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Shortwave Shortwave Diathermy Diathermy Chapter 9 Chapter 9

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Page 1: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Shortwave Shortwave DiathermyDiathermy

Chapter 9Chapter 9

Page 2: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

DescriptionDescription

High-frequency electrical currentsHigh-frequency electrical currents– Radio wavesRadio waves

Pass through the tissuesPass through the tissues Cause molecular vibrationCause molecular vibration Results in deep heatingResults in deep heating Capable of heating large volumes of Capable of heating large volumes of

tissuestissues Causes both thermal and nonthermal Causes both thermal and nonthermal

effectseffects

Page 3: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

UsesUses

Thermal EffectsThermal Effects Deep heatDeep heat Increased blood Increased blood

flowflow Increased cell Increased cell

metabolismmetabolism Increased tissue Increased tissue

extensibilityextensibility Muscular relaxationMuscular relaxation Possible changes in Possible changes in

enzyme reactionsenzyme reactions

Nonthermal EffectsNonthermal Effects Edema reductionEdema reduction Lymphedema Lymphedema

reductionreduction Superficial wound Superficial wound

healinghealing Treatment of Treatment of

venous stasis venous stasis ulcersulcers

Page 4: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Types of Shortwave Types of Shortwave DiathermyDiathermy

Induction FieldInduction FieldCapacitive FieldCapacitive Field

Page 5: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Induction Field Induction Field DiathermyDiathermy

Places the patient in the Places the patient in the electromagnetic fieldelectromagnetic field

Selectively heats muscleSelectively heats muscle Also referred to as:Also referred to as:

– Condenser field diathermyCondenser field diathermy– Magnetic field diathermyMagnetic field diathermy

Page 6: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Induction Field Diathermy Induction Field Diathermy (Cont.)(Cont.)

A coil is housed within a A coil is housed within a drumdrum

Current flowing within Current flowing within the coil produces a the coil produces a rotating magnetic fieldrotating magnetic field

Magnetic field produces Magnetic field produces eddy currents in the eddy currents in the tissuestissues

Eddy currents cause Eddy currents cause friction that produce heatfriction that produce heat

Although rare, cables are Although rare, cables are sometimes used in place sometimes used in place of drumsof drums

Page 7: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Capacitive Field DiathermyCapacitive Field Diathermy

Uses the patient’s tissues as a part of the circuitUses the patient’s tissues as a part of the circuit The tissues’ electrical resistance produces heatThe tissues’ electrical resistance produces heat Selectively heats skinSelectively heats skin

– Muscle is heated via conduction from the adiposeMuscle is heated via conduction from the adipose Also referred to as “condenser field diathermy”Also referred to as “condenser field diathermy”

Page 8: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Capacitive Field Diathermy Capacitive Field Diathermy (Cont.)(Cont.)

Heat is produced by Heat is produced by the dipole effectthe dipole effect

Charge particles Charge particles within membrane within membrane align with the fieldalign with the field

The movement The movement produces heatproduces heat

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Page 9: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Modes of ApplicationModes of Application

ContinuousContinuous Increases tissue temperatureIncreases tissue temperature Increased risk of burnsIncreased risk of burns

PulsedPulsed May or may not increase temperatureMay or may not increase temperature Pulses allow for increased treatment Pulses allow for increased treatment

intensity and durationintensity and duration Not the same as “nonthermal”Not the same as “nonthermal”

Page 10: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Ultrasound & SWD Ultrasound & SWD Comparison Comparison

UltrasoundUltrasound Shortwave DiathermyShortwave DiathermyEnergy typeEnergy type AcousticalAcoustical ElectromagneticElectromagneticTissue heatedTissue heated Collage-richCollage-rich C: Skin, adipose tissueC: Skin, adipose tissue

I: Muscle, vesselsI: Muscle, vesselsTissue volumeTissue volume Small (20 cmSmall (20 cm22)) Large (200 cmLarge (200 cm22))Temp increaseTemp increase 1 MHz: > 6.31 MHz: > 6.3°°FF C: > 7C: > 7°°FF

3 MHz: > 14.93 MHz: > 14.9°°FF I: > 18I: > 18°°FFHeat retentionHeat retention 3 min3 min > 9 min> 9 min

C = Capacitive methodC = Capacitive methodI = Induction methodI = Induction method

Page 11: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Biophysical EffectsBiophysical Effects

InflammationInflammation Assists in removal of cellular debris Assists in removal of cellular debris

and toxinsand toxins Nonthermal:Nonthermal:

– Alters diffusion rate across the cell Alters diffusion rate across the cell membranemembrane

ThermalThermal– Increases intramuscular metabolismIncreases intramuscular metabolism

Page 12: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Biophysical EffectsBiophysical Effects

Blood and Fluid DynamicsBlood and Fluid Dynamics Vasodilation increases:Vasodilation increases:

– Blood flowBlood flow– Capillary filtrationCapillary filtration– Capillary pressureCapillary pressure– Oxygen perfusionOxygen perfusion

Increased fibroblastic activity and capillary Increased fibroblastic activity and capillary growthgrowth

Effects occur deeper than other forms of Effects occur deeper than other forms of heatheat

Page 13: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Biophysical EffectsBiophysical Effects

Tissue ElasticityTissue Elasticity SWD can vigorously heat deep SWD can vigorously heat deep

tissues tissues Alters collagen properties, allowing it Alters collagen properties, allowing it

to elongateto elongate Requires stretching during and/or Requires stretching during and/or

immediately following the treatmentimmediately following the treatment Multiple treatments are requiredMultiple treatments are required

Page 14: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

Biophysical EffectsBiophysical Effects

Wound HealingWound Healing Nonthermal SWD increases rate of Nonthermal SWD increases rate of

phagocytosisphagocytosis Number of mature collage bundles Number of mature collage bundles

increaseincrease ATP activity increases (assisting ATP activity increases (assisting

wound regeneration)wound regeneration) Necrosed muscle fibers decreaseNecrosed muscle fibers decrease

Page 15: Shortwave Diathermy Chapter 9. Description High-frequency electrical currents High-frequency electrical currents –Radio waves Pass through the tissues

ContraindicationsContraindications Metal implants or metal Metal implants or metal

jewelry (be aware of body jewelry (be aware of body piercings)piercings)

Cardiac pacemakersCardiac pacemakers Ischemic areasIschemic areas Peripheral vascular diseasePeripheral vascular disease Perspiration and moist Perspiration and moist

dressings: The water dressings: The water collects and concentrates collects and concentrates the heat.the heat.

Tendency to hemorrhage, Tendency to hemorrhage, including menstruation.including menstruation.

PregnancyPregnancy Fever Fever

Sensory lossSensory loss CancerCancer Areas of particular Areas of particular

sensitivity:sensitivity:– Epiphyseal plates in Epiphyseal plates in

childrenchildren– The genitalsThe genitals– Sites of infectionSites of infection– The abdomen with an The abdomen with an

implanted intrauterine implanted intrauterine device (IUD)device (IUD)

– The eyes and faceThe eyes and face– Application through the Application through the

skullskull