Ultrasound Physics

170 Questions  I  By Paga
Ultrasound Physics
Ultrasound Physics Questions

  
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1.  Which is not an acoustic variable?
A.
B.
C.
D.
2.  All of the following are true EXCEPT:
A.
B.
C.
D.
3.  Put in decreasing order
A.
B.
C.
D.
4.  Which of the following sound waves is ultrasonic and least useful in diagnostic imaging?
A.
B.
C.
D.
E.
5.  What is the frequency of a wave with 1msec period?
A.
B.
C.
D.
6.  If the frequency of an US wave is doubled, what happens to the period?
A.
B.
C.
D.
7.  The units of pulse repetition frequency are:
A.
B.
C.
D.
8.  The time from the beginning of a pulse until its end is__________?
A.
B.
C.
D.
9.  The time that a transducer is pulsing is measured at 18 seconds in one hour of total elapsed time.  What is the duty factor?
A.
B.
C.
D.
10.  If a wave's amplitude is doubled, what happens to the power?
A.
B.
C.
D.
11.  If the level of an acoustic variable ranges from 55 to 105, what is the amplitude?
A.
B.
C.
D.
12.  If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what happened to the power?
A.
B.
C.
D.
13.  Put these intensities in decreasing order
A.
B.
C.
D.
E.
14.  The duty factor for continuous wave ultrasound is
A.
B.
C.
D.
15.  What is the minimum value of the SP/SA factor?
A.
B.
C.
D.
16.  Which pair of intensities has the same value for continuous wave US?
A.
B.
C.
D.
17.  The fundamental frequency of a transcucer is 2.5 MHz.  What is the second harmonic frequency?
A.
B.
C.
D.
18.  A pulse is emitted by a transducer and is traveling in soft tissue.  The go-return time, or time of flight, of a sound pulse is 130 microseconds.  What is the reflector depth?
A.
B.
C.
D.
E.
19.  What is the approximate attenuation coefficient of 1MHz US in soft tissue?
A.
B.
C.
D.
20.  The relaive output of an US instrument is calibrated in dB and the operator increases the output by 60 dB.  The beam intensity is increased by which of the following?
A.
B.
C.
D.
E.
21.  The more pixels per inch:
A.
B.
C.
D.
22.  If we increase the transducer diameter, the beam diameter in the far zone is:
A.
B.
C.
23.  If the transducer diameter increases, the lateral resolution at its smallest dimension is
A.
B.
C.
24.  If we increase the frequency the near zone length is
A.
B.
C.
25.  If the frequency is decreased, the numerical value of the radial resolution is
A.
B.
C.
26.  If the spatial pulse length is 10 mm, what is the axial resolution?
A.
B.
C.
D.
27.  Which of the following is the best lateral resolution?
A.
B.
C.
D.
28.  What is the meaning of thermal index = 37
A.
B.
C.
D.
29.  The interaction of microscopic bubbles and ultrasound form the basis for cavitation bioeffects.  Which of the following forms of cavitation are most likely to produce microstreaming in the intracellular fluid and shear stresses?
A.
B.
C.
D.
E.
30.  Which of the following has the greatest output intensity
A.
B.
C.
D.
31.  Which of the following best decribes the empirical approach to the study of bioeffects?
A.
B.
C.
D.
E.
32.  Which of the following best describes the mechanistic approach to the study of bioeffects?
A.
B.
C.
D.
E.
33.  The propagation speed of US in the AIUM test object is?
A.
B.
C.
D.
34.  Enhancement, multipath and side lobes result in:
A.
B.
C.
D.
35.  A mirror image artifact can appear along side of the true anatomy.
A.
B.
36.  If the lines per frame is increased while the imaging depth is unchanged then:
A.
B.
C.
D.
37.  The more pixels per inch:
A.
B.
C.
D.
38.  If we increase the transducer diameter, the beam diameter in the far zone is
A.
B.
C.
39.  If the transducer diameter increases, the lateral resolution at its smalles dimension is
A.
B.
C.
40.  If we increase the frequency the near zone length is
A.
B.
C.
41.  If the frequency is decreased, the numberical value of the radial resolution is
A.
B.
C.
42.  If the spatial pulse length is 10mm, what is the axial resolution?
A.
B.
C.
D.
43.  Which of the following is the best lateral resolution?
A.
B.
C.
D.
44.  What are the units of longitudinal resolution?
A.
B.
C.
D.
45.  The range equation relates distant from the reflector to __________ and __________.
A.
B.
C.
D.
46.  Doppler shifts always occur if the source and observer are in motion relative to each other and the angle between the motion and the sound beam is not 90 degrees.
A.
B.
47.  What is the most typical Doppler shift measured clinically?
A.
B.
C.
D.
E.
48.  Assuming a constant frequency, what happens if the diameter of an unfocused circular transducer is increased?
A.
B.
C.
D.
E.
49.  Which one of the following sets of properties of a test phantom is most relevant when assessing depth calibration accuracy?
A.
B.
C.
D.
E.
50.  Doppler shifts are always created when the source and receiver are in motion relative to each other.
A.
B.
51.  Fill in of an anechoic structure such as a cyst is known as all of the following EXCEPT?
A.
B.
C.
D.
52.  According to the AIUM statement on bioeffects, there have been no concirmed bioeffects below intensities of _________ watts per square centimeter SPTA.
A.
B.
C.
D.
E.
53.  What component of the US unit contains the memory bank?
A.
B.
C.
D.
54.  Changing which of the following would not cause any change in a hard copy image output?
A.
B.
C.
D.
E.
55.  What are typical clinical Doppler frequencies?
A.
B.
C.
D.
56.  If 3 MHz sound has 2DB of attenuation in 1cm of tissue, what is the amount of attenuation of 6MHz sound in 0.5cm of the same tissue
A.
B.
C.
D.
57.  The distance to a target is doubled.  The time of flight for a pulse to travel to the target and back is
A.
B.
C.
D.
58.  The gray scale can be changed by the sonographer
A.
B.
59.  How many bits are needed to represent 14 shades of gray?
A.
B.
C.
D.
E.
60.  The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased.  Frequency
A.
B.
61.  The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased. FRAME RATE (TRUE OR FALSE)
A.
B.
62.  The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased.  (Sector Angle)
A.
B.
63.  The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased. (IMAGING DEPTH)
A.
B.
64.  The manufacturer increases the number of lines per frame.  As a result, which of the following may have to decreased. Power Output
A.
B.
65.  All of the following will improve temporal resolution EXCEPT:
A.
B.
C.
D.
E.
66.  What artifact has a grainy appearance and is caused by the interference effects of scattered sound?
A.
B.
C.
D.
E.
67.  Multiple reflections that are equally spaced are called:
A.
B.
C.
D.
68.  Axial resolution is affected by focusing.
A.
B.
69.  Which of the following choces determines the signal amplitude in the transducers of an ultrasound system?
A.
B.
C.
D.
E.
70.  The angle between an US pulse and the boundary between two media is 90 degrees.  What is this called?
A.
B.
C.
D.
71.  Refraction only occurs if there is :
A.
B.
C.
D.
72.  The most likely amount of reflection at a boundary between soft tissue is:
A.
B.
C.
D.
73.  Sound is traveling from medium 1 to medium 2.  Propagation speeds of M1 and M2 are 1600m/s and 1500m/s respectively.  There is oblique incidence.
A.
B.
C.
74.  Depth calibration of a machine measures 100 mm spaced wires to be 90 mm apart.  Scanning reflectors 50 mm apart, what will the machine calculate the distance to be?
A.
B.
C.
D.
75.  In an analog scan converter, what component stores the image data?
A.
B.
C.
D.
76.  When the US machine displays only strong reflecting objects and nothing else, the sonographer should
A.
B.
C.
D.
77.  If a reflector is moved twice as far away from the tranducer, how will this affect the time of flight of a sound pulse?
A.
B.
C.
D.
78.  You are performing a quality assurance study on an ultrasound system using a tissue equivalent phantom.  You make an adjustment using a knob on the system console that changes the appearance of reflector brightness from fully bright to barely visible.  What are you evaluating?
A.
B.
C.
D.
E.
79.  At what location in a sound beam is the SPTA intensity the highest?
A.
B.
C.
D.
E.
80.  What determines the frequency of a sound beam from a pulsed transducer?
A.
B.
C.
D.
81.  The impredance of tissue is 3 x 10^5 rayls and for the PZT crystal is 6 x 10 ^6 rayls.  What is the best impedance for the matching layer?
A.
B.
C.
D.
E.
82.  What can pulsed Doppler measure that continuous wave cannot?
A.
B.
C.
D.
E.
83.  What is the fraction of time that sound is transmitting?
A.
B.
C.
D.
84.  If the SPTA of the following were equal, which would have the lowest SPPA?
A.
B.
C.
D.
E.
85.  The dB is defined as the _______________ of two intensities
A.
B.
C.
D.
86.  If the power of a sound wave is increased by a factor of 8 how many decibles is this?
A.
B.
C.
D.
87.  An ultrasound system is set at 0 dB and is transmitting at full intensity.  What is the output power when the system is transmitting at 50% of full intensity?
A.
B.
C.
D.
E.
88.  An ultrasound system is set at 0 dB and is tranmitting at full intensity. What is the output power when the system is transmitting at 10% of full intensity?
A.
B.
C.
D.
E.
89.  What may be a unit of amplitude?
A.
B.
C.
D.
E.
90.  A Doppler exam is performed with a 5MHz probe and a PRF of 15kHz.  Which of these Doppler shifts will create aliasing?
A.
B.
C.
D.
91.  According to the AIUM statement on bioeffects, there have been no confirmed bioeffects below intensities of __________ watts per square centimeter SPTA.
A.
B.
C.
D.
E.
92.  Which of the following is not a measure of area?
A.
B.
C.
D.
93.  Which of the following is true of all waves?
A.
B.
C.
D.
94.  Is Intensity an acoustic variable?
A.
B.
95.  A force is applied to a surface.  If the force is tripled and the surface area over which the force is applied is also tripled, what is the new pressure?
A.
B.
C.
D.
96.  Which of the following units are appropriate to describe the period of an acoustic wave?  More than one answer maybe correct.
A.
B.
C.
D.
97.  Two waves arrive at the same location and interfere.  The resultant sound wave is smaller that either of the two original waves.  What is this called?
A.
B.
C.
D.
98.  Ultrasound is defined as a sound with a frequency of
A.
B.
C.
D.
99.  Compare two sound waves. A and B.  The frequency of a wave A is one-third that of wave B.  How does the period of a wave A compare the period of wave B?
A.
B.
C.
D.
100.  Which of the following wave is ultrasonic and least useful in diagnotic ultrasound?
A.
B.
C.
D.
101.  True of False:  With standard diagnostic imaging instrumentation, the sonographer has the ability to vary the amplitude of a sound wave produced by the transducer.
A.
B.
102.  The power of an ultrasound wave can be reported with which of the following units? More than one answer maybe correct.
A.
B.
C.
D.
103.  The maximum value of the density of an acoustic wave is 60 lb/in^2 while the minimum density is 20 lb/in^2.  What is the amplitude of the wave?
A.
B.
C.
D.
104.  The final amplitude of an acoustic wave is reduced to one-half of its original value.  The final power is _______ the original power.
A.
B.
C.
D.
105.  The amplitude of an acoustic wave decreases from 27 pascals to 9 pascals.  If the initial power in the wave was 27 watts, what is the wave final power?
A.
B.
C.
D.
106.  What are the units of intensity?
A.
B.
C.
D.
107.  If the power in an ultrasound beam is unchanged, while at the same time, the beam area doubles, then the beams's intensity
A.
B.
C.
D.
108.  What happens to an acoustic beams's intensity when the power in the beam increases by 25% while the cross sectional area of the beam remain the same?
A.
B.
C.
D.
109.  When the power in an acoustic beam is doubled and the cross sectional area of the beam is halved, then the intensity of the beam is
A.
B.
C.
D.
110.  What determines the intensity of an ultrasound beam after it has traveled through the body?
A.
B.
C.
D.
111.  What happens to the intensity of an ultrasound beam when the beam's cross-sectional area remains unchanged while the amplitude of the wave triples.
A.
B.
C.
D.
112.  The wavelength of a cycle in an ultrasound wave can be reported with which units?
A.
B.
C.
D.
113.  Which of the following terms best describes the relationship between frequency and wavelength for sound traveling in soft tissue?
A.
B.
C.
D.
114.  (TRUE OR FALSE) The power in the wave increases as it travels through the mass. (An ultrasound pulse propagates from soft tissue through a mass.  Sound's propagation speed in the mass is 1575 m/s.)
A.
B.
115.  The frequency closest to the lower limits of US is:
A.
B.
C.
D.
116.  Which of the following sound waves is ultrasonic and least useful in diagnostic imaging?
A.
B.
C.
D.
E.
117.  _____________ is the distance covered by one cycle
A.
B.
C.
D.
118.  If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength?
A.
B.
C.
D.
119.  If the frequency is decreased, the numberical value of the radial resolution is
A.
B.
C.
120.  If we increase the frequency, the near zone length is
A.
B.
C.
121.  The digital scan converter has a number of pixels assigned to each bit.
A.
B.
122.  The more bits per pixel
A.
B.
C.
D.
123.  What is the actual time that an US machine is creating a pulse?
A.
B.
C.
D.
124.  The angle of incidence of an US beam is perpendicular to an interface.  The two media have the same propagation speeds.  What process cannot occur?
A.
B.
C.
D.
125.  What is the most typical Doppler shift measured clinically?
A.
B.
C.
D.
E.
126.  If the frequency is decreased, the numerical value of the radial resolution is
A.
B.
C.
127.  The digital scan converter has a number of pixels assigned to each bit.
A.
B.
128.  The more bits per pixel
A.
B.
C.
D.
129.  Increasing the frequency increases the penetration depth.
A.
B.
130.  All of the following will improve temporal resolution EXCEPT
A.
B.
C.
D.
E.
131.  What componet of a transducer changes electrial to mechanical and mechanical back to electrical engery?
A.
B.
C.
D.
132.  What determines the frequency of a sound beam from a pulsed transducer?
A.
B.
C.
D.
133.  What measures the output of the a transducer?
A.
B.
C.
D.
134.  Which type of artifact appears most commonly with highly reflective objects?
A.
B.
C.
D.
E.
135.  Which of the following will result in the highest mechanical index?
A.
B.
C.
D.
136.  All of the following statements reqarding in-vitro bioeffects are true EXCEPT
A.
B.
C.
D.
137.  Which of the following is not used to measure the output of ultrasound systems?
A.
B.
C.
D.
E.
138.  Under which circumstance is cavitation most likely to occur?
A.
B.
C.
D.
139.  Post processing occurs when the image
A.
B.
C.
D.
140.  What happens to venous blood flow to the heart during expiration?
A.
B.
C.
141.  Which of the following has a propagation speed closest to "soft tissue"?
A.
B.
C.
D.
142.  What is displayed on the y axis of an m-mode image?
A.
B.
C.
D.
143.  An amplifier of an ultrasound system increases the voltage of a signal from 0.0001 to 0.1 volt.  What is the amplification?
A.
B.
C.
D.
144.  Which of the following will result in the greatest number of shades of gray in a digital image display?
A.
B.
C.
D.
E.
145.  With good images on the CRT but not on the strip chart recorder, one should
A.
B.
C.
D.
146.  Shadowing may result from high amounts of reflection of US energy.
A.
B.
147.  Where are harmonics created?
A.
B.
C.
D.
148.  How is range ambiguty artifact eliminated?
A.
B.
C.
D.
149.  For Doppler, which incident angle reults in no shift?
A.
B.
C.
D.
150.  Which transducer would be best to image superficial structures?
A.
B.
C.
D.
151.  What information does Doppler shift provide?
A.
B.
C.
D.
152.  Circumferences are usually measured in:
A.
B.
C.
D.
153.  Decimal uses a base of 10, binary uses a base of
A.
B.
C.
D.
154.  If the frame rate increases and the lines per frame is unchanged, what else must happen?
A.
B.
C.
D.
155.  How many decibels is related to 90% decrease in imaging power?
A.
B.
C.
D.
156.  If the output of an US machine is calibrated in dB and the output is increased by 20 dB, the beam intensity is increased
A.
B.
C.
D.
157.  Which has the greatest amount of attenuation?
A.
B.
C.
D.
158.  Refraction only occurs if there is :
A.
B.
C.
D.
159.  With normal incidence, what factors affect refraction of US?
A.
B.
C.
D.
160.  Which of the following is associated with power mode Doppler?
A.
B.
C.
D.
E.
161.  The sonographer cannot change, directly or indirectly, the duty factor of an US machines.
A.
B.
162.  There have not been biological effects from US found in the laboratory.
A.
B.
163.  As the impedances of two media become vastly different, the
A.
B.
C.
D.
164.  What is the minimum value of the duty factor?
A.
B.
C.
D.
165.  Assuming a fixed frequency, what happens if the diameter of an ultrasound circular transducer is increased?
A.
B.
C.
D.
E.
166.  From a safety standpoint, which one of the following methods is best?
A.
B.
C.
D.
E.
167.  Which one of the following instruments is a component that stores digital echo signal information?
A.
B.
C.
D.
E.
168.  The dynamic range of the receiver of an ultrasound instrument refers to the
A.
B.
C.
D.
E.
169.  A sound wave leaves its source and travels through air.  The speed of sound in air is 330 m/sec.  One second later, an echo returns to the source.  At what distance from the source is the reflector that produced the echo?
A.
B.
C.
D.
E.