Simulation of Gaussian-beam photothermal effect of gastric tumor based on COMSOL

Abstract

The lasers used in biomedical engineering, laser nuclear physics and other fields are generally Gaussian beam with nonuniform energy distribution. Compared with point light source, the propagation direction of beam is more concentrated macroscopically. The light energy of a point source diffuses in all directions. It is of great significance to study the propagation of Gaussian light source in biological tissue. In this paper, finite element analysis is used to model and simulate the light transmission and biological heat transfer of Gaussian finite width pulse beam on gastric tumor tissue by COMSOL software. In this study, the object is composed of air, water layer, gastric tissue and gastric tumor. A Gaussian beam with a wavelength of 532nm and a point light source are irradiated on the object respectively. Observed the loss of light energy on various objects and the temperature change caused by the absorption of light energy in biological tissues. The experimental results show that the Gaussian beam has better penetration in the direction perpendicular to the object. Only 1.35% of the light energy is lost in the water layer, while 10% of the light energy generated by the point source is lost in the water layer. Because less light energy arrives at biological tissues in the point light source experiment, the temperature rise of biological tissues is correspondingly reduced. This study has a certain theoretical significance for photoacoustic imaging (PAI) or thermal radiation therapy of gastric tissue.