This document discusses therapeutic ultrasound. It defines ultrasound as acoustic vibrations too high for human hearing between 0.5-5 MHz. It describes ultrasound parameters like intensity, duration, and mark-space ratio. It discusses continuous and pulsed wave types and dosage considerations. Application methods like direct contact, immersion, and pads are covered. Physiological effects include increased blood flow and permeability. Indications include injuries while contraindications involve cancers or implants. Precautions to avoid burns are described.

1. THERAPEUTIC ULTRASOUND
Dr. Dheeraj Lamba
Associate Professor/ Head Department of
Physiotherapy

2. At the end of this lesson the student will be able to:
• State the definition of Ultrasound.
• Describe the Parameters of Ultrasound.
• Demonstrate the methods of application of ultrasound.
• Determine the dosage of ultrasound.
• Demonstrate an understanding about the Uses,
Physiological and therapeutic effects.
• Identify the contraindications and dangers.
• Demonstrate the method of Phonophoresis.
OBJECTIVES:

3. DEFINITION:
• A form of acoustic vibrations occurring at a frequency
that is too high to be perceived by the human ear.
• The therapeutic frequency is in the range of 0.5 to 5
MHz.
• Commonly used frequency in physiotherapy is 1MHz
and 3MHz.

4. PIEZOELECTRIC EFFECT :
• It is the ability of certain materials to generate an electric
charge in response to applied mechanical stress.
• Reverse piezoelectric effect –electrical energy is used to
produce mechanical stress and deformation

6. PARAMETERS
• Intensity / output.
• Duration
• Mark- Space ratio.

7. TYPES OF ULTRASOUND WAVES
• Continuous Wave - no interruption of beam: best for maximum
buildup, sometimes heat.
• Pulsed Wave - intermittent “on-off” beam modulation. It ensures that
the energy available in each pulse (pulsed averaged intensity) is
high enough for mechanical rather than thermal effects.
• It is represented as
• The mark : space ratio
It is the ratio of the pulse length to the interval.

9. Ultrasound Machine & Coupling Agent
Dispensers

10. METHODS OF APPLICATION
• Direct method / contact cream method.
• Bath method or immersion technique.
• Bag method.

11. Direct method
• Gel or Creams should be
applied over the
treatment part
• Only use approved
coupling agents.
• Remove air bubbles by
passing sound head over
area (before power is
increased)
© 2005 – FA Davis

12. Immersion Technique
• Used to treat irregularly
shaped areas.
• The limb is immersed in a
tub of degassed water.
• Transducer is held appx. 1”
from the body part.
• Avoid the formation of air
bubbles.
© 2005 – FA Davis

13. Pad (Bladder) Method
• A mass of conductive gel
– Commercial pads
– Self-made bladders
• Conforms to the
treatment area.
• Commercial pads help
limit the size of the
treatment area.
© 2005 – FA Davis

14. DOSAGE
MODES:
Continuous – to heat tissue/scar breakdown.
Pulsed (50%, 20%) – to heal tissue.
FREQUENCY:
1 MHz – US energy will penetrate to a depth of 2.5 to 5
cm. Given for deep lesions.
3 MHz – US energy will penetrate to a depth of 1.5 cm.
Given for superficial lesions.

15. INTENSITY:
 To heal: 0.05 – 0.8 W/cm2
 To heat:
0.8 w/cm2 – 1.0 w/cm2 for superficial tissues.
Greater than 1.5 w/cm2 for deeper tissues

16. MECHANICAL EFFECTS
• Cavitation's.
• Acoustic streaming.
• Standing waves.
• Micro massage.

17. Cavitations:
Formation of gas bubbles that expand & compress due to
pressure changes in tissue fluids.
• Stable cavitation
Occurs when the bubbles oscillate to and fro within the
ultrasound pressure waves but remain intact.
• Transient (or collapse) cavitation
Occurs when the volume of the bubble changes rapidly
and then collapses
Causes high pressure and temperature changes .
Results in gross damage to tissues.

18. Acoustic Streaming
• Unidirectional flow currents in a fluid due to the presence
of sound waves.
• Exerts viscous stress on the cell membrane and
increase membrane permeability.
Standing waves
• Formed due to reflected waves being superimposed on
the incident waves.
• Possibility of marked local heating where the amplitude
of the combined waves is high.

19. Micromassage
The micromassage effect of ultrasound occurs at a
cellular level where the cells are alternately compressed
and then pulled further apart.
The waves of compression and rarefaction may produce
a form of micromassage, which could reduce oedema.

21. PHYSIOLOGICAL EFFECTS
• Increased peripheral arterial blood flow.
• Increased tissue metabolism.
• Increased permeability of membrane.
• Increased pain threshold.
• Relief of muscle spasm.

22. THERAPEUTIC EFFECTS
• Pain relief.
• Resolution of inflammation.
• Effect on healing.

23. Physiological and therapeutic effects

24. INDICATIONS
• Bursitis.
• Tendonitis.
• Pressure sores.
• TMJ syndrome.
• Sports injuries.
• Capsulitis.
• Contractures
• Plantar fascitis.
• Calcaneal spur.
• Tennis / Golfer's elbow.
• Coccydynia.
• OA / RA.
• Scars.
.

25. CONTRAINDICATIONS
• Rapid dividing tissues -Neoplasm's
• Pregnant Uterus.
• Epiphyseal Plates
• Infections.
• Vascular Problems
Hemorrhage.
Hematoma.
Haemarthrosis.
Thrombosis.
Thrombophlebitis.
Ischemia.

26. • Radiotherapy.
• Metal / plastic / acrylic implant.
• Pace maker.
• Avoid specialized tissues – eyes, ears, ovaries and
testes.
• Central nervous system tissue.
• Anesthetic areas.

27. DANGERS
• Burns could occur if the heat generated exceeded the
physiological ability to dissipate it.
• Tissue destruction would result from transient cavitation.
• Blood cell stasis and endothelial damage may occur if
there is standing wave formation.
These dangers are more likely with high-intensity
continuous output with a stationary head or over bony
prominences.

28. PRECAUTIONS
• Check thermal sensation.
• Use the right dosage.
• Move the transducer.
• Avoid bony prominences.
• Avoid excess heat sensation.
• Don’t keep the ultrasound head in air when the machine
is ON.
• Maintain good contact between ultrasound head and
tissues.
• Test the equipment.

29. PHONOPHORESIS
It is the movement of drugs through skin into the
subcutaneous tissues under the influence of ultrasound.
• Ultrasound facilitates the passage of some drugs into
and through the skin.
• The effects are due both to absorption of the drug and to
the ultrasound.
• Lower ultrasonic frequencies lead to deeper drug
penetration.
• Pulsing ultrasound lead to better drug penetration.