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 tissues 3.0 MHz or 3.3 MHz penetrates more superficial tissues Phonophoresis – 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

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/podcasts.xhtml#discussions