Ultrasound

Question 1

T/F: Ultrasound uses sound waves at high frequencies?

Answer 1

True

Question 2

What type of modality is ultrasound?

Answer 2

Deep heating

Question 3

Can ultrasound penetrate fat?

Answer 3

Yes, it can be used to heat muscles, tendons, ligaments, joint capsules, scar tissue etc

Question 4

What is the most common heating modality used by chiropractors in the US?

Answer 4

Moist hot packs ( 71%)

Question 5

What is the most common heating modality used by chiropractors of all nations?

Answer 5

Ultrasound

Question 6

Electrical current is passed through _________ causing it to vibrate?

Answer 6

a crystal

Question 7

What is the frequency range of musculoskeletal treatments?

Answer 7

800,000 Hz to 3.3MHz

Question 8

How do you calculate duty cycle?

Answer 8

Dividing time sound is delivered by the total treatment time

Question 9

What does a duty cycle of 100% mean?

Answer 9

Continuous Ultrasound

Question 10

What is the result of continuous ultrasound?

Answer 10

Tissue heating

Question 11

What is the result of pulsed ultrasound?

Answer 11

Mechanical/non-thermal effects

Question 12

What is the Piezoelectric effect?

Answer 12

Mechanical deformation of a crystal causes an electrical current to form

Question 13

Explain the Reverse Piezoelectric effect

Answer 13

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

Question 14

What is ERA?

Answer 14

Effective Radiating Area: Area of the sound head that produces sound energy. Always smaller than the size of the ultrasound head!

Question 15

What is BNR?

Answer 15

Beam Nonuniformity Ratio: Ultrasound beams are not uniform across the US head.
BNR= the amount of variability of the beam.
Ratio between the peak intensity of the US beam divided by the average intensity of the US beam.
Used to compare quality of machines.

Question 16

What is the Ideal BNR?

Answer 16

1:1 but within range of 2:1-8:1.

Question 17

What does a 2:1 BNR mean?

Answer 17

At 1W/cm^2, the peak intensity is 2 W/cm^2

Question 18

T/F: Lower the BNR the more uniform the intensity of the sound wave

Answer 18

True!

Question 19

What is PAMBNR?

Answer 19

Peak area of the Maximum beam nonuniformity

Describes the area of the sound head covered by the peak intensity

Question 20

Does a LARGE or small PAMBNR mean less uniform heating?

Answer 20

LARGER

Question 21

What is the best conducting media for ultrasound?

Answer 21

Gel and Gel pads specifically designed for US

Question 22

T/F:Underwater is a type of direct ultrasound?

Answer 22

False; It is a type of indirect ultrasound

Question 23

Why do you not want to use a metal bucked for underwater US?

Answer 23

Because it will cause reflection of the sound waves.

Question 24

What do you need change about your technique when going from standard US to underwater US?

Answer 24

Increase intensity or Increase time of treatment.

Question 25

Is it normal for bubbles to form on patients skin during underwater US?

Answer 25

Yes, wipe them off from skin and sound head occasionally during the treatment.

Question 26

Which frequency of US is more superficial?

Answer 26

``` High Frequency (3MHz): absorbed more rapidly therefore affects superficial tissues ```

Question 27

Which frequency is for deeper tissues?

Answer 27

Low Frequency (1MHz): absorbed at a slower rate therefore affects deeper tissues

Question 28

What type of tissues absorb most sound energy from US?

Answer 28

Bone, tendon, cartilage, ligaments, and joint | capsules absorb most

Question 29

Which type of tissues absorb the least amount of sound energy from US?

Answer 29

Skin and fat absorb the least

Question 30

More Watts = ???

Answer 30

More heating NOT greater penetration

Question 31

Frequency affects what two things?

Answer 31

Depth and Time

Question 32

What is reflection in terms of US scattering?

Answer 32

Reflection: the reversal of the direction of | propagation of the ultrasound wave

Question 33

What is refraction in terms of US scattering?

Answer 33

Refraction: change of ultrasound wave from a straight path when passing obliquely from one medium to another

Question 34

T/F: Tissues close to the bone: periosteum, tendons, and aponeurotic attachment of muscle, cartilaginous coverings of joint surfaces, and peripheral nerves lying close to bones receive increased dose (increased heating)

Answer 34

TRUE

Question 35

``` T/F: The bending of US energy within tissue can lead to concentrations of US at the point of refraction ```

Answer 35

TRUE

Question 36

What is the main effect of US?

Answer 36

Tissue heating

Question 37

What are the Therapeutic Effects of US?

Answer 37

``` • Increase extensibility of collagen fibers of tendons and joint capsules • Increase blood flow • Increase cell metabolism • Increase collagen synthesis • Decreased joint stiffness • Decreased muscle spasm • Enhanced tendon, ligament, and muscle healing ```

Question 38

Do superficial or deep tissues cool more rapidly?

Answer 38

Superficial!

Question 39

Any tissue manipulation or stretching should | be performed when?

Answer 39

Immediately after ultrasound treatment

Question 40

What is acoustical streaming?

Answer 40

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

Question 41

What is cavitation?

Answer 41

– Formation of gas filled bubbles from pressure changes in tissue fluids – Bubbles expand and contract with ultrasound waves

Question 42

What are the different types of Cavitation?

Answer 42

Stable and Unstable

Question 43

Define Stable cavitation

Answer 43

Rhythmic expansion and contraction of bubbles during repeated pressure changes over many acoustic cycles – Facilitates fluid movement and membrane transport

Question 44

Define Unstable cavitation

Answer 44

– Collapse of gas bubbles which may cause tissue damage – Associated with low frequency high intensity ultrasound (not therapeutic)

Question 45

What are the contraindications for US?

Answer 45

* 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 OK) * Near or over electronic implants * Unknown etiology

Question 46

What are the risks associated with US?

Answer 46

May alter bone growth. | Avoid bony prominences..

Question 47

Describe the movement of the US head when apply therapy

Answer 47

• Slow controlled movement of the US head | – 2–4 cm2/s (2 inches per sec)

Question 48

What is the treatment time for US?

Answer 48

Generally 5-8 minutes.

Question 49

What is the maximum time you can treat someone with US?

Answer 49

NEVER treat for more than a total of 15 | minutes (several treatment areas)

Question 50

What do you do if you have a large treatment area?

Answer 50

– break it up into 2 or 3 smaller areas and treat | for 5 minutes per region

Question 51

Phonophoresis is AKA what?

Answer 51

Sonophoresis

Question 52

What is Phonophoresis/Sonophoresis?

Answer 52

Uses sound energy to drive medication | into the tissue

Question 53

Why would someone use Combo US therapy?

Answer 53

``` Research is lacking but claims for use include: – trigger points – epicondylitis – superficial pain areas – decrease adhesions ```

Question 54

What is combo US therapy?

Answer 54

Theoretically to create effects of both US and electrical stimulation Ultrasound head becomes the treating electrode when used with a dispersal pad

Question 55

LIPUS stands for what?

Answer 55

Low intensity Pulsed US

Question 56

When would you use LIPUS?

Answer 56

To stimulate the healing of a fracture. | • Good evidence for effectiveness

Question 57

What is NCLFUS?

Answer 57

Noncontact Low-Frequency US

Question 58

When would you use NCLFUS?

Answer 58

Wound cleaning and debridement • US propels sterile saline across wound • Stimulates healing