Clinical Applications of Lasers — Selective Absorption

Abstract

Lasers are finding many applications in the fields of medicine and surgery because of the unique qualities of the light produced. Monochromatic light can be produced at wavelengths preferentially absorbed by targeted tissues be they naturally absorbing or labelled by applied chromophore. Lasers have high output radiances which can cause permanent changes in tissues. Light is commonly associated with the production of heat, which can denature, coagulate or vaporise tissues depending on the energy output and the exposure time. Specific interactions causing a localised heating and tissue ablation require short pulses, and laser outputs can range from femtoseconds to continuous wave operation. The low divergence of light allows for non-contact methods of treatment and reduces the risk of infection. Light emitted from lasers is usually plane polarised, and this property may be of use in modifying cell behaviour.