Physics Quiz 4
A sonographer adjusts the maximum imaging depth of an ultrasound system. What also changes pulse repetition period wavelength pulse repetition frequency frequency
PRP and PRF
What is the duty factor if the pulse duration is 1 millisecond and the pulse repetition period is 1 second?
The duty factor is 0.001 or 0.1% 0.001/1 =0.001
What is the duty factor if the pulse duration is 1 microsecond and the pulse repetition period is 1 ms
The duty factor is 0.001 or 10^-3 10^-6 / 10^-3 = 10^-3
The speed of 5 MHz continuous wave is 1.8 km/sec. The wave is then pulsed with a duty factor of 0.5. Calculate the new propagation speed
The propagation speed for pulsed and continuous would be the same; 1.8km/s. Because traveling through the same medium
T or F: PRF and pulse repetition period are determined only by the imaging depth
True
T or F: the sonographer cannot change the duration of a sound pulse unless the transducers are switched.
True
T or F: while imaging soft tissue, the spatial pulse length does not change as long as the components of the ultrasound system are the same
True
T or F: The pulse duration of an ultrasound and transducer system does not change significantly as long as the system components remains unchanged
True pulse duration is the timespan that a pulse exists and is determined by the system and transducer and usually remains constant
T or F: Two waves can have identical PRFs, even if their frequencies are different
True. Frequency and pulse repetition frequency are unrelated
T or F: Two waves can have identical PRFs even if their periods are different
True. Period and pulse repetition frequency are unrelated
Two transducers send ultrasound pulses into soft tissue. One transducer emits sound with a 4 MHz frequency and the other produces sound at a 6 MHz frequency. Each pulse contains 4 cycles. Which has a greater spatial pulse length? a. 6 MHz b. 4 MHz c. they are the same d. cannot be determine
b. 4 MHz because it has the longer wavelength so then it has the longer spatial pulse length
Which of the following terms does not belong with the others? a. low duty factor b. shallow imaging c. low PRF d. long pulse repetition period
b. shallow imaging. The other three are associated with deep imaging.
Which of these four pulses with PRFs listed below has the shortest pulse repetition period? a. 12 kHz b. 6000 Hz c. 20 kHz d. 1 kHz
c. 20 kHz: Pulse repetition period is the reciprocal of pulse repetition frequency. Highest pulse repetition frequency has shortest pulse repetition period
Four pulses have pulse repetition periods as listed below. Which of the following four waves has the highest pulse repetition frequency? A. 8s b. 80ms c. 5 ms d. 400 ks
c. 5 ms: the pulse with the shortest pulse duration will have the highest pulse repetition frequecny
Which of the following terms does not belong wit the others? a. high duty factor b. shallow imaging c. low PRF d. short pulse repetition period
c. low PRF: is associated with deep imaging. The others are associated with shallow imaging
Which of the following best describes the spatial pulse length? a. frequency x wavelength b. PRF x wavelength c. wavelength x number of cycles in the pulse d. duty factor x the wavelength
c. wavelength x number of cycles in the pulse
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? PRF
decrease
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? duty factor
decrease
Four waves have pulse repetition periods as listed below. Which of the following four waves has the lowest pulse repetition frequency? a. 6 s b. 80 us c. 8000 ns d. 800 ms
A. 8 s: the pulse with the longest pulse duration will have the lowest pulse repetition frequency
A sonographer is using a 3MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease or remain the same? Wavelength
decrease
A sonographer is using a 3MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease or remain the same? period
decrease
If all other factors remain unchanged, what happens to the duty factor (increases, decreases or remains the same) when the pulse repetition increases?
decreases
If all other factors remain unchanged, what happens to the duty factor (increases, decreases, or remains the same) when imaging the imaging depth increases?
decreases
A sonographer is using a 3MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease or remain the same? frequency
increase
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? pulse repetition period
increases
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? intensity
increases
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? power
increases
If all other factors remain unchanged, what happens to the duty facto (increases, decreases or remains the same) when the pulse repetition frequency increases?
increases
If all other factors remain unchanged, what happens to the duty factor (increases, decreases, or remains the same) when the monographer uses a new transducer with a longer pulse duration?
increases
The spatial pulse length describes certain characteristics of an ultrasound pulse. What are the units?
meters (distance)
The pulse duration is expressed in the same units as the
period (both measures of time)
What is the pulse duration equal to?
period multiplied by the number of cycles in the pulse
_______ is the time from the start of a pulse to the end of that pulse
pulse duration
By changing the imaging depth, which of the following does the operator also change a. pulse repetition frequency b. duty factor c. propagation speed d. pulse repetition period e. amplitude f. spatial pulse length
pulse repetition frequency duty factor pulse repetition period
_________ is the time from the start of a pulse to the start of the next pulse
pulse repetition period
pulse repetition frequency is the reciprocal of
pulse repetition period
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? Amplitude
remain the same
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? Wavelength
remain the same
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? frequency
remain the same
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? period
remain the same
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? pulse duration
remain the same
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? spatial pulse length
remain the same
A sonographer adjusts the depth view of an ultrasound scan from 8 cm to 16 cm. Would each of the parameters increase, decrease or remain the same? speed
remain the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? Wavelength
remain the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? frequency
remain the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? period
remain the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? speed
remain the same
A sonographer is using a 3MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease or remain the same? PRF
remain the same
A sonographer is using a 3MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease or remain the same? intensity
remain the same
A sonographer is using a 3MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease or remain the same? pulse repetition period
remain the same
A sonographer is using a 3MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease or remain the same? speed
remain the same
Using a specific transducer, what happens to the spatial pulse length as the sonographer increases the maximum imaging depth?
remains eh same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? PRF
remains the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? duty factor
remains the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? pulse duration
remains the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? pulse repetition period
remains the same
A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would each of the following parameters increase, decrease or remain the same? spatial pulse length
remains the same
What happens to the pulse duration when a sonographer decreases the maximum imaging depth in an ultrasound scan?
remains the same
What determines the pulse duration?
the source
On what does the pulse repetition period depend on?
the source of the sound wave
Which of these four values for pulse repetition frequency would have the longest pulse repetition period? a. 2kHz b. 4000 Hz c. 6 Hz d. 1kHz
C. 6 Hz: pulse repetition period is the reciprocal of pulse repetition frequency. The lowest pulse repetition frequency is the longest pulse repetition period
In diagnostic imaging what determines the spatial pulse length?
the ultrasound image and the medium it is traveling through
What are the units of pulse duration
units of time (sec, years, etc) 0.3 -2us
What is the duty factor if the pulse duration is 1 us and the pulse repetition period is 1 us? A. 100% B. 0.1 c. 0.01 d. 0.001
D. 0.001
T or F: the pulse duration cannot be changed under any circumstance or by any action of the sonographer
False sonographer can alter the pulse duration by using a different imaging transducer or ultrasound system
T or F: Two waves can have identical pulse repetition frequencies, even if their pulse repetition periods are different.
False: two waves can never have identical PRFs if their pulse repetition period are different
T or F: A sonographer can adjust the duration of an acoustic pulse since it depends on the pulses propagation speed?
False; sonographer cannot change pulse duration! and it does not depend on propagation speed
T or F: a sonographer can adjust the duration of an acoustic pulse since it depends upon the maximum imaging depth
Fase; pulse duration is a constant value
