types of diathermy final presentation ppt

1. 1. Shortwave Diathermy (SWD)
2. Microwave Diathermy(MWD)
3. Ultrosonic Diathermy

2.  Microwave Diathermy (MWD) is a high frequency
electromagnetic radiation lies between infrared
and shortwave. Their frequency ranges
between 300-3000MHz, with corresponding
wavelengths of 1m-10mm.
Frequency MHz Wavelength Cm
2450 12.33
915 32.7
433.9 69

3.  Power supply
 Magnetron
 Timing circuit
 Applicators (emitter, a director)

4.  The high frequencies of
micro-thermy are obtained
from the magnetron,
which is perforated with
tiny holes, through which
the electrons flow into the
treatment heads.
 The special design of the
treatment heads shapes
focuses the field directly at
the target area.
 The whole device is used to
direct the waves onto the
tissues.

5. Applicator must be very flat to avoid reflection of
energy .
Circular shape Rectangular shaped
Diameter 4-6inches 4.5X5/ 5X21 inches
Temperature Maximum at periphery of
each radiation area
Maximum at central of
radiation area

6.  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 Absorption,

7.  MWD are strongly absorbed by tissues with high fluid
content 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) are
penetrated to 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).

8. Principle Related to Use 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.

9. When the electromagnetic radiation of MWD enters the body
causes
 Ionic movement (vibration).
 Rotation of dipoled.
 Distortion of 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

10. 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

11. Spacing of Applicators
 For small treatment area is 2-6cm
 For large treatment area is 10-15cm
The MWD requires warm-up period of 4 minutes, to allowed the
magnetron to develop enough energy
Intensity of Treatment
 Sensation of warmth
 Feel no more than a mild comfortable warmth.
Trim of Treatment: 20 -30minutes
Frequency of Treatment; daily or alternating days
depending on
 Response to treatment
 Patients condition/availability

13.  Def.: SWD is a modality that produces
deep heating via conversion of
electromagnetic energy to thermal energy.
 The pattern of heat produced depend on:
Freq. used.
Type of SWD unit.
Water content of the tissues.

14.  Shortwave diathermy current freq.
10 – 100 MHz
 (The shortest radiofrequency wave is used in therapeutic
diathermy.)
 the commonly used in medical work having
freq. of 27.12 MHz with wavelength of 11
meters

15.  Modalities:
 either continuous or pulsed (PSWD).
 PSWD: application of series of short pulses
of SWD so that short periods of SWD
interrupted by gaps where there is no SWD.
 The pt. receives lower dose of SWD energy
if compared with continuous SWD applied of
the same time.
 The tissues will receive lower thermal load.

16.  SWD: produce both deep and sup. Tissue
heating, under certain controlled conditions
 it’s applied for 20 min at the max tolerable
dose

17.  Induction Field
 Capacitive Field

18. • Places the patient in
the electromagnetic field
• Current flowing within the
coil produces a
rotating magnetic field
• Magnetic field produces
eddy currents in the tissues
• Eddy currents cause friction
that produce heat
• Selectively heats muscle
• Also referred to as:
 – Magnetic field diathermy

19. • Uses the patient’s tissues
as a part of the circuit
• The tissues’
electrical
resistance produces heat
• Selectively heats skin
– Muscle is heated via
conduction from the
adipose
• Also referred to as “condenser
field diathermy”

20.  Flexible pads: consist
of metal electrode
encased in rubber
and produce an
electrostatic field.

21. • Space plates:
consist of a rigid
metal electrode
encased in
 a Perspex cover
electrostatic
field.

22.  Coil or cable
electrode consists of
a wire with plugs
at either end creates
electromagnetic
field.

23. • The monode :
flat, rigid coil
encased in
plastic cover 
electromagnetic
field.

24. • The diplode :
or drum
electrode, consists of
a flat coil electrode
encased in a Perspex
cover with two wings
 electromagnetic
field

25. ULTRASOUND DIATHERMY
 Ultrasound diathermy uses sound waves to treat
deep tissues.
 Heat is generated by the vibration of the tissue.
 This promotes blood flow into the area.
 It is used for many types of musculoskeletal sprains,
strains, and fractures.

26. LONGWAVE DIATHERMY
 Long wave diathermy is based on capacitor field
method.
It can work in heavy voltage fluctuation
Long wave can be used as an alternative for shortwave
diathermy applications.
 it is portable and light weight .

27. DIATHERMY PROVIDES RELIEF IN:
 ARTHRITIS
BACK PAIN
MUSCLE SPASMS
NEURALGIA
MYOSITIS
SPRAINS AND STRAINS
TENDONITIS
BONE INJURIES
BURSITIS

28. UNWANTED EFFECTS
OF DIATHERMY
The electromagnetic energy used in diathermy can cause
extreme heat in metal devices such as bone pins, dental
fillings, and metal sutures causing burns
 During diathermy treatment, the patient becomes a part
of the electrical field. Touching a bare metal object, such
as a cabinet, during diathermy can cause a shock or burn.

29. RISKS ASSOCIATED
WITH DIATHERMY
Diathermy should be avoided in following cases:
 implanted metal devices
 peripheral vascular disease
 tissue with restricted blood supply (ischemia)
 cancer
 bleeding disorders , wound dressings
 severe heart, liver, or kidney conditions
 pregnancy