2. Increases
Answer As density decreases, speed
3. solid, liquid, air
Answer List air, solid and liquid in order from fastest to slowest in regard to the speed at which sound will travel through
them
4. Compressibility
Answer What is Bulk Modulus synonymous with?
5. Longitudinal and mechanical waves
Answer What kind of waves are sound waves?
6. the speed at which a wave travels through a medium
Answer Define
propagation speed
7. the length of space one cycle takes up
Answer Define
wavelength
8. a traveling variation of acoustic variables
Answer Define
soundwave
9. the number of cycles that occur in one second
Answer Define
Answer frequency
10. the time it takes for one cycle to occur
Answer Define
Period
11. is inversely proportional to
Answer Frequency wavelength
12. 4,8,12
Answer The first few even harmonics of 2 MHz are MHz
13. 20,000
Answer 20 kHz is equal to Hz
14. Increases
Answer If you switch to a lower frequency for penetration, the wavelength of the transducer
, DUTEC170 TEST QUESTIONS
15. 1.2 mm
Answer What is the SPL in soft tissue for a 4 cycle pulse, using a frequency of 5 MHz?
16. 0.14 microseconds
Answer What is the period of a 7 MHz transducer in soft tissue?
17. 7 MHz
Answer What would be the frequency for a .22 mm wavelength in soft tissue?
18. 0.51 mm
Answer The wavelength of 3 MHz ultrasound in soft tissue is
19. Half the original intensity
Answer What does 3 dB of attenuation mean?
20. 0.4 mm
Answer What is the SPL of a 4 cycle pulse with a wavelength of 0.1 mm?
21. is decreased
Answer If the number of cycles in a pulse is reduced, the pulse duration
22. strength
Answer Amplitude and intensity are indicators of the sound wave's
23. 1.3 microseconds
Answer Calculate the pulse duration for a 3 MHz transducer in soft tissue with a 4 cycle pulse
24. Stiffness
Answer Propagation speed is primarily determined by the of the medium
25. Absorption, Scattering and reflection
Answer Attenuation encompasses and
26. to facilitate passage of ultrasound into human tissue
Answer The purpose of the coupling medium is
27. maximum imaging depth
Answer Increasing the transducer frequency decreases the .
, DUTEC170 TEST QUESTIONS
28. curie point
Answer The critical temperature an ultrasound transducer cannot exceed is called the
.
29. 5-30
Answer Doppler ultrasound pulses are typically cycles long.
30. Rarefactions
Answer Regions of lower pressure and density are called
31. a.)
Pulsed wave (there is an on and off period in each pulse) b.)
Red
Answer Pulse Repetition Period (PRP) Blue
Answer Pulse Duration (PD)
Black
Answer Rest Period
With regard to the image Discuss what kind of
ultrasound wave you are seeing. Also, define what each
arrow represents.
x-axis = measuring time
32. 1.54 mm/microsecond
Answer The average propagation speed in human soft tissue is
33. 2.0 mm
Answer If the wavelength is 0.5 mm, the SPL for a 4 cycle pulse is
34. 100
Answer What is the duty factor for CW doppler?
35. a.) What causes harmonics?
Harmonics are caused by the natural resonance that occurs as sound passes through a
medium (in our case human tissue).
b.) Do we as sonographers produce harmonics with our machines?
No, we tell our machine to listen for the harmonics that are naturally generated within
the body after we've sent sound into a patient.
c.) Is there a benefit to using harmonics?
It can help to produce a higher quality image, with better contrast, and fewer
artifacts.