Week 4: Ultrasound and More Flashcards
Ultrasound contraindications
Bleeding
Decreased sensation
Decreased circulation or DVT
Infection
Malignancy
Over implants
Carotid sinus or cervical ganglia
Growth plates in children
over eyes, heart, genitalia
over cement/plastic
over pregnant woman areas
over pace maker
vascular problems
How far can ultrasound reach under the skin?
5cm
What is attenuation?
The decrease in ultrasound intensity as it travels due to absorption/reflection/refraction
As you increase _______, absorption of Ultrasound increases
frequency
Ultrasound passes through ___________ and is absorbed into ___________
passes through high water content
absorbed into high protein content (tendons)
Ultrasound penetration and absorption are ______ related
inversely
In what order do tissues absorb ultrasound?
LOW - Blood -> Fat -> Nerve -> Muscle -> Skin -> Tendon -> Cartilage/Bone - HIGH
What absorbs more ultrasound muscle or nerves?
muscle
What absorbs the most ultra sound?
What absorbs the least?
Most: bones
Least: blood
Why must you keep an ultrasound moving and keep it level to the skin w/ coupling gel
To prevent hot spots, and prevent reflection from the air
(air reflects 99% of ultrasound)
How does ultrasound work?
Piezoelectric crystals expand and contract w/ AC electric current, causing sound waves
What is the ERA of an ultra sound?
What is the general rule for treatment area?
Effective radiating area, the part that produces the sound waves note: slightly smaller than the actual transducer size, energy output is greatest at the center
Treatment area should be 2-3 times the ERA
What is collimation?
What gives you more?
The focus on the ultrasound beam
As per the slides: A larger transducer with a higher frequency
What is BNR for ultrasound?
Beam nonuniformity
the peak intensity compared to the average intensity, usually set as a ratio. Lower is better. 1:1 is ideal but not possible. Aim for 2:1 or 3:1
Better BNR = Less risk for hotspots
When should you set ultrasound to a duty cycle (1:5 / 20%) vs havingit continous
Duty cycle for non-thermal effects
continious for thermal effects
What frequency of ultrasound do you use for Deep tissues?
For superficial tissues?
Deep- 1MHz
Superficial- 3MHz
How is intensity measured for ultrasound?
W/cm^2 (power unit per area)
When you increase intensity or frequency on ultrasound, you decrease ____________
treatment time
What is nonthermal ultrasound for?
Mild thermal?
Moderate?
Vigorous?
Acute injury/edema
Subacute/hematoma
Chronic inflammation/trigger point
Collagen Stretch
T or F: Water can be used as a medium to apply ultrasound
T
Best for oddly shaped surfaces like the malleoli of the feet
note: use increased intensity as water cannot transmit as well as the gel
How long is the typical ultrasound treatment time?
5-10 minutes
How much heat change is considered mild?
Moderate?
Vigorous?
Mild - 1 C
Moderate - 2 C
VIgorous - 4 C
Ultrasound caution: tissue damage at __C
Continue only if ______
_____effect
45C
There is improvement
Placebo Effect
What is the delivery of medication using ultrasound called?
Phonophoresis
What is ultraviolent light therapy used for?
Chronic ulcer/wounds
What are contraindications to ultraviolent light?
Areas receiving radiation
Diabetes
herpes
Pellagra
Photosensitive medication
Skin Cancer
SLE
TB
What is laser therapy used for?
Using Infared and visible light
For wounds
Tendon/ligament injury
arthritis
edema reduction
soft tissue injury
scar
triggerpoin t
How much depth can laser therapy have?
What kind of light penetrates the deepest?
How does it help wound healing?
2cm
Red and near-infrared
Increase ATP synthesis
proliferation of immune cells
increased blodflow
may modulate pain