the novel MWA trocar has been numerically analyzed using finite element method-based software. The novel trocar consists of a flexible dual tine supplied with a microwave power of 15 W at 2.45/6 GHz for an ablation time of 10 min for all the cases. Various combinations of supplied energy and deploying lengths result in tumor ablations ranging from 2.7 to 4 cm in diameter. Supplying energy at high frequency (6 GHz) to the trocar results in ablating tumors (> 4 cm) with spherical ablation region. The novel trocar generated large ablation regions which are 2-3 times bigger than the tumors obtained using existing single-slot non-cooled trocars. This research on novel trocar may help clinicians in treating large size tumors of symmetric and asymmetric shapes by overcoming the problem associated with precise position of trocar into the tissue.

Finite element simulation of multilayer model to simulate fine needle insertion mechanism into iliac crest for bone marrow biopsy.

The main aim of this work is to use a finite element technique (FEM) to gain understanding about the bone marrow biopsy (BMB) needle insertion process and needle-tissue interactions in the human iliac crest. A multi-layer iliac crest model consists of stratum corneum, dermis, epidermis, hypodermis, cortical, and cancellous bone has been established. This paper proposes a FE model that examines all phases of tissue deformation, including puncture, cutting, needle-tissue interaction, and various stress-strain values for BMB needle during interaction. The results explain the needle-tissue interface and show the potential of this technique to estimate bone damage and tissue deformation for multiple needle dimensions, coefficient of friction, and penetration speeds. The insertion and extraction force of conical-shaped needles in the multi-layered iliac crest model decreased by 18.92% and 37.5%, respectively, as the needle diameter reduced from 11 G to 20 G. It has also been found that the significant insertion motion raises the deformation of the tissue due to the augmented frictional forces but reduces the strain perpendicular to the penetration direction closer to the needle tip. The simulation outcomes are helpful for the optimal design of fine biopsy needles used to perform the bone marrow biopsies.

Numerical study to establish relationship between coagulation volume and target tip temperature during temperature-controlled radiofrequency ablation.

The present study aims at proposing a relationship between the coagulation volume and the target tip temperature in different tissues (viz., liver, lung, kidney, and breast) during temperature-controlled radiofrequency ablation (RFA). A 20-min RFA has been modelled using commercially available monopolar multi-tine electrode subjected to different target tip temperatures that varied from 70°C to 100°C with an increment of 10°C. A closed-loop feedback proportional-integral-derivative (PID) controller has been employed within the finite element model to perform temperature-controlled RFA. The coagulation necrosis has been attained by solving the coupled electric field distribution, the Pennes bioheat and the first-order Arrhenius rate equations within the three-dimensional finite element model of different tissues. The computational study considers temperature-dependent electrical and thermal conductivities along with the non-linear piecewise model of blood perfusion. The comparison between coagulation volume obtained from the numerical and in vitro experimental studies has been done to evaluate the aptness of the numerical models. In the present study, a total of 20 numerical simulations have been performed along with 12 experiments on tissue-mimicking phantom gel using RFA device. The study revealed a strong dependence of the coagulation volume on the pre-set target tip temperature and ablation time during RFA application. Further, the effect of target tip temperature on the applied input voltage has been studied in different tissues. Based on the results attained from the numerical study, statistical correlations between the coagulation volume and treatment time have been developed at different target tip temperatures for each tissue.

Temperature-controlled radiofrequency ablation of different tissues using two-compartment models.

PURPOSE: This study aims to analyse the efficacy of temperature-controlled radiofrequency ablation (RFA) in different tissues. MATERIALS AND METHODS: A three-dimensional, 12 cm cubical model representing the healthy tissue has been studied in which spherical tumour of 2.5 cm has been embedded. Different body sites considered in the study are liver, kidney, lung and breast. The thermo-electric analysis has been performed to estimate the temperature distribution and ablation volume. A programmable temperature-controlled RFA has been employed by incorporating the closed-loop feedback PID controller. The model fidelity and integrity have been evaluated by comparing the numerical results with the experimental in vitro results obtained during RFA of polyacrylamide tissue-mimicking phantom gel. RESULTS: The results revealed that significant variations persist among the input voltage requirements and the temperature distributions within different tissues of interest. The highest ablation volume has been produced in hypovascular lungs whereas least ablation volume has been produced in kidney being a highly perfused tissue. The variation in optimal treatment time for complete necrosis of tumour along with quantification of damage to the surrounding healthy tissue has also been reported. CONCLUSIONS: The results show that the surrounding tissue environment significantly affects the ablation volume produced during RFA. The optimal treatment time for complete tumour ablation can play a critical role in minimising the damage to the surrounding healthy tissue and ensuring safe and risk free application of RFA. The obtained results emphasise the need for developing organ-specific clinical protocols and systems during RFA of tumour.

Thermal analysis of induced damage to the healthy cell during RFA of breast tumor.

Effective pre-clinical computational modeling strategies have been demonstrated in this article to enable risk free clinical application of radiofrequency ablation (RFA) of breast tumor. The present study (a) determines various optimal regulating parameters required for RFA of tumor and (b) introduces an essential clinical monitoring scheme to minimize the extent of damage to the healthy cell during RFA of tumor. The therapeutic capabilities offered by RFA of breast tumor, viz., the rise in local temperature and induced thermal damage have been predicted by integrating the bioheat transfer model, the electric field distribution model and the thermal damage model. The mathematical model has been validated with the experimental results available in the literature. The results revealed that, the effective damage of tumor volume sparing healthy tissue essentially depends on the voltage, the exposure time, the local heat distribution, the tumor stage and the electrode geometric configuration. It has been confirmed that, the assessment of damage front can accurately determine the extent of damage as compared to the thermal front. The study further evaluates the damaged healthy and tumor volumes due to RFA of different stages of breast cancer. The assessment of cell survival and damage fractions discloses the propensity of reappearance/healing of tumor cells after treatment.

Suitability of frequency modulated thermal wave imaging for skin cancer detection-A theoretical prediction.

A theoretical study on the quantification of surface thermal response of cancerous human skin using the frequency modulated thermal wave imaging (FMTWI) technique has been presented in this article. For the first time, the use of the FMTWI technique for the detection and the differentiation of skin cancer has been demonstrated in this article. A three dimensional multilayered skin has been considered with the counter-current blood vessels in individual skin layers along with different stages of cancerous lesions based on geometrical, thermal and physical parameters available in the literature. Transient surface thermal responses of melanoma during FMTWI of skin cancer have been obtained by integrating the heat transfer model for biological tissue along with the flow model for blood vessels. It has been observed from the numerical results that, flow of blood in the subsurface region leads to a substantial alteration on the surface thermal response of the human skin. The alteration due to blood flow further causes a reduction in the performance of the thermal imaging technique during the thermal evaluation of earliest melanoma stages (small volume) compared to relatively large volume. Based on theoretical study, it has been predicted that the method is suitable for detection and differentiation of melanoma with comparatively large volume than the earliest development stages (small volume). The study has also performed phase based image analysis of the raw thermograms to resolve the different stages of melanoma volume. The phase images have been found to be clearly individuate the different development stages of melanoma compared to raw thermograms.

Thermographic evaluation of early melanoma within the vascularized skin using combined non-Newtonian blood flow and bioheat models.

A theoretical study on vascularized skin model to predict the thermal evaluation criteria of early melanoma using the dynamic thermal imaging technique is presented in this article. Thermographic evaluation of melanoma has been carried out during the thermal recovery of skin from undercooled condition. During thermal recovery, the skin has been exposed to natural convection, radiation, and evaporation. The thermal responses of melanoma have been evaluated by integrating the bioheat model for multi-layered skin with the momentum as well as energy conservation equations for blood flow. Differential changes in the surface thermal response of various melanoma stages except that of the early stage have been determined. It has been predicted that the thermal response due to subsurface blood flow overpowers the response of early melanoma. Hence, the study suggests that the quantification of early melanoma diagnosis using thermography has not reached a matured stage yet. Therefore, the study presents a systematic analysis of various intermediate melanoma stages to determine the thermal evaluation criteria of early melanoma. The comprehensive modeling effort made in this work supports the prediction of the disease outcome and relates the thermal response with the variation in patho-physiological, thermal and geometrical parameters.