The Radiation Element Method Coupled with the Bioheat Transfer Equation Applied to the Analysis of the Photothermal Effect of Tissues

Abstract

The purpose of this study is to develop the radiation element method by ray emission method (REM²) code appropriate for coupling with the bioheat transfer equation, and to clarify the photothermal effect of various parameters inside biological tissues. First, the REM², which involves the air-tissue interface effect, is validated with the existing literature. In order to clarify the effects of optical and thermophysical properties of biological tissues, a one-dimensional tissue model of CW light transport and bioheat transfer is employed. The present study provides nondimensional results, which are obtained by varying refractive index, extinction coefficient, scattering albedo, blood perfusion parameter, and conduction-radiation parameter, show valuable guidance for understanding the coupled light and bioheat transport in tissues.

The authors acknowledge Prof. Isami Nitta at Niigata University and Prof. Subhash C. Mishra at the Indian Institute of Technology Guwahati for their valuable advice, and Messrs. Junnosuke Okajima, Naoya Ogasawara, and Yoshiyuki Satoh at Tohoku University for their kind collaborations.