Mathematical simulation of temperature distribution in tumor tissue and surrounding healthy tissue treated by laser combined with indocyanine green

Radio-frequency (RF) ablation is one of the most widely used methods for the treatment of hepatic malignancies. A finite element method (FEM) analysis was employed to determine the thermal dose delivered to the tumor/tissue region. We simulated heating within a RF probe implanted in generic tumor surrounded by healthy tissue using ANSYS. The 3-D model consists of a tumor / tissue region into which the RF probe is embedded inside the tumor. One-quarter symmetry was then invoked. The blood flow was modeled using Penne’s bio-heat transfer equation with differing perfusion rates between the healthy tissue and tumor volume based on literature values. The resulting temperature distribution throughout the region was determined over time. A program was written in Visual Basic to extract the temperature distribution data in the tumor/tissue region and calculate the thermal dose throughout the region. This was done by using a time–temperature Arrhenius relationship for chemical and physical rate process. Tissue necrosis is assumed complete when a thermal dose of one hour has been achieved at 43 °C. In the present study, the geometry of the electrode had a significant effect on the size of the volume of necrosis. It was found that the lower portion of the tumor did not receive the specified thermal dose relative to the upper portion of the tumor in single setting during the RF ablation therapy. This might be due to the Ni-Ti electrode, which protruded only from the top surface of the trocar. The effectiveness of the existing probe can be improved by having one more set of electrodes protruding out from the lower curved surface of the trocar. It was found that the modified probe significantly improved heating in the lower portion of tumor/tissue area, providing more symmetry between the upper and lower portion.

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Nanoparticles in enhancing microwave imaging and microwave Hyperthermia effect for liver cancer treatment

REVIEWS ON ADVANCED MATERIALS SCIENCE ◽

10.1515/rams-2021-0014 ◽

2021 ◽

Vol 60 (1) ◽

pp. 223-236

Author(s):

Walaa Maamoun ◽

Mohamed I. Badawi ◽

Ayman A Aly ◽

Y. Khedr

Keyword(s):

Silver Nanoparticles ◽

Liver Cancer ◽

Cancer Treatment ◽

Electromagnetic Waves ◽

Microwave Imaging ◽

Healthy Tissue ◽

Cancer Tissue ◽

Hyperthermia Treatment ◽

Hyperthermia Therapy ◽

Surrounding Healthy Tissue

Abstract Hyperthermia therapy is a promising therapy for liver cancer treatment that utilizes external electromagnetic waves to heat the tumor zone to preferentially kill or minimize cancer cells. Nevertheless, it’s a challenge to realize localized heating of the cancer tissue without harming the surrounding healthy tissue. This research proposes to utilize nanoparticles as microwave absorbers to enhance microwave imaging and achieve localized hyperthermia therapy. A realistic 3D abdomen model has been segmented using 3D Slicer segmentation software, and then the obtained segmented CAD model exported to Computer Simulation Technology (CST STUDIO) for applying the Finite Element Modeling (FEM). Next investigating both imaging and treatment capability. Finally, the specific absorption rate (SAR) and temperature distribution were computed without nanoparticles and with different types of nanoparticles such as gold (GNPs) and silver nanoparticles at frequency 915 MHz. By comparing the achived results, it was seen that Silver nanoparticles can make a great enhancement in raising the temperature. However, this result was unsatisfactory but, after adding gold nanoparticles the temperature exceed 42°C, at frequency 915 MHz which is achieving the hyperthermia treatment without harming the nearby healthy tissue, GNPs also can achieve a great enhancement in SAR result

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The Influence of Ozone on Tumor Tissue in Comparison with Healthy Tissue (in vitro)

Ozone Science and Engineering ◽

10.1080/01919519008552455 ◽

1990 ◽

Vol 12 (1) ◽

pp. 65-72 ◽

Cited By ~ 8

Author(s):

J. WashüTtl ◽

R. Viebahn ◽

I. Steiner

Keyword(s):

Tumor Tissue ◽

Healthy Tissue

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4081 Quantifying pH buffering capacity and kinetics of tumor and healthy tissue to understand and exploit differences in biology

Journal of Clinical and Translational Science ◽

10.1017/cts.2020.89 ◽

2020 ◽

Vol 4 (s1) ◽

pp. 15-15

Author(s):

A. Colleen Crouch ◽

Emily A. Thompson ◽

Mark D. Pagel ◽

Erik N.K. Cressman

Keyword(s):

Tumor Tissue ◽

Ex Vivo ◽

Buffering Capacity ◽

The Body ◽

Healthy Tissue ◽

Buffer System ◽

Bicarbonate Buffer ◽

Ph Buffering ◽

Acidocest Mri

OBJECTIVES/GOALS: The purpose of this work is to investigate natural buffering capacity of liver tissue and tumors, to understand and exploit differences for therapy. Using this work, we will determine the concentrations of reagents (acids or bases) used in ablation treatment to optimize treatment by increasing tumor toxicity and minimizing healthy tissue toxicity. METHODS/STUDY POPULATION: For this preliminary study, two methods will be used: benchtop pH experiments ex vivo and non-invasive imaging using acidoCEST MRI in vivo. For ex vivo, two types of tissues will be tested: non-cancerous liver and tumor tissue from HepG2 inoculated mice (n = 10). After mice are euthanized, pH will be measured in tissue homogenates at baseline and then the homogenates will be placed in either acidic (acetic acid) or basic (sodium hydroxide) solutions with varied concentrations (0.5–10M) and time recorded until pH returns to baseline. For in vivo imaging, Mia PaCA-2 flank model mice (n = 10) will be imaged with acidoCEST MRI to quantify pH at baseline. Mice will then be injected intratumorally with (up to 100 μL of) acid or base at increasing concentrations and imaged to quantify pH changes in the tumor. RESULTS/ANTICIPATED RESULTS: For this study, buffering capacity is defined as the concentration threshold for which tissue can buffer pH back to within normal range. Non-cancerous tissue is likely to buffer a wider range of concentrations compared to tumor tissue. From the benchtop experiment, comparison of time-to-buffer will be made for each concentration of acid/base for the two tissue types. AcidoCEST MRI will provide in vivo buffering capacity and potentially demonstrate tumor heterogeneity of buffering capacity. For both experiments, a pH vs. concentration curve for the two tissue types will allow for comparison of ex vivo to in vivo experiments, which will differentiate contributions of local tissue buffering capacity from the full body’s natural bicarbonate buffer system that depends on respiration and blood flow. DISCUSSION/SIGNIFICANCE OF IMPACT: The pH of the body must be maintained within a narrow range. With cancer, impairment in regulation of tumor metabolism causes acidosis, lowering extracellular pH in tumors. It remains unclear if pH plays a role in local recurrence or tumor toxicity. This work will determine if acidoCEST MRI can measure deliberate alteration of pH and how this change affects biology.

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Temperature distribution in target tumor tissue and photothermal tissue destruction during laser immunotherapy

10.1117/12.2209692 ◽

2016 ◽

Author(s):

Austin Doughty ◽

Aamr Hasanjee ◽

Alex Pettitt ◽

Kegan Silk ◽

Hong Liu ◽

...

Keyword(s):

Temperature Distribution ◽

Tumor Tissue ◽

Tissue Destruction ◽

Laser Immunotherapy

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Study of microflora in stomach cancer and gastritis.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.e15516 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. e15516-e15516

Author(s):

Tatiana Zykova ◽

Oleg Ivanovich Kit ◽

Yuri Gevorkyan ◽

Vladislav Legostaev ◽

Olga A. Bogomolova

Keyword(s):

Cell Carcinoma ◽

Stomach Cancer ◽

Tumor Tissue ◽

Signet Ring Cell ◽

Healthy Tissue ◽

Candida Spp ◽

Signet Ring ◽

Ring Cell ◽

Undifferentiated Cancer ◽

Staphylococcus Spp

e15516 Background: The purpose of the study was to compare the rates of bacterial and fungal colonization of the mucosa in stomach cancer and gastritis. Methods: 59 tumor and healthy tissue samples in stomach cancer and 33 stomach mucosa bioptates in gastritis were studied. DNAs were extracted by the adsorption method. DNAs of Enterobacteriaceae, Staphylococcus spp., Streptococcus spp., Candida spp., Bacteroides spp. were determined by real-time PCR. Results: 40.0% of 30 patients with stomach cancer had adenocarcinoma, 13.3% – signet ring cell carcinoma, 6.7% – undifferentiated cancer, 6.7% – NHL, 3.3% – squamous cell carcinoma, 6.7% – combined signet ring cell carcinoma and neuroendocrine or undifferentiated cancer, 23.3% – combined adenocarcinoma and neuroendocrine, signet ring cell or undifferentiated cancer. The comparison group included 33 patients with morphologically verified superficial gastritis. DNA of Bacteroides spp. was found in tumor and healthy tissues of 80.0% of cancer patients; it was not found in gastritis. DNA of B. fragilis was found in all tumor tissue samples, BFT – in 8.3% of them. The mean amount of Enterobacteriaceae in tumor tissue was 6.7x105 copy/ml, in healthy tissue – 7.0x105 copy/ml, in bioptates in gastritis – 4.0х102 copy/ml; Staphylococcus spp. – 3.4х102 copy/ml, 2.6х102 copy/ml and 8.7х101 copy/ml, Streptococcus spp. – 9.1х105 copy/ml, 1.3х105 copy/ml and 5.1х103 copy/ml, respectively. Thus, the amount of Enterobacteriaceae in tumor tissue in stomach cancer exceeded the value in gastritis by 1675 times, Staphylococcus spp. – by 3.9 times, Streptococcus spp. – by 178 times. Genes of resistance to the penicillin class TEM were found in 50.0% of patients with stomach cancer and in 8.7% of patients with gastritis. DNAs of Candida spp. in stomach cancer were found in 40% of patients in tumor tissue and in 31.0% in healthy tissue, in gastritis – in 8.3% of patients. Conclusions: Enterobacteriaceae and Streptococcus spp., mostly combined, dominate among microflora colonizing gastric mucosa in stomach cancer. The established differences in microbiocenosis in stomach cancer in comparison with gastritis suggest the possible involvement of aerobic and anaerobic microflora in the process of malignant transformation.

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