Banca de DEFESA: ÍCARO KLEISSON ARAÚJO LUCENA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ÍCARO KLEISSON ARAÚJO LUCENA
DATE: 01/12/2023
TIME: 10:00
LOCAL: Sala 415, CETEC, UFRN
TITLE:

MODEL VALIDATION FOR NUMERICAL CALCULATIONS OF HEAT TRANSFER IN PHOTOTHERMAL THERAPIES

KEY WORDS:

Monte Carlo, radiation scattering, finite volume method, tre-dimensional and transient heat transfer

PAGES: 61
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUBÁREA: Fenômenos de Transporte
SPECIALTY: Transferência de Calor
SUMMARY:

Cancer is known to affect humans since ancient times and continues to be the subject of intense research aimed at improving therapeutic approaches. In this context, hyperthermic therapies stand out, notably Interstitial Laser Therapy (ILT) and Plasmonic Photothermal Therapy (PPTT). Despite the use of numerical methods in simulating hyperthermic treatments, these approaches often exhibit inaccuracies and uncertainties, which makes model validation theimperative to ensure result reliability. The core of this study is to validate hyperthermia models by comparing temperature distributions derived from simulations with those obtained from a real ILT protocol for breast cancer treatment. In this treatment, laser irradiation is delivered using an optical fiber inserted into the center of the tumor, which has an approximately spherical shape. In addition to the optical fiber, the protocol involves the use of other devices to control the energy delivered to the tissue. Among the relevant elements are: (1) the optical fiber, (2) the cooling system, crucial to prevent damage to the optical fiber tip and reduce direct contact with human tissue, and (3) probes equipped with thermocouples, used to measure temperatures at specific locations. The simulation covers the numerical solution of the Bioheat Transfer Equation (PBHTM) and the Radiative Transfer Equation (RTE), where the divergence of heat flux obtained from the RTE serves as the source term in the PBHTM. The numerical solution provides temperature distributions in the region of interest, encompassing the tumor and surrounding tissues. Thermal and optical properties of the tissues were obtained from specialized literature, while laser properties were obtained from an operating manual. In the simulation, tissue properties were assumed to be those of healthy breast tissue. For the simulations, it was considered a cylindrical piece of brest tissue, with a length of 4 cm (Z) and a radius of 2 cm (R). The location of the optical fiber tip within this cilinder was at R=0 and Z=2 cm. According to the protocol, the total irradiation time was 2100 s, using a semiconductor diode laser with a wavelength of 805 nm, operating at 5 W, and a light beam diameter of 600 μm (equivalent to the optical fiber diameter). The radius of the cooled region was considered to be 1 mm. The study includes a comparison between two laser operation regimes, continuous and pulsed (with 0.1 s intervals between pulses), and two distinct thermocouple positioning configurations based on the protocol, for temperature acquisition. The simulation results exhibited agreement with protocol measurements, displaying low percentage errors, indicating the models' capacity to accurately estimate the temperature field.

COMMITTEE MEMBERS:
Interno - 2014591 - ANDRE JESUS SOARES MAURENTE
Externo ao Programa - 1235107 - GEORGE SANTOS MARINHO - UFRNExterno à Instituição - FRANCIS HENRIQUE RAMOS FRANÇA