Ultrasound Physics 1 (ch. 1-3)

skill is directly proportional to practice

directly related/directly proportional

Golf score is inversely related to skill

inversely related/inversely proportional

skill is directly proportional to practice

directly related/directly proportional

Golf score is inversely related to skill

inversely related/inversely proportional

2 and ½ are reciprocals

reciprocal relationship

unit labels for length

cm, feet

unit labels for area

cm², ft²

unit labels for volume

cm³, ft³

pair belonging together

appropriate/complementary relationships

sound waves carry…

energy from one location to another

sound is a ____/____ wave

mechanical/acoustic

sound travels in a _____ through a ____

straight line; medium

sound cannot travel through…

a vacuum

(acoustic variable) pressure is the concentrations of ______

force in an area

units for pressure

pascals (Pa)

(acoustic variable) density is the concentration of

mass in volume

units for density

kg/cm³

(acoustic variable) distance is the measure of…

particle motion

units for distance

cm, feet, mile

seven acoustic parameters

period, frequency, amplitude, power, intensity, wavelength, propagation speed

number of cycles per second

frequency

frequency values in U/S; changeable?

2-15 MHz; no

time it takes wave to vibrate a single cycle

period

time values in U/S; changeable?

0.06-0.5 microseconds (Ms); no

frequency affects ___ and ___

penetration; image quality

frequency and period are ___ related

inversely

the “bigness” of the wave

amplitude

units of amplitude (3)

pressure, density, and particle motion/distance units

amplitude values in U/S; changeable?

1 million-3 million pascals (MPa); yes

rate of energy transfer or rate at which work is performed

power

power values in U/S; changeable?

4-90 mW; yes (0.004-0.090)

relation of amplitude and power equation

power (proportional) amplitude²

concentration of energy in a sound beam

intensity

intensity values in U/S; changeable?

0.01-300 W/cm²; yes

intensity is ___ to power

proportional

intensity is ____ related to area

inversely

relationship of intensity and amplitude equation

intensity (proportional) amplitude²

distance of one complete cycle

wavelength

wavelength values in U/S; changeable?

0.1-0.8 mm; no

wavelength in soft tissue

1.54 mm

higher quality images = ___ frequencies and ___ wavelengths

higher; shorter

distance speed at which a sound wave travels through a medium in one second

propagation speed

propagation speed values in U/S; changeable?

500-4,000 m/s; no

frequency x wavelength =

propagation speed

ability to resist compression

stiffness

relative weight of a material

density

rule of thumbs with speed

stiffness and speed directly related

density and speed inversely related

stiffness has the most

influence

what parameters are determined by a source (5)

period, frequency, amplitude, power, intensity

what parameter is determined by a source and medium

wavelength

what parameter is determined by a medium

speed

the effects of the medium upon the sound wave

acoustic propagation properties

the effects of the sound wave upon the biologic tissue through which it passes

biologic effects

bigness parameters

amplitude, power, intensity

which parameters are/aren’t adjustable

are: amplitude, power, intensity

aren’t: frequency, period, wavelength, speed