1. Ultrasound

2. Ultrasound What is Ultrasound
Defined as sound w/ frequency > 20,000 cycles per sec
Ultrasound travels thru materials
Thermal & non-thermal properties

3. Ultrasound Terminology
Transducer (sound head) – converts electrical energy into sound energy
Power (W) – amount of sound energy per unit of time
Intensity (W/cm2) – amount of power per unit time

4. Ultrasound
Terminology
Continuous US
Pulsed US

5. Ultrasound Terminology Pulsed US Duty cycles
20% duty cycle – 20% on : 80% off
50% duty cycle – 50% on : 50% off

6. Ultrasound Terminology Frequency – number of cycles per sec (Hz)
1.0 MHz penetrates deeper tissues
3.0 MHz or 3.3 MHz penetrates more superficial tissues
Phonophoresis – application of US with a topical drug

7. Generation of Ultrasound
Crystals in the sound head expand & contract in response to electrical current resulting in resonating ultrasound

8. Effects of Ultrasound
Thermal Effects
Tissues Affected

9. Effects of Ultrasound Thermal Effects
Factors Affecting the Amount of Temperature Increase
Areas of increased collagen content achieve higher temps
Areas of greater circulation cooler faster
Thicker tissues heat slower

10. Effects of Ultrasound Thermal Effects
Applying Other Physical Agents in Conjunction With Ultrasound
Hot pack prior to US
US & electrical stimulation
US & cryotherapy – used to limit/control thermal effects of US

11. Effects of Ultrasound Nonthermal Effects Increase intracellular Ca
Increase skin & membrane permeability (phonophoresis)
Increase macrophage response
Increase protein synthesis by fibroblasts

12. Clinical Applications of Ultrasound
Soft Tissue Shortening
Thermal effects
Pain Control

13. Clinical Applications of Ultrasound
Dermal Ulcers
Thermal effects
Increased macrophage activity
Increased protein synthesis by fibroblasts

14. Clinical Applications of Ultrasound
Surgical Skin Incisions
Thermal effects
Increase macrophage response
Increase protein synthesis by fibroblasts

15. Clinical Applications of Ultrasound
Tendon Injuries
Thermal effects
Increase macrophage response
Increase protein synthesis by fibroblasts

16. Clinical Applications of Ultrasound

17. Clinical Applications of Ultrasound
Bone Fractures
Promotes healing
Simulates osteoblast activity
Increase intracellular Ca
Reabsorption of Calcium Deposits
Unknown how this occurs

18. Clinical Applications of Ultrasound
Carpal Tunnel Syndrome
Phonophoresis
Unit on phonophoresis in your book is required reading

23. Contraindications for the Use of Ultrasound
Malignant Tumor
Pregnancy
Central Nervous System Tissue
Joint Cement

24. Contraindications for the Use of Ultrasound
Plastic Components
Pacemaker
Thrombus
Eyes
Reproductive Organs

25. Precautions for the Applications of Ultrasound
Acute Inflammation
Epiphyseal Plates
Fractures (high frequency US)
Breast Implants

26. Adverse Effects of Ultrasound
Adverse effects are “rare”
Burn is the most common adverse effect

29. Ultrasound
Autosound video

35. Torn Peroneal Tendon After Lateral Ankle Sprain

36. Use of Ultrasound Debate