Quiz
Physical basis of Doppler ultrasound imaging - Medical Physics - MCQs
Questions in this quiz (33)
1Doppler shift applies to:
- AAll wave phenomena
- BUltrasound
- CInfrared EM waves
2The contact gel used in ultrasonography (echography) is for:
- AProtection of the body from harmful ultrasound
- BEfficient transmission of sound waves into the tissue
- CImprovement of skin elasticity in the area of study
3In medical imaging, Doppler echography is most appropriate for:
- ADeep body targets
- BMoving body targets
- CSurface targets
4Which of the following waves do cannot propagate in vacuum?
- ARadiowaves
- BX-rays
- CUltrasound
5In what form is the information received with Doppler Echography displayed?
- ABy sound
- BBy one dimensional image
- CBy two dimensional image with artificial coloring
6Doppler frequency (shift) is:
- AThe infrared spectrum of light, studied by Doppler
- BThe frequency generated by ultrasonic transducer
- CThe difference between emitted and reflected (received) frequency between to objects in relative motion.
7For which of the following numerical Doppler frequency shifts is the blood speed the highest?
- A1210 Hz
- B800 Hz
- C1530 Hz
8Is it possible to tell the direction of motion of erythrocytes from the sign of the Doppler shift Δf = f - f0?
- AYes, when Δf > 0 erythrocytes move towards the transducer
- BYes, when Δf > 0erythrocytes move away from the transducer
- CNo, the sign of Δf does not tell the direction of motion
9If shorter wavelengths of ultrasound are less penetrating in human tissue, then which of the following frequencies is most appropriate for DEEP tissue and organ imaging?
- A8 MHz
- B3 MHz
- C20 MHz
10Doppler shift is defined as:
- AThe frequency difference between emitted and received signals for observers at relative motion
- BThe difference in acoustic impedance between two transmitting mediums
- CThe intensity difference between emitted and reflected waves
11At what angle (Θ) to the surface of the body should the ultrasonic probe be applied in order to gain a maximum Doppler shift? Consider that Doppler shift is proportional to cos (Θ).
- AΘ = 45⁰ (cos 45 = 0.7)
- BΘ = 90⁰ (cos 90 = 0)
- CΘ = 60⁰ (cos 60 = 0.5)
12The speed of ultrasound in human tissue depends on:
- AThe properties of the tissue
- BThe properties of the apparatus
- CThe speed of (ultra)sound does not depend on the tissue
13The so called “reverse piezoelectric effect” finds application in:
- AUltrasound generation
- BX-ray tubes
- CLasers
14Ultrasound can propagate through:
- AVacuum
- BMatter
- CEverywhere where light propagates
15Phonophoresis is:
- ATherapeutic application of ultrasound
- BDiagnostic application of ultrasound
- CMethod for sterilization
16Infrasound of certain frequency and intensity can:
- ADamage internal organs
- BIncrease temperature of tissues
- CRearrange water molecules
17Infrasound CANNOT propagate through:
- ASoft tissue
- BBones
- CVacuum
18Choose the correct statement:
- AUltrasound is completely harmless for humans and animals
- BSound reflection depends on the transparency of the medium
- CSound impedance does not depend on frequency (for linear mediums)
19Choose the correct range:
- AAudible sound: 103 Hz—106 Hz
- BInfrasound: 3 Hz—10 Hz
- CUltrasound: 10 kHz—10 kHz
20The resonant frequency of the vestibular system is in the range of:
- AUltrasound
- BInfrasound
- CUltraviolet
21The direct piezoelectric effect is used for:
- AUltrasound detectors
- BUltrasound generators
- CElectrophoresis
22Piezoelectric effect is defined as:
- AElectric polarization of solids under mechanical stress
- BElectro-mechanical coupling of objects falling off the tower of Pisa
- CElectric polarization in a solid due to temperature gradient.
23Does human tissue exhibit piezoelectric properties?
- ANo, the human body exhibits only capacitive properties
- BNo, piezoelectric properties are observed in inorganic crystals
- CYes, tissue such a collagen has piezoelectric properties
24Which statement is correct?
- AThe size of the ultrasonic equipment (echograph) influences the acoustic density of imaged tissue.
- BThe precision of the ultrasonic instrument does not have an effect on the quality of received images
- CThe ultrasonic image, displayed on the monitor, represents the acoustic density of studied tissues.
25Mechanical waves with frequency above 20 kHz are called:
- AInfrasound
- BUltrasound
- CP-waves
26Infrasound is:
- AElectromagnetic waves with frequency under 20 Hz
- BMechanical waves with frequency above 20 Hz
- CNone of the above
27If Δf is the change in frequency between emitted and received ultrasound signals due to Doppler effect during measurement of the linear speed of blood, then:
- AThe speed of blood relative to the stationary transducer (emitter and receiver) is as much great as Δf is greater
- BBlood motion does not affect Δf
- CThe speed of blood relative to the stationary transducer is greater when Δf is smaller.
28Which natural science studies infrasound?
- APediatrics
- BSeismology
- CDental medicine
29Mechanical waves used for destruction of kidney stones, in procedure called “lithotripsy”, cause minimal damage to surrounding tissues because:
- AMechanical waves do not propagate through the surrounding tissue
- BAcoustic pressure in the surrounding tissue is greatly reduced compared tothe pressure induced in the kidney stones
- CMechanical waves do not have negative effect on soft tissue
30Ultrasound waves propagate through human tissue as:
- ALongitudinal waves
- BTransverse waves
- CBoth, longitudinal and transverse modes
31Can humans sense infrasound waves?
- AOnly when the intensity of the wave is sufficiently high for the ear to detect
- BNo, that’s why they are called infra-sound
- CThey can be sensed as vibrations by the tactile receptors of the skin
32The resonant frequency of the internal organs is in the range of:
- A10 MHz
- BInfrasound
- CUltrasound
33Which of the following is used in Doppler echography?
- AMagnetic resonance
- BVacuum tubes
- CPiezoelectric effect
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- Medical Physics Quiz on Physical basis of Doppler ultrasound imaging - Medical Physics - MCQs, created by Hussain Basheer on 23/11/2018.
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- Hussain Basheer
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