diathermy

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Short-wave diathermy (1944)

Diathermy (Greek for “heat penetration”, English diathermy ), also high-frequency thermal therapy , is an electrotherapeutic method of physical therapies in medicine, in which heat is generated in the body tissue with the help of high-frequency electrical current. With the diathermy can also be in the depth of a heat development produce, as opposed to the use of infra-red waves of red light treatment , mainly heat the skin surface.

In diathermy, electrodes are either placed on the skin that are connected to the high-frequency source, or the skin area concerned is irradiated via an antenna that is connected to the generator. In this case, part of it also gets deeper and can induce eddy currents in the tissue, which lead to the development of heat. The choice of frequency and the imaginary part of the relative permittivity of the tissue determine the extent to which the heat is generated in the depth.

parameter

The following frequency ranges are permitted for diathermy:

  • 13.56 MHz, 27.12 MHz ( wavelength 11 m) and 40.68 MHz shortwave therapy. Penetration depth more than 20 cm.
  • 434 MHz (wavelength 69 cm) as decimeter wave therapy
  • 2450 MHz (2.45 GHz; wavelength 12 cm) as so-called microwave therapy. Penetration depth only a few centimeters, the heating is very much determined by the water content of the tissue, see also dielectric heating .

The applied power can be up to several hundred watts . Diathermy devices work in the so-called ISM bands in order to disturb neighboring radio systems as little as possible.

Indications

Electrotherapy methods are mainly used to improve blood circulation , stimulate the metabolism, for sciatica , rheumatism , osteoarthritis or to reduce the tone of muscle tension and to relieve spasms.

Further applications are maxillary and frontal sinus inflammation or spread; however, these treatments are less common today due to the proximity of the eyes with poor blood circulation and the possible thermal damage to them caused by this.

Short wave therapy

Capacitor field method

The tissues are heated differently depending on their electrical properties. Vibrational energy is converted into heat. Materials and tissues with a high ohmic resistance (fatty tissue, connective tissue, bones) in particular heat up, whereas the well-conducting muscles hardly heat up.

Coil field method

Eddy currents are induced in tissue in the electromagnetic field of an induction coil as a result of the electromagnetic induction. The density of these eddy currents depends on the conductivity of the tissue (water-containing tissue conducts well, fatty tissue poorly)

Pulsed electromagnetic field therapy

This electrical therapy (English Pulsed Electromagnetic Field Therapy , PEMFT or PEMF, also Pulsed Magnetic Therapy , Pulse Magnetotherapy ) is mainly used in orthopedics for the treatment of pseudoarthroses , bone healing and the like. a. used by physiotherapists . Magnetic impulses are sent through the injured tissue, creating currents that stimulate cell repair.

d'Arsonvalisation (lineis method)

In this therapy (named after Jacques-Arsène d'Arsonval ), short-term high-frequency pulses of high voltage are used to generate brush discharges from a therapy electrode ( Geissler tube ). Depending on how far the electrode has been removed, the discharges are felt either as tingling, occasionally in connection with slight fibrillary muscle twitching, or strong skin irritation with muscle contraction. If the electrode is in contact with the body, the practitioner's fingers can form the counter electrode, thereby stimulating nerves or acupuncture points. The method is used to promote blood circulation, stimulate metabolism, activate muscles and relieve pain.

Electrosurgery

Surgical diathermy ( electrosurgery ) describes a procedure in which high-frequency electricity is used to separate or locally destroy (necrotize) tissue. It is used especially in tissue with a high blood flow to keep bleeding low. Frequencies from 300 kHz to mostly not more than 4 MHz are used.

Surgical diathermy is also used to remove tattoos . Here, the skin cells are destroyed by heat using an electric current.

Contraindications ( contraindications )

In diathermy, electromagnetic fields are created that can interfere with a pacemaker .

literature

Individual evidence

  1. ^ Armin Lange: Physical Medicine , page 150, Google Books Facsimile, accessed on December 1, 2011.
  2. ^ Armin Lange: Physical Medicine , page 150, Google Books Facsimile, accessed on December 1, 2011.
  3. ^ Therapeutic indications for thezeileis method , accessed on November 25, 2011.