ultrasound & shockwave Flashcards
Ultrasound frequency Is higher than sound human can hear. T or F.
- True
What is the ultrasound frequency?
- 20,000 cycles per second or hertz
What is seen at the inner end of the transducer head?
- piezoelectric head
AC stands for
Alternating current
Ultrasound is produced through ____ through ______
- Reverse piezoelectric effect
- Through application of high frequency AC to a piezoelectric crystal
- Causes mechanical change to piezoelectric crystal
Most commonly used piezoelectric material
- Plumbium zirconium titanate
All types of piezoelectric material used
- Plumbium zirconium titanate
- Quartz
- Barium titanate
When crystal expands
- It compresses material in front of it
When crystal compresses
- It rarefies the material
Alternating compression-rarefaction is
- Ultrasound wave
Outside crystal is the
- Plate
Fresnel zone is the
- Near field
Describe the fresnel zone
- Absence of divergence
- Maxima and minima are close to each other
Length of near field depends on
- Diameter of treatment head
- Frequency
Fraunhofer zone is the
- Far field
Describe the fraunhofer zone
- More divergent
- Nearly absent interference that gradually decreases with increasing distance to transducer
○ Decreased with increasing distance to transducer
○ Practical application: underwater technique
- Nearly absent interference that gradually decreases with increasing distance to transducer
Body tissue should be in which field
- Between near and far field
- Has nicest sound wave
- Not too divergent or convergent
Ultrasound is attenuated in the tissue by
- Absorption, reflection, refraction
Attenuation
Decreasing US intensity as wave travels through tissue
Attenuation is greatest with
- High collagen content
High US frequencies
Critical angle of Ultrasound
- 15 degrees
Ultrasound heats tissues with
- High collagen content
- High absorption coefficient
What are tissues with high collagen content
- Tendons
- Ligaments
- Joint capsules
- Fascia
Ultrasound is ideal for muscles. T or F.
- False
For thermal effects, US should be in what mode?
- Continuous
Thermal effects of US
- Increase metabolic rate
- Reduction of pain and spasm
- Inc nerve conduction velocity
- Inc in blood flow
- Inc tissue extensibility
Non thermal effects is given in what mode?
- Pulsed mode
Non-thermal effects
- Inc cell membrane permeability
- Inc intracellular calcium ions
- Promotes macrophage responsiveness
- Inc protein synthesis by fibroblasts
Acoustic streaming
- Steady circular flow of cellular fluids induced by US
- Reason for US being used in phonophoresis
○ US pushes meds into body
- Reason for US being used in phonophoresis
Cavitation
- Formation, pulsation and growth of gas-filled bubbles
- Responsible for cell permeability
- Macrophages and fibroblasts
Micromassage
- Microscopic movement or oscillation of body fluids and tissues
Indications for thermal
- Pain
- Before stretching shortened soft tissues
- When needs increase of blood flow
Indications for non thermal
- Accelerate tissue healing
○ Ulcers, surgical skin incisions, tendon injuries, bone fractures- Phonophoresis/sonophoresis
○ Transdermal localized drug delivery
- Phonophoresis/sonophoresis
Mild thermal effects increase body temp by
- 1 degree
Mild thermal effects are for
- Subacute injury hematoma
Moderate thermal effects inc body temp by
2 deg
Moderate thermal effects are for
- Chronic inflammation
- Pain
- Trigger points
Vigorous thermal inc body temp by
- 4 degrees
Vigorous thermal is for
- stretching
Patient shouldn’t feel anything during US. T or F.
- False, pt should feel warmth
Parameters of US
- Frequency
- Intensity
- Duty cycle
- Treatment duration
- Effective radiating area
Duty cycle for continuous is
- 100%
3 mhz is used for
- Superficial
Max temp achieved is higher in
- 3 mhz
- Because nearer and more concentrated target area
High frequency usually partnered with
Low intensity
Higher temperatures in achieved in tissues with
- High collagen content
Depth of penetration for 3mhz
1 to 2 cm deep
Depth of penetration for 1 mhz
Up to 5 cm deep
In near field, energy distribution is uniform or not uniform?
- Not uniform
In far field, energy distribution is
- Uniform but more divergent
For non-thermal effects duty cycle usually starts at
- 20% for acute stage
If targeting thermal effects, pt should feel
- Warmth that is very mild
Usual intensity in clinics is
- 1.5 W/cm2
Beam non-uniformity ratio is
- Ratio of spatial peak intensity to spatial average intensity
Spatial average intensity is
- What you set on machine
If BNR is 6:1, and you set US to 1.5 w/cm2 what is the spatial peak intensity?
- 9 W/cm^2
When shortened soft tissues, what setting will you do
- 0.5-1.0 W/cm^2, 3mhz, 5-10 mins
- 1.5-2.5 W/cm^2, 1 mhz, used for 5-10 mins
Stretching is recommended to be applied during heating and maintained for 5-10 mins after US. T or F.
True
For painful areas, setting is
- 0.5-3.0 w/cm^2, 1 or 3 mhz, for 3-10 mins
For wound healing, setting is
- 0.5-1.0 w/cm^2, 3mhz, 20% duty cycle for 3-10 mins
- Surrounding wound
- Can be underwater technique
For acute tendon and ligamental repair, setting is
- 0.5-1.0 w/cm^2, 3 mhz, pulsed mode
- Accelerates tissue healing
For chronic tendon and ligamental repair, setting is
- High enough intensity to increase tissue temp in continuous mode
- To address tissue shortening
For bone fracture, setting is
- 0.15 w/cm^2, 1.5 mhz, pulse mode 20% duty cycle, 15-20 mins
For carpal tunnel syndrome, setting is
- 0.5-1.0 w/cm2, 1 mhz, pulsed 1:4 for 5-15 mins
For phonophoresis
0.5-1 w/cm2, 3mhz, 20% duty cycle for 5-10 mins
Duration is dependent on
- Effective radiating area
Usually 5-10 mins is for
- each treatment area that is 2x the ERA
If era is 10 cm2 and area of body is 20 cm2, time should be
5-10 mins
If era is 10mc2 and area of body part is 40 cm2, duration should be
- 10-20 mins
Duration is generally increased when
- Lower intensities or lower frequencies are used
- Areas larger than twice the era
- Heating effects are desired
If area of body is more than twice the era, intensity is higher. T or f.
- False
Methods of application
- Direct
- Glove or balloon technique
- Underwater
Glove technique used for
- Irregular surface areas
Rate of moving US head
- Between 2 and 8 cm/sec
Strokes overlapping half of era is not recommended. T or F.
- F
Properties of gel
- Non staining
- Not irritating to skin
- Ease of application
- Cost
Examples of gel
- Soni gel
- Degassed water
- Aquasonic gel and mineral oil
Can we apply HMP before US?
- Yes
What’s the effect of applying HMP before US?
- Increase temp of skin while not affecting deeper tissue layers
Can we apply cryo before US?
- If US for thermal effects, no.
Contraindications (8)
- Tumor
- Pregnancy (not near abdomen)
- CNS tissue (4 inches away)
- Joint cement or plastic components of arthroplasty
- Pacemaker (cannot apply near chest, 6 inches away)
- Thrombophlebitis
- Over the eyes
- Reproductive organs
Precaution
- Acute inflammation (use pulse mode)
- Epiphyseal plates in children
- Fractures (use very low dose)
- Breast implants (can pop)
documentation
- US duty cycle ○ Continuous or pulse mode - Size of head - Frequency - Intensity - Duration in mins - Area of body ○ Laterality ○ Body part - Patient position ○ If you stretched an area, etc. - Method of application - Goal or rationale
