Ultrasound

Question 1

Can we as humans hear the sounds that ultrasound gives off?

Answer 1

no

Question 2

what does ultrasound do?

Answer 2

it has a deep heating modality that penetrates skin and subcutaneous fat
it is used to heat muscles, tendons, ligaments, joints capsules and scar tissues
it also has non thermal mechanical effects

Question 3

can ultrasound heal bone fractures?

Answer 3

slowly, in low intensities

Question 4

can ultrasound help heal wounds?

Answer 4

yes, when it is non-contact, low frequencies

Question 5

what is the most common use for ultrasound among chiropractors?

Answer 5

deep heating modality

Question 6

what is the second most common heating modality in the US?

Answer 6

ultrasound

Question 7

How does ultrasound work?

Answer 7

an electrical current is passed through a crystal causing it to vibrate
this causes soundwaves to be generated

Question 8

crystal is usually what kind of material?

Answer 8

quartz, lead zirconate, lead titanate, barium titanate, nickel colbalt ferrite about 2-3mm in thickness

Question 9

what is the duty cycle of ultrasound?

Answer 9

divide time sound is delivered by total treatment time

Question 10

continuous vs pulsed?

Answer 10

continuous- 100%

pulsed- 20-50%

Question 11

piezoelectric effect

Answer 11

mechanical deformation of a crystal causes an electrical current to form

Question 12

reverse piezoelectric effect

Answer 12

alternating current is passed through a crystal
results in very fast contraction and expansion of the crystal
vibration produces high frequency sound waves

Question 13

why must ultrasound have well insulated cables?

Answer 13

because it requires a high voltage

Question 14

another name for near field? What is the near field?

Answer 14

fresnel zone

treatment area

Question 15

another name for farfield?

Answer 15

Fraunhofer zone

Question 16

what are the coupling agents used with ultrasound?

Answer 16

gel
gel pad
tap water

Question 17

spatial peak intensity

Answer 17

maximum intensity delivered during continuous ultrasound energy

Question 18

spatial average intensity

Answer 18

average intensity delivered during pulsed delivery of ultraound energy

Question 19

ERA

Answer 19

effective radiating area
area of the sound head that produces sound energy
always smaller than the size of the ultrasound heat

Question 20

BNR

Answer 20

beam nonuniformity ratio
amount of variability of the beam
ratio between the peak intensity of the ultrasound beam divided by the average intensity of the ultrasound beam
used to compare quality of different machines

Question 21

what is the acceptable range of BNR?

Answer 21

1:1, but within the range of 2:1 and 8:1 is acceptable

Question 22

why does the BNR ratio need to be so low?

Answer 22

allows for more uniform intensity of the sound wave
eliminates hot spots
allows for higher dosage without discomfort
allows for greatest comfor and safety

Question 23

PAMBNR

Answer 23

peak area of the maximum beam nonuniformity ratio
large= peak intensity covers a larger area of the sound head
small= peak intensity covers a small area
larger= less uniform heating

Question 24

when using ultrasound, where must the head be on the skin?

Answer 24

flat against skin

Question 25

describe underwater ultrasound

Answer 25

indirect used in plastic (not metal) bucket sound head needs to be parallel to the part

Question 26

True or false: more watts in ultrasound do NOT mean greater penetration

Answer 26

true

Question 27

frequency of ultrasound

Answer 27

typically 1-3 MHz | frequency dictates depth of heating

Question 28

high frequency (3mHz)

Answer 28

absorbed more rapidly therefore affects superficial tissues

Question 29

low frequency (1MHz)

Answer 29

absorbed at a slower rate therefore affects deeper tissues

Question 30

which kind of ultrasound is best for getting to the bone, tendon, cartilage, ligaments, and joint capsules?

Answer 30

continuous

Question 31

reflection

Answer 31

the reversal of the direction of propagation of the ultrasound wave acoustic impedance of muscle, fat and water is low, therefore the tissue closest to bone gets increased heating

Question 32

refraction

Answer 32

change of ultrasound wave from a straight path when pasing obliquely from one medium to another can lead to concentrations of ultrasound at the point of refraction (where tendon joins bone)

Question 33

What are the effects of ustrasound?

Answer 33

causes increase in metabolic actiivty which increases oxygen demand, which leads to increased blood flow

Question 34

what are the therapeutic effects of ultrasound

Answer 34

increase extensibility of collagen fibers of tendons and joint capsules increase blood flow increase cell metabolism increase collegen synthesis decreased joint stiffness decreased muscle spasm enhanced tendon, ligament and muscle healing

Question 35

which tissues heal more rapidly after an ultrasound treatment?

Answer 35

superficial layers

Question 36

what should you do immediately after the ultrasound treatment?

Answer 36

manipulation or stretching

Question 37

what are the effects of non thermal tissues?

Answer 37

affects tissue healing and alters cellular activity stimulation of fibroblast activity increased blood flow increased proteins associated with injury repair

Question 38

how does non thermal ultrasound work?

Answer 38

through acoustical streaming and stable cavitation

Question 39

acoustical streaming

Answer 39

movement of fluids along cell membranes due to mechanical pressure exerted by the sound waves

Question 40

microstreaming

Answer 40

movement that occurs in direction of the sound waves | facilitates fluid movement and inceases cell membrane permeability

Question 41

cavitation

Answer 41

formation of gas filled bubles from pressure changes in tissue fluids bubbles expand and contract with ultrasound waves

Question 42

stable cavitation

Answer 42

rhythmic expansion and contraciton of bubbles during repeated pressure changes over many acoustic cycles facilitates fluid movment and membrane transport

Question 43

unstable cavitation

Answer 43

collapse of gas bubbles which may cause tissue damage | associated with low frequency, high intensity ultrasound (not therapeutic)

Question 44

what are the contraindications of ultrasound?

Answer 44

``` malignancy hemorrhage ischemia thrombus infection gonads eye pelvic, abdominal and lumbar areas of pregnant women spinal cord after laminectomy plastic and cemented implants (metal is okay) near or over electronic implants unknown etiology ```

Question 45

what are the risks for ultrasound?

Answer 45

``` bony prominences (avoid, use indirect technique, smaller sound head) epiphyseal plate (may alter bone growth) ```

Question 46

what is the treatment size usually?

Answer 46

5-8 minutes

Question 47

what are the stipulations for treatment time?

Answer 47

depends on size of treatment area never treat for more than a total of 15 minutes break large treatment areas into 2 or 3 smaller areas and treat for 5 minutes per region

Question 48

what is phonophoresis

Answer 48

AKA sonophoresis similar to iontophoresis uses sound energy to drive medication into the tissue medication does not need to have a charge

Question 49

what are the "uses" for ultrasound and electrical stimulation?

Answer 49

trigger points epicondylitis superficial pain areas decrease adhesions

Question 50

ultrasound head becomes what when using both ultrasound and electrical stimulation?

Answer 50

treating electrode

Question 51

what is low intensity pulsed ultrasound used for?

Answer 51

fracture healing | home units for patients to apply 1 time a day for 20 minutes

Question 52

what is non contact low frequency ultrasound used for?

Answer 52

wound cleaning and debridement propels sterile saline across wound stimulates healing