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