Open AccessTwo-compartment mathematical modeling in RF tumor ablation: New insight when irreversible changes in electrical conductivity are considered
Author(s) -
Dora Luz Castro-López,
Macarena Trujillo,
Enrique Berjano,
Ricardo RomeroMéndez
Publication year - 2020
Publication title -
mathematical biosciences and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.451
H-Index - 45
eISSN - 1551-0018
pISSN - 1547-1063
DOI - 10.3934/mbe.2020405
Subject(s) - compartment (ship) , ablation , arrhenius equation , thermal conductivity , electrical resistivity and conductivity , thermal conduction , radiofrequency ablation , conductivity , bioheat transfer , materials science , piecewise , thermodynamics , mechanics , chemistry , biomedical engineering , thermal , mathematics , physics , composite material , medicine , activation energy , geology , mathematical analysis , oceanography , organic chemistry , quantum mechanics
The objective was to explore variations of temperature distribution and coagulation zone size computed by a two-compartment radiofrequency ablation (RFA) model when including simultaneously reversible changes in the tissue electrical conductivity (σ) due to temperature and irreversible changes due to thermal coagulation. Two-compartment (tumor and healthy tissue) models were built and simulated. Reversible change of σ was modeled by a piecewise function characterized by increments of +1.5%/℃ up to 100 ℃, and a 100 times smaller value from 100 ℃ onwards. Irreversible changes of σ were modeled using an Arrhenius model. We assumed that both tumor and healthy tissue had a different initial σ value (as suggested by the experimental data in the literature) and tended towards a common value as thermal damage progressed (necrotized tissue). We modeled a constant impedance protocol based on 90 V pulses voltage and three tumor diameters (2, 3 and 4 cm). Computer simulations showed that the differences between both models were only 0.1 and 0.2 cm for axial and transverse diameters, respectively, and this small difference was reflected in the similar temperature distributions computed by both models. In view of the available experimental data on changes of electrical conductivity in tumors and healthy tissue during heating, our results suggest that irreversible changes in electrical conductivity do not have a significant impact on coagulation zone size in two-compartment RFA models.