Theoretical analysis of thermal response in biological skin tissue subjected to multiple laser beams

Laser has become a well-accepted technique for surgical procedures. To fit the physically irradiated area to the clinically planned target area, a multifibre laser system can be used. This paper theoretically investigated the temperature distribution in a three-dimensional biological tissue when irradiated by multifibre lasers with the aids of the dual-phase-lag (DPL) bio-heat conduction model. First, four laser beams located on the corners of a square are used as the heat sources. The method of separation of variables is adopted to obtain the analytical expression of temperature. The characteristics of DPL bio-heat transfer model and the difference with Pennes model were checked graphically. It is found that the effect of multiple laser beams on temperature response differs from those of single laser beam distinctly. A second heating phenomenon occurs and the contour of a square with curved corners are obtained. Then the laser beams are located to form a triangle and a trapezoid and the corresponding temperature responses are studied. Different irradiated zone can be obtained and accomplished by changing the spot size, the arrangement layout and the interval distance of the laser beams.