The medical laser: an indispensable tool of the physician and surgeon

The enormous proliferation of developments in the field of lasers has brought many changes and improvements to medicine. Lasers generate electromagnetic radiation unique in nature: Their light is coherent, collimated, and monochromatic. Because of these qualities, laser rays can be focused to very small spots of enormous power density. The wavelengths produced by a particular type of laser are determined by the characteristic energy levels of the emitting elements in the laser medium. The wavelengths of lasers currently used in therapy and surgery range from about 400 nm to 10,600 nm; at surgical power densities and at these wavelengths, because photonic ionization of atoms does not take place, laser rays are not oncogenic. Lasers can be used for converting radiant energy into heat in living tissues, for stimulating or moderating chemical reactions, or for mechanically disrupting histologic structure. Argon-ion, carbon dioxide, helium-neon, neodymium-doped yttrium-aluminum-garnet, ruby, organic-dye, and krypton-ion lasers are frequently used in medicine for therapeutic, analytical, or surgical applications. Laser use in medicine will increase as new developments bring forth new applications.