Ultrasound SPI Chapter 1 Questions
In clinical imaging, the wavelength typically measures between
0.1 to 0.8 mm
which of the following would be considered ultrasonic
0.5 MHz
The typical range of frequency for diagnostic ultrasound imaging is
1-20 MHz
The duty factor (DF) for CW ultrasound is
100%
What is the total amount of attenuation that occurs if a 6.0 MHz sound beam travels through 4 cm of soft tissue?
12 dB
which of the following is considered to be the speed of sound in soft tissue
1540 m/s
If the angle of incidence is 40 degrees, what is the angle of transmission at the interface if medium 1 has a propagation speed of 1320 m/s and medium 2 has a propagation speed of 1700 m/s?
>40 degrees greater than
An increase in Pulse Repetition Frequency (PRF) would lead to
An increase in Duty Factor (DF)
As sound wave travels through the human body, the intensity of the sound wave decreases as a result of
Attenuation
Adding damping to the transducer improves which type of resolution?
Axial Resolution
Which of the following would have the highest propagation speed?
Bone
As imaging depth increases, the Pulse Repetition Frequency (PRF)must
Decrease
The inertia of the medium describes its
Density
The percentage of time that the ultrasound system is producing pulses of ultrasound describes the
Duty Factor
As imaging depth incrases, the Pulse Repetition Period (PRP)
Increases
All of the following are true of wavelength except
It is equal to the period divided by the frequency
Which of the following would have the lowest propagation speed?
Lung Tissue
Micro denotes
Millionth
Spatial Pulse Length (SPL) can be calculated by
Multiplying the number of cycles by the wavelength
Pressure is typically expressed in
Pascals
Which of the following is defined as only the active time?
Pulse Duration (PD)
Which of the following is defined as the number of ultrasound pulses emitted in 1 second?
Pulse Repetition Frequency (PRF)
What time is defined as the beginning of one pulse to the beginning of the next pulse and, therefore, includes both the on and off time
Pulse Repetition Period (PRP)
The change in the direction of the original sound wave that occurs when sound interacts with 2 different tissue types that have a different propagation speed is referred to as
Refraction
Which of the following requires an oblique interface and a propagation speed mismatch?
Refraction
Which of the following describes the amount of refraction that occurs at an interface?
Snells Law
Which of the following is described as the ability of an object to resist compression and relates to the hardness of a medium?
Stiffness
Which of the following is described as the distance over which one cycle occurs?
Wavelength
Which of the following is determined by the sound source and medium?
Wavelength
the maximum or minimum value of an acoustic variable minus the equilibrium value of that variable describes the
amplitude
The prefix centi denotes
hundrendths
what term is defined as the power of a wave divided by the area over which the power is distributed?
intensity
What is the change in intensity if the power decreases by half?
intensity is halved
Density and propagation speed are
inversely related
What is the change in power if the amplitude triples
it increases 9 times
What are the units of Duty Factor (DF)
it is a percentage %
Density is typically measured in
kilograms per centimeter cubed
transducers have material within them that when electronically stimulated produces ultrasound waves. this is most likely some form of
lead zirconate titanate
sound is technically a
mechanical and longitudinal wave
Which of the following is an appropriate unit of measurement for propagation speed?
millimeters per microsecond
What are the units for pressure?
pascals or pounds per square inch
If only the density of a medium is increase, then the
propagation speed will decrease
The portion of the sound beam where the molecules are farther apart describes an area of
rarefarction
All of the following relate to the strength of the sound wave except
wavelength
The major component of attenuation is
Absorption
Areas of high pressure and density are refered to as
Compression
Which of the following is determined by the sound source only
Frequency
The attenuation coefficient in soft tissue is equal to
One-half of the operating frequency
Damping the sound beam
Reduces the spatial pulse length SPL
All of the following are true of power except
as amplitude increases power remains the same