short wave diathermy srs

Sreeraj S R

SHORT WAVE DIATHERMY-

-

-

-

-

+

+

+

+

+

+

Sreeraj S R

�Dia means through

�Thermo means temperature /heat.

�Frequency of 27.12 MHz

�Wavelength greater than 11meter

Description

� High-frequency electrical currents› Radio waves

� Pass through the tissues

� Cause molecular vibration

� Results in deep heating

� Capable of heating large volumes of tissues

� Causes both thermal and non thermal effects

Sreeraj S R

Production

Sreeraj S R

Effects on Tissues

• Ionic motion

• Dipole rotation

• Molecular distortion

Sreeraj S R

Physiological effect

Effects on

1. Metabolism

2. Circulation

3. Nervous tissue

4. Muscle tissue

Sreeraj S R

Therapeutic Effect

Effects on

1. Inflammation

2. Bacterial Infection

3. Relief of pain

4. Traumatic conditions

5. Reduce healing time

Sreeraj S R

Types of Shortwave Diathermy

Induction Field

Capacitive Field

Sreeraj S R

Induction Field Diathermy

• Places the patient in theelectromagnetic field

• Current flowing within thecoil produces a rotatingmagnetic field

• Magnetic field produceseddy currents in the tissues

• Eddy currents cause frictionthat produce heat

• Selectively heats muscle

• Also referred to as:

– Magnetic field diathermy

Sreeraj S R

Capacitive Field Diathermy

• 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”

Sreeraj S R

TYPES OF ELECTRODES

� Flexible pads:

consist of metal

electrode

encased in rubber

and produce an

electrostatic field.

Sreeraj S R

TYPES OF ELECTRODES

• Space plates: consist

of a rigid metal

electrode encased in

a Perspex cover �

electrostatic field.

Sreeraj S R

TYPES OF ELECTRODES

• Coil or cable

electrode consists of

a wire with plugs at

either end creates

electromagnetic

field.

Sreeraj S R

TYPES OF ELECTRODES

• The monode :

flat, rigid coil

encased in plastic

cover

� electromagnetic

field.

Sreeraj S R

TYPES OF ELECTRODES

• The diplode : or

drum electrode,

consists of a flat coil

electrode encased in

a Perspex cover with

two wings

• � electromagnetic

field

Sreeraj S R

FACTORS INFLUENCE FIELD DISTRIBUTION IN S.W.D

� Spacing :

allows the lines of force in the electrostatic field to divergebefore entering the tissues. This prevents concentration ofheat in the superficial tissues and ensures more heatingthrough the part.

• Spacing provided by:

1. wrapping flexible pads in towel.

2. flat felt spacing pads

between pad electrode and

skin

3. air when using space plates.

Sreeraj S R


• Normal spacing �

even field distribution.

• Increased spacing � deep field concentration.

• Decreased spacing�superficial concentration.

Sreeraj S R


�Electrode size:

if the electrodes are too smallthan the diameter of treatedpart� line of force will beconcentrated superficially.

� If the electrodes are markedlylarger� the line of force willbe lost in the air.

� Ideally, the electrodes shouldbe slightly larger than the areatreated.

Sreeraj S R


• To concentrate heat

on one aspect of the

part the electrode

should be unequal in

size (smaller one

placed over the area

where concentration

of heat is required).

Sreeraj S R


• You can produce concentration of heat by

using equal size electrodes but with unequal

spacing (25 mm over concentrated area and

more than 30 mm on other electrode).

Sreeraj S R


• Metal: metal causes the lines of force to

concentrate on the metal

Sreeraj S R

THERAPEUTIC VARIATION IN THE FIELD DISTRIBUTION

• Coplanar application to treatstructures on one aspect of thebody. If the spacing is less than 25mm� more concentration in thesuperficial tissue. If spacingincreases� more depth achieved.

• The distance betweenadjacent ends must begreater than the sum of skinelectrode distance (A+B)otherwise the line of forcewill pass directly betweenelectrodes rather thantissues.

Sreeraj S R


• Contra planar applications

Two flexible pads, twospace plates orflexible pad with aspace plate are used.It is essential to put acotton towel betweenthe two limbs toabsorb anyperspiration.

Sreeraj S R


• Cross-fire application:

• For the treatment ofsinuses, space platespositioned diagonally,after half of treatmenttime the positions arealternate. This ensuresthat all aspects of thesinus membrane areheated.

• Care must be taken toavoid direct placementover the eye, uterinedisorders such asdysmenorrhoea.

Sreeraj S R


• Application using a

coil electrode:

1. The coil wound

evenly firmly

2. Pancake application

Sreeraj S R


• Application using

diplode:

• Adjust wings of

diplode parallel

to the skin of the

treated area,

electromagnetic

field will

produce.

Sreeraj S R

Dangers

1. Burns

• Concentration of electric field

• Excess current

• Impaired blood flow

• Hypersensitive skin

• Leads touching skin

2. Scalds

3. Electric shock

4. Overdose

5. Precipitation of gangrene

6. Faintness

7. Giddiness

Sreeraj S R

Contraindications

• Metal implants or metal jewelry (be aware of body piercings)

• Cardiac pacemakers

• Ischemic areas

• Peripheral vascular disease

• Perspiration and moist dressings: The water collects and concentrates the heat.

• Tendency to hemorrhage, including menstruation.

• Pregnancy

• Fever

• Sensory loss

• Cancer

• Deep X ray

• Tumours

• Unreliable patients

• Areas of particular sensitivity:

– Epiphyseal plates in children

– The genitals

– Sites of infection

– The abdomen with an implanted intrauterine device (IUD)

– The eyes and face

– Application through the skull

short wave diathermy srs

Technology