Key Terms 5/6/7

Question 1

Intensity

Answer 1

a beams power divided by its area

Question 2

5 key words related to intensity

Answer 2

spatial peak average temporal pulsed

Question 3

Intensity measurement methods

Answer 3

SPTP SATP SPTA SPPA SAPA SATA

Question 4

Commandments of intensity

Answer 4

10 of the most important ways that intensity is difened and measured

Question 5

Decibel notation

Answer 5

relative measurement comparision ratio logarithmic

Question 6

Logarithms

Answer 6

a novel method of rating numbers as the logarithm increases by 1 the actual number increases by 10

Question 7

Positive & negative decibels

Answer 7

rep[ort decebels that are increasing or decreasing

Question 8

Decibels & intensities

Answer 8

decibels require 2 intensities, the start level and the actual level at time of measurement, the measured is divided by the start and you get your ratio

Question 9

Attenuation

Answer 9

is the weakening of sound waves as the travel

Question 10

Distance and attenuation

Answer 10

they are directly related, as you travel farther the amount attenuation is greater

Question 11

Frequency and attenuation

Answer 11

directly related, the higher the prequency the higher the attenuation

Question 12

Reflection

Answer 12

a sound waves energy as it strikes a boundry and is redirected back to the source

Question 13

Scattering

Answer 13

random redirection of ultrasound in many directions

Question 14

Absorption

Answer 14

occurs when ultrasonic energy is converted into another form such as heat

Question 15

Specular reflection

Answer 15

the striking of a smooth boundry and the reflection of the beam

Question 16

Diffuse reflection

Answer 16

the striking of a rough boundry and the diffuse reflection of the beam

Question 17

Rayleigh scattering

Answer 17

omni directional scattering of sound waves interaction of ultrasound and RBC’s results in Rayleigh scattering when freq doubles scattering is 16 times greater

Question 18

Attenuation coefficient

Answer 18

number of decibels of attenuation that occurs when sound travels one centimeter units dB/cm

Question 19

Attenuation coefficient in soft tissue

Answer 19

one half the freq

Question 20

Attenuation in media

Answer 20

varies based on density of the media water low air extremely high

Question 21

Half value layer

Answer 21

distance aound travels in a tissue that reduces the intensity to one half its original value

Question 22

Impedance

Answer 22

acoustic resistance to sound traveling in a medium

Question 23

Range equation

Answer 23

the distance calculated by the time the sound takes to travel to the reflector in the body and return to the transducer

Question 24

Time of flight

Answer 24

elapsed time from pulse creatoin to pulse reception also called go return time

Question 25

PRP imaging depth

Answer 25

shallow imaging equals short PRP deeper equals longer PRP

Question 26

PRF imaging depth

Answer 26

shallow imaging equals higher PRF deeper imaging equals lower PRF

Question 27

Reflection and transmission

Answer 27

reflection is the redirection of sound when it strikes a boundry transmission is the sound energy that passes through the boundry and continues on