Non-Fourier Laser-Tissue Heating Analysis: A Bio-heat Transfer Equation Comparison
Abstract
This study is aimed to examine limitations of the Fourier's law-based Pennes' bio-heat diffusion equation and the inclusion of a time-lag term to overcome those limitations. The estimates provided for the time-lag are based on available optical and thermal properties of the skin tissue. Contemporary methods used to model laser-tissue interactions most commonly employ Pennes' bio-heat equation. Despite its successful implementation in many applications, Pennes' equation reflects some unrealistic assumptions, such as the condition of infinite thermal propagation speed. While in many applications the effect of this assumption may be negligible, evidence shows that this assumption may produce unrealistic temperature profiles in extreme cases (such as laser heating applications) depending on the complexity of the tissue structure. To provide a theoretical framework, a linearized constitutive heat flux equation introduced by researchers in the 1960s is shown to unify the classical Pennes' bio-heat equation with the Thermal Wave Model for Bio-heat Transfer and some other alternative models. This perspective highlights the similarities and fundamental differences between the approaches. This report also aims to introduce and discuss the advantages and disadvantages of alternate models to correct these assumptions. A detailed overview of modern alternatives to Pennes' equation, including a numerical comparison between a thermal relaxation time method, the classical Pennes' bio-heat equation, and a fractional Pennes' equation, is provided.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 18, 2023
- Accession Number
- AD1222479
Entities
People
- Andrew. W. Wharmby
- Elharith M. Ahmed
- Matthew G. Seman
- Raniero A. Lara-garduno
- Sara Botelho-andrade
Organizations
- 711th Human Performance Wing