Diathermy equipment, sometimes used by physicians, chiropractors, dentists, and other medical professionals, generally consists of tools that can heat tissues under the skin. This can be in the form of radio frequency equipment, some of which can be dielectric or inductive coupled. Other types of diathermy equipment are microwave and ultrasonic systems. There are also various kinds of surgical tools based on heating tissues; the basic ones typically include monopolar and bipolar diathermy systems.
Radio frequency diathermy equipment can be dielectric, which generally involves two metal electrodes placed on opposite sides or the same side of the body. An alternating electric current typically flows between the two, and the tissues heat up because the molecules move rapidly to align with the changing field. Power controls can be used to alter the strength of the electric field. In turn, the intensity of the heating is normally controlled this way.
Inductive coupled equipment usually has a magnetic coil contained inside of an applicator. The intensity of magnetic currents and electric fields can produce varying levels of heat in the body. Some physicians operate radio frequency diathermy equipment in a continuous mode, while others choose to pulse the output.
Some diathermy machines use microwave energy to generate motion in the body’s molecules and produce heat. These devices often have a director for the microwave energy, which can also be integrated within an applicator. They are typically applied to the treatment area like the radio frequency system. Both of these systems can cause serious injuries if the diathermy equipment is not used properly, or if the patient has a metal implant such as a pacemaker or cochlear implant. Protective equipment, such as isolated circuits and circuit breakers, are often connected to the system during operation.
Aside from therapeutic applications, other reasons for diathermy include the cutting and clotting of tissues during surgery. Monopolar diathermy equipment typically applies energy, from 200 kilohertz to 6 megahertz, between a neutral and an active electrode from which the heating is applied. Different waveforms are used for cutting or coagulation to produce the appropriate level of heat. Bipolar diathermy usually involves less power, with heat usually applied through a type of forceps used on a local area, so the energy doesn’t pass directly through the body. The operation of various types of diathermy equipment is often regulated by regional agencies, so configuration and use are appropriate for protection against possible burns, fires, and explosions.