# Shared Flashcard Set

## Details

Ultrasound Physics
Edelman Chapt 4-6
24
Physics
Professional
09/19/2014

Term
 Which of these four values for pulse repetition frequency would have the longest pulse repetition periodA. 2kHzB. 4,000 HzC. 6 HzD. 1 kHz
Definition
 C. 6 Hz Pulse repetition period is the reciprocal of pulse repetition frequency. This choice has the lowest pulse repetition frequency and, thus, the longest pulse repetition period.
Term
 Four pulses have pulse repetitition periods as listed below. Which of the following four waves has the highest pulse repetition frequency?A. 8 sB. 80 msC. 5 msD. 400 ks
Definition
 C. 5 ms. The pulse with the shortest pulse duration will have the highest pulse repetition frequency.
Term
 Which of these four pulses with PRFs listed below has the shortest pulse repetition period?A. 12 kHzB. 6,000 HzC. 20 kHzD. 400 ks
Definition
 C. 20 kHz Pulse repetition period is the reciprocal of pulse repetition frequency. This answer has the highest pulse repetition frequency and, thus, the shortest pulse repetition period.
Term
 Four waves have pulse repetition periods as listed below. Which of the following four waves has the lowest pulse repetition frequency.A. 8 sB. 80 usC. 8000 nsD. 800 ms
Definition
 A. 8 s. The pulse with the longest pulse duration will have the lowest pulse repetition frequency.
Term
 True or False. Two waves can have identical pulse repetition frequencies, even if their pulse repetition periods are different.
Definition
 False. Two waves can never have identical PRFs if their pulse repetition periods are different.
Term
 True of False. Two waves can have identical PRFs, even if their periods are different.
Definition
 True. Period and pulse repetition frequency are unrelated.
Term
 True or False. Two waves can have identical PRFs, even if their frequencies are different.
Definition
 True. Frequency and pulse repetition frequency are unrelated.
Term
 True or False. PRF and pulse repetition period are determined only by the imaging depth.
Definition
 True. This is a very important concept.
Term
 If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when the pulse repetition frequency increases?
Definition
 increases
Term
 If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when imaging depth increases?
Definition
 decreases
Term
 If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when pulse repetition period increases?
Definition
 decreases
Term
 If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when the sonographer uses a new transducer with a longer pulse duration?
Definition
 increases
Term
 What is the duty factor if the pulse duration is 1 us and the pulse repetition period is 1 msA. 100 %B. 0.1C. 0.01D. 0.001
Definition
 5. D
Term
 Which of the following terms does not belong with the others?A. high duty factorB. shallow imagingC. low PRFD. short pulse repetition period
Definition
 C. Low PRF is associated with deep imaging. The other three choices are all associated with shallow imaging.
Term
 Which of the following terms does not belong with the others?A. low duty factorB. shallow imagingC. low PRFD. long pulse repetition period
Definition
 B. Shallow imaging does not belong. The other three choices are all associated with deep imaging.
Term
 _______ is the time from the start of a pulse to the end of that pulse.
Definition
 Pulse duration
Term
 _______ is the time from the start of a pulse to the start of the next pulse.
Definition
 Pulse repetition period
Term
 By changing the imaging depth, which of the folowing does the operator also change (more than 1 may be correct)?A. pulse repetion frequencyB. duty factorC. propagation speedD. pulse repetition periodE. amplitudeF. spatial pulse length
Definition
 A, pulse repetition frequency.B, duty factor.D, pulse repetition period.
Term
 The speed of a 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.
Definition
 The propagation speed for the pulsed and continuous wave sound is the same; in this case, 1.8 km/s. It depends only upon the medium through which the sound travels
Term
 What is the duty factor if the pulse duration is 1 microsecond, and the pulse repetition period is 1 ms?
Definition
 The duty factor is 0.001, or 10 neg 3. 10 neg 6 divided by 10 neg 3 = 10 neg 3, or 0.001.
Term
 What is the duty factor if the pulse duration is 1 millisecond, and the pulse repetition period is 1 second?
Definition
 The duty factor is 0.001 or 0.1% 0.001 divided by 1.0 = 0.001.
Term
 A sonographer adjusts the depth of view of an ultrasound scan form 8 cm to 16 cm. Would each of the following parameters increase, decrease, or remain the same?A periodB. frequencyC. wavelengthD. speedE. amplitude (initial)F. pulse durationG PRFH. duty factorI. spatial pulse lengthJ. pulse repetition period
Definition
 A. remains the sameB. remains the sameC. remains the sameD. remains the sameE remains the sameF. remains the sameG decreasesH. decreasesI. remains the sameJ. increases
Term
 A sonographer is using a 3 MHz 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?A. periodB. frequencyC. wavelengthD. speedE. intensity (initial)F. PRFG. pulse repetition period
Definition
 A.decreasesB increasesC decreasesD remains the sameF. remains the sameG. remains the same
Term
 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?A. periodB frequencyC. wavelengthD. speedE. power (initial)F intensity (initial)G. pulse durationH. PRFI. duty factorJ. spatial pulse lengthK. pulse repetition period
Definition
 A. remains the sameB. remains the sameC. remains the sameD. remains the sameE. increasesF increasesG. remains the sameH. remains the sameI remains the sameJ. remains the sameK. remains the same
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