Radiative heating of superficial human tissues with the use of water-filtered infrared-A radiation: A computational modeling

A computational model of both the absorbed radiation and transient temperature fields in multilayer superficial human tissues in the case of an external water-filtered infrared-A irradiation is developed. A novel simplified model for radiative transfer is based on local 1-D solutions taking into account the oblique incidence of radiation at the periphery of the heated region. The computational study of a model problem at typical geometrical, optical, and thermal parameters confirms the acceptable accuracy of the 1-D solution for the temperature field formed in human tissues during thermal treatment with periodic infrared irradiation. The effects of uncertainties in spectral absorption coefficients and thermal conductivity of biological tissues on thermal treatment parameters are analyzed. It is shown that the temperature response to periodic water-filtered infrared-A heating can be used to estimate optical properties of human tissues. The calculations show that the decrease in convective heat transfer with the heating of air in the gap between the radiation source and the body surface has to be taken into account.