Therapeutic Applications of Lasers

This chapter discusses the physico-chemical processes at the origin of different therapeutic effects and illustrates the description of some representative indications. It starts by describing the optical phenomena involved in the interaction between light and biological tissue. The interaction between a light beam and any material media involves three different phenomena: reflection, absorption, and scattering. It is possible to classify the interaction between the laser light and biological tissue according to four types of effects as a function of the applied irradiance and the duration of exposure. The four types of effects are electromechanical effect, photoablative effect, thermal effect, and photochemical effect. The current lasers are more compact, reliable, easy to use and their beam can be, for the majority of them, injected into optical fibers.