Pulsed US

Question 1

Pulse Duration

Define:
Units:
Determined by:
Changed by Sonographer?

Answer 1

Define: the time from the START of a pulse to the END of that pulse (actual time that the pulse is “on”)

Units: seconds

Determined by: sound source

Changed by Sonographer? no it is a characteristic of the transducer

Question 2

Pulse duration is determined by the ____________ in each pulse and the _________ of each cycle

Answer 2

number of cycles

period`

Question 3

Pulse Repetition Period

Answer 3

duration of time form the START of one pulse to the START of the next pulse (“on” time plus “listening” time)

Question 4

What is the only thing the sonographer changes in pulsed ultrasound?

Answer 4

the listening time between pulses

Question 5

As depth increases, PRP ___

as depth decreases, PRP ___

Answer 5

increases; decreases

Question 6

PRF

Answer 6

The # of pulses that occur in one second - also, how frequently the pulses are generated

Question 7

The PRF depends on _________

Answer 7

imaging depth

Question 8

shallowing images have a ______ PRF

Answer 8

higher

Question 9

deeper images have a ________ PRF

Answer 9

lower

Question 10

standard unit for PRF?

standard unit for PRP?

Answer 10

Hz

seconds

Question 11

If PRF is given in KHz, what will PRP be changed to?

Answer 11

miliseconds

Question 12

Duty Factor

Answer 12

the PERCENTAGE or FRACTION of time that the pulse is transmitted

*important for intensity

Question 13

Duty Factor increases when (3 things):

Answer 13

1. imaging depth decreases
2. PRP decreases
3. PRF increases

Question 14

Axial Res =

Answer 14

image quality

Question 15

SPL

Answer 15

The distance from the start of a pulse to the end of that pulse

Question 16

SPL determines _____ resolution

Answer 16

axial

Question 17

Imaging depth effects with 3 factors?

Answer 17

1. Duty factor
2. PRP
3. PRF

Question 18

Intensity

Answer 18

concentration of the power in a beam

Question 19

What are 5 key words that relate to Intensity and what to do they mean?

Answer 19

1. peak - max value
2. average - mean value
3. spatial - distance/space
4. temporal - time (transmit & recieve)
5. pulse - only the time the pulse exists (transmit only)

Question 20

What are 6 intensity descriptors?

Answer 20

1. SPTP (spatial peak, temporal peak)
2. SATP (spatial average, temporal peak)
3. SPTA (spatial peak, temporal average) *Bioeffects
4. SATA (spatial average, temporal average)
5. SPPA (spatial peak, pulse average)
6. SAPA (spatial average, peak average)