Ultrasound and Phonophoresis Flashcards
1
Q
Ultrasound: Transducer head size
A
- Range from 1-10 cm
- 5cm most common
- Should be relative to treatment area size:
- wrist- 1cm,
- shoulder/leg - 5cm
2
Q
Ultrasound: Spatial average intensity
A
- Total power (watts) divided by area (cm2) of transducer head
- Typically the measurement used in documenting US treatments (0.25 w/cm2 - 2.0 w/cm2) (measure of intensity)
3
Q
Ultrasound: Beam non-uniformity ratio
A
- Ratio of spatial peak intensity to average intensity
- Lower BNR = more uniform energy distribution and less risk of tissue damage
- Should be between 2:1 and 6:1
- Ideal 1:1 is not technically feasible
4
Q
Ultrasound: Duty cycle
A
- The fraction of time the US is on over one pulse period time on/time on+time off
- Duty cycle of 50% or less is considered pulsed
5
Q
Ultrasound: Structures with high attenuation
A
Hight protein and collagen content - muscles, tendons, ligaments, capsules
6
Q
Ultrasound: Depth of penetration
A
- 3-5 cm
- At 3 MHz - greater attenuation in superficial tissues (e.g. TMJ)
- At 1MHz - increased heat production in deep layers due to less superficial scatter
7
Q
Ultrasound: Thermal effects
A
- Produced by continuous US at 0.5-3 W/cm2 (intensity will vary depending on tissue type and pathology)
- Increased:
- Tissue temp,
- pain threshold,
- collagen extensibility,
- enzyme activity,
- tissue perfusion,
- temp at tissue interfaces.
- Alteration of nerve conduction velocity.
- Excessively high temps may produce sudden, strong ache due to overheating periosteal tissue - reduce intensity or increase surface area.
8
Q
Ultrasound: Non-thermal effects:
A
- Generated by very low intensity or pulsed US.
- Typically duty cycles of 20-50%
- Cavitation and Acoustic Streaming Effects
9
Q
Ultrasound: Non-thermal effects: Cavitation
A
- Cavitation:
- Alternating compression and expansion of small gas bubbles caused by mechanical pressure waves.
- Stable cavitation:
- Bubbles resonate but no tissue damage.
- May be responsible for diffusional changes in cell membranes.
- Unstable cavitation:
- Severe collapse of gas bubbles - can result in local tissue destruction due to high temps.
10
Q
Ultrasound: Non-thermal effects: Acoustic Streaming
A
- Acoustic streaming:
- Movement of fluids along the boundaries of cell membranes resulting from mechanical pressure wave.
- May produce:
- Alterations in cell membrane activity,
- increase:
- cell wall permeability,
- intracellular calcium,
- macrophage response,
- protein synthesis.
- May be of some value in tissue healing.
11
Q
Ultrasound: Goals/indications
A
- Modulate pain -
- increase CT extensibility,
- reduce inflammation,
- accelerate healing rate,
- reduce joint restriction/muscle spasm.
12
Q
Ultrasound: Precautions
A
- Acute inflammation,
- breast implants,
- open epiphyses,
- healing fractures.
13
Q
Ultrasound: Contraindications
A
- Impaired circulation/cognition/sensation
- Thrombophlebitis,
- joint cement,
- plastic components,
- over vital areas (ear, brain, heart, eye, cervical ganglia, carotid sinuses, reproductive organs, SC, pacemakers, pregnant uterus)
14
Q
Ultrasound: Procedures - Direct content
A
- Apply generous amount of coupling medium
- Move head slowly in overlapping circles or long strokes
- Do not cover an area greater than 2-3x size of the ERA per five minutes of treatment
- While head is moving turn up intensity to desired level
- lower intensities for acute conditions or thin tissue;
- higher intensities for chronic conditions or thick tissue.
- Treatment time: 3-10 mins depending area, intensity, condition and frequency
15
Q
Ultrasound: Procedures - indirect contact (water immersion)
A
- Use with irregular bod parts
- Plastic container preferred to decrease reflection
- Place part in water
- Place sound head in water, 0.5-1” from skin surface at right angle to body part
- Move head slowly - if using stationary technique decrease intensity or use pulsed US
- Turn up intensity to desired level
- Periodically wipe off any air bubbles that form on sound head or body part during treatment
