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