Ch. 5 Physics: Intensities

Question 1

Refers to distance or space.

Answer 1

Spatial (space/location)

Question 2

True or false:
An US beam has the same intensity at different locations

Answer 2

False. They do not have the same intensity at different locations.

Question 3

Refers to all time, pulse duration and receiving.

Answer 3

Temporal (time)

Question 4

True or false:
The pulsed beam does not have the same intensity at different times.

Answer 4

True

Question 5

Refers to the transmit time only.
(the average intensity of the pulse duration only)

Answer 5

Pulsed

Question 6

Defines the maximum value of intensity measured at a given time or place.

Answer 6

Peak

Question 7

Defines the averaged value of intensity that is measured along a beams path (spatial) or during the time it is sent (temporal).

Answer 7

Average

Question 8

Describes the effects that the intensity of the ultrasound beam will have.

Answer 8

Bioeffects

Question 9

The intensity of a sound beam will vary depending on _______ and ______ it is measured

Answer 9

Where (spatial/location) and when (temporal/ time)

Question 10

The intensity of an ultrasound beam varies at different _______ along its path.

Answer 10

depths

Question 11

The intensity will also be different at varying ____________ locations (center > periphery)

Answer 11

side to side

Question 12

Pulsed ultrasound is mostly ___________ (receiving) time with a small amount of __________ (transmitting)

Answer 12

listening
talking

Question 13

Isp

Answer 13

Spatial peak intensity

Question 14

Isp is the beams intensity at the ___________________________

Answer 14

Location where it is maximum

Question 15

Isa

Answer 15

Spatial average intensity

Question 16

Isa is the average intensity across the beams entire ___________________________

Answer 16

Cross sectional area

Question 17

True or false:
Spatial peak intensity is always higher than the spatial average intensity.

Answer 17

True

Question 18

Itp

Answer 18

Temporal peak intensity

Question 19

What does the Itp measure?

Answer 19

the intensity of a beam at the point in time of its maximal value

Question 20

Imax

Answer 20

Average intensity temporal peak

Question 21

Measures the average intensity during the most intense half- cycle of a wave. Average intensity of the wave in which the temporal peak was obtained.

Answer 21

Imax

Question 22

Ipa

Answer 22

Pulse average intensity

Question 23

Measures the average intensity during the pulse duration only.

Answer 23

Ipa

Question 24

Ita

Answer 24

Temporal average intensity

Question 25

Measures the average intensity during the entire PRP including both the transmit and receive times.

Answer 25

Ita

Question 26

What are the intensities in increasing order?

Answer 26

Ita Ipa Imax Itp

Question 27

What is the highest intensity?

Answer 27

Itp

Question 28

What is the second highest intensity?

Answer 28

Imax

Question 29

What is the third highest intensity?

Answer 29

Ipa

Question 30

What is the lowest intensity?

Answer 30

Ita

Question 31

is a measurement at the location of maximum intensity, and the instant in time when the most powerful part of the pulse passes.

Answer 31

SPTP

Question 32

is a measurement at the location of maximum intensity, averaged over the pulse duration (transmitting time only)

Answer 32

SPPA

Question 33

is a measurement at the location of maximum intensity, and averaged over the PRP (transmitting and receiving)

Answer 33

SPTA

Question 34

Is a measurement of the beam cross section area and over all of time.

Answer 34

SATA

Question 35

Which intensity factor is most closely correlated to tissue heating?

Answer 35

SPTA

Question 36

What are the units for all intensities?

Answer 36

Watts/cm^2