spi ch 1 spi review

in clinical imaging, the wavelength measures between:

0.1 to 0.8 mm

the duty factor for continuous wave ultrasound is:

100%

what is the total amount of attenuation that occurs if a 6.0 MHz sound beam travels through 4cm of soft tissue

12 dB

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

as imaging depth increases, pulse repetition period:

Increases

if pulse repetition frequency increases, then duty factor:

Increases

which of the following describes the amount of refraction that occurs at interface?

Snell's law

the major component of attenuation is:

absorption

the maximum value or minimum value of an acoustic variable minus the equilibrium value that variable describes the:

amplitude

an increase in pulse repetition frequency would lead to

an increase in duty factor

all of the following are true of power except:

as amplitude increases, power remains the same

as a sound wave travels through the human body, the intensity of the sound wave decreases as a result of:

attenuation, absorption, and scattering

what is defined as the ability of the ultrasound system to image structures that are positioned parallel to the sound beam as separate structures?

axial resolution

areas of high pressure and density are referred to as:

compressions

what is essentially equal to 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:

inversly related

what is the change in power if the amplitude triples?

it increases nine times

all of the following are true of wavelength except:

it is equal to the period divided by the frequency

density is typically measured in:

kilograms per centimeter cubed

tranducers have material within them that, when electronically stimulated, produces ultrasound waves. this is most likely some form of:

lead zirconate titanate

which of the following would have the lowest propagation speed?

lung tissue

sound is technically a:

mechanical and longitudinal wave

which of the following is an appropriate unit of measurement for propagation speed?

millimeters per microsecond

micro denotes:

millionth

spatial pulse length can be calculated by:

multiplying the number of cycles times the wavelength

the change in the direction of the original sound wave that occurs when sound interacts with two different tissue types that have a different propagation speed is referred to as:

refraction

which of the following is described as the ability of an object to resist compression and relates to the hardness of a medium?

stiffness

all of the following are true of stiffness except:

stiffness and propagation speed are indirectly associated

which of the following would be considered ultrasonic?

1Mhz

the attenuation coefficient in soft tissue is equal to:

one half the operating frequency

the typical range of frequency for diagnostic ultrasound imaging is:

1 to 30 MHz

which of the following is considered the speed of sound in soft tissue?

1,540 m/s

which of the following would have the highest propagation speed?

bone

as imaging depth increases, the pulse repetition frequency 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

which of the following is determined by the sound source only?

frequency

the prefix centi denotes:

hundredths

pressure is typically expressed in:

pascals

what is pressure measured in?

pascasls or pounds per square inch

if only the density of a medium is increased, then the:

propagation speed will decrease

which of the following is defined as only the active time?

pulse duration

which of the following is defined as the number of ultrasound pulses emitted in 1 second?

pulse repetition frequency

what 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

the portion of the sound beam where the molecules are pulled apart describes an area of:

rarefaction

damping of the sound beam:

reduces the spatial pulse length

all of the following reate to strength of the sound wave except:

wavelength

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