Ultrasound

Question 1

what happens to the conversion of ultrasound?

Answer 1

mechanical energy is produced by the sound waves and converted into thermal energy after being absorbed by the body tissues

Question 2

what type of wave is this: molecular displacement is along in which the wave travels

Answer 2

longitudinal

Question 3

what can longitudinal waves travel through?

Answer 3

solids and liquids = soft tissue & bone

Question 4

what do transverse waves travel through?

Answer 4

solids = bone

Question 5

what is the frequency range for a therapeutic US?

Answer 5

.75 to 3MHz

Question 6

acoustic impedance is the ability to ____ sound depending on tissue density

Answer 6

transmit

Question 7

examples of low acoustic impedance

Answer 7

blood, water, fat

Question 8

examples of high acoustic impedance

Answer 8

bone, muscle, peripheral nerve, collagen - high protein content

Question 9

what is reflection and refraction dependent upon?

Answer 9

difference of magnitude of the impedances between two tissue types

Question 10

_____ increases when energy strikes perpendicular to its path.

Answer 10

reflection

Question 11

_____ minimized when energy strikes perpendicular to tissue.

Answer 11

refraction

Question 12

name this: reflected energy meets and adds to transmitted energy

Answer 12

standing wave/hot spot

Question 13

which pizeoelectric effect has to do with ultrasound?

Answer 13

indirect

Question 14

at what frequency does transmission take place at the superficial tisses?

Answer 14

1MHz

Question 15

what is the nonthermal effect that can occur with a continuous wave?

Question 16

equation of duty cycle

Answer 16

duration of pulse x 100 / pulse period

Question 17

what is this called: magnitude of vibration in a wave.

Answer 17

amplitude

Question 18

describe power.

Answer 18

total amount of US energy in a beam

Question 19

what does the spatial peak intensity range from?

Answer 19

.25 to 3 cm^2

Question 20

what is labeled as intensity for a continuous US

Answer 20

spatial average intensity

Question 21

what is labeled as intensity for a pulsed US? what does this NOT account for?

Answer 21

spatial average temporal peak intensity

duty cycle

Question 22

name this: averaging power b/w both on and off period of pulse cycle

Answer 22

spatial average temporal average intensity

mean of on and off time

Question 23

what does a lower BNR mean?

Answer 23

more BNR output

Question 24

recommended BNR value

Answer 24

2-6

Question 25

nonthermal effects?

Answer 25

stable cavitation and nonthermal cavitation, acoustic microstreaming

Question 26

what does unstable cavitation cause?

Answer 26

local tissue damage

Question 27

the higher the intensity, the ___ the treatment time.

Answer 27

shorter

Question 28

what are the treatment methods used to administer medications through phonophoresis?

Answer 28

hydrocortisone, dexamethasone