Laser-Induced Boiling of Biological Fluids

Laser-induced boiling and the associated foaming of biological fluids (aqueous solutions of surfactants, proteins, fluids containing dispersed phase) on laser heaters that convert near-IR laser radiation (0.97 μm, 1.47 μm) into heat are considered. The objects of study were model fluids and biological fluids, sera, as well as recorded ultrasound images of boiling human endocystosis fluid and blood obtained in the process of laser treatment of cysts and veins under ultrasound guidance. In the proposed approach, the modification and destruction of biotissue does not occur via direct laser heating but due to rapid heat delivery by two-phase jet streams that form during bubble boiling of the liquid, on the one hand, and, on the other hand, as a result of the cessation of blood flow caused by occlusion (closing) of vessel foam. During laser surgery in the veins, the blood, in addition to boiling, simultaneously foams under the action of laser heating. There is a previously undescribed effect in which a solution of denatured blood proteins foams upon boiling. The foam that has arisen in the vessel lumen causes a vein occlusion, which leads to the cessation of bleeding (hemostasis).