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63 Cards in this Set

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A collection of short bursts of acoustic energy (or cycles) traveling as a single unit are called what?
Pulsed Sound
The actual time from the start of a pulse to the end of that pulse; ON/Transmit time
Pulse Duration
PULSE DURATION: units?
Time
PULSE DURATION: determined by?
Source
PULSE DURATION: adjustable?
No
How is PULSE DURATION & # OF CYLCES IN PULSE related?
Directly Related
How is PULSE DURATION & PERIOD related? formula?
Directly Related
PD (microsec) = #cycles x period (microsec)
How is PULSE DURATION & FREQUENCY related? formula?
Inversely Related
PD (microsec) = #cycles / freq (MHz)
This type of pulsed sound is created by many cycles in the pulse OR individual cycles with long periods
Pulsed sound of LONG duration
This type of pulsed sound is created by few cycles in the pulse OR individual cycles with short periods
Pulsed sound of SHORT duration
In clinical imaging how many cycles does a pulse typically contain?
2-4 cycles
What type of pulse is more desirable in diagnostic imaging & why?
Shorter duration & shorter length pulses, because they create images of greater accuracy
The distance that a pulse occupies in space from the start to the end of a pulse
Spatial Pulse Length
SPATIAL PULSE LENGTH: units?
Distance
SPATIAL PULSE LENGTH: determined by source or medium?
Both (Source & Medium)
SPATIAL PULSE LENGTH: adjustable?
No
How is SPATIAL PULSE LENGTH & # PULSE CYCLES related?
Directly Related
SPL (mm) = #cycles x wavelength (mm)
How is SPATIAL PULSE LENGTH & WAVELENGTH related?
Directly Related
SPL (mm) = #cycles x wavelength (mm)
How is SPATIAL PULSE LENGTH & FREQUENCY related?
Inversely Related
What is the difference between PULSE DURATION & SPATIAL PULSE LENGTH?
PD = TIME that the pulse is ON (microseconds)
SPL = DISTANCE of the pulse end-to-end (mm)
This type of pulsed wave is created by many cycles in the pulse OR cycles with longer wavelengths
Pulsed waves of LONG duration
This type of pulsed wave is created by few cycles in the pulse OR cycles with shorter wavelengths
Pulsed waves of SHORT duration
The time from the start of one pulse to the start of the next pulse; includes one ON time and one OFF/Listening time
Pulse Repitition Period
PULSE REPITION PERIOD: units?
Time
PULSE REPITION PERIOD: determined by source or medium?
Source
PULSE REPITION PERIOD: adjustable?
Yes
The maximum distance into the body that an ultrasound system is imaging; adjustable by sonography
Depth of View
How is PULSE REPITITION PERIOD & DEPTH OF VIEW related?
Directly Related
What are the 2 components of PULSE REPITITION PERIOD?
Transmit Time (On) & Receive Time (Off\Listening)
Is Transmit Time or Receive Time adjustable by the sonongrapher?
Only Receive Time is adjustable by the sonongrapher
The # of pulses that an ultrasound system transmits in the medium each second
Pulse Repitition Frequency
PULSE REPITITION FREQUENCY: units?
Hertz (Hz) or per second
PULSE REPITITION FREQUENCY: determined by source or medium?
Source
PULSE REPITITION FREQUENCY: adjustable?
Yes
How are PULSE REPITITION FREQUENCY & DEPTH OF VIEW related?
Inversely Related
How are PULSE REPITITION PERIOD & PULSE REPITITION FREQUENCY related?
Inversely Related & Reciprocals
The percentage or fraction of time that the system is transmitting a pulse
Duty Factor
DUTY FACTOR: units?
None - it is a %
DUTY FACTOR: determined by source or medium?
Source
DUTY FACTOR: adjustable?
Yes
How is DUTY FACTOR calculated?
DF (%) = (PD/PRP) x 100
What are the minimum and maximum values for DUTY FACTOR?
0% - 100%
What is the relationship between PULSE REPETITION PERIOD and PERIOD?
Unrelated
When the system is imaging at shallow depths, the time from one pulse to the next is ___
Short
When the system is imaging more deeply, the time from one pulse to the next is ___
Longer
What is the relationship between PULSE REPETITION FREQUENCY and FREQUENCY?
Unrelated
When the system is imaging shallow, the pulse repetition frequency is ___
Higher
When the system is imaging deeper, the pulse repetition frequency is ___
Lower
Which of these four values for PRF would have the longest PRP?
A. 2 kHz
B. 4,000 Hz
C. 6 Hz
D. 1 kHz
C
Four pulses have PRPs as listed below. Which of the following four waves has the highest PRF?
A. 8 s
B. 80 ms
C. 5 ms
D. 400 ks
C
Which of these four pulses with PRFs listed below has the shortest PRP?
A. 12 kHz
B. 6,000 Hz
C. 20 kHz
D. 1 kHz
C
Four waves have PRPs as listed below. Which of the following four waves has the lowest PRF?
A. 8 s
B. 80 microseconds
C. 8000 ns
D. 800 ms
A
T/F: two waves can have identical PRFs, even if their PRPs are different
F
T/F: two waves can have identical PRFs, even if their periods are different
T
T/F: two waves can have identical PRFs, even if their frequencies are different
T
T/F: PRF and PRP are determined only by the imaging depth
T (important concept!)
If you have a duty factor of 100%, what modality are you using?
Continuous Wave Doppler
The following factors define what type of imaging?
- less listening
- shorter PRP
- higher PRF
- higher duty factor
Shallow Imaging
The following factors define what type of imaging?
- more listening
- longer PRP
- lower PRF
- lower duty factor
Deeper Imaging
Name the five parameters that are all determined only by the source
Pulse Duration
PRP
PRF
Duty Factor
Name the parameter that is determined by both the source and medium
Spatial Pulse Length
Name the two parameters which do not change with imaging depth
Pulse Duration
Spatial Pulse Length
Name the three parameters which do change with imaging depth
PRP
PRF
Duty Factor