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quiz #1 – ultrasound
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what is ultrasound
high-frequency sound waves >20,000 Hz
therapeutic ultrasound 1–3 million hertz
how deep does ultrasound penetrate
approximately 5 cm
how does ultrasound produce heat
through friction
true or false – absorption decreases with density of tissue
True
False
false – absorption increases with density of tissue
what is cavitation
the creation of bubbles
bad for blood
cerebral spinal fluid– don't cross the spinal cord, okay to go parallel with the spinal cord
eyes- don't go over forehead
what does this picture represent
refraction
What is refraction?
a change in direction of the soundwave due to different density of tissues
what does this picture represent
reflection
What occurs with reflection?
the wave doesn't penetrate but instead bounces off
true or false – the periosteum of the bone is at risk for burns when performing ultrasound
True
False
true- this would occur due to reflection
what is piezoelectric effect
AC passes into crystal which vibrates at same frequency as AC
what is transduction
change of one energy to another
Vibration to electricity and electricity to vibration
how is the intensity of ultrasound measured and what is a typical value used in the clinic?
Watts/cm squared or Watts
.5-2.5 watts/cm squared
true or false – crystals in ultrasound heads are now synthetically made
True
False
true
the typical outlet has a frequency of _____ Hz
And power of _______V
60 Hertz
120 V
Inductor
Resistor
capacitor
which frequency will penetrate the body at a greater depth?
A) 1 MHz
B) 3 MHz
A) 1 MHz
how long does the typical ultrasound treatment last
5– 10 min.
what are some examples of coupling medias
ultrasound gel
water
true or false – ultrasound treatments always cover a large area
True
False
false – areas treated are always small
what are some of the therapeutic effects of ultrasound
relieve pain– thermal effect
increase elasticity of tissue – thermal effect
reduce inflammation – thermal effect
break adhesions/mineral deposits – mechanical effect
push drugs through the skin – mechanical effect (steroid products)
what are the indications for ultrasound
subacute/chronic inflammation
joint contractures
muscle spasms
scar tissue (be careful with thermal modality on a scar)
trigger points
calcium deposits
plantar warts
chronic ulcers
what are some of the contraindications for ultrasound
acute inflammation
hemorrhage
vital organs – heart, neck, etc.
epiphyseal growth plates
fractures (will break up the new callus)
malignant tumor (break off cancerous cells)
pregnant abdomen
infection
thrombophlebitis (causes swelling and pain)
impaired sensation
impaired circulation
metal implants
Author
BPT
ID
64111
Card Set
quiz #1 – ultrasound
Description
ultrasound
Updated
2011-02-27T01:57:41Z
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