Oriental Medicine: Laser

LASER, an acronym for Light Amplification by Stimulated Emission of Radiation, was developed in the early '60s. It is a form of electromagnetic radiation, in the visible or infrared region of the light spectrum, generated by stimulating a medium, which may be solid or gaseous, under special conditions. The beam of light thus generated has uses in almost every area of technology which exist today.

Laser was first used in the medical field as a focussed, high power beam with photo thermal effects in which tissue was vapourised by the intense heat. During the early phase of its use as a surgical tool, it was noted that there appeared to be less pain and inflammation following laser surgery than conventional surgery.

It was postulated that this effect was related to the use of surgical lasers with a Gaussian beam mode (see fig) In this mode the power of laser is highest at the centre of the beam with the power then falling off in a bell-shaped curve with the weakest power at the periphery of the beam diffusing out into the undamaged tissues (2). This phenomenon was called the "alpha-phenomenon" (35). Thus the "low power" segment of the beam was postulated to be responsible for the decreased pain and inflammation in the wound. Workers in the field recognised this effect. Laser devices were manufactured in which power densities and energy densities of laser were lowered to a point where no photo thermal effects occurred but the photo-osmotic, photo-ionic and photo-enzymatic effects were still operative. Thus the use of "cold" laser or "soft" laser, as it was first known, came into medical use.

The earliest experimental application of low power laser in medicine was first reported in 1968 by Endre Mester in Hungary. He described the use of Ruby and Argon lasers in the promotion of healing of chronic ulcers. In 1974, Heinrich Plogg of Fort Coulombe, Canada, presented his work on the use of "needleless acupuncture" and pain attenuation. The first clinical applications of the GaAIAs diode laser appeared in the literature in 1981.

Since then a multitude of devices, from many different countries, generating a variety of laser beams of varying power, wavelengths, frequencies and claims of clinical effects have been brought onto the market.

Its use is now widespread in almost every medical specialty, especially dermatology, ophthalmology and medical acupuncture.

Japan and several Scandinavian countries are at the forefront of clinical research work with laser. Low Level Laser Therapy (LLLT) is also used in Australia, Canada, France, Korea, People's Republic of China, U.K. and many other countries. A tissue repair research unit, examining the effects of laser, now exists at Guy's Hospital, London. Many centres of research are now developing around the world.

It is to be noted that laser machines are used widely by physiotherapists, veterinary surgeons (3) as well as practitioners of alternate therapies. It is unregulated by any authority at the present time, apart from the need for the equipment to conform to Australian standard safety regulations.

The aim of this position paper is to present the current views of the Australian Medical Acupuncture College on the use of laser.

The photo-chemical effects of light in medicine are well known, e.g. blue light is absorbed by bilirubin and thus undergoes photo-chemical change. This is the basis of the treatment of neonatal jaundice. Another use is that of ultraviolet light to treat psoriasis in PUVA treatment. The use of a laser as a mechanism to induce photo-chemical changes in tissues is an extension of this effect.