ultrasound. ultrasound what is ultrasound what is ultrasound defined as sound w/ frequency >...
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Ultrasound
Ultrasound
What is Ultrasound Defined as sound
w/ frequency > 20,000 cycles per sec
Ultrasound travels thru materials
Thermal & non-thermal properties
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
Ultrasound
Terminology Continuous US Pulsed US
Ultrasound Terminology
Pulsed US Duty cycles
20% duty cycle – 20% on : 80% off
50% duty cycle – 50% on : 50% off
Ultrasound
Terminology Frequency – number of cycles per
sec (Hz)1.0 MHz penetrates deeper tissues3.0 MHz or 3.3 MHz penetrates more
superficial tissuesPhonophoresis – application of US
with a topical drug
Generation of Ultrasound
Crystals in the sound head expand & contract in response to electrical current resulting in resonating ultrasound
Effects of Ultrasound
Thermal Effects Tissues Affected
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
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
Effects of Ultrasound
Nonthermal Effects Increase intracellular Ca Increase skin & membrane
permeability (phonophoresis) Increase macrophage response Increase protein synthesis by
fibroblasts
Clinical Applications of Ultrasound
Soft Tissue Shortening Thermal effects
Pain Control Thermal effects
Clinical Applications of Ultrasound
Dermal Ulcers Thermal effects Increased
macrophage activity
Increased protein synthesis by fibroblasts
Clinical Applications of Ultrasound
Surgical Skin Incisions Thermal effects Increase
macrophage response
Increase protein synthesis by fibroblasts
Clinical Applications of Ultrasound
Tendon Injuries Thermal effects Increase
macrophage response
Increase protein synthesis by fibroblasts
Clinical Applications of Ultrasound
Clinical Applications of Ultrasound
Bone Fractures Promotes healing Simulates
osteoblast activity Increase
intracellular Ca Reabsorption of
Calcium Deposits Unknown how this
occurs
Clinical Applications of Ultrasound
Carpal Tunnel Syndrome Phonophoresis
Unit on phonophoresis in your book is required reading
Contraindications for the Use of Ultrasound
Malignant Tumor Pregnancy Central Nervous System Tissue Joint Cement
Contraindications for the Use of Ultrasound
Plastic Components Pacemaker Thrombus Eyes Reproductive Organs
Precautions for the Applications of
Ultrasound Acute Inflammation Epiphyseal Plates Fractures (high frequency US) Breast Implants
Adverse Effects of Ultrasound
Adverse effects are “rare” Burn is the most common adverse
effect
Ultrasound
Autosound video
Torn Peroneal Tendon After Lateral Ankle Sprain
Use of Ultrasound Debate http://ptjournal.apta.org/site/misc/podca
sts.xhtml#discussions