Modelling of the heat accumulation process during short and ultrashort pulsed laser irradiation of bone tissue.

Evgeny Yakovlev,Galina Shandybina,Alexandra Shamova

doi:10.1364/boe.10.003030

Abstract

An analytical model is presented that qualitatively describes the cooling of a biological tissue after irradiation with short and ultrashort laser pulses. The assumption that the distribution of temperature at the initial moment of surface cooling repeats the distribution of the absorbed laser energy allowed us to use the thermal conductivity approximation in both cases. The experimental results of irradiation of dry bone with nanosecond and femtosecond laser pulses are compared with the calculated data. The necessity of taking into account the change in the optical parameters of hard tissue in the field of laser irradiation during its treatment by nanosecond and femtosecond laser pulses and the key role of residual heating in its carbonization around the exposure region is shown. The application of the model to a particular biological tissue can significantly simplify the search for optimal parameters of lasers for surgical procedures.

Highlights

Laser technologies are successfully used in a wide variety of medical fields such as surgery [1,2,3,4,5], therapy [5,6], cosmetology [7,8,9,10] and for effective treatment of medical instruments [11]
The validity of the proposed model of heat accumulation was checked by comparing the calculated radial distributions of the residual temperature of dry bone surface according to Eq (6) for various laser pulse durations with the experimental data
The assumption that the distribution of temperature in the laser impact zone at the initial moment of biological tissue surface cooling repeats the distribution of the absorbed laser energy, allowed us to use the simple thermal conductivity approximation for the analysis of the residual heating of biological tissue surface by trains of nanosecond and femtosecond laser pulses

Summary

Introduction

Laser technologies are successfully used in a wide variety of medical fields such as surgery [1,2,3,4,5], therapy [5,6], cosmetology [7,8,9,10] and for effective treatment of medical instruments [11]. The use of lasers in medicine is based on the management of biological, physical and chemical processes during laser irradiation of biological tissue [12]. In this case, the considerable difference in the processes of laser interaction with the biological medium under the conditions of varying laser parameters is observed [12,13]. A wide range of phenomena occurring during laser irradiation of biological tissues have been studied. It should be noted that the most medical applications of laser radiation are based on the effect of heating of biological tissues [13]

Methods

Results

Conclusion