therapeutic ultrasound

Therapeutic Therapeutic UltrasoundUltrasound

Chapter 8Chapter 8

DescriptionDescription

Acoustical energy (sound waves) Acoustical energy (sound waves) above the range of human hearingabove the range of human hearing– Therapeutic range: 0.75 to 3.3 MHzTherapeutic range: 0.75 to 3.3 MHz

Effects:Effects:– ThermalThermal– Nonthermal (mechanical)Nonthermal (mechanical)

UsesUses

Calcific bursitisCalcific bursitis Inflammatory conditionsInflammatory conditions Joint contracturesJoint contractures PainPain Muscle spasmMuscle spasm Acute orthopedic injuries (low pulses, Acute orthopedic injuries (low pulses,

low intensity) low intensity)

Production of UltrasoundProduction of Ultrasound

An alternating current An alternating current is passed through a is passed through a crystalcrystal

The current causes the The current causes the crystal to vibratecrystal to vibrate– Electropiezo effectElectropiezo effect

Vibrating crystal Vibrating crystal produce high-produce high-frequency sound frequency sound waveswaves

Effective Radiating Area Effective Radiating Area (ERA)(ERA)

Area of the crystal that Area of the crystal that actually produces sound actually produces sound waveswaves– Produces more than 5% of Produces more than 5% of

the energy at 5 mm from the energy at 5 mm from the transducer facethe transducer face

ERA is always smaller than ERA is always smaller than the transducer facethe transducer face

Energy is concentrated Energy is concentrated near the centernear the center

ERA

Beam ProfileBeam Profile Multiple waves emerge Multiple waves emerge

from the headfrom the head Energy diverges as it Energy diverges as it

moves away from the moves away from the sourcesource

Energy is uniform close to Energy is uniform close to the headthe head– Near zone (Fresnel zone)Near zone (Fresnel zone)

Becomes less consistent Becomes less consistent farther away from the farther away from the headhead– Spatial peak intensitySpatial peak intensity Spatial Peak Intensity

Beam Nonuniformity Ratio Beam Nonuniformity Ratio (BNR)(BNR)

Describes the amount of variation Describes the amount of variation in the beamin the beam

Ratio between:Ratio between:– Spatial peak intensity (SPI)Spatial peak intensity (SPI)– Average intensity (SAI - metered Average intensity (SAI - metered

output)output)– BNR = SPI/SAIBNR = SPI/SAI

Perfect beam would have a BNR Perfect beam would have a BNR of 1:1of 1:1

Minimally acceptable BNR is 8:1Minimally acceptable BNR is 8:1 The actual peak output is equal The actual peak output is equal

to the SAI * the BNRto the SAI * the BNR– 10 W total output * 6:1 BNR10 W total output * 6:1 BNR– 60 watt SPI60 watt SPI

Spatial Peak Intensity

Spatial Average Intensity(Displayed on the unit)

Modes of ApplicationModes of Application

ContinuousContinuous Ultrasonic energy is constantly producedUltrasonic energy is constantly produced Can produce thermal effects based on:Can produce thermal effects based on:

– Output intensityOutput intensity– Treatment durationTreatment duration

PulsedPulsed Ultrasonic output is regularly interruptedUltrasonic output is regularly interrupted Produces nonthermal effectsProduces nonthermal effects

Pulsed OutputPulsed Output

Ultrasonic output is cycled Ultrasonic output is cycled “On” and “Off”“On” and “Off”– On = Pulse lengthOn = Pulse length– Off = Pulse intervalOff = Pulse interval

Expressed as a Expressed as a Duty Duty CycleCycle– ON/(ON+OFF) * 100ON/(ON+OFF) * 100– 20mSec/(20mSec+10mSec) 20mSec/(20mSec+10mSec)

* 100* 100– 20/30 * 10020/30 * 100– 67%67%

Continuous Output (100% Duty Cycle)

Pulsed Output (67% Duty Cycle)

Output FrequencyOutput Frequency

Measured in megahertz (MHz)Measured in megahertz (MHz)– 1 MHz = 1,000,000 waves per 1 MHz = 1,000,000 waves per

secondsecond Determines the depth of effectsDetermines the depth of effects 1 MHz Output1 MHz Output

– Penetrates 5 to 7 cmPenetrates 5 to 7 cm– Thermal effects last longerThermal effects last longer– More divergent beamMore divergent beam

3 MHz Output3 MHz Output– Penetrates 2 to 3 cmPenetrates 2 to 3 cm– Heats 3 times faster than 1 MHz Heats 3 times faster than 1 MHz

outputoutput– More collimated beamMore collimated beam

Power and IntensityPower and IntensitySpatial Average IntensitySpatial Average Intensity

Spatial Average Temporal Peak Spatial Average Temporal Peak IntensityIntensity

Spatial Average Temporal Average Spatial Average Temporal Average IntensityIntensity

Spatial Average Intensity Spatial Average Intensity (SAI)(SAI)

Describes the energy per unit of areaDescribes the energy per unit of area Total output (watts)/areaTotal output (watts)/area

– Watts/effective radiating area (cmWatts/effective radiating area (cm22))– W/cmW/cm22

15 watts being applied with a 10 cm15 watts being applied with a 10 cm22 ERA ERA – 15 Watts / 10 cm15 Watts / 10 cm22

– 1.5 W/cm1.5 W/cm22

Power Measures – Pulsed Power Measures – Pulsed OutputOutput

Spatial Average Temporal Spatial Average Temporal Peak Intensity (SATP)Peak Intensity (SATP)

The average energy The average energy delivered during the “On” delivered during the “On” time of the duty cycle.time of the duty cycle.

Spatial Average Temporal Spatial Average Temporal Average Intensity Average Intensity (SATA)(SATA)

Energy delivered over timeEnergy delivered over time– Spatial Average Intensity * Spatial Average Intensity *

Duty CycleDuty Cycle Meaningful only during Meaningful only during

pulsed outputpulsed output

Biophysical EffectsBiophysical Effects

ThermalThermal

Thermal EffectsThermal Effects Increased sensory nerve conduction velocityIncreased sensory nerve conduction velocity Increased motor nerve conduction velocityIncreased motor nerve conduction velocity Increased extensibility of collagen-rich Increased extensibility of collagen-rich Increased vascular permeability structuresIncreased vascular permeability structures Increased collagen depositionIncreased collagen deposition Increased blood flowIncreased blood flow Reduction of muscle spasmReduction of muscle spasm Increased macrophage activityIncreased macrophage activity Enhanced adhesion of leukocytes to damaged Enhanced adhesion of leukocytes to damaged

endothelial cellsendothelial cells

Heating ClassificationsHeating Classifications

IncreaseIncrease Used ForUsed For

MildMild 11°°CC Mild inflammationMild inflammationAccelerate metabolismAccelerate metabolism

ModerateModerate 22°° – 3 – 3°°CC Decreasing muscle Decreasing muscle spasmspasm

Decreasing painDecreasing painIncreasing blood flowIncreasing blood flowChronic inflammationChronic inflammation

VigorousVigorous 33°° – 4 – 4°°CC Tissue elongationTissue elongationScar tissue reductionScar tissue reduction

Heating RateHeating Rate

Heating rate and magnitude is based Heating rate and magnitude is based on:on:– Duty cycleDuty cycle– Output frequencyOutput frequency– IntensityIntensity– Target tissuesTarget tissues– Size of the treatment areaSize of the treatment area

Thermal EffectsThermal Effects Same as other heat modalitiesSame as other heat modalities

– Smaller volume of tissueSmaller volume of tissue– Shorter duration of effectsShorter duration of effects

Preheat the skin with a moist heat packPreheat the skin with a moist heat pack– Decreases the time to reach vigorous heatingDecreases the time to reach vigorous heating

Poorly vascularized, collagen-rich tissues Poorly vascularized, collagen-rich tissues are preferentially heatedare preferentially heated– Fascia, tendon, scar tissueFascia, tendon, scar tissue

Tissues containing an increased proportion Tissues containing an increased proportion of fluid do not heat as wellof fluid do not heat as well– Adipose tissue, articular fluidAdipose tissue, articular fluid


NonthermalNonthermal

Nonthermal EffectsNonthermal Effects Increased cell membrane Increased cell membrane

permeabilitypermeability Altered rates of diffusion Altered rates of diffusion

across the cell membraneacross the cell membrane

Increased vascular Increased vascular permeabilitypermeability

Secretion of cytokines Secretion of cytokines

Increased blood flowIncreased blood flow Increased fibroblastic Increased fibroblastic

activity activity Stimulation of Stimulation of

phagocytosis phagocytosis

Granulation tissue Granulation tissue productionproduction

Synthesis of proteinSynthesis of protein Synthesis of Synthesis of

collagencollagen Reduction of edemaReduction of edema Diffusion of ionsDiffusion of ions Tissue regenerationTissue regeneration Formation of Formation of

stronger deformable stronger deformable connective tissue connective tissue

Nonthermal ApplicationNonthermal Application

Pulsed outputPulsed output– 20 to 25% duty cycle20 to 25% duty cycle– Nonthermal output intensityNonthermal output intensity

Continuous outputContinuous output– 100% duty cycle100% duty cycle– Output intensity of less than 0.3 W/cmOutput intensity of less than 0.3 W/cm22

Acoustical StreamingAcoustical Streaming

Ultrasound causes interstitial Ultrasound causes interstitial fluids to flowfluids to flow

Fluids strike cell membranesFluids strike cell membranes Produce Produce eddy currentseddy currents Eddy currents displace ions Eddy currents displace ions

and moleculesand molecules Alter:Alter:

– Cell membrane permeabilityCell membrane permeability– Cellular functionCellular function

Effect on Injury Effect on Injury ResponseResponse

Cellular ResponseCellular Response

Acoustical streaming:Acoustical streaming:– Increases cell membrane permeabilityIncreases cell membrane permeability– Alters cell membrane diffusion rateAlters cell membrane diffusion rate– Increased histamine releaseIncreased histamine release– Mast cell degranulationMast cell degranulation– Increased rate of protein synthesisIncreased rate of protein synthesis

Thermal effects:Thermal effects:– Increased cell metabolismIncreased cell metabolism– Increased rate of inflammationIncreased rate of inflammation

InflammationInflammation

May lead to an earlier onset of May lead to an earlier onset of proliferationproliferation– Increased fibroblast proliferationIncreased fibroblast proliferation– Release of growth factors and plateletsRelease of growth factors and platelets

Increased macrophage activityIncreased macrophage activity Leukocytes bind to damaged Leukocytes bind to damaged

endothelial cellsendothelial cells Cell division is increasedCell division is increased

InflammationInflammation

Frequency SpecificityFrequency Specificity 1 MHz Output1 MHz Output

– Release of preformed fibroblastsRelease of preformed fibroblasts 3 MHz Output3 MHz Output

– Increased synthesis and secretion of Increased synthesis and secretion of fibroblast precursorsfibroblast precursors Increased in areas of high collagen Increased in areas of high collagen

concentrationconcentration

Blood and Fluid DynamicsBlood and Fluid Dynamics

May increase blood flow for 45 May increase blood flow for 45 minutesminutes– Thermal effectsThermal effects– Decreased vascular toneDecreased vascular tone– Histamine releaseHistamine release

Causes vasodilationCauses vasodilation

Moist heat application prior to Moist heat application prior to treatment decreases net increase in treatment decreases net increase in blood flowblood flow

Pain ControlPain Control

Direct Pain ReductionDirect Pain Reduction Increased nerve cell sodium permeabilityIncreased nerve cell sodium permeability Alters nerve functionAlters nerve function Increases pain thresholdIncreases pain thresholdIndirect Pain ReductionIndirect Pain Reduction Increased blood flowIncreased blood flow Increased capillary permeabilityIncreased capillary permeability Increased oxygen deliveryIncreased oxygen delivery Decreased muscle spasmDecreased muscle spasm

Muscle SpasmMuscle Spasm

Reduced secondary to:Reduced secondary to:– Decreased painDecreased pain– Altered nerve conduction velocityAltered nerve conduction velocity– Increased temperature (counterirritant Increased temperature (counterirritant

effect)effect)– Muscle relaxationMuscle relaxation

Tissue ElasticityTissue Elasticity

Ultrasound preferentially heats collagen-Ultrasound preferentially heats collagen-rich tissues (tendon, fascia, scar tissue)rich tissues (tendon, fascia, scar tissue)

Temperature must be increased 7.2Temperature must be increased 7.2°°FF Stretching window lasts approximately 3 Stretching window lasts approximately 3

minutes following the treatmentminutes following the treatment– Place tissues on stretch during applicationPlace tissues on stretch during application– Perform stretching/mobilization immediately Perform stretching/mobilization immediately

following the treatmentfollowing the treatment Multiple treatments are required to gain Multiple treatments are required to gain

lengthlength

Wound HealingWound Healing

Tendon HealingTendon Healing Continuous US application Continuous US application

may:may:– Increase tensile strengthIncrease tensile strength– Increase collagen depositionIncrease collagen deposition

Skin UlcersSkin Ulcers 3 MHz, low-intensity 3 MHz, low-intensity

pulsed output may assist pulsed output may assist the healing processthe healing process

Cover the wound with an Cover the wound with an occlusive dressingocclusive dressing

Electromagnetic FieldElectromagnetic Field

In vitro bone deformation produces In vitro bone deformation produces piezoelectric currents and streaming piezoelectric currents and streaming potentialspotentials

Electromagnetic (EM) devices are based Electromagnetic (EM) devices are based on Wolff’s Law that bone responds to on Wolff’s Law that bone responds to mechanical stress: Exogenous EM fields mechanical stress: Exogenous EM fields may simulate mechanical loading and may simulate mechanical loading and stimulate bone growth and repairstimulate bone growth and repair

Clinical efficacy very controversialClinical efficacy very controversial

Types of EM DevicesTypes of EM Devices

MicroamperesMicroamperes Direct electrical currentDirect electrical current Capacitively coupled electric fieldsCapacitively coupled electric fields Pulsed electromagnetic fields Pulsed electromagnetic fields

(PEMF)(PEMF)

PEMFPEMF

Approved by the FDA for the treatment of Approved by the FDA for the treatment of non-unionsnon-unions

Efficacy of bone stimulation appears to be Efficacy of bone stimulation appears to be frequency dependentfrequency dependent– Extremely low frequency (ELF) sinusoidal Extremely low frequency (ELF) sinusoidal

electric fields in the physiologic range are most electric fields in the physiologic range are most effective (15 to 30 Hz range)effective (15 to 30 Hz range)

– Specifically, PEMF signals in the 20 to 30 Hz Specifically, PEMF signals in the 20 to 30 Hz range appear more effective than those below range appear more effective than those below 10 Hz10 Hz

UltrasoundUltrasound

Low-intensity ultrasound is approved Low-intensity ultrasound is approved by the FDA for stimulating healing of by the FDA for stimulating healing of fresh fracturesfresh fractures

Modulates signal transduction, Modulates signal transduction, increases gene expression, increases increases gene expression, increases blood flow, enhances bone blood flow, enhances bone remodeling and increases callus remodeling and increases callus torsional strength in animal modelstorsional strength in animal models


Human clinical trials show a Human clinical trials show a decreased time of healing in fresh decreased time of healing in fresh fracturesfractures

Has also been shown to decrease the Has also been shown to decrease the healing time in smokers potentially healing time in smokers potentially reversing the ill effects of smokingreversing the ill effects of smoking

Fracture HealingFracture Healing Low-intensity pulsed Low-intensity pulsed

outputoutput Accelerates rate of fracture Accelerates rate of fracture

healing for:healing for:– Acute fracturesAcute fractures– Nonunion fracturesNonunion fractures– Stress fracturesStress fractures

Requires specialized unitRequires specialized unit Biophysical Effects:Biophysical Effects:

– Mechanical (sound) energy Mechanical (sound) energy strikes bonestrikes bone

– Microvibration of bone Microvibration of bone triggers growth triggers growth (osteogenesis)(osteogenesis)

PARAMETERSPARAMETERSFrequencyFrequency 1.5 MHz1.5 MHzERAERA 3.88 cm3.88 cm22

IntensityIntensity 30 mW/cm30 mW/cm22

Treatment DurationTreatment Duration 20 minutes20 minutesDailyDaily

ContraindicationsContraindications Acute conditions (thermal Acute conditions (thermal

mode)mode) Ischemic areasIschemic areas Areas of impaired Areas of impaired

circulationcirculation Over areas of deep vein Over areas of deep vein

thrombosisthrombosis Anesthetic areasAnesthetic areas Over cancerous tumors Over cancerous tumors Sites of active infection or Sites of active infection or

sepsissepsis Over the spinal cord or Over the spinal cord or

large nerve plexus in high large nerve plexus in high dosesdoses

Exposed penetrating metal Exposed penetrating metal (eg, external fixation (eg, external fixation devices) devices)

Around the eyes, heart, Around the eyes, heart, skull, or genitalsskull, or genitals

Over the thorax in the Over the thorax in the presence of an implanted presence of an implanted pacemakerpacemaker

Pregnancy when used over Pregnancy when used over the pelvic or lumbar areasthe pelvic or lumbar areas

Over a fracture site before Over a fracture site before healing is completehealing is complete

Stress fracture sites or Stress fracture sites or sites of osteoporosissites of osteoporosis

Over the pelvic or lumbar Over the pelvic or lumbar area in menstruating area in menstruating female patients female patients

Where are we going?Where are we going?

UltrsoundUltrsound Ultrasound uses:Ultrasound uses:

– Diagnostic (low intensity) Diagnostic (low intensity) FractureFracture

– Surgical (high intensity)Surgical (high intensity)

– TherapeuticTherapeutic

Therapeutic US widely used Therapeutic US widely used for deep heatfor deep heat


Primary clinical use:Primary clinical use:– Soft tissue repairSoft tissue repair

– Pain relief (analgesia)Pain relief (analgesia)

Effective Radiating Area Effective Radiating Area (ERA)(ERA)

Total area on surface of Total area on surface of transducer producing soundwavetransducer producing soundwave

Ideally ERA should match size of Ideally ERA should match size of transducertransducer

Treatment area should not Treatment area should not exceed 2-3 times ERAexceed 2-3 times ERA

Frequency of UltrasoundFrequency of Ultrasound Determined by number of times Determined by number of times

crystal deformed/sec.crystal deformed/sec. 2 most common utilized in U.S.2 most common utilized in U.S.

– 1.0 MHz1.0 MHz

– 3.0 MHz3.0 MHz

Determines depth of penetration, Determines depth of penetration, unlike ESunlike ES

Frequency of UltrasoundFrequency of Ultrasound Inverse relationship between frequency Inverse relationship between frequency

and depth of penetrationand depth of penetration Penetrating depths:Penetrating depths:

– 1.0 MHz: 2-5 cm1.0 MHz: 2-5 cm

– 3.0 MHz: 1-2 cm3.0 MHz: 1-2 cm Absorption rate increases with higher Absorption rate increases with higher

frequencyfrequency

Pulsed vs ContinuousPulsed vs Continuous

Most new generators produce Most new generators produce bothboth

Both produce thermal & Both produce thermal & nonthermal effectsnonthermal effects

Pulsed vs ContinuousPulsed vs Continuous Continuous:Continuous:

– Sound intensity remains the sameSound intensity remains the same– Commonly used for thermal effectsCommonly used for thermal effects

Pulsed vs ContinuousPulsed vs Continuous Pulsed:Pulsed:

– Intensity periodically interruptedIntensity periodically interrupted– Average intensity reduced over timeAverage intensity reduced over time

Physiological Effects Physiological Effects of Ultrasoundof Ultrasound

Thermal effectsThermal effects

Non-thermal effectsNon-thermal effects

– CavitationCavitation

– Acoustic microstreamingAcoustic microstreaming

Thermal EffectsThermal Effects

Clinical effects:Clinical effects:

– Increased extensibility of collagen Increased extensibility of collagen fibersfibers tendonstendons

joint capsulejoint capsule

– Decreased joint stiffnessDecreased joint stiffness

Thermal EffectsThermal Effects Clinical effects:Clinical effects:

– Reduction in muscle spasmReduction in muscle spasm

– Pain modulationPain modulation

– Increased blood flowIncreased blood flow

– Increased nerve conductionIncreased nerve conduction

Thermal EffectsThermal Effects Primary advantage of USPrimary advantage of US

– Selective heating of tissues high in Selective heating of tissues high in collagencollagen

– Non-thermal effects are occurringNon-thermal effects are occurring

Non-thermal (Mechanical) Non-thermal (Mechanical) EffectsEffects

Primary physiological Primary physiological effects are cavitation and effects are cavitation and acoustic microstreamingacoustic microstreaming

Cavitation:Cavitation:– Formation of gas-filled Formation of gas-filled

bubbles in tissue fluidsbubbles in tissue fluids– Expansion/compression of Expansion/compression of

bubbles either stable or bubbles either stable or unstableunstable


Acoustic microstreaming:Acoustic microstreaming:– Unidirectional movement of Unidirectional movement of

fluids along cell membrane fluids along cell membrane boundariesboundaries

– Produces high viscous Produces high viscous stressesstresses

– Alters membrane structure & Alters membrane structure & functionfunction

– Increased permeability to Increased permeability to ionic influxionic influx


Potential therapeutic effects from Potential therapeutic effects from cavitation & microstreamingcavitation & microstreaming

– Stim. of fibroblast activity increases Stim. of fibroblast activity increases protein synthesis & tissue repairprotein synthesis & tissue repair

– Increased blood flowIncreased blood flow

– bone healing & repair of non-union bone healing & repair of non-union fracturesfractures

UltrasoundUltrasound IndicationsIndications

– Increase deep tissue Increase deep tissue heatheat

– Decrease Decrease inflammationinflammation

– Decrease muscle Decrease muscle spasmsspasms

– Decrease painDecrease pain– Increase extensibility Increase extensibility

of collagen tissueof collagen tissue– Decrease pain of Decrease pain of

neuromasneuromas– Decrease joint Decrease joint

adhesionsadhesions– Treat myositis Treat myositis

ossificansossificans

ContraindicationsContraindications– HemorrhageHemorrhage– InfectionInfection– ThrombophlebitisThrombophlebitis– Suspected malignancySuspected malignancy– Impaired circulation or Impaired circulation or

sensationsensation– Stress fracture sitesStress fracture sites– Epiphyseal growth Epiphyseal growth

platesplates– Over the Eyes, Heart, Over the Eyes, Heart,

Spine, or genitalsSpine, or genitals

Treatment FrequencyTreatment Frequency

Ultrasound has cumulative effectsUltrasound has cumulative effects

· Daily for 10 days – low irritability and · Daily for 10 days – low irritability and scarscar

· 3-4 times/week – moderate irritability · 3-4 times/week – moderate irritability for 3-for 3- 4 weeks 4 weeks

· 2 times /week – high irritability 4-5 · 2 times /week – high irritability 4-5 weeksweeks

· If no change after 3-4 sessions, change · If no change after 3-4 sessions, change settings or discontinue. settings or discontinue.

· Stop after 10-15 treatments· Stop after 10-15 treatments

Sound Head MovementSound Head Movement

Never stay stationaryNever stay stationary Keep it moving, slow and gentle with Keep it moving, slow and gentle with

constant pressure.constant pressure. This will minimize the risk of creating This will minimize the risk of creating

unstable cavitation andunstable cavitation and Standing waves that is detrimental Standing waves that is detrimental

damaging to soft tissuedamaging to soft tissue 1 inch = 1 second1 inch = 1 second

Movement of the Movement of the TransducerTransducer

4 cm4 cm22/sec/sec Remaining stationary can cause problemsRemaining stationary can cause problems Moving too rapidly decreases the total Moving too rapidly decreases the total

amount of energy absorbed per unit areaamount of energy absorbed per unit area– May cause clinician to treat larger area and the May cause clinician to treat larger area and the

desired temps. May not be attaineddesired temps. May not be attained Slower strokes can be easier maintainedSlower strokes can be easier maintained If patient complains of pain or excessive If patient complains of pain or excessive

heat, then heat, then decrease intensitydecrease intensity but increase but increase timetime

Apply constant pressure – not too much & Apply constant pressure – not too much & not too littlenot too little

Coupling AgentsCoupling Agents Optimal agent – distilled HOptimal agent – distilled H220 0 (.2% reflection)(.2% reflection)

Modern units have a shut down Modern units have a shut down mechanism if sound head becomes too hot mechanism if sound head becomes too hot (Dynatron beeps; red lights on (Dynatron beeps; red lights on Chattanoogas)Chattanoogas)– Improperly coupled head causes Improperly coupled head causes temp. temp.

Types of agents:Types of agents:– DirectDirect

– HH220 immersion0 immersion

– BladderBladder Reduce amount of air bubblesReduce amount of air bubbles

Direct CouplingDirect Coupling

Effectiveness is Effectiveness is if body part is hair, if body part is hair, irregular shaped, or uncleanirregular shaped, or unclean

Must maintain firm, constant Must maintain firm, constant pressurepressure

Various gels utilized Various gels utilized

Water ImmersionWater Immersion Used for odd shaped partsUsed for odd shaped parts Place head approx. 1” away from partPlace head approx. 1” away from part Operator’s hand should not be Operator’s hand should not be

immersed No metal on part or immersed No metal on part or operator’s handoperator’s hand

Ceramic tub is recommendedCeramic tub is recommended If nondistilled HIf nondistilled H220 is used, intensity can 0 is used, intensity can

be be .5 w/cm .5 w/cm22 because of air & minerals because of air & minerals Don’t touch skin except to briefly sweep Don’t touch skin except to briefly sweep

skin when bubbles formskin when bubbles form

Bladder Bladder

HH220 filled balloon or plastic bag 0 filled balloon or plastic bag coated with coupling gelcoated with coupling gel

Use on irregular shape partUse on irregular shape part Place gel on skin, then place the Place gel on skin, then place the

bladder on the part, and then place bladder on the part, and then place gel on bladdergel on bladder

Make sure all air pockets are Make sure all air pockets are removed from bladderremoved from bladder

US SpecificsUS Specifics

BurningBurning Tissue DensityTissue Density Gel applicationGel application Burning the US head with no tissue Burning the US head with no tissue

contactcontact

PhonophoresisPhonophoresis

DescriptionDescription

Use of therapeutic ultrasound to Use of therapeutic ultrasound to assist in diffusion of medication assist in diffusion of medication through the skinthrough the skin

Increases the diameter of skin Increases the diameter of skin portals to allow the medication to portals to allow the medication to passpass– PoresPores– Hair folliclesHair follicles


Medication is introduced over a large Medication is introduced over a large areaarea– Relative to an injectionRelative to an injection

NoninvasiveNoninvasive Medication may not be filtered by the Medication may not be filtered by the

liverliver– Reducing metabolic elimination of the Reducing metabolic elimination of the

medicinemedicine

Transdermal ApplicationTransdermal Application

Medication must diffuse through:Medication must diffuse through:– Enzymatic barrier of the epidermisEnzymatic barrier of the epidermis– Stratum corneumStratum corneum

Rate-limiting barrier to absorptionRate-limiting barrier to absorption Medications must be able to diffuse across Medications must be able to diffuse across

this barrierthis barrier

Medication is stored in subcutaneous Medication is stored in subcutaneous tissues for some time before being tissues for some time before being diffused deeperdiffused deeper

Skin InfluencesSkin Influences

Medication uptake is improved when Medication uptake is improved when the skin is:the skin is:– Well hydratedWell hydrated– Has a high density of skin portalsHas a high density of skin portals– Highly vascularizedHighly vascularized– Relatively thinRelatively thin– ““Younger” skin tends to have better Younger” skin tends to have better

diffusion characteristics than “older” diffusion characteristics than “older” skin.skin.

Ultrasound Influences on Ultrasound Influences on DiffusionDiffusion

Thermal EffectsThermal Effects Increase kinetic energyIncrease kinetic energy Increase portal cross-sectionIncrease portal cross-section Increase circulationIncrease circulation Increase capillary permeabilityIncrease capillary permeabilityNonthermal EffectsNonthermal Effects Altered cell resting potentialAltered cell resting potential Increased cell membrane permeabilityIncreased cell membrane permeability Increased molecular permeabilityIncreased molecular permeability

Phonophoresis MedicationsPhonophoresis Medications

Either prescription or nonprescriptionEither prescription or nonprescription Low molecular size and weightLow molecular size and weight

– Most medications used can be applied Most medications used can be applied transdermally without ultrasoundtransdermally without ultrasound

Controlled medications require a Controlled medications require a prescription prescription for the patient being treatedfor the patient being treated

Medication is often mixed in an inert Medication is often mixed in an inert basebase– Base must be able to transmit ultrasonic Base must be able to transmit ultrasonic

energyenergy

Common MedicationsCommon Medications

TypeType IndicationsIndications ExampleExample

Corticosteroid Corticosteroid Inflammation Inflammation HydrocortisoneHydrocortisone

DexamethasoneDexamethasone

SalicylatesSalicylates InflammationInflammation

PainPain

AnestheticAnesthetic PainPain LidocaineLidocaine

Trigger pointsTrigger points

Application TipsApplication Tips

Moist heat pack prior to application:Moist heat pack prior to application:– Increase blood flowIncrease blood flow– Increase kinetic energyIncrease kinetic energy– Increase skin portalsIncrease skin portals

Following treatmentFollowing treatment– Leave medication on skinLeave medication on skin– Cover with an occlusive dressingCover with an occlusive dressing– Moist heat pack re-application Moist heat pack re-application maymay

assist in further absorptionassist in further absorption

Low-frequency US Low-frequency US PhonophoresisPhonophoresis

Parameters:Parameters:– 20 kHz output frequency20 kHz output frequency– 125 mW/cm125 mW/cm22

– Pulsed outputPulsed output Benefits:Benefits:

– Allows medications with a larger size Allows medications with a larger size and weight to diffuseand weight to diffuse

– More efficient medication deliveryMore efficient medication delivery

therapeutic ultrasound

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