scholarly journals Monte Carlo Simulations of Heat Deposition During Photothermal Skin Cancer Therapy Using Nanoparticles

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 343
Author(s):  
J. Charles G. Jeynes ◽  
Freddy Wordingham ◽  
Laura J. Moran ◽  
Alison Curnow ◽  
Tim J. Harries
Keyword(s):  
Monte Carlo ◽  
Skin Cancer ◽  
Monte Carlo Simulations ◽  
Photothermal Therapy ◽  
Normal Tissue ◽  
Heat Diffusion ◽  
Thermal Dose ◽  
Plasmonic Nanoparticle ◽  
Heat Deposition ◽  
Invaluable Tool

Photothermal therapy using nanoparticles is a promising new approach for the treatment of cancer. The principle is to utilise plasmonic nanoparticle light interaction for efficient heat conversion. However, there are many hurdles to overcome before it can be accepted in clinical practice. One issue is a current poor characterization of the thermal dose that is distributed over the tumour region and the surrounding normal tissue. Here, we use Monte Carlo simulations of photon radiative transfer through tissue and subsequent heat diffusion calculations, to model the spatial thermal dose in a skin cancer model. We validate our heat rise simulations against experimental data from the literature and estimate the concentration of nanorods in the tumor that are associated with the heat rise. We use the cumulative equivalent minutes at 43 °C (CEM43) metric to analyse the percentage cell kill across the tumour and the surrounding normal tissue. Overall, we show that computer simulations of photothermal therapy are an invaluable tool to fully characterize thermal dose within tumour and normal tissue.

MO-E-AUD B-02: Antiproton Therapy: Monte Carlo Simulations of Normal Tissue Equivalent Dose From Annihilation Neutrons

2008 ◽  
Vol 35 (6Part19) ◽  
pp. 2874-2874
Author(s):  
B Fahimian ◽  
J DeMarco ◽  
M Holzscheiter ◽  
R Keyes ◽  
N Bassler ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Normal Tissue ◽  
Equivalent Dose ◽  
Tissue Equivalent

Study of the Bioheat Equation Using Monte Carlo Simulations for Local Magnetic Hyperthermia

2008 ◽  
Author(s):  
Gustavo Gutierrez ◽  
Mauricio Giordano
Keyword(s):  
Monte Carlo ◽  
Random Walk ◽  
Heat Equation ◽  
Monte Carlo Simulations ◽  
Cancer Cells ◽  
High Temperatures ◽  
Heat Diffusion ◽  
Maximum Temperature ◽  
Heat Diffusion Equation ◽  
Spherical Domain

Hyperthermia is a type of cancer treatment in which cancer cells are exposed to high temperatures (up to 44–45°C). Research has shown that high temperatures can damage and kill cancer cells, by a localized and concentrated heating source. By killing cancer cells and damaging proteins and structures within cells, hyperthermia may shrink tumors, with minimal injury to normal tissues. Penne’s bio-heat equation is used to model a heat diffusion process inside a tumor, modeled as a spherical domain with magnetic nanoparticles distributed within the diseased tissue. These magnetic particles are considered as point heat sources. Heat is generated as the result of magnetic relaxation mechanisms (Brownian and Neel relaxation) by the application of alternating magnetic fields. The Bio-Heat equation is solved using Monte Carlo techniques. Monte Carlo simulations are based on departing random walkers from the point where temperature is going to be determined. The probability in each step of the random walk is given by the coefficients of the nodal temperatures after a Finite Difference Discretization of the Penne’s bio-heat diffusion equation. The main advantage of Monte Carlo simulations versus classical numerical methods lies in the possibility of solving the temperature in a specific point without solving for all the points within the domain. This feature and the fact that each random walk is independent from each other results in an easy parallelization of the computer code. Parametric studies of the temperature profiles are carried out to study the effect of different parameters like the heat generation rate, perfusion rate and diameter of the point source on the maximum temperature and on the temperature profile.

scholarly journals Numerical Study on Factors Affecting the Induction of Apoptotic Temperatures of Tumor in the Multi-Layer Skin Structure Using Monte Carlo Method

2021 ◽  
Vol 11 (3) ◽  
pp. 1103
Author(s):  
Donghyuk Kim ◽  
Sukkyung Kang ◽  
Hyunjung Kim
Keyword(s):  
Monte Carlo ◽  
Numerical Analysis ◽  
Monte Carlo Method ◽  
Skin Cancer ◽  
Photothermal Therapy ◽  
Volume Fraction ◽  
Numerical Study ◽  
Secondary Infection ◽  
Reticular Dermis ◽  
Therapy Effect

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.

Evaluation of bone dose arising from skin cancer brachytherapy: A comparison between 192Ir and 60Co sources through Monte Carlo simulations

2021 ◽  
Vol 205 ◽  
pp. 106089
Author(s):  
Sahar Sheikholeslami ◽  
Shaghayegh Khodaverdian ◽  
Fatemeh Hashemzaei ◽  
Parvin Ghobadi ◽  
Mahdi Ghorbani ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Skin Cancer ◽  
Monte Carlo Simulations

Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

1996 ◽  
Vol 54 ◽  
pp. 478-479
Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter
Keyword(s):  
Monte Carlo ◽  
Quantitative Analysis ◽  
Monte Carlo Simulations ◽  
Cross Section ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Magnesium Ferrite ◽  
X Ray ◽  
Interaction Volume ◽  
Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

MONTE CARLO SIMULATIONS OF ELECTRON DRIFT VELOCITIES IN THE NOBLE GASES AND THEIR MIXTURES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-63-C7-64
Author(s):  
A. J. Davies ◽  
J. Dutton ◽  
C. J. Evans ◽  
A. Goodings ◽  
P.K. Stewart
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Noble Gases ◽  
Electron Drift
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