Microwave diathermy (MWD) is a therapeutic modality that uses electromagnetic radiation between 300-3000MHz to induce deep heating of tissues. MWD generates an electrical field that is strongly absorbed by fluid-rich tissues, causing ionic movement and heat. It can effectively penetrate tissues to a depth of 4.5cm. MWD is used to relieve pain, promote healing, and increase tissue extensibility through its physiological effects on metabolism, blood supply, and nerves. Proper application of MWD requires screening for contraindications, monitoring for safety, and documentation of treatment parameters.

1. MICROWAVE DIATHERMY
(MWD)

2. Diathermy
Diathermy is a Greek word for “ through heating”, in which
a high frequency (>10.000Hz)
An electromagnetic current is applied to induce deep
heating within body tissue, to induce physiological effects
for therapeutic purposes.
1. Shortwave Diathermy (SWD)
2. Microwave Diathermy(MWD)
3. Pulsed Electromagnetic (PEM)

3. Microwave Diathermy
 Microwave Diathermy (MWD) is a high-frequency
electromagnetic radiation that lies between infrared and
shortwave.
 Their frequency ranges between 300-3000MHz, with
corresponding wavelengths of 1m-10mm.

4. Microwave Diathermy Generator
 Power supply
 Magnetron
 Timing circuit
 Applicators (emitter, a director)

5. Principles Of MWD
 Deep heating modality
 Emits strong electrical field/ little magnetic field.
 Depth of penetration is frequency dependent.
 Produces much more localized & concentrated heating
effect than SWD.
 Providing a more shallow tissue heating effect, depends on
the type of tissue involved.
 Reflection, Refraction, and Absorption

6. Principle Of MWD
 MWD are strongly absorbed by tissues with high fluid
content and are heated most, while penetrated by tissues
with low fluid content (e.g. fat or bones).
 Tissues with low water content (fat) are penetrated to a
greater depth (half value thickness=3.5cm).
 Tissue with high water content (muscle, blood) is
penetrated to a superficial depth (=0.7cm).
The effective depth of MWD penetration (half-value depth)
is about 4.5 cm, so the depth of heating is intermediate
between that of infrared radiation (2cm) and short wave
diathermy (>5cm).

7. Principle of MWD
 The patients does not form apart of the circuit in MWD, so no
tuning is necessary as in SWD.
 Transmits as free space radiation, so needs only one emitter
(applicator).
 No Metal should be within 4 feet of MWD, since it will
interfere with the signal.
 Spacing is required between the skin and the applicators
with MWD, where the applicator on a short wave unit my be
placed in contact with treatment area.

8. Physiological and Therapeutic Effects of MWD
When the electromagnetic radiation of MWD enters the
body causes
◦ Ionic movement (vibration).
◦ Rotation of dipoles.
◦ Distortion of the non-polar molecule
Physiological effects Therapeutic effects
Effects on metabolism
Effects on blood supply
Effects on nervous tissue
Effects on muscular tissue
Effects on sweat glands
Relief of pain and muscle spasm
Promote healing
Infection
Increase the extensibility

9.  Soft tissue injury
 Mobilization
 Pain relief
 Eyes: Irradiation to the eyes may develop
opacities/cataracts.
 Malignancy: should not be applied to regions of malignant
growth or tuberculosis.
 Cardiac pacemakers
 Genital area (sterility)
 Pregnancy (miscarriage, hemorrhage)
 Unreliable patients
 Metallic implants,
 Hypersensitivity to heat,
 Impaired sensation
 Circulatory defects: Such as hemorrhage, thrombosis,
phlebitis, and other vascular lesions.
Contradictions of MWD
Indications

10. Burn
1. Poor techniques
2. Inability of tissue to dissipate heat (circulatory defect)
3. Inability to detect heat (impaired sensation)
4. Implanted metal
5. Moist skin
6. Treatment near the eye
Pregnancy (miscarriage, hemorrhage)
Damage to the eye
Damage to the equipment
Dangerous of MWD

11. Microwave Diathermy
Advantages
 Operation of the machine is simple
 Comfortable for the patient
 Localized heat to small surfaces
 No overheating if precautions are followed
Disadvantages
 Not for deep structures
 Heats only one aspect of the joint
 Risk of burn

12. General Guideline &
Safety
 Question patients (contraindications and previous treatment).
 Position of the patient ( comfort, support, relaxed).
 Inspect the part to be treated (check for skin rashes, infection, or
open wounds).
 If indicated, drape the area with toweling.
 Place electrodes on the treated area then switch on the machine.
 Set pulse duration, pulse frequency, and treatment time, and adjust
intensity.
 Periodically ask the patient if the heating is too vigorous.
 When the timer shuts off, terminate the treatment and turn all dials
to zero.
 Assess treatment efficiency ( inspect area, feedback from patients ).
 Record treatment parameters

13. THANK YOU