Ultrasound Application Flashcards
Number of compressions - rarefactions cycles per second (MHz)
Frequency
An increased frequency equals
a decreased depth of penetration
3 MHz penetrates
1-2cm deep
1 MHz penetrates
Up to 5cm dependent on intensity and absorption
Sound is audible at
20 kHz (one KHz = 1000 cycles per second)
Percentage of time the sound head is delivering sound waves. This determines whether you are delivering continuous or pulsed ultrasound
Duty Cycle
Duty Cycle for Continuous ultrasound is
100%
Duty cycle for pulsed ultrasound is
20% (this reflects the sound head is on 20%)
How long do thermal effects last post tx.
8-10min
Use pulsed ultrasound in which stage
Acute stages, when the client does not improve from continuous or in cases where the client experiences periosteal pain (a dull ache)
Strength of the acoustic energy at the site of the application
Dosage or Intensity
How is intensity measured
Measured in power per unit area of the sound head - w/cm squared
Typical w/cm2 for therapeutic purposes
0.1-2.0
w/cm2 must be ____ to produce thermal effect
1.0
w/cm2 for acute conditions
0.1-0.5
w/cm2 for subacute conditions
0.5-1.0
w/cm2 for chronic conditions
1.0-2.0
w/cm2 used for pulsed ultrasound
0.7 or 0.8
Time of ultrasound
Duration of application of sound wave is measured in minutes
Duration of the ultrasound tx. is determined by
The area treated: Count how many sound heads it takes to cover the area you wish to treat. That number equals the number of minutes of treatment.
Typicalle 5-12min
Max number of treatments
12-14
Then you need to skip 2 weeks if you really need to continue.
(Ultrasound can deplete red and white blood cells which need time for re-generation)
8 contraindications for ultrasound
1) Never on the eye, heart, pregnant uterus, or reproductive organs.
2) Never over CNS tissue or pacemaker
3) Malignancy or area of infection
4) Area of decreased circulation or thrombophlebitis
5) Area of impaired sensation
6) Never a high intensity (over 1.0) over growth plates: Can do low intensity for under 18 years.
7) Never allow sound head to be stationary
8) Stop it the pt. has any pain
3 Precautions for ultrasound
1) Metal or plastic implants: Keep moving
2) Unhealed fracture sites
3) Acute inflammation or edema
Application of Ultrasound
Position body part in a position of relaxation, apply medium, and set parameters.
Spread medium evenly over testing tolerance for sound head pressure if needed.
While moving the sound head turn on, move constantly in an overlapping pattern.
Assure sound head is in full contact with skin entire time by rotating around body part to assure full contact.
