Lasers revolutionize medicine. (includes advantages and disadvantages, up and coming laser techniques, etc.)

in Canada today, almost every major hospital uses laser technology to perform certain procedures. As the devices become less expensive and specialists in their use more numerous, lasers are gradually moving into smaller medical centres, taking on newer tasks.

As early as 1917, Albert Einstein had developed the theoretical basis for lasers. The term L-A-S-E-R is an acronym for Light Amplification by Stimulated Emission of Radiation (radiation here meaning light radiation). However, it was only in 1960, following much work by Soviet and U.S. scientists, that an American team of researchers finally overcame the technological hurdles and assembled the first rudimentary but workable laser. Since then, lasers have undergone a rapid advance. Surgeons were quick to recognize the potential for a highly focussed cutting beam. By 1965, the first laser was in use for treating certain eye problems, such as a tom retina. Although the early machines were cumbersome and impractical, by the early 1970s argon lasers were being used experimentally for several medical procedures, including the treatment of diabetic eye problems and removal of small skin growths. Today the instruments are ubiquitous - contributing to areas as diverse as Beatlemania light shows, removing hemorrhoids and eradicating birthmarks. Laser technology has found its way into a broad range of medical specialties: from gynecology, gastroenternology, denistry, dermatology, urology, opthalomology and neurology to ear, nose, and throat surgery, and cancer treatment. Lasers can seal off bleeding blood vessels, kill malignant cells and vaporize away small growths in inaccessible parts of the body, such as the bowel and vocal cords, avoiding the need for surgery. As the machines become cheaper, more manageable and "userfriendly," small hospitals and clinics are acquiring their own laser centres. Their rapidly expanding repertoire brings significant benefits, in some cases almost replacing conventional therapy. The laser hasn't yet quite usurped the surgeon's knife but if present trends continue, the surgical scalpel may ultimately retire to medical museums, along with leech jars and cupping basins. What is a laser? A laser device strengthens or amplifies light, producing a highly directional, very powerful light beam - much like focussing sunlight through a magnifying glass to produce a beam concentrated enough to light a fire. (SEE DIAGRAM). The typical laser, such as the carbon dioxide type, is a tube filled with gas, which is electrically excited" (other lasers may use different gases, liquids or solids as their medium). As an electric current passes through the tube, the gas molecules become charged or excited and emit absorbed or excess energy as photons - tiny "packages of light." The light is reflected back and forth by mirrors at either end of the tube, a process that amplifies the energy, producing an intense light beam of a single wavelength or colour. The beam comes out through a partially silvered mirror at one end of the device as an ultra fine, very strong light beam that can deliver extreme heat. In producing light beans with different properties, laser technology takes advantage of the special characteristics of a whole range of gases, solids and liquids, some of them exotic elements - including argon, krypton, neodyminum, titanium and holmium. Depending on the substance used, the laser beam has a longer or shorter wavelength. The wavelength and pulse time determine the laser's properties - its colour and what it can do. For instance, carbon dioxide lasers operate in the infra-red spectrum, invisible to the human eye; argon lasers…