UPDATE COMPREHENSIVE QUESTIONS
AND CORRECT ANSWERS| ALREADY
GRADED A+/PASSED 100%
Example of nonspecular reflector - correct answer-red blood cells
What happens to spatial pulse length when frequency increases? - correct answer-decreases
Axial resolution is dependent on? - correct answer-wavelength
Lateral resolution is dependent on? - correct answer-beam diameter
Where does the beam of an unfocused transducer diverge? - correct answer-Fraunhofer zone
Reverberation artifacts are a result of - correct answer-two or more strong reflecting surfaces
True/False: Grating lobes are essential for the proper operation of a linear phased array. -
correct answer-False
True/False: Electronically steered scanners always produce higher resolution images than do mechanicall
y steered scanners. - correct answer-False
True/False: An annular array scanner uses mechanical beam steering. - correct answer-True
True/False: AKlinear sequenced array cannot be dynamically focused. - correct answer-False
registration or B-mode alignment - correct answer-
Which AIUM test object function utilizes all the groups of wires in the AIUM 100 mm test object?
,axial resolution - correct answer-
Which AIUM test object function utilizes the A group of wires in the AIUM 100 mm test object?
lateral resolution - correct answer-
Which AIUM test object function utilizes the B group of wires in the AIUM 100 mm test object?
dead zone - correct answer-
Which AIUM test object function utilizes the D group of wires in the AIUM 100 mm test object?
depth calibration - correct answer-
Which AIUM test object function utilizes the C or E groups of wires in the AIUM 100 mm test object?
What happens to axial resolution when spatial pulse length is decreased? - correct answer-improves
How much will a 3.5 MHz pulse be attenuated after passing through 2 cm of soft tissue? -
correct answer-3.5 dB
Propagation speed errors result in - correct answer-improper axial position
Enhancement is caused by - correct answer-weakly attenuatingKstructures
The Doppler shift frequency is - correct answer-directly proportional to the velocity of the reflector
The number of frames per second necessary for a real-time image to be flicker free is - correct answer-
more than 15
True/False: The SPTA intensity will always be larger than the SATA intensity. - correct answer-True
The intensity of the ultrasound beam is usually greater at the focal zone because of - correct answer-
the smaller beam diameter
,If the amplitude is doubled, the intensity is - correct answer-quadrupled
The attenuation for soft tissue is - correct answer-increased with tissue thickness
The acoustic impedance of the matching layer - correct answer-
can be chosen to improve transmission into the body
True/False: In a pulse-echo system, the quality factor should be made as large as possible. -
correct answer-False
True/False: The beam diameter is constant in the near zone. - correct answer-False
The operating frequency is dependent on - correct answer-thickness of the crystal
The period of an ultrasound wave is - correct answer-the time of one wavelength
The dynamic range of a system is - correct answer-
the ratio of smallest to largest power level that the system can handle
True/False: The intensity of an ultrasonic beam can be measured with radiation force balance. -
correct answer-True
Increasing the pulse repetition period - correct answer-
increases the maximum depth that can be imaged
Ultrasound bioeffects - correct answer-are not confirmed below 100 mW/cm² SPTA
True/False: No refraction can occur at an interface if the media impedances are equal. - correct answer-
False
True/False: Smaller transducers always produce smaller beam diameters. - correct answer-False
, True/False: The ultrasound beam profile can be measured with a hydrophone. - correct answer-True
True/False: The pulsed-
Doppler system yields better depth resolution than the continuous wave (CW) system. - correct answer-
True
True/False: The gray-
scale display was made possible when digital scan convertersKreplaced analog scan converters. -
correct answer-False
True/False: Videotape recorders operatingKat 30 frames per second cannot be used with mechanical real
-time units because the fram rate is too slow. - correct answer-False
True/False: Linear phased array scanners need no form of mechanical focusing because focusing is perfo
rmed electronically. - correct answer-False
True/False: The fram rate of real-
time scanners depends on the number of lines used to form the image. - correct answer-True
True/False: It is not possible to steer an annular phased array electronically. - correct answer-True
True/False: The near zone length should be kept as short as possible. - correct answer-False
What percentage of intensity of an ultrasound pulse incident on an interface of 0.25 and 0.75 rayls is refl
ected? - correct answer-25%
Axial resolution can be improved by using - correct answer-higher frequency transducers
When particle motion of a medium is parallel to the direction of a wave propagation, the wave being tra
nsmitted is called a - correct answer-longitudinal wave