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