Questão 1
Questão
Doppler shift applies to:
Responda
-
All wave phenomena
-
Ultrasound
-
Infrared EM waves
Questão 2
Questão
The contact gel used in ultrasonography (echography) is for:
Responda
-
Protection of the body from harmful ultrasound
-
Efficient transmission of sound waves into the tissue
-
Improvement of skin elasticity in the area of study
Questão 3
Questão
In medical imaging, Doppler echography is most appropriate for:
Responda
-
Deep body targets
-
Moving body targets
-
Surface targets
Questão 4
Questão
Which of the following waves do cannot propagate in vacuum?
Responda
-
Radiowaves
-
X-rays
-
Ultrasound
Questão 5
Questão
In what form is the information received with Doppler Echography displayed?
Questão 6
Questão
Doppler frequency (shift) is:
Responda
-
The infrared spectrum of light, studied by Doppler
-
The frequency generated by ultrasonic transducer
-
The difference between emitted and reflected (received) frequency between to objects in relative motion.
Questão 7
Questão
For which of the following numerical Doppler frequency shifts is the blood speed the highest?
Questão 8
Questão
Is it possible to tell the direction of motion of erythrocytes from the sign of the Doppler shift Δf = f - f0?
Responda
-
Yes, when Δf > 0 erythrocytes move towards the transducer
-
Yes, when Δf > 0erythrocytes move away from the transducer
-
No, the sign of Δf does not tell the direction of motion
Questão 9
Questão
If 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?
Questão 10
Questão
Doppler shift is defined as:
Responda
-
The frequency difference between emitted and received signals for observers at relative motion
-
The difference in acoustic impedance between two transmitting mediums
-
The intensity difference between emitted and reflected waves
Questão 11
Questão
At 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).
Responda
-
Θ = 45⁰ (cos 45 = 0.7)
-
Θ = 90⁰ (cos 90 = 0)
-
Θ = 60⁰ (cos 60 = 0.5)
Questão 12
Questão
The speed of ultrasound in human tissue depends on:
Responda
-
The properties of the tissue
-
The properties of the apparatus
-
The speed of (ultra)sound does not depend on the tissue
Questão 13
Questão
The so called “reverse piezoelectric effect” finds application in:
Responda
-
Ultrasound generation
-
X-ray tubes
-
Lasers
Questão 14
Questão
Ultrasound can propagate through:
Questão 15
Questão
Phonophoresis is:
Questão 16
Questão
Infrasound of certain frequency and intensity can:
Questão 17
Questão
Infrasound CANNOT propagate through:
Questão 18
Questão
Choose the correct statement:
Responda
-
Ultrasound is completely harmless for humans and animals
-
Sound reflection depends on the transparency of the medium
-
Sound impedance does not depend on frequency (for linear mediums)
Questão 19
Questão
Choose the correct range:
Questão 20
Questão
The resonant frequency of the vestibular system is in the range of:
Responda
-
Ultrasound
-
Infrasound
-
Ultraviolet
Questão 21
Questão
The direct piezoelectric effect is used for:
Responda
-
Ultrasound detectors
-
Ultrasound generators
-
Electrophoresis
Questão 22
Questão
Piezoelectric effect is defined as:
Responda
-
Electric polarization of solids under mechanical stress
-
Electro-mechanical coupling of objects falling off the tower of Pisa
-
Electric polarization in a solid due to temperature gradient.
Questão 23
Questão
Does human tissue exhibit piezoelectric properties?
Responda
-
No, the human body exhibits only capacitive properties
-
No, piezoelectric properties are observed in inorganic crystals
-
Yes, tissue such a collagen has piezoelectric properties
Questão 24
Questão
Which statement is correct?
Responda
-
The size of the ultrasonic equipment (echograph) influences the acoustic density of imaged tissue.
-
The precision of the ultrasonic instrument does not have an effect on the quality of received images
-
The ultrasonic image, displayed on the monitor, represents the acoustic density of studied tissues.
Questão 25
Questão
Mechanical waves with frequency above 20 kHz are called:
Responda
-
Infrasound
-
Ultrasound
-
P-waves
Questão 26
Questão 27
Questão
If 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:
Responda
-
The speed of blood relative to the stationary transducer (emitter and receiver) is as much great as Δf is greater
-
Blood motion does not affect Δf
-
The speed of blood relative to the stationary transducer is greater when Δf is smaller.
Questão 28
Questão
Which natural science studies infrasound?
Responda
-
Pediatrics
-
Seismology
-
Dental medicine
Questão 29
Questão
Mechanical waves used for destruction of kidney stones, in procedure called “lithotripsy”, cause minimal damage to surrounding tissues because:
Responda
-
Mechanical waves do not propagate through the surrounding tissue
-
Acoustic pressure in the surrounding tissue is greatly reduced compared tothe pressure induced in the kidney stones
-
Mechanical waves do not have negative effect on soft tissue
Questão 30
Questão
Ultrasound waves propagate through human tissue as:
Questão 31
Questão
Can humans sense infrasound waves?
Responda
-
Only when the intensity of the wave is sufficiently high for the ear to detect
-
No, that’s why they are called infra-sound
-
They can be sensed as vibrations by the tactile receptors of the skin
Questão 32
Questão
The resonant frequency of the internal organs is in the range of:
Responda
-
10 MHz
-
Infrasound
-
Ultrasound
Questão 33
Questão
Which of the following is used in Doppler echography?
Responda
-
Magnetic resonance
-
Vacuum tubes
-
Piezoelectric effect