Modalities: Ultrasound Flashcards

1
Q

To achieve thermal effects, should continuous or pulsed ultrasound be used?

A

Continuous Ultrasound

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2
Q

How is US energy/intensity distributed on the surface over of the transducer?

A

Not uniformly distributed

  • causes a higher energy in the center of the US beam relative to the surrounding areas.
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3
Q

How to reduce the effects of a hot spot?

A

Continuously moving the sound head.

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4
Q

How is Spatial Average Intensity measured?

A

Intensity - Total Power (Watts) divided by the area (cm2)

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5
Q

What is Beam Nonuniformity Ratio (BNR), relation to tissue damage?

A

Ratio of spatial peak intensity to spatial average intensity; don’t think that is important tbh

[important maybe]

  • Lower the BNR the more uniform the energy distribution, less risk for tissue damage
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6
Q

What is the ideal BNR?

A

Between 2:1 and 6:1

(an ideal 1:1 is not technically feasible)

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7
Q

To achieve nonthermal effects, should continuous or pulsed ultrasound be used?

A

Pulsed Ultrasound (acute soft tissue injuries)

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8
Q

What is the Duty Cycle?

A

Percentage of ON Time to the Total Time; (time on + time off)

e.g:

  • 2 msec on / (2 on + 8 0ff msec = 20%)
  • 20% duty cycle = on time 2 msec and off time 8 msec.
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9
Q

What is Attenuation

A

Reduction of acoustical energy as it passes through soft tissue.

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10
Q

What tissue type produces the highest absorption?

A

Tissues with high collagen and protein content

  • muscles
  • tendon
  • ligaments
  • joint capsules
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11
Q

Depth of penetration at 3 MHz?

A

Greater heat production in superficial layers. (TMJ)

  • 1-2 cm
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12
Q

Depth of penetration at 1 MHz?

A

Increased heat production in deep layers/tissues.

  • </= 5 cm
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13
Q

What intensity range will result in desired thermal effects?

A

Continuous US: Range 0.5 - 3 w/cm2

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14
Q

What can cause undesirable effects to thermal US?

A
  • Excessive high temperatures may produce overheating of periosteal tissue.
  • Insufficient coupling agent may produce discomfort “hot-spot”.
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15
Q

What to do in the instance of periosteal pain

A
  • Reduce intensity (w/cm2)
  • Increase surface area of treatment if periosteal pain is expressed.
  • Add more coupling agent
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16
Q

Typical duty cycle for nonthermal intervention?

A

20-50% duty cycles.

17
Q

What may cause diffusional changes in cell membranes?

A

Stable Cavitation

18
Q

Goals and Indications of US?

A
  • Modulate pain
  • increase tissue extensibility
  • Reduce soft-tissue inflammation
  • Accelerate tissue healing
19
Q

Precautions to US?

A
  • Healing Fractures
20
Q

Contraindication to US: Physiological

A
  • Impaired circulation
  • Impaired sensation and cognitive functions
  • Malignant tumors
  • Over area of thrombophlebitis
  • Active Bleeding
21
Q

Contraindications to US: Surgical

A
  • Joint cement
  • Plastic components
  • Cardiac Pacemakers
22
Q

Contraindications to US: body regions/part, areas to avoid during pregnancy?

A
  • Abdomen, low back, uterus during pregnancy
  • Vital areas; brain, ears, eyes, cervical ganglia, carotid sinus, reproductive organs
23
Q

How to select the appropriate sound head size

A

Effective Radiation Area (ERA) 1/2 the size of the treatment area

24
Q

What area size should we not cover/treat with US?

A

2-3 times the size of the ERA

25
Q

Intensity Considerations: Lower Intensity?

A
  • Acute Conditions
  • Thin Tissues (wrist joint)
26
Q

Intensity Considerations: Higher Intensity?

A
  • Chronic Conditions
  • Thicker Tissues (lower back)
27
Q

What are reasons for periosteal pain?

A
  • High intensity
  • Momentary slowing/cessation of movement of sound head
28
Q

What type of US therapy is indicated for irregular body parts?

A

Water immersion, keeping sound head 1 cm from skin surface

29
Q

What is Phonophoresis?

A

Use of US to drive medication through the skin into deep tissues.

30
Q

Drug for Local Analgesic effect with Phonophoresis?

A
  • Lidocaine
  • Salicylates
31
Q

Drug for Anti-inflammatory effect with Phonophoresis?

A
  • Dexamethasone
32
Q

Contraindication to US: Children

A
  • Open epiphyses in children (<18 lbs)
33
Q

If an infection is present, should US be utilized?

A

NO! It is Contraindicated

34
Q

Continuous or Pulsed US for Phonophoresis?

A

Pulsed (20-50%)

35
Q

Treatment Time for Phonophoresis?

A

5-10 Minutes

36
Q

What is the recommended Duration of Treatment for US?

A

5-10 minutes/2 x ERA

37
Q

What is the recommendation for Ultrasound Intensity for Thermal Effects utilizing a 3 MHZ Frequency?

A

0.5 W/cm2

38
Q

What is the recommendation for Ultrasound Intensity for Thermal Effects utilizing a 1 MHz Frequency?

A

1.5-2.0 W/cm2

39
Q

What is the recommendation for Ultrasound Intensity for Non-Thermal Effects utilizing a 1 MHz or 3 MHz Frequency?

A

0.5-1.0 w/cm2