UltraSound Flashcards
When is 1 mHz absorbed? US
5-7 cm
when is 3 mHz absorbed? US
3 cm
What would you use for deep muscles? US
1 mHz
what would you use for superficial muscles? US
3 mHz
Which frequency will heat the fastest? US
3 mHz
How is US treatment time calculated?
treatment time is 2x ERA
10cm2 ERA = Rx time would be 5-10 min
What is the beam non-uniformity ratio?
ratio between the transducers peak intensity and spatial intensity
smaller ratios mean beam is more uniform
should be 6:1
what is spatial average intensity?
avg intensity of the US output over area of transducer
what is spatial peak intensity?
peak intensity over area of transducer
Attenuation rates
Blood-3
Fat-13
Muscle-24
Blood vessel-32
Skin-39
Tendon-59
Cartilage-68
Bone-96
Where is peak beam? US
Central third of ERA
What is the reverse piezoelectric effect?
Crystal is compressed and expanded by sending SC through it which causes a compression and expansion of the crystals
Does intensity have anything to do with depth of penetration?
No
How is frequency and depth penetration related
Inversely proportional
Spatial avg intensity equation
Power (watts)/ ERA (cm2)
What duty cycle is used for pulsed US?
20 %
How is duty cycle calculated ?
Duration of pulse (time on)/ pulse period(time on +time off)
How do you get significant US heating ?
US must be applied to an area 2x the size of ERA
vigorous heating
increase of about 7 deg
will result in increase distensibility
what is the insurance cap for US
8 min
1mhz heat 6 F
11 min
3mHz heat 6F
6 min
max US treatments
2-3xweek
10-15 treatments
effects of thermal US
-increased collagen extensibility
-increase blood flow
-decrease pain
-reduction of Muscle spasms
-decrease joint stiffness
-reduction of chronic inflammation
effects of nonthermal US
-increased fibroblastic activity
-increased protein synthesis
-tissue regen
-reduction of edema
-bone healing
-pain modulation
-modulate membrane properties
-alter cellular proliferation
-increase in proteins assosciated with inflammation
-could modify inflammatory response
-impact protein function
what is the baseline muscle temp
36-37 deg C
mild heating in US
increase 1 deg C to acc metabolic rate
mod heating in US
increase 2-3 deg C to reduce muscle spasms, pain, chronic inflammation, increase blood flow
vigorously heating in US
increase 3-4 deg C decreases viscoelastic properties of collagen
what does US depend on
size of treatment area
settings of US
condition
vigoruous heating
1mHz 10-12 min
how fast should you move the sound head?
4cm/sec
US thermal contraindications
pregnancy
active bone growth
Tb
active bleeding
impaired circulation
cancer
US thermal precautions
plastic or cemented implants
spinal cord injury
US Pulsed contra indication
cancer
active bleeding
pregnancy
US pulsed precautions
active bone growth
area of infection
acute injury
impaired cognition
skin disease
plastic or cemented implants
nerve injuries
US for phonophoresis
US to enhance absorption of topical agents
hydrocortisone or analgesics applied
3 mhz
20%
.5-.75 w/cm2
5-10 min
US for soft tissue shortening
increases extensibility, decreases risk of tissue damage
continous
1 or 3 mHz
2-3 w/cm2
5-10 min
3-5x week
US for Dermal ulcers
accelerate healing of vascular and pressure ulcers
1 mHz
duty:20%
1 W/Cm 2
5 min
3-5xweek
US for acute tendon injuries
increase permability and cell degranulation, histamine release, rate of protein synthesis, macrophage response
1-3 mHz
20%
.8-1.2 w/cm2
5-10min
12 treatments over 4-6 weeks
US for chronic tendon injuries
accelerate metabolic rate, reduce ms spasm/pain, alterate nerve conduction, increase circulation, increase soft tissue extensibility
1-3 mHz
100%
1-2 w/cm2
5-10 min
12 treatments over 4-6 weeks
US for tendon repairs
faciliate healing
1-3 mHz
100%
.5-1.5 w/cm2
3-5 min
decrease intensity to minimze adverse effects postop
US for bone fracture
acc bone healing??
controversial
continous
1-1.5 w/cm2
20%
15-20 min daily
US for carpal tunnel syndrome
continous
1 or 3 mHz
.5-1.5 w/cm2
5-10 min
5x/week for 4 weeks
US for bursitis
1 or 3 mHz
1 w/cm2
5-10 min
3xweek/ 3-4 weeks
