Therapeutic Ultrasound is a deep heating modality used in physiotherapy to provide relief from pain and facilitate healing process

1. BY
ODUENYI CHRISTIAN
PHYSIOTHERAPY DEPARTMENT
BENUE STATE UNIVERSITY TEACHING
HOSPITAL(BSUTH), MAKURDI.
9/15/2015
1
Therapeutic Ultrasound in
Physiotherapy

2. Introduction
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Ultrasound is used in medicine for:
Diagnosis
Destruction of tissue
Therapy

3. Definition
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Ultrasound is a mechanical vibration at any
frequency above the audible sound range
Ultrasound therapy (UST) is the application of ultra
frequency sound waves (1 – 3MHZ) to tissues in
order to promote healing and reduce pain and
swelling.
Therapeutic Us used in physiotherapy ranges from
0.5 to 5MHZ but most us machine are set at 1MHZ
and/or 3MHZ
Classified as a deep heating modality

4. Production of ultrasound
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The inverse piezoelectric effect is used in production of
ultrasonic sound waves.
Examples of piezoelectic materials are quartz,barium
titanate and lead zirconate titanate (PZT).
Application of high frequency alternating current to the
PZT crystal of the transducer transforms the electrical
energy into vibratory sound wave (ultrasound)s

5. Transmission of US wave
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Through solid, liquid and gases in form of
compression and separation of molecule
Normally cylindrical and longitudinal in fashion
Velocity higher in materials of high density
Air 340 m/s, water 1410m/s, muscle 1540m/s, Bone
3500m/s.

6. Properties of ultrasound beam
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Reflection
Refraction Attenuation
Absorption
 Passing through the tissue US energy is dissipated =
attenuation
 Half Value Distance = 4cm for 1MHZ and 2cm for
3MHZ
 Acoustic Impedance(Z)

7. Depth of penetration
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 1MHZ= deeper tissues at
depth 3 to 5cm
 3MHZ= superficial
Tissues at depth 1 to 2cm
 Depth of Penetration is
inversely proportional to
frequency
Near and Far Field
 Wave fonts from
different parts travel
different distances
causing interference
between adjacent fonts

8. Near and far field
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 The near field also
known as the Fransel
zone is the convergent
region
 The far field known as
the fraunhofer zone is
the divergent region
 Length of Fresnel zone =
r2 / λ where r=radius of
transducer.
 Therapeutic us utilizes
the near field
 Frequency of US and
radius of transducer
need to be considered for
tissue depth above
6.5cm(shortest)

9. Coupling media
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 Ultrasound waves are not transmitted by air, thus
some couplant which does transmit them must be
interposed
 Unfortunately no couplant affords perfect
transmission & only a percentage of the original
intensity is transmitted to the patient.
Aquasonic gel 72.6%
Glycerol 67 %
Distilled water 59 %
Petroleum jelly 0 %
Air 0 %

10. Characteristics of a coupling media
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1. Acoustic impedance similar to tissue
2. High transmissivity for US
3. Low suceptibility to bubble formation
4. Chemically inactive in nature
5. A hypoallergic character
6. High viscosity
7. Cheap
8. Relative sterility

11. US beam parameters
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 Mode type : continuous and pulsed. Pulsed Mark
Space(M:S) ratio: 1:1, 1:2, 1:4 etc.
 Power: amount of acoustic energy per unit time (watts)
 Intensity: power per unit area of the ultrasound head
(watts/cm2). Space average intensity and time
averaged/space average intensity(pulsed).
 Frequency: number of compression-rarefaction cycles
per unit of time, usually expressed in cycles per second
(Hertz)
 Effective radiating area (ERA): The area of the
transducer from which the US energy radiates
 Duty cycle: The proportion of total treatment the
ultrasound was on

12. Depth of penetration
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Majority of the ultrasound generators used in
physiotherapy are set at a frequency of 1MHZ and/or
3MHZ.
The depth of penetration of ultrasound beam is
inversely proportional to the frequency
1MHZ ultrasound beam has a depth of penetration of
3-5cm and absorbed in deeper tissues
3MHZ ultrasound beam with a depth of penetration of
1-2cm and is absorbed in the superficial tissues

13. Treatment Protocols
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Preparation of the Machine
Preparation of the Patient
Set up the treatment
Termination of treatment
Documentation

14. Protocols
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 Preparation of the machine
 Position
 Inspect
 Be assured of functionality
 Bring all accessories closer:
• Aquasonic gel
• Cotton wool
• Methylated spirit
• Water in a bowl
 Preparation of the patient
 Inform your patient
 Remove metals
 Expose the Rx part
 Remove hair if necessary
 Wash or swab
 Inspect the Rx part
 Check for intact sensation
 Demand co-operation
 Set-up up the Rx
 Secure pt.'s comfort and stability of Rx
part
 Plug dead, supply and power on
 Select Rx programme
 Apply coupling media
 Ensure the transducer is in contact with
the coupling media on the skin
 Start now
 Keeping asking how the pt.'s feels

15. protocols
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 Termination
 Return intensity to zero
 Remove transducer
 Cut the mains supply
 Clean the skin and the
transducer
 Inspect
 Documentation
 Date
 Machine
 Intensity
 Frequency
 Mode
 duration
 Coupulant
 Region
 Response of Rx`

16. Application
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Principles
 Rx surface parallel to the skin
 Even pressure maintained to
exclude air and balance
irregularities in sonic field
 Transducer moved
continuously over the skin
surface
 Rate of movement must be
slow enough to allow tissue to
deform and fast enough to
avoid hot spots
 Pattern of movement- series
of overlapping parallel
strokes, circles or figure 8
Techniques of Application
1. Direct contact
2. Water bath: degased water
of comfortable temperature,
transducer held 1cm
parallel to the skin inside
the water keeping
3. Water bag

17. Dosage
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 Factors to consider
 Receny of injury
 Depth of tissue
 Nature of the lesion
 Size of the area
 Attenuation
 Area of transducer
 Acute conditions
 Intensity: 0.25 or 0.5
watts/cm2
 Time: 2-3minutes
 Failure to improve progress to
0.8watts/cm2 or increase
time to 4 0r 5minutes
 Chronic conditions
 Start dose: 0.8watts/cm2 for
4minutes
 Failure to improve progress to
1watts/cm2 for 4minutes,
1watts /cm2 for 6minutes, to
1.5watts/cm2 for 6minutes,
1.5watts/cm2 for 8minutes,
2watts/cm2 for 8minutes
 Note: A dose of 2watts/cm2
for 8minutes is maximum
permitted

18. Physiological effects
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Chemical Reactions
Biological Responses
Mechanical Responses
Thermal Effects

19. Physiological effects
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 Chemical reaction
Ultrasound vibration
stimulate tissue to enhance
chemical reactions and
processes and ensure
circulation of necessary
elements and radicals for
recombination.
 Biological responses
 Increase membrane
permeability which
enhances transfer of fluid
and nutrients to tissues
 Acoustic Streaming: is
unidirectional flow of
tissue components which
occurs particularly at the
cell membrane. Streaming
produce changes in the rate
of protein synthesis and
could thus have a role in
the stimulation of repair.

20. Physiological effects
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 Mechanical responses
 micro massage: cells are
alternately compressed and
then pulled further apart.
This increase mobility of
intracellular fluids and
thus helps to reduce
oedema.
 Tendon extensibility:
ultrasound apparently
increases the extensibility
of tendons, muscles and
scar tissues.
 Thermal effects: as
ultrasonic waves are
absorbed they are
converted to thermal
energy (heat)

21. Clinical application of US
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 Soft tissue injuries
 Oedema
 Varicose ulcers
 Pain control
 Chronic rheumatoid and arthritic conitions
 Tendon injuries
 Resorption of calcium deposits
 Bone fractures
 Carpal tunnel syndrome
 phonophoresis

22. Contraindications
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Vascular conditions
Radiotherapy
Tumours
Pregnancy
Cardiac disease
Implant
Anaesthetic area
Acute sepsis

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Time to Demonstrate

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Ask your Questions and make your
contributions

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A Big Thank You