Ultra Sound Flashcards
What is sound?
Sound consists of waves that transmit energy by alternating compressing and rarefying material
“Ultra” means what for Usound?
- Usound can be greater then 20,000 Hz
How is sound transmitted?
Through a medium that travels through a material
What is the definition of frequency in sound waves?
The number of compression - rarefaction cycles per unit of time, expressed in cycles per second or Hz
At what frequency is therapeutic Usound used?
3 HHz million cycles per second
What determines which frequency is used with therapeutic ultrasound?
It depends on the depth of tissue needed to pernetrate
Continuous Usound
- Increases tissue temperature
Pulsed Usound
Non-thermal effects
Duty Cycle for Usound?
is the amount of on/off time
Continuous Duty Cycle?
100%
Mot common duty cycle for pulsed Usound?
1/5 Ratio, 20%/80%
In what measurement is the intensity of the Usound registered on the Usound unit?
W/cm^2
Cavitation
The formation, growth and pulsation of gas-filled bubbles caused by Usound
Stable Cavitation
- Bubbles oscillate in size throughout many cycles, but don’t burst
Unstable Cavitation
Bubbles grow over a number of cycles and suddenly implode
ERA
Effective Radiating Area
Contraindications of Usound
- Malignant Tumor
- Pregnancy
- CNS Tissue
- Joint Cement
- Plastic Components
- Pacemaker
- Thrombophlebitis
- Eyes
- Reproductive Organs
- Superficial Bone
What is the purpose of thermal treatment of Usound?
- Increase metabolic rate
- Decrease pain
- Decrease mm spasm
- Alternation of nerve conduction velocity
- Increase circulation
- Increase soft tissue extensibility
What should take place immediately after Usound?
- Exercise
- Stretching
- STM
- Use it or lose it
How long should Usound be done?
5-10 minutes, 2x the size of the ERA
If a pt reports pain with Usound what should you do?
Adjust parameters or stop treatment and check pt
What can cause pain with Usound?
- Intensity is too high or low
- Holding Usound head in one spot
- Not enough medium
- Not keeping the Usound head flat
Amount of Gel used?
Enough medium to eliminate air between area and sound head
Movement of Usound head?
Over lap by 1/2 of ERA, circles, switchback, figure 8
