Diathermy

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Diathermy

• Shortwave and Microwave Daithermy

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General Information

• Another form of deep heat
• Out of favor with the PT community for the last
  several years.
• In general shortwave diathermy is effective for
  deep heating of deeper structures.
• Microwave diathermy has been used for smaller
  body parts such as the hands

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Indications

• Any condition where it is desirable to increase
  the temperature mild to moderately.
• Increase the extensibility of tissues in
  musculoskeletal disorders

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Contraindications

• Acute conditions
• Tumors
• Metallic implants
• Foreign bodies
• PPM

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Precautions Specific to Diathermy

• 1. Use special care to avoid contact between skin
  and cables from main unit.
• 2. During treatment, do not allow pt. to touch
  metallic objects
• 3. Be especially vigilant with pateitns where
  loss of normal sensation may result such as DM,
  Arteriosclerosis

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Where is Diathermy on the EMS?

• Diathermy is located in the radio frequency
  portion of the EMS. Diathermy uses nonionizing
  electromagnetic energy from the spectrum.

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Wavelength?

• Shortwave diathermy- 11meters (3-30m).
• Microwave diathermy- 12cm (.03-3m)
• Secondary to its long wavelength, it has potent
  effects in deeper tissues of underlying m and CT.
  Tissue type, position of the body part and
  position of the diathermy electrodes influence
  the oscillation frequency in the pt. circuit.

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How does the pt get diathermy?

• Oscillation circuitry transfers energy to the
  patient. The pt. oscillation circuit has to be
  in resonance with the machine circuit.
• This is done by matching the frequency of the pt.
  circuit, with that of the machine.
• Like tuning in a radio.
• Some units self tune

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Procedure to tune pt. in

• Check the output indicator without changing the
  power output.
• When the output indicator is at its max point the
  two are in tune.
• When in tune, the oscillating frequency of the
  pt. circuit resultant output is gt10mHz

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Frequency

• SWD 27.12 mHz
• MWD2450mHz

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Types of Shortwave Diathermy

• Induction field diathermy strong magnetic
  forces are produced by the pt. circuit which then
  induces a electrical current within the body
  part. A single induction field coil is made of
  metal shaped into a coil, which is highly
  conductive. Deepest form of Diathermy

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Types cont

• Capacitive field Separate pads or airspaced
  drums are used as the electrode. The pt. is
  placed between the electrodes or the plastic
  drums. The intensity and depths of penetration
  are determined by the shape and distance between
  the electrodes. Much is absorbed by fat. Most
  effective when there is little fat. Field is
  placed perpendicular to the area to be heated.

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Capacitive field
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Induction field