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Ultrasound > Therapeutic US > Flashcards

Therapeutic US Flashcards

1
Q

What frequency is US?

A

> 20,000 Hz

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2
Q

What frequency is therapeutic US?

A

1.0-3.0MHz

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3
Q

What type of tissue can be treated with therapeutic US?

A

soft tissue 1-5cm deep

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4
Q

the transducer contains what type of crystal? how is it deformed? what is condensation? what is rarefraction? what’s an US wave?

A
  • piezoelectric
  • voltage used to deform crystal
  • condensation is when crystal expands and compresses material in front of it
  • rarefraction is when crystal retracts, dispersing material in front of it
  • US wave= repeated cycles of compression/expansion of the crysal
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5
Q

What is intensity? And how is it measured?

A

strength of US (W/cm^2)

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6
Q

What is frequency and what does it effect?

A
  • number of times a molecule oscillates within 1 second

- affects the depth of penetration of the US

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7
Q

What’s depth:frequency rule?

A
  • higher frequencies penetrate deeper areas
  • 3MHz for superficial regions <2.5 cm deep.
  • 1MHz for deep regions 2.5-5cm deep
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8
Q

What are the modes of US and when do you use each?

A

Continuous- thermal affects

Pulsed- non-thermal effects

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9
Q

What is duty cycle and what mode is it related to?

A
  • related to pulsed mode

- percent of time during one pulse that the beam is present

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10
Q

What is the effective radiating area?

A

-a little smaller than the sound head because there is cement around the crystal

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11
Q

spatial peak intensity

A

place on transducer with highest intensity

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12
Q

spatial average intensity

A

average intensity about the tranducer

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13
Q

non-uniformity beam ratio

A
  • ratio of spatial peak intensity to spatial average intensity
  • smaller ratio = more uniform beam
  • acceptable for clinical use is <6:1 ratio
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14
Q

Contraindications for therapeutic US

A
  • in region of cardiac pacemaker
  • during pregnancy, over pelvic, abdominal, or lumbar regions
  • to eyes
  • over male/female reproductive organs
  • in region of active bleeding or infection
  • in region of tumor/malignancy
  • in region of DVT/ thrombophlebites
  • over heat, stellate, or cervical ganglia
  • over epiphyseal plates of growing bones
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15
Q

Precautions for US

A
  • over areas of sensory deficits
  • on patients who are unable to clearly communicate
  • over cemented prosthesis/ areas where plastic components are used
  • fractures
  • breast implants
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16
Q

What are the effects of US in biological tissues? What are effects influenced by?

A
  • thermal effects- chronic sprains and strains, pain relief and decreased ROM
  • non thermal effects- tissue regeneration, protein synthesis in fibroblasts, tendon repair
  • influenced by properties of materials and the angle from which the energy strikes them
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17
Q

physiological effects of US

A

Thermal: increasing tissue temperature of superficial and deep tissue

  • increase local blood flow
  • increase collagen extensibility
  • reduce pain
  • reduce muscle spasm
  • increased enzyme activity
  • produce mild inflammatory response

Non thermal:

  • promote soft tissue and bony tissue repair
  • increased cell and tissue membrane permeability
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18
Q

What is acoustic impedence?

A
  • ability of a material to transmit sound
  • low impedence= high transmission and little sound absorbed
  • high impedence = low transmission and lots of energy absorbtion
  • i.e. blood = low impedence, bone = high
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19
Q

what are standing waves?

A

combined energies of 2 waves with an area of increased intensity
–> keep transducer moving!!!

20
Q

what is attenuation?

A
  • a measure of the decrease in sound energy as the sound travels, either by absorption, reflection, or refraction
  • denser tissues w/ high protein (ie collagen) absorb US energy most effectively

blood< skin< tendon< cartilage<bone

21
Q

what tissues experience high thermal effects? which experience low?

A

high absorption coefficients –> high collagen content –> greater thermal effects

low absorption coefficient –> low collagen content–> lesser thermal effects

22
Q

how thermal effects are usefull

A

improve blood flow, nerve conduction, tissue extensibility

  • accelerate metabolic rate
  • decreased muscle guarding
  • decreased pain perception
  • increased soft tissue extensibility
  • increased blood flow
23
Q

how much temperature increase do you need for:

  • increased metabolic rate
  • reduce muscle spasm and pain, and increase blood flow
  • increase tissue extensibility and inhibit sympathetic activity?
A
  • 1 deg C
  • 2-3 deg C
  • 4 deg C
24
Q

applying hot pack affects tissues how deep?

A

superficial 1-2mm of skin

25
Q

heat or ice before US?

A
  • hot pack doesn’t do much
  • fastest rate of heating came with warming the conduction medium
  • don’t ice because could numb area and decrease sensation
26
Q

non thermal effects of therapeutic US

A

microstreaming = small-magnitude movements that occur in the ions surrounding cells and within intracellular and extracellular fluids which is created with changing cell membrane permeability

cavitation = pulsation of small gas bubbles present in body fluids from compression and rarefraction, which is responsible for diffusion and cellular function changes

  • increase intracellular calcium levles
  • increase mast cell degranulation
  • promotes macrophage responsiveness
  • increases rate of protein synthesis by fibroblasts and tendon cells
  • stimulates proteoglycan synthesis
27
Q

Why use a coupling medium?

A
  • US waves don’t travel effectively through air

- space between transducer and body can cause energy to reflect back to transducer and overheat and damage it

28
Q

settings to increase temperature in superficial tissues?

A

Continuous (100% duty cycle)
freq= 3MHz
duration= 5-10 min.
intensity= 0.5-1.0 W/cm^2

29
Q

Settings to increase temperature in deep tissues?

A

Continuous (100% duty cycle)
freq= 1MHz
duration = 5-10 min
intensity= 1.5-2.0 W/cm^2

30
Q

settings for non thermal effects in superficial tissues?

A

Pulsed (20% duty cycle)
freq= 3MHz
duration = 5-10 min
Intensity = 0.5- 1.0 W/cm^2

31
Q

settings for non thermal effects in deep tissues?

A

pulsed (20% duty cycle)
freq= 1MHz
duration = 5-10 min
Intensity= 0.5 - 1.0 W/cm^2

32
Q

Settings to increase soft tissue extensibility

A 
duration = 5-10 min
deep tissue:
freq=1MHz
intensity = 1.5-2.0 W/cm^2
superficial tissue:
freq = 3MHz
intensity = 0.5-1.0 W/cm^2

apply stretch during heating and maintain after US application (for at least 4 min) while tissue is cooling

33
Q

settings pain control

A 
duration = 3-10 min
deep:
freq= 1MHz
intensity= 1.5-2.0 W/cm^2
superficial 
freq = 3MHz
intensity = 0.5-1.0 MHz
34
Q

US for wound healing?

A

maybe pulsed? currently not enough evidence to support it.
20% duty cycle
3MHz freq
0.8-1.0 W/cm^2 intensity
duration = 5-10 min
- use gel and apply US around wound OR use US coupling sheet OR place transducer under water

35
Q

US for healing surgical skin incision

A

believed to accelerate evolution of angiogenesis by altering cell membrane permeability (calcium ions) and stimulation angiogenic factor synthesis and release by macrophages

PULSED
20% duty cycle
freq = 3MHz
intensity = 0.5-0.8W/cm^2
duration = 3-5 minutes, 3-5 times a week
36
Q

US for tendon and ligament injuries?

A

mixed findings, but research supports early use of US for facilitation of tendon healing after rupture with surgical repair
PULSED, low intensity (0.5-1.0W/cm^2) during acute phase.
20% duty cycle
freq= 1 or 3 MHz
Intensity = 0.5-1.0 W/cm^2
duration 2-5 min

later, CONTINUOUS and high intensity with stretching if chronic tendonitis accompanied by tissue shortening due to scarring
100% duty cycle
intensity = 1.0-2.5 W/cm^2
duration = 3-5 min.

37
Q

US for bone healing

A

20% duty cycle
freq = 1.5 MHz
intensity = 30 mW/cm^2
20 min daily

38
Q

US for musculoskeletal conditions of lower limb

A

currently no high quality evidence available to suggest ther. US is effective

39
Q

What is phonophoresis and what are its advantages?

A
  • thermal drug delivery
    Advantages:
  • higher initial drug concentration at delivery site
  • avoid gastric irritation
  • avoid first pass metabolism by liver
  • avoid pain/trauma/infection risk associated with injection
  • allows delivery to larger area than is readily achieved by injection
40
Q

US for heel pain?

A

no strong evidence to support

41
Q

US for achilles tendon pain?

A

US as effective as the eccentric loading exercises. more studies needed

42
Q

US and ankle ligaments?

A

ice and US improved pain, swelling, and function compared to immobalization

43
Q

US and knee injuries?

A

US and ice more effective than ice alone, phonophoresis or iontophoresis for pain associated with extensor mechanism.
more research needed!

44
Q

US and lateral epicondylitis?

A

one study supports

45
Q

US and calcific tendonopathy of supraspinatus?

A

one study supports

46
Q

SR of treating people with pain, musculoskeletal injuries and soft tissue lesions

A

only 2/10 suggest US is more effective

8/10 did not!

Ultrasound (1 decks)

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